Øystein Kravdal

• Harrison, Joseph; Sullivan, Frank; Keenan, Katherine; Kravdal, Øystein & Kulu, Hill (2026). Migrant mortality across contexts and generations: A comparative study of Norway and England and Wales. Demographic Research. ISSN 1435-9871. 55, p. 533–572. doi: 10.4054/DemRes.2026.55.18.
• Beck, Kathryn Christine; Kravdal, Øystein; Magnus, Maria Christine; Wörn, Jonathan & Flatø, Martin (2026). From Menarche to Motherhood: Fertility Patterns by Age at Menarche Across 40 Years in Norway. SocArXiv. doi: 10.31235/osf.io/w4j79_v1. Full text in Research Archive Show summary

  Age at menarche marks the onset of reproductive capacity, but its association with fertility has likely changed over time amid secular shifts in both menarcheal timing and fertility behavior. In this study, we examine how menarcheal timing is associated with first-birth timing, childlessness, and completed fertility across 40-years of birth cohorts in Norway using regional health survey data linked to administrative registers for over 60,000 women. Earlier age at menarche was associated with earlier entry into motherhood, although this association weakened in younger cohorts. By contrast, late menarche became increasingly associated with delayed first births and, in younger cohorts, with slightly lower completed fertility. These patterns were not explained by shared family background between siblings or by differences in educational trajectories between menarche groups. The findings suggest that developmental timing may play a larger role in explaining divergence in fertility outcomes, particularly with regards to the timing of childbearing, as family formation has shifted to later ages and life courses have become more individualized. These findings underscore how biological characteristics and social context jointly shape reproductive life courses and the importance of incorporating biological and developmental factors alongside social factors into demographic research on fertility change.

• Kravdal, Øystein; Grundy, Emily & Hart, Rannveig Kaldager (2026). Health Influences on Second‐ and Third‐Birth Probabilities in Norway. Population and Development Review. ISSN 0098-7921. 52(2), p. 613–650. doi: 10.1111/padr.70066. Full text in Research Archive Show summary

  Abstract We examined how several health variables were associated with mothers’ probability of having a second or third child and the timing of the second birth. Data from the Norwegian Mother, Father and Child Cohort Study (MoBa) and linked registers were used. Parents with certain potentially chronic health problems before or in pregnancy were less likely than others to have an additional (especially a second) child, net of differences in relationship status, education, and economic resources. Some pregnancy‐related and largely temporary health problems during the most recent previous pregnancy and adverse birth experiences were associated with reduced probabilities of a second or third birth, or both, as was generally poor physical health six months after birth and postnatal depression. The latter health indicators may reflect health implications of pregnancy, delivery, and having a relatively “demanding” young child, as well as underlying health problems. Only a few estimates suggested associations between indicators of potentially chronic health problems of the most recently born child and subsequent fertility, but fertility was reduced among one‐child mothers whose first child had colic and among one‐ and two‐child mothers whose most recently born child slept little. Possible reasons for and implications of these health–fertility associations are discussed.

• Goisis, Alice & Kravdal, Øystein (2026). Assisted Reproductive Technologies and Offspring's School Grades by Maternal Education. Paediatric and Perinatal Epidemiology. ISSN 0269-5022. 40(7), p. 805–810. doi: 10.1111/ppe.70181. Full text in Research Archive
• Halkjelsvik, Torleif Bjordal; Christiansen, Solveig Tobie Glestad; Moan, Inger Synnøve & Kravdal, Øystein (2025). The socioeconomic, health, and family situation of adult siblings of patients with substance use diagnosis: A descriptive registry study. Drug and Alcohol Dependence. ISSN 0376-8716. 276, p. 1–10. doi: 10.1016/j.drugalcdep.2025.112918. Full text in Research Archive Show summary

  Background Few studies have considered the characteristics of adult siblings of individuals with substance use diagnosis. We report on their family situation, labour market attachment, education, and healthcare utilisation. Methods Using Norwegian register data, we identified 131,249 siblings of individuals with substance use diagnoses recorded between 2008 and 2018 (‘SUD-Siblings’). A subsample of 112,320 siblings with no substance use diagnosis themselves ('SUD SiblingsExcl') was matched by age and gender to a comparison group with no substance use diagnosis among either the individuals or their siblings (‘Comparison’). We compared proportions and means. Results SUD-SiblingsExcl were more often divorced (13.8 %) than the Comparison group (11.3 %), fewer had work as the main income source (75.3 % vs. 83.3 %), and a larger share received disability pension (13.8 % vs. 8.6 %) or had sickness absence (23.2 % vs. 19.2 %). A greater proportion had consulted a general practitioner (75.2 % vs. 71.6 %), especially relating to mental health (17.4 % vs. 12.6 %) and musculoskeletal issues (29.9 % vs. 26.7 %). Hospital admissions were more common (8.5 % vs. 7.1 %; p-values of all above comparisons <.001). Conclusions Adult siblings of individuals with substance use diagnosis face substantial challenges compared to individuals without siblings with such diagnoses. They are more likely to be divorced, less likely to have work as their main income source, and show higher levels of health challenges, as indicated by higher sickness absence, disability pension rates, and healthcare use.

• Kravdal, Øystein; Flatø, Martin & Torvik, Fartein Ask (2025). Fertility among Norwegian Women and Men with Mental Disorders. European Journal of Population. ISSN 0168-6577. 41. doi: 10.1007/s10680-025-09739-5. Full text in Research Archive Show summary

  We analysed the associations between mental disorders and women’s and men’s first-, second- and third-birth rates in 2010–2018, using register data for the full Norwegian population. Having had at least one consultation for depression in primary or specialised health care in the calendar year before the preceding year was associated with lower birth rates. According to a simulation, the birth-rate reduction corresponds to a reduction in completed fertility from 1.60 births per woman among those without any of the mental disorders under study, to 1.34 among those with depression throughout the reproductive period. The corresponding numbers for men were 1.41 and 0.90. The associations between anxiety and fertility were of similar magnitude, while fertility was even lower among individuals with bipolar disorder, eating disorder or personality disorder. The simulated completed fertility was lowest among women and men with schizophrenia (0.36 and 0.16, respectively). However, to the extent that individuals with these mental disorders enter parenthood, many of the estimates suggested that they do so at a relatively early age. The associations between mental disorders and fertility became weaker when partnership, education and income were controlled for, and when characteristics shared by siblings were taken into account in family fixed-effects models.

• Kravdal, Øystein (2025). Should we be concerned about low fertility? A discussion of six possible arguments. Demographic Research. ISSN 1435-9871. 53, p. 373–418. doi: 10.4054/demres.2025.53.14. Full text in Research Archive
• Broek, Thijs van den & Kravdal, Øystein (2025). Gray divorce among migrants and non-migrants in Norway: trends and implications for mental healthcare use. The journals of gerontology. Series B, Psychological sciences and social sciences. ISSN 1079-5014. 80(8). doi: 10.1093/geronb/gbaf118. Full text in Research Archive Show summary

  Abstract Objectives The literature on gray divorce, that is, marital dissolution at age 50 or later, has hitherto had little consideration for differences between migrants and non-migrants. Differing family attitudes and socio-economic characteristics may, however, lead to differences between non-migrants and (specific groups of) migrants in gray divorce risks and in the mental health implications of gray divorce. We assess such differences by comparing native Norwegians and five groups of migrants (from Nordic countries; Western Europe; Eastern Europe; North Africa, Turkey, and Middle East; Asia) in Norway. Methods Drawing on administrative data covering Norway’s full population, group-specific age-standardized divorce rates for the period 1990–2018 are calculated. Group-specific trajectories of mental healthcare use around gray divorce are estimated for the shorter period 2008–2018, using linear probability fixed-effects models. Results Age-standardized gray divorce rates have risen for native Norwegians. Rates for migrants are somewhat higher, but for migrants from Eastern Europe, from North Africa, Turkey and the Middle East, and from Asia, no increase in gray divorce risks can be noted. Mental healthcare use rises in the years prior to divorce, peaks in the year of divorce and then declines again. This pattern is largely similar for native Norwegians and the five migrant groups. Discussion Despite typically more negative attitudes toward divorce in several migrant communities, gray divorce rates tend to be higher in some migrant groups than among native Norwegians. The mental healthcare use trajectories around gray divorce in native Norwegians and in the migrant groups considered are highly similar.

• Christiansen, Solveig Tobie Glestad; Halkjelsvik, Torleif; Moan, Inger Synnøve & Kravdal, Øystein (2025). The socioeconomic, health, and family situation of parents of patients with substance use diagnosis: A descriptive registry study. Drug and Alcohol Dependence. ISSN 0376-8716. 276. doi: 10.1016/j.drugalcdep.2025.112892. Full text in Research Archive
• Chanfreau, Jenny; Goisis, Alice & Kravdal, Øystein (2025). Conceptualizing and Measuring the Contribution of Assisted Reproductive Technologies to Fertility Rates. Population and Development Review. ISSN 0098-7921. 51(2), p. 828–857. doi: 10.1111/padr.70009. Full text in Research Archive Show summary

  Against the backdrop of the rising use of assisted reproductive technologies (ART), we argue that more reflection on the measurement and conceptualization of the contribution of ART to fertility rates is warranted. First, despite evidence of marked sociodemographic stratification in ART use, research on the ART contribution to fertility rates has largely overlooked how ART contributes differently to fertility levels across sociodemographic groups. Second, existing work tends to be ambiguous regarding what fertility would have looked like if ART had not been available. We demonstrate the importance of these points through period (1986–2018) and cohort (women born in 1949–1974) analyses using data from the Norwegian Population Registers. We demonstrate empirically the absolute and relative variation in the contribution of ART to fertility across sociodemographic subgroups. Whereas the relative ART contribution was highest and increasing steeply in recent years for women 40+, in absolute terms it was substantially higher for women in their thirties. Unlike natural fertility, differences in the absolute contribution of ART to the fertility of education groups were increasing over time. Then, considering a range of assumptions, we show that the “crude” contribution of ART may be either an overestimation or an underestimation compared to the “net” contribution. Our results prompt important reflections on how ART is framed in policy and scholarship.

• Kravdal, Øystein; Wörn, Jonathan; Hart, Rannveig Kaldager & Reme, Bjørn-Atle (2024). The influence of parental cancer on the mental health of children and young adults: Evidence from Norwegian register data on healthcare consultations. Demographic Research. ISSN 1435-9871. 50, p. 763–796. doi: 10.4054/DEMRES.2024.50.27. Full text in Research Archive Show summary

  Objective: The aim was to examine how parental cancer affects the mental health of offspring aged 6–30, and age variations in this effect. Methods: Individual fixed-effects models were estimated from register data covering the entire Norwegian population in 2010–2018. The outcome variable was whether the individual (offspring) had at least one consultation within a year with a general practitioner (GP) or specialist where a mental health diagnosis or symptom was reported. Results: The consultation probability was higher after a parental cancer diagnosis than before (e.g., 15% higher in the first year after the diagnosis). This was to a large extent driven by subsequent parental deaths, but there was also a small post-diagnosis increase among offspring whose parent survived the observation period. The consultation probability increased by 83% the year a parent died among offspring who were 19–30 at that time, after a smaller increase over a few of the preceding years. A decline occurred later. The death seemed to have a weaker, but more lasting, effect on those who were 8–18 years old at the time of the death, and these did not experience a clear pre-death increase. Conclusions: Parental cancer death seems to weaken offspring’s mental health – and no less among young adults than among children. By contrast, having a parent with cancer who remains alive at least throughout the observation period has relatively little impact. Contribution: We show associations between parental cancer and offspring’s mental health, paying special attention to whether the parent dies. This may inform discussions about supporting offspring.

• Wörn, Jonathan; Balbo, Nicoletta; Hank, Karsten & Kravdal, Øystein (2024). The temporal alignment of mental health consultations across family members: a study of Norwegian adolescents, their parents, and siblings. Social Psychiatry and Psychiatric Epidemiology. ISSN 0933-7954. doi: 10.1007/s00127-024-02803-1. Full text in Research Archive Show summary

  Purpose Mental health problems among adolescents have become more prevalent in recent years. Parents’ and siblings’ mental health might be affected by living with a depressed adolescent. This study examines how the mental health of family members develops in the years before and after an adolescent seeks help for depression. Methods Unique Norwegian register data that cover the full population are used to estimate models with individual fixed effects. The development in the probability of mental health consultations for parents and older siblings in families with a second-born adolescent seeking help for depression from a GP for the first time is compared to the respective development in families where the second-born adolescent has not had such health care consultation. Results Results indicate that adolescents’ depression consultations are associated with a simultaneous increase in mental health consultations in parents and siblings. Mothers and fathers are affected similarly, although the effect seems to be short-lived. Siblings experience a short-term increase in mental health consultations, in addition to a steeper long-term increase across the observation period, compared to peers in families where the second-born adolescent does not seek help for depression. Events that might affect the mental health of multiple family members simultaneously, specifically parental breakup and unemployment, did not explain the observed patterns. Conclusion Help-seeking for mental health problems is temporally aligned across family members. Intra- and intergenerational spillovers might contribute to this.

• Barclay, Kieron; Kolk, Martin & Kravdal, Øystein (2024). Birth Spacing and Parents’ Physical and Mental Health: An Analysis Using Individual and Sibling Fixed Effects. Demography. ISSN 0070-3370. 61(2), p. 393–418. doi: 10.1215/00703370-11204828. Full text in Research Archive Show summary

  Abstract An extensive literature has examined the relationship between birth spacing and subsequent health outcomes for parents, particularly for mothers. However, this research has drawn almost exclusively on observational research designs, and almost all studies have been limited to adjusting for observable factors that could confound the relationship between birth spacing and health outcomes. In this study, we use Norwegian register data to examine the relationship between birth spacing and the number of general practitioner consultations for mothers’ and fathers’ physical and mental health concerns immediately after childbirth (1–5 and 6–11 months after childbirth), in the medium term (5–6 years after childbearing), and in the long term (10–11 years after childbearing). To examine short-term health outcomes, we estimate individual fixed-effects models: we hold constant factors that could influence parents’ birth spacing behavior and their health, comparing health outcomes after different births to the same parent. We apply sibling fixed effects in our analysis of medium- and long-term outcomes, holding constant mothers’ and fathers’ family backgrounds. The results from our analyses that do not apply individual or sibling fixed effects are consistent with much of the previous literature: shorter and longer birth intervals are associated with worse health outcomes than birth intervals of approximately 2–3 years. Estimates from individual fixed-effects models suggest that particularly short intervals have a modest negative effect on maternal mental health in the short term, with more ambiguous evidence that particularly short or long intervals might modestly influence short-, medium-, and long-term physical health outcomes. Overall, these results are consistent with small to negligible effects of birth spacing behavior on (non-pregnancy-related) parental health outcomes.

• Christiansen, Solveig Tobie Glestad & Kravdal, Øystein (2023). Number of children and disability pension due to mental and musculoskeletal disorders: A longitudinal register-based study in Norway. Population Studies. ISSN 0032-4728. 77(2), p. 335–346. doi: 10.1080/00324728.2023.2195847. Full text in Research Archive Show summary

  Earlier research has documented a relationship between parity and all-cause mortality, as well as parity and cause-specific mortality (e.g. cancer and cardiovascular disease mortality). Less is known about the relationship between parity and two very common (but less deadly) types of disorder: mental and musculoskeletal. We examine the association between parity and risk of disability pensioning from all causes and due to mental or musculoskeletal disorders, using Norwegian register data. In addition to controlling for adult socio-demographic characteristics, we control for unobserved confounding from family background by estimating sibling fixed-effects models. We find a higher risk of disability pensioning among the childless and those with one child than for parents with two children, both for all causes combined and for mental disorders. Childless men and fathers with one child also experience excess risk of being pensioned due to musculoskeletal disorders. For mental disorders, we find a positive association with high parity, particularly for men.

• Evensen, Miriam; Klitkou, Søren Toksvig; Tollånes, Mette Christophersen; Juliusson, Pétur Benedikt & Kravdal, Øystein (2023). Parental income gradients in child and adolescent mortality: Norwegian trends over half a century. Scandinavian Journal of Public Health. ISSN 1403-4948. doi: 10.1177/14034948231151990. Full text in Research Archive Show summary

  Background: Child mortality has declined rapidly over the last century in many high-income countries. However, little is known about the socio-economic differences in this decline and whether these vary across causes of death. Methods: We used register data that included all Norwegian births between 1968 and 2010 (2.1 million), and we analysed how all-cause and cause-specific child (0–4 years) and adolescent (5–20 years) mortality rates vary with relative parental income the year before the birth. Results: Child and adolescent all-cause mortality decreased with increasing parental relative income within all birth cohorts. Among children aged 0–4 years, the socio-economic gradient in all-cause mortality and in mortality due to external causes, sudden infant deaths and perinatal factors declined over the period, while there was no systematic decline in mortality from congenital malformations. Among children aged 5–20 years, the gradient did not weaken similarly, although there were indications of declines in the socio-economic gradient related to all-cause deaths and deaths because of suicides and other external causes. While the absolute differences in mortality declined over time, the relative differences remained stable. Conclusions: Although children of low-income parents still have elevated mortality, there has been a large reduction in child mortality in all socio-economic groups across 50 years for all causes combined and most of the groups of specific causes of death.

• Kravdal, Øystein; Syse, Astri; Dang, Thang Dinh; Baranowska-Rataj, Anna & Hart, Rannveig Kaldager (2023). Mental Health Penalties of Childbearing in a Family Friendly Welfare State. OSF Preprints. doi: 10.31235/osf.io/9v6h8. Full text in Research Archive
• Christiansen, Solveig Tobie Glestad & Kravdal, Øystein (2023). Union Status and Disability Pension. European Journal of Population. ISSN 0168-6577. 39(1). doi: 10.1007/s10680-023-09670-7. Full text in Research Archive Show summary

  Abstract A lot is known about the association between marital status and mortality, and some of these studies have included data on cohabitation. Studies on the association with health problems, rather than mortality, are often based on self-reported health outcomes, and results from these studies are mixed. As cohabitation is now widespread, more studies that include data on cohabitation are needed. We use Norwegian register data that include detailed information about union status and all cases of disability pensioning from 2005 to 2016. We employ Cox regression analysis and a within-family design in order to control for hard to measure childhood characteristics. Compared to the married, the cohabiting have a somewhat higher risk of receiving disability pension due to mental disorders, and for men also due to physical disorders. Receipt of disability pension is most common among the never married, especially for men. The association between union status and disability pensioning is stronger for mental than for physical disorders.

• Kravdal, Øystein & Wörn, Jonathan (2023). Mental and Physical Health Trajectories of Norwegian Parents and Children before and after Union Dissolution. Population and Development Review. ISSN 0098-7921. 49(1), p. 71–103. doi: 10.1111/padr.12530. Full text in Research Archive Show summary

  The aim was to examine the mental and physical health trajectories of mothers, fathers, and children before and after union dissolution. Register data covering the entire Norwegian population, and including information on consultations with general practitioners in 2006–2018, were used. Constant unobserved characteristics were controlled for with individual fixed effects. As judged by the number of consultations, mothers’ and fathers’ mental health deteriorates before the dissolution but improves immediately afterwards. In contrast, a worsening mental health among children before the dissolution is followed by an even more adverse development afterwards. There is only modest evidence of predissolution increases in noninfectious physical diseases, but more clearly rising numbers afterwards especially for mothers and daughters. Less adverse trends are seen for infections, although mothers experience a sharp temporary increase at the breakup time. On the whole, mothers’ health is more adversely affected by dissolution than that of fathers. Daughters may have a disadvantage compared to sons, but results vary across model specifications. The results suggest that effects on children's health do not operate through parents’ health. With respect to union type, the health changes before and after dissolution of a consensual union are not very different from those before and after marital separation.

• Kravdal, Øystein; Wörn, Jonathan & Reme, Bjørn-Atle (2022). Mental health benefits of cohabitation and marriage: A longitudinal analysis of Norwegian register data. Population Studies. ISSN 0032-4728. doi: 10.1080/00324728.2022.2063933. Full text in Research Archive Show summary

  The aim is to examine how mental health is affected by cohabitation and marriage. Individual fixed-effects models are estimated from Norwegian register data containing information about consultations with a general practitioner because of mental health conditions in 2006–19. Mental health, as indicated by annual number of consultations, improves over several years before cohabitation. For those marrying their cohabiting partner, there is a weak further reduction in consultations until the wedding, but no decline afterwards. In other words, formalization of the union does not seem to confer additional mental health benefits. However, marriage may be considered a marker of favourable earlier development in mental health. In contrast, there is further improvement after direct marriage, as well as stronger improvement over the years just preceding direct marriage. Patterns are quite similar for women and men. Overall, the results suggest that the mental health benefits of cohabitation and marriage are similar.

• Aradhya, Siddartha; Tegunimataka, Anna; Kravdal, Øystein; Martikainen, Pekka; Myrskylä, Mikko & Barclay, Kieron [Show all 7 contributors for this article] (2022). Maternal age and the risk of low birthweight and pre-term delivery: A pan-Nordic comparison. International Journal of Epidemiology. ISSN 0300-5771. 52(1), p. 156–164. doi: 10.1093/ije/dyac211. Full text in Research Archive Show summary

  Abstract Background Advanced maternal age at birth is considered a risk factor for adverse birth outcomes. A recent study applying a sibling design has shown, however, that the association might be confounded by unobserved maternal characteristics. Methods Using total population register data on all live singleton births during the period 1999–2012 in Denmark (N = 580 133; 90% population coverage), Norway (N = 540 890) and Sweden (N = 941 403) and from 2001–2014 in Finland (N = 568 026), we test whether advanced maternal age at birth independently increases the risk of low birthweight (LBW) (&amp;lt;2500 g) and pre-term birth (&amp;lt;37 weeks gestation). We estimated within-family models to reduce confounding by unobserved maternal characteristics shared by siblings using three model specifications: Model 0 examines the bivariate association; Model 1 adjusts for parity and sex; Model 2 for parity, sex and birth year. Results The main results (Model 1) show an increased risk in LBW and pre-term delivery with increasing maternal ages. For example, compared with maternal ages of 26–27 years, maternal ages of 38–39 years display a 2.2, 0.9, 2.1 and 2.4 percentage point increase in the risk of LBW in Denmark, Finland, Norway and Sweden, respectively. The same patterns hold for pre-term delivery. Conclusions Advanced maternal age is independently associated with higher risk of poor perinatal health outcomes even after adjusting for all observed and unobserved factors shared between siblings.

• Sigle, Wendy & Kravdal, Øystein (2021). With age comes ...? An examination of gendered differences in the resource advantages associated with parental age in Norway. Comparative population studies. ISSN 1869-8980. 46, p. 363–386. doi: 10.12765/CPoS-2021-13. Full text in Research Archive
• Kravdal, Øystein (2021). Sex Differences in Childlessness in Norway: Identification of Underlying Demographic Drivers. European Journal of Population. ISSN 0168-6577. 37, p. 1023–1041. doi: 10.1007/s10680-021-09590-4. Full text in Research Archive Show summary

  Abstract In Norway, as in many other rich countries, childlessness is more common among men than women and has also increased more among men. Over the last 15 years, the gap in childlessness between 45-year-old women and men has widened from 5.8 to 10.2 percentage points, according to national register data. In the Norwegian-born subgroup, the gap has increased by 2.4 percentage points, from 5.8 to 8.2. The goal of the study was to identify the demographic drivers of this development, using a quite simple, but original, decomposition approach. The components reflect changes in relative cohort sizes, whether the child has one native and one immigrant parent, whether the father was older than 45, and whether one of the parents already had a child, no longer lived in Norway at age 45, or was unidentified. It was found that the modestly increasing sex gap in childlessness among the Norwegian-born is largely linked to changes in cohort sizes, i.e. fertility trends. Changes in re-partnership have actually contributed weakly in the opposite direction: It has become more common especially among men to have the first child with a partner who already had a child, and thus not contribute to bringing also that person out of childlessness. The importance of the various components is different for immigrants, among whom the sex gap in childlessness has increased particularly much. This development may also reflect that especially male immigrants perhaps have children in the home country who are not included in the Norwegian register.

• Goisis, Alice; Håberg, Siri Eldevik; Hanevik, Hans Ivar; Magnus, Maria Christine & Kravdal, Øystein (2020). The demographics of assisted reproductive technology births in a Nordic country. Human Reproduction. ISSN 0268-1161. 35(6), p. 1441–1450. doi: 10.1093/humrep/deaa055. Full text in Research Archive Show summary

  Study question: What are the socio-demographic characteristics of families in Norway who have children after assisted reproductive technology (ART), and have these characteristics changed over time? Summary answer: Parents who conceive through ART in Norway tend to be advantaged families, and their socio-demographic profile has not changed considerably over the period 1985-2014. What is known already: A small number of studies show that couples who conceive through ART tend to be socio-economically advantaged. Study design, size, duration: Norwegian Population Register, the Medical Birth Register and the national data bases were linked to study all live births in Norway between 1985 and 2014. Participants/materials, setting, methods: The sample consisted of 1 757 768 live births. Simple bivariate analyses were performed to describe the socio-demographic characteristics of parents who conceived through ART and changes in these characteristics over the time period 1985-2014. We used linear probability models to estimate the association between parental income and giving birth after ART from 2000 to 2014, before and after adjustment for maternal age at delivery, education and area of residence. Main results and the role of chance: Parents conceiving through ART were more likely to be older, with the highest levels of income and education, and married. Their socio-demographic profiles did not change considerably during the period 1985-2014. In the unadjusted model, parents belonging to the top income quartile were 4.2 percentage points more likely (95% CI: 4.1 to 4.3) to have conceived through ART than parents who belonged to the bottom income quartile. Adjustment for maternal age only partially reduced the income disparities (for the top income quartile by 35% (β = 2.7 with 95% CI: 2.5 to 2.8)). Additional adjustment for maternal education, marital status and area of residence did not further attenuate the associations. Limitations, reasons for caution: The data does not enable us to tell whether the lower numbers of children conceived through ART amongst more disadvantaged individuals is caused by lower success rates with ART treatment, lower demand of ART services or barriers faced in access to ART. The study focuses on Norway, a context characterised by high subsidisation of ART services. Wider implications of the findings: Even though in Norway access to ART services is highly subsidised, the results highlight important and persisting social inequities in use of ART. The results also indicate that children born after ART grow up in resourceful environments, which will benefit their development and well-being.

• Kravdal, Øystein (2020). Effects of previous birth interval length on child outcomes can be estimated in a sibling analysis even when there are only two siblings. Paediatric and Perinatal Epidemiology. ISSN 0269-5022. p. 1–9. doi: 10.1111/ppe.12732. Full text in Research Archive
• Kravdal, Øystein; Tverdal, Aage & Grundy, Emily (2020). The association between parity, CVD mortality and CVD risk factors among Norwegian women and men. European Journal of Public Health. ISSN 1101-1262. 30(6), p. 1133–1139. doi: 10.1093/eurpub/ckz235. Full text in Research Archive Show summary

  Several studies have shown that women and men with two children have lower mortality than the childless, but there is less certainty about mortality, including CVD mortality, at higher parities and meagre knowledge about factors underlying the parity–mortality relationship. The association between parity and CVD mortality was analyzed by estimating discrete-time hazard models for women and men aged 40–80 in 1975–2015. Register data covering the entire Norwegian population were used, and the models included a larger number of relevant sociodemographic control variables than in many previous studies. To analyze the relationship between parity and seven CVD risk factors, logistic models including the same variables as the mortality models were estimated from the CONOR collection of health surveys, linked to the register data. Men (but not women) who had four or more children had higher mortality from CVD than those with two, although this excess mortality was not observed for the heart disease sub-group. Overweight, possibly in part a result of less physical activity, seems to play a role in this. All CVD risk factors except smoking and alcohol may contribute to the relatively high CVD mortality among childless. Childbearing is related to a number of well-known CVD risk factors, and becoming a parent or having an additional child is, on the whole, associated with lower—or at least not higher—CVD mortality in Norway. However, for men family sizes beyond three children are associated with increased CVD mortality, with risks of overweight one possible pathway.

• Kravdal, Øystein; Magnus, Per; Moum, Bjørn & Høivik, Marte Lie (2020). Childbearing is Associated with a Short-term Reduced Risk of Crohn’s Disease in Mothers. American Journal of Epidemiology. ISSN 0002-9262. 189(4), p. 294–304. doi: 10.1093/aje/kwz285. Full text in Research Archive Show summary

  Our aim in this study was to analyze the importance of childbearing for risk of inflammatory bowel disease. Using data from the Norwegian Population Register and the Norwegian Patient Register, we fitted discrete-time hazard models for diagnosis of Crohn disease (CD) or ulcerative colitis (UC) among men and women aged 18–81 years in 2011–2016. Year and various sociodemographic factors were controlled for. The data included 4,304 CD cases and 8,866 UC cases. Women whose youngest child was ≤4 years of age had lower CD risk the following year than childless women (odds ratio (OR) = 0.73, 95% confidence interval (CI): 0.62, 0.86). There was no such reduction in CD risk among fathers. Men whose youngest child was aged ≥20 years had higher risks of CD (OR = 1.22, 95% CI: 1.01, 1.49) and UC (OR = 1.15, 95% CI: 1.02, 1.30) than childless men. UC risk was also increased among men whose youngest child was aged ≤4 years (OR = 1.14, 95% CI: 1.02, 1.27). The short-term reduction in women’s CD risk after a birth may reflect biological effects of pregnancy. Alternatively, it may reflect residual confounding or lifestyle effects of parenthood that are of special relevance for CD in women. In particular, differences in use of oral contraceptives (which it was not possible to control for) may have contributed to the observed pattern.

• Kravdal, Øystein; Magnus, Per; Moum, Bjørn & Høivik, Marte Lie (2020). Association of Childbearing with a Short-Term Reduced Risk of Crohn Disease in Mothers. American Journal of Epidemiology. ISSN 0002-9262. 189(4), p. 294–304. doi: 10.1093/aje/kwz285. Full text in Research Archive
• Kravdal, Øystein (2020). Are sibling models a suitable tool in analyses of how reproductive factors affect child mortality? Demographic Research. ISSN 1435-9871. 42(28), p. 777–798. doi: 10.4054/DemRes.2020.42.28. Full text in Research Archive Show summary

  Background: Several studies of how reproductive factors affect child mortality or other child outcomes have been based on sibling comparisons. With such models one controls for unobserved determinants of the outcome that are shared by the siblings and linked to the reproductive process. However, it has been shown mathematically that estimates from sibling models are biased when the outcome for one sibling affects the exposure for another, and this is precisely the situation when the outcome is child mortality and the exposure is aspects of the mother’s reproductive behaviour. The goal of this analysis was to find out, by means of simulation, whether the bias really matters in practice. Results: All simulation experiments showed that, when there was an effect of infant mortality on subsequent fertility, the estimated effect of higher maternal age was considerably more adverse than the true effect, while the effects of higher birth order and very short or very long birth interval were biased in the opposite direction. Contribution: Although it is possible that the bias is unimportant in other situations than those examined here, a reasonable conclusion is that one should have serious doubts about sibling model estimates of effects of reproductive factors on infant or child mortality. Stated differently, we may know less about these effects than we tend to think and need other alternatives to a ‘naïve’ regression model than the sibling approach. Obviously, there may be problems also when analysing other child outcomes that affect subsequent fertility, through mortality or otherwise.

• Kravdal, Øystein (2019). Taking birth year into account when analysing effects of maternal age on child health and other outcomes: The value of a multilevel-multiprocess model compared to a sibling model. Demographic Research. ISSN 1435-9871. 40, p. 1249–1290. doi: 10.4054/DemRes.2019.40.43. Full text in Research Archive Show summary

  Background: When analysing effects of maternal age on child outcomes, many researchers estimate sibling models to control for unobserved factors shared between siblings. Some have included birth year in these models, as it is linked to maternal age and may also have independent effects. However, this creates a linear-dependence problem. Objective: One aim is to illustrate how misleading the results may actually be when attempts are made to separate effects of maternal age and birth year in a sibling analysis. Another goal is to present and discuss the multilevel-multiprocess model as an alternative. Methods: Infant mortality was chosen as the outcome. Births and infant deaths were simulated from a multilevel-multiprocess model that included two equations for fertility, with a joint random effect, and one equation for infant mortality, with another random effect. The two random effects were set to be correlated. The effects of the independent variables were taken from simpler models estimated from register data. Various sibling models and multilevel-multiprocess models were estimated from these simulated births and deaths. In some simulations, two standard assumptions about the random effects were intentionally violated. Contribution: The paper illustrates how problematic it is to include both maternal age and birth year in a sibling model. Also, if only maternal age is included, but along with other reproductive variables, small categories should be used. It is argued that a multilevel-multiprocess model may be used instead to separate effects of maternal age and birth year, but this approach also has limitations, which are discussed.

• Kravdal, Øystein (2019). Research note: What kind of individual-level effects of childbearing would we ideally be interested in learning about? The important distinction between expected, unexpected, varying and general effects. Journal of Population Research. ISSN 1443-2447. 36(1), p. 1–12. doi: 10.1007/s12546-018-9218-7. Full text in Research Archive
• Kravdal, Øystein & Grundy, Emily (2019). Children’s age at parental divorce and depression in early and mid-adulthood. Population Studies. ISSN 0032-4728. 73(1), p. 37–56. doi: 10.1080/00324728.2018.1549747. Full text in Research Archive Show summary

  This study aimed to assess whether children’s age at their parents’ divorce is associated with depression in early and mid-adulthood, as indicated by medication purchase. A sibling comparison method was used to control for unobserved factors shared between siblings. The data were extracted from the Norwegian Population Register and Norwegian Prescription Database and included about 181,000 individuals aged 20–44 who had experienced parental divorce and 636,000 who had not. Controlling for age in 2004, sex, and birth order, children who were aged 15–19 when their parents divorced were 12 per cent less likely to purchase antidepressants as adults in 2004–08 than those experiencing the divorce aged 0–4. The corresponding reduction for those aged 20+ at the time of divorce was 19 per cent. However, the association between age at parental divorce and antidepressant purchases was only evident among women and those whose mothers had low education.

• Kravdal, Øystein (2018). New evidence about effects of reproductive variables on child mortality in sub-Saharan Africa. Population Studies. ISSN 0032-4728. 72(2), p. 139–156. doi: 10.1080/00324728.2018.1439180. Full text in Research Archive Show summary

  There is still considerable uncertainty about how reproductive factors affect child mortality. This study, based on Demographic and Health Survey data from 28 countries in sub-Saharan Africa, shows that mortality is highest for firstborn children with very young mothers. Other children with young mothers, or of high birth order, also experience high mortality. Net of maternal age and birth order, a short preceding birth interval is associated with above average mortality. These patterns change, however, if time-invariant unobserved mother-level characteristics of importance for both mortality and fertility are controlled for in a multilevel–multiprocess model. Most importantly, there are smaller advantages associated with longer birth intervals and being older at first birth. The implications of alternative reproductive ‘strategies’ are discussed, taking into account that if the mother is older at birth, the child will also be born in a later calendar year, when mortality may be lower.

• Kravdal, Øystein; Grundy, Emily & Keenan, Katherine (2018). The increasing mortality advantage of the married: The role played by education. Demographic Research. ISSN 1435-9871. 38, p. 471–512. doi: 10.4054/DemRes.2018.38.20. Full text in Research Archive
• Bævre, Kåre; Kravdal, Øystein & Christiansen, Solveig Tobie Glestad (2018). Befolkningen i Norge. In Grøholt, Else Karin; Bøhler, Linn & Hånes, Hanna (Ed.), Folkehelserapporten - Helsetilstanden i Norge. Folkehelseinstituttet. Full text in Research Archive
• Kravdal, Øystein (2017). Large and Growing Social Inequality in Mortality in Norway: The Combined Importance of Marital Status and Own and Spouse's Education. Population and Development Review. ISSN 0098-7921. 43(4), p. 645–665. doi: 10.1111/padr.12096. Full text in Research Archive
• Kravdal, Øystein; Grundy, Emily & Skirbekk, Vegard (2017). Fertility history and use of antidepressant medication in late mid-life: a register-based analysis of Norwegian women and men. Aging & Mental Health. ISSN 1360-7863. 21(5), p. 477–486. doi: 10.1080/13607863.2015.1118010. Full text in Research Archive Show summary

  Objectives: Life course influences on later life depression may include parenting trajectories. We investigate associations between number and timing of births and use of antidepressant medication in late mid-life using data on the whole Norwegian population. Methods: We estimated logistic regression models to analyse variations in the purchase of antidepressants between 2004 and 2008 by timing of births and number of children among women and men aged 45 73, using Norwegian population register data. We controlled for age, education, marital and partnership status, and (in some models) family background shared among siblings. Results: Mothers and fathers of two or more children were generally less likely to purchase antidepressants than the childless. Mothers who started childbearing before age 22 were an exception, although according to sibling models they were not more likely to purchase antidepressants. All models showed that women who became mothers before age 26 and had only one child had higher odds of medication purchase than the childless. Older age at first birth was generally associated with lower risks of antidepressant purchase. Conclusion: This analysis of high-quality data for a national population indicates that early motherhood, childlessness and low parity are associated with higher usage of antidepressants in late mid-life. Our data did not allow identification of mediating pathways, and we lacked information on early mental and physical health and some other potentially important confounders not shared between siblings. Furthermore purchase of antidepressants is not a perfect indicator of depression. Those concerns aside, the results suggest complex effects of fertility on depression that merit further investigation.

• Kravdal, Øystein & Grundy, Emily (2016). Health effects of parental deaths among adults in Norway: Purchases of prescription medicine before and after bereavement. SSM - Population Health. ISSN 2352-8273. 2, p. 868–875. doi: 10.1016/j.ssmph.2016.10.013. Full text in Research Archive Show summary

  We analyse effects of parental deaths on the health of women and men aged 18–59 in 2004–2008, indicated by purchases of prescription medicines. Register data covering the entire Norwegian population were used, and fixed-effects models were estimated to control for unobserved time-invariant individual factors. A parent's death seemed to have immediate adverse consequences in both main age groups considered (18–39, 40–59), although effects were lower in the older group. Some results suggested that this health disadvantage widened with increasing time since the parent's death. However, effects were weak: the annual number of different medicines purchased was only increased by 1–7% as a result of losing a parent. Death of a parent was associated with an immediate increase in purchases of medication for mental diseases, and there were indications of a physical response as well. As time since the parental death increased, there was a decline in the purchase of medication for mental diseases, but an opposite trend with respect to medication for other diseases. On the whole, maternal and paternal deaths had the same impact, and effects on daughters and sons were of the same magnitude.

• Kinge, Jonas Minet; Steingrímsdóttir, Ólöf Anna; Strand, Bjørn Heine & Kravdal, Øystein (2016). Can socioeconomic factors explain geographic variation in overweight in Norway? SSM - Population Health. ISSN 2352-8273. 2, p. 333–340. doi: 10.1016/j.ssmph.2016.04.010. Full text in Research Archive Show summary

  We explore if the geographic variation in excess body-mass in Norway can be explained by socioeconomic status, as this has consequences for public policy. The analysis was based on individual height and weight for 198,311 Norwegian youth in 2011, 2012 and 2013, stemming from a compulsory screening for military service, which covers the whole population aged seventeen. These data were merged with municipality-level socioeconomic status (SES) variables and we estimated both ecological models and two-level models with a random term at the municipality level. Overweight was negatively associated with income, education and occupation at municipality level. Furthermore, the municipality-level variance in overweight was reduced by 57% in females and 40% in males, when SES factors were taken into account. This suggests that successful interventions aimed at reducing socioeconomic variation in overweight will also contribute to reducing the geographic variation in overweight, especially in females.

• Kravdal, Øystein; Alver, Kari; Bævre, Kåre; Kinge, Jonas Minet; Meisfjord, Jørgen Rajan & Steingrímsdóttir, Ólöf Anna [Show all 7 contributors for this article] (2015). How much of the variation in mortality across Norwegian municipalities is explained by the socio-demographic characteristics of the population? Health and Place. ISSN 1353-8292. 33, p. 148–158. doi: 10.1016/j.healthplace.2015.02.013. Full text in Research Archive
• Grundy, Emily & Kravdal, Øystein (2014). Do short birth intervals have long-term implications for parental health? Results from analyses of complete cohort Norwegian register data. Journal of Epidemiology and Community Health. ISSN 0143-005X. 68(10), p. 958–964. doi: 10.1136/jech-2014-204191. Full text in Research Archive
• Kravdal, Øystein & Grundy, Emily (2014). Underuse of medication for circulatory disorders among unmarried women and men in Norway. BMC Pharmacology and Toxicology. 15:65. doi: 10.1186/2050-6511-15-65. Full text in Research Archive Show summary

  Background It is well established that unmarried people have higher mortality from circulatory diseases and higher all-cause mortality than the married, and these marital status differences seem to be increasing. However, much remains to be known about the underlying mechanisms. Our objective was to examine marital status differences in the purchase of medication for circulatory diseases, and risk factors for them, which may indicate underuse of such medication by some marital status groups. Methods Using data from registers covering the entire Norwegian population, we analysed marital status differences in the purchase of medicine for eight circulatory disorders by people aged 50-79 in 2004-2008. These differences were compared with those in circulatory disease mortality during 2004-2007, considered as indicating probable differences in disease burden. Results The unmarried had 1.4-2.8 times higher mortality from the four types of circulatory diseases considered. However, the never-married in particular purchased less medicine for these diseases, or precursor risk factors of these diseases, primarily because of a low chance of making a first purchase. The picture was more mixed for the divorced and widowed. Both groups purchased less of some of these medicines than the married, but, especially in the case of the widowed, relatively more of other types of medicine. In contrast to the never-married, divorced and widowed people were as least as likely as the married to make a first purchase, but adherence rates thereafter, indicated by continuing purchases, were lower. Conclusion The most plausible interpretation of the findings is that compared with married people, especially the never-married more often have circulatory disorders that are undiagnosed or for which they for other reasons underuse medication. Inadequate use of these potentially very efficient medicines in such a large population group is a serious public health challenge which needs further investigation. It is possible that marital status differences in use of medicines for circulatory disorders combined with an increasing importance of these medicines have contributed to the widening marital status gap in mortality observed in several countries. This also requires further investigation.

• Sigle-Rushton, Wendy; Lyngstad, Torkild Hovde; Andersen, Patrick Lie & Kravdal, Øystein (2014). Proceed with caution? Parents' union dissolution and children's educational achievement. Journal of Marriage and Family. ISSN 0022-2445. 76(1), p. 161–174. doi: 10.1111/jomf.12075. Full text in Research Archive
• Bævre, Kåre & Kravdal, Øystein (2014). The effects of earlier income variation on mortality: An analysis of Norwegian register data. Population Studies. ISSN 0032-4728. 68(1), p. 81–94. doi: 10.1080/00324728.2013.824603. Full text in Research Archive
• Kravdal, Øystein (2014). The Estimation of Fertility Effects on Happiness: Even More Difficult than Usually Acknowledged. European Journal of Population. ISSN 0168-6577. 30(3), p. 263–290. doi: 10.1007/s10680-013-9310-9. Full text in Research Archive
• Kodzi, Ivy & Kravdal, Øystein (2013). What has high fertility got to do with the low birth weight problem in Africa? Demographic Research. ISSN 1435-9871. 28, p. 713–731. doi: 10.4054/demres.2013.28.25. Full text in Research Archive
• Kravdal, Øystein; Kodzi, Ivy & Sigle-Rushton, Wendy (2013). Effects of the Number and Age of Siblings on Educational Transitions in Sub-Saharan Africa. Studies in family planning. ISSN 0039-3665. 44(3), p. 275–297. doi: 10.1111/j.1728-4465.2013.00358.x. Full text in Research Archive
• Kravdal, Øystein (2013). The poorer cancer survival among the unmarried in Norway: Is Much explained by comorbidities? Social Science and Medicine. ISSN 0277-9536. 81, p. 42–52. doi: 10.1016/j.socscimed.2013.01.012. Full text in Research Archive
• Shkolnikov, Vladimir; Andreev, E; Jdanov, D; Jasilonis, D; Kravdal, Øystein & Vågerø, D [Show all 7 contributors for this article] (2012). Increasing absolute mortality disparities by education in Finland, Norway and Sweden, 1971-2000. Journal of Epidemiology and Community Health. ISSN 0143-005X. 66(4), p. 372–378. doi: 10.1136/jech.2009.104786. Full text in Research Archive
• Syse, Astri; Lyngstad, Torkild Hovde & Kravdal, Øystein (2012). Is mortality after childhood cancer dependent on social or economic resources of parents? A population-based study. International Journal of Cancer. ISSN 0020-7136. 130(8), p. 1870–1878. doi: 10.1002/ijc.26186. Full text in Research Archive

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• Kravdal, Øystein (2026). Barn har blitt en klassemarkør. [Journal]. Dagsavisen. Full text in Research Archive
• Kravdal, Øystein & Hart, Rannveig Kaldager (2026). Health around the time of first birth matters for future fertility. Full text in Research Archive
• Kravdal, Øystein (2026). Fødselstallene har lenge gått ned. Nå har forskere sett på hva som skjedde i 2007. [Journal]. Aftenposten. Full text in Research Archive Show summary

  To nye forskningsartikler spør om smarttelefonen har fungert som prevensjonsmiddel.

• Dommermuth, Lars; Lappegård, Trude; Kravdal, Øystein; Lyngstad, Torkild Hovde & Tønnessen, Marianne (2026). (+) Demografifaget trenger et hjem. Full text in Research Archive Show summary

  Til tross for at befolkningsspørsmål er politisk brennbare, finnes det ikke noe samlet demografisk forskningsmiljø i Norge. Vi trenger minst ett nasjonalt senter for demografi.

• Kravdal, Øystein; Flatø, Martin & Torvik, Fartein Ask (2025). Mental disorder and (reduced) fertility in Norway. N-IUSSP. doi: https:/www.niussp.org/fertility-and-reproduction/mental-disorder-and-reduced-fertility-in-norway/. Full text in Research Archive
• Alice, Goisis,; Jenny, Chanfreau, & Kravdal, Øystein (2025). The growing role of ART in fertility rates in Norway. N-IUSSP. doi: https:/www.niussp.org/fertility-and-reproduction/the-growing-role-of-art-in-fertility-rates-in-norway/. Full text in Research Archive
• Kravdal, Øystein (2025). Fruktbarheten i Norge. doi: 10.4045/tidsskr.25.0253. Full text in Research Archive
• Kravdal, Øystein (2025). Lavt barnetall i Norge. Hvordan kom vi dit, og er det noe problem? [Internet]. YouTube. Full text in Research Archive
• Kravdal, Øystein (2025). Concerns about low fertility: Steps towards a clearer debate and perhaps less alarmism. Population Europe Discussion paper. doi: https:/population-europe.eu/research/policy-insights/concerns-about-low-fertility-steps-towards-clearer-debate-and-perhaps-less. Full text in Research Archive
• Wörn, Jonathan; Balbo, Nicoletta; Hank, Karsten & Kravdal, Øystein (2024). Teenage Mental Health Problems and the Co-Development of Parent and Sibling Mental Health. Full text in Research Archive
• Wörn, Jonathan; Balbo, Nicoletta; Hank, Karsten & Kravdal, Øystein (2024). Teenage Mental Health Problems and the Co-Development of Parent and Sibling Mental Health. Full text in Research Archive
• Bolano, Danilo; Balbo, Nicoletta; Kravdal, Øystein & Wörn, Jonathan (2024). The Life Course of Fragile Families: The Disability of a Child as a Shaping Factor of Parents’ Family and Fertility Behaviors. Full text in Research Archive
• Bolano, Danilo; Balbo, Nicoletta; Kravdal, Øystein & Wörn, Jonathan (2024). The Life Course of Fragile Families: The Disability of a Child as a Shaping Factor of Parents’ Family and Fertility Behaviors. Full text in Research Archive
• Hart, Rannveig Kaldager; Baranowska-Rataj, Anna; Dang, Thang Dinh; Kravdal, Øystein & Syse, Astri (2024). Mental Health Penalties of Childbearing in a Family Friendly Welfare State. Full text in Research Archive
• Hart, Rannveig Kaldager; Baranowska-Rataj, Anna; Dang, Thang Dinh; Kravdal, Øystein & Syse, Astri (2024). Mental Health Penalties of Childbearing in a Family Friendly Welfare State. Full text in Research Archive
• Jenssen, Anna B.; Bergsvik, Janna; Dommermuth, Lars; Kravdal, Øystein & Tømmerås, Ane Margrete (2024). Historien om gamlemor. [Journal]. Dagens Næringsliv Magasinet. Full text in Research Archive
• Syse, Astri; Kravdal, Øystein; Rostoft, Siri; Thomas, Michael & Hart, Rannveig Kaldager (2024). Illness in Marital or Cohabiting Partners: Implications for Welfare Uptake and Labor Market Efforts. Full text in Research Archive
• Bolano, Danilo; Balbo, Nicoletta & Kravdal, Øystein (2023). Child Disability: a shaping factor of the parental life course. A study based on population register data. Full text in Research Archive
• Hart, Rannveig Kaldager; Kravdal, Øystein; Dang, Thang Dinh; Syse, Astri & Baranowska-Rataj, Anna (2023). Mental Health Penalties of Childbearing in a Family Friendly Welfare State. Full text in Research Archive
• Kravdal, Øystein (2023). The Influence of Parental Cancer on the Mental Health of Children and Young Adults. Full text in Research Archive
• Hart, Rannveig Kaldager; Håberg, Siri Eldevik; Magnus, Per Minor & Kravdal, Øystein (2023). Hvorfor faller fruktbarheten så dramatisk? Full text in Research Archive
• Dregelid, Solrun; Flatø, Martin & Kravdal, Øystein (2023). Helt alene. [Internet]. Nettavisen. Full text in Research Archive
• Kravdal, Øystein (2022). Response to letter: Sibling models—An underused tool with limitations. Paediatric and Perinatal Epidemiology. ISSN 0269-5022. 36(1), p. 168–168. doi: 10.1111/ppe.12833. Full text in Research Archive
• Kravdal, Øystein (2022). To dager gamle Gabriel er sjelden vare. Fødseltallene faller over hele landet. [Journal]. Bergens Tidende. Full text in Research Archive
• Kravdal, Øystein (2022). Enebarn har dårligere helse som voksne. [Internet]. forskning.no. Full text in Research Archive
• Kravdal, Øystein (2022). Single mer utsatt for sykdom. [Journal]. Dagbladet. Full text in Research Archive
• Kravdal, Øystein (2021). No, it is not too good to be true. Paediatric and Perinatal Epidemiology. ISSN 0269-5022. doi: 10.1111/ppe.12799. Full text in Research Archive
• Kravdal, Øystein (2019). The increasing mortality advantage of the married. Full text in Research Archive
• Kravdal, Øystein (2019). Individnivå-konsekvenser av lav fruktbarhet. Full text in Research Archive
• Kravdal, Øystein (2018). Hva betyr barnetall og familiesituasjon for barns helse? Full text in Research Archive
• Kravdal, Øystein (2018). The increasing mortality advantage of the married. Full text in Research Archive
• Kravdal, Øystein (2018). The growing mortality advantage of the married. Full text in Research Archive
• Kravdal, Øystein (2018). Children’s Age at Parental Divorce and Depression in Early and Mid-Adulthood. Full text in Research Archive
• Kravdal, Øystein (2018). The growing mortality advantage of the married. Full text in Research Archive
• Kravdal, Øystein (2016). Not so Low Fertility in Norway—A Result of Affluence, Liberal Values, Gender-Equality Ideals, and the Welfare State. In Rindfuss, Ronald & Choe, Minja Kim (Ed.), Low Fertility, Institutions, and Their Policies: Variations across Industrialized Countries. Springer. ISSN 9783319329970. p. 13–47. doi: 10.1007/978-3-319-32997-0. Full text in Research Archive
• Kravdal, Øystein (2016). Expected and unexpected consequences of childbearing - a methodologically and politically important distinction that is overlooked. Full text in Research Archive
• Kravdal, Øystein (2016). Familie og helse. Full text in Research Archive
• Kravdal, Øystein (2015). Fertility history and use of antidepressant medication in late mid-life: a register-based analysis of Norwegian women and men. Full text in Research Archive
• Kravdal, Øystein (2015). How much of the variation in mortality across Norwegian municipalities is explained by the socio-demographic characteristics of the population?. Full text in Research Archive
• Kravdal, Øystein (2014). The estimation of fertility effects on happiness: Even more difficult than usually acknowledged. Full text in Research Archive
• Kravdal, Øystein (2014). The relatively high fertility in Norway – a result of affluence, liberal values, gender-equality ideals, and the welfare state. Full text in Research Archive
• Kravdal, Øystein (2013). The importance of women’s education for fertility in sub-Saharan Africa: A multilevel perspective. Full text in Research Archive
• Kravdal, Øystein (2013). Further evidence of community education effects on fertility in sub-Saharan Africa. Full text in Research Archive
• Kravdal, Øystein (2013). Education in sub-Saharan Africa: A new look at the effects of the number of siblings. Full text in Research Archive
• Kravdal, Øystein (2013). Some reflections on the four papers on fertility (timing) and gender. Full text in Research Archive
• Kravdal, Øystein (2013). The importance of women's education for fertility in sub-Saharan Africa: A multilevel perspective. Full text in Research Archive
• Kravdal, Øystein (2013). Norwegian register data: Some experiences to share with other social scientists and epidemiologists. Full text in Research Archive
• Bergsvik, Janna; Lappegård, Trude & Kravdal, Øystein (2021). Couples in context: Understanding family dynamics in Norway. Universitetet i Oslo. Full text in Research Archive Show summary

  This thesis studies how fertility, couple specialization and union stability in Norway are interrelated and linked to wider social structures such as family policy, gender roles and neighborhoods. It consists of an introduction and five independent articles: One based on a systematic review of international studies on effects of policy measures on fertility and four based on empirical analyses of Norwegian register data using descriptive and quasi-experimental techniques. With declining birth rates since 2009, fertility has received political attention in Norway. The literature review shows that the generous Norwegian family policies may have helped to elevate fertility levels. Yet, empirical analyses from this thesis show that children still entail income losses for women, and increasingly for young men too. Furthermore, the finding that couples break up more frequently if the woman earns more than the man shows that gender roles continue to be important in Norway in influencing family behavior. Empirical analyses also point to housing and family-friendly infrastructure as key factors for families, as couples with many children select into the same types of neighborhoods.

• Hart, Rannveig Kaldager & Kravdal, Øystein (2020). Fallende fruktbarhet i Norge. Hva kan det skyldes og hva kan man gjøre med det hvis det oppfattes som et problem? Folkehelseinstituttet. ISSN 9788284060606. Full text in Research Archive
• Tønnessen, Marianne & Kravdal, Øystein (2017). Demographic consequences of migration. Universitetet i Oslo. Full text in Research Archive Show summary

  This dissertation comprises five essays on demographic consequences of international and internal migration: The essay «Why immigrant fertility in Norway has declined» shows that the fertility decline among immigrant women in Norway since 2000 mainly can be attributed to lower fertility among newly arrived immigrants. Immigration may generate more immigration. «Forecasting immigration in official population projections using an econometric model» shows how this mechanism, along with other determinants of migration, is used to project future immigration to Norway. In origin areas, emigration affects families left behind. «Fathers’ whereabouts and children’s welfare in Malawi» compares health and welfare of children whose father is a migrant with that of other children. Migrants may be affected by norms in the destination area, also regarding preferences for children’s sex. This is discussed in «Changing trend? Sex ratios of children born to Indian immigrants in Norway revisited». Finally, «Childhood residential mobility and long-term outcomes» examines the effect of childhood relocations on several outcomes, including early mortality and early parenthood.

• Kravdal, Øystein (2016). New evidence about effects of reproductive variables on child mortality in sub-Saharan Africa. Universitetet i Oslo. Full text in Research Archive

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