A matter of time: Bateman's principles and mating success as count and duration across social strata in contemporary Finland.

Bateman's principles heavily influence the understanding of human reproductive behaviour. Yet, few rigorous studies on Bateman's principles in contemporary industrialized populations exist. Most studies use small samples, exclude non-marital unions, and disregard recent insights on within-population heterogeneity in mating strategies. We assess mating success and reproductive success using population-wide Finnish register data on marital and non-marital cohabitations and fertility. We examine variability across social strata in the Bateman principles and analyse the mate count, the cumulated duration with a mate, and the association with reproductive success. Results support Bateman's first and second principles. Regarding Bateman's third principle, the number of mates is more positively associated with reproductive success for men than women, but this association is driven by ever having a mate. Having more than one mate is on average associated with lower reproductive success. However, for men in the lowest income quartile, having more than one mate positively predicts reproductive success. Longer union duration is associated with higher reproductive success, and more so for men. We note that sex differences in the relationship between mating success and reproductive success differ by social strata, and argue that mate duration may be an important component of mating success alongside mate count.

Forced Migration and the Childbearing of Women and Men: A Disruption of the Tempo and Quantum of Fertility?

It is well known that migrant fertility is associated with age at migration, but little is known about this relationship for forced migrants. We study an example of displacement in which the entire population of Finnish Karelia was forced to move elsewhere in Finland in the 1940s. This displacement was unique because of its size and scale, because we have data on almost the whole population of both men and women who moved, and because of the similarity between origin and destination. These aspects enable us to investigate the disruptive impact of forced migration, net of other factors such as adaptation and selection. For all ages at migration from one to 20, female forced migrants had lower levels of completed fertility than similar women born in present-day Finland, which suggests a permanent impact of migration. However, women born in the same year as the initial forced migration showed no difference, which may indicate the presence of a counterbalancing fertility-increasing effect, as observed elsewhere for people born during a humanitarian crisis. There is less evidence of an impact for men, which suggests a gendered impact of forced migration-and its timing-on fertility. Results are similar after controlling for social and spatial mobility, indicating that there may be no major trade-off between reproduction and these forms of mobility.

Less Is More? Repartnering and Completed Cohort Fertility in Finland.

An extensive literature theorizes the role of repartnering for cohort fertility and whether union dissolution can be an engine for fertility. A large share of higher order unions are nonmarital cohabitations, but most previous studies on completed cohort fertility have analyzed only marital unions, and none have incorporated nonmarital cohabitations using population-level data. To analyze the relationship between the number of unions and cohort fertility for men and women, we use Poisson regression with Finnish register data to enumerate every birth, marriage, and cohabitation among the 1969-1972 birth cohorts at ages 18-46. We show that dissolutions of first cohabitations are the main pathway to repartnering and that most higher order unions are cohabitations. Nonmarital repartnering is a strong predictor of low fertility. In contrast, remarriage is positively associated with cohort fertility. Because the bulk of first-union dissolutions and higher order unions are nonmarital, repartnering is not an efficient engine for fertility at the aggregate level. Marriage and cohabitation are far from indistinguishable in a country often described as a second demographic transition forerunner.

Childlessness and union histories: evidence from Finnish population register data.

From an evolutionary perspective, childlessness may be considered a failure, as it implies that there will be no direct transmission of one's genetic material to later generations. It is also a pressing social issue, because in many contemporary advanced societies, levels of childlessness have increased, and particularly so among men. The absence of a partner is naturally a fundamental determinant of childlessness. Empirical evidence on how childlessness relates to individuals' partnership histories is nevertheless limited. This issue was analysed with Finnish population register data, which allow the complete cohabitation and marriage histories of individuals from age 18 years to be observed. For women and men born between 1969 and 1971, logistic regression models were estimated for childlessness at age 40 by partnership histories in terms of various stages in the process of union formation and dissolution, and accounting for several socioeconomic variables. A strong link between union histories and childlessness was found, with short partnership spells raising the risk of not becoming a parent. Later age when leaving the parental home raised female childlessness, while a short first-union duration related more strongly to male childlessness. These findings may be considered as providing insights into how specific life-history strategies affect reproductive outcomes, and highlight the need to develop new approaches to understand this feature of social inequality.

Five-year change in morale is associated with negative life events in very old age.

OBJECTIVES: The objectives were to study changes in morale in individuals 85 years and older, and to assess the effect of negative life events on morale over a five-year follow-up period. METHOD: The present study is based on longitudinal data from the Umeå85+/GERDA-study, including individuals 85 years and older at baseline (n = 204). Morale was measured with the Philadelphia Geriatric Center Morale Scale (PGCMS). Negative life events were assessed using an index including 13 negative life events occurring during the follow-up period. Linear regression was used for the multivariate analyses. RESULTS: The majority of the sample (69.1%) had no significant changes in morale during the five-year follow-up. However, the accumulation of negative life events was significantly associated with a greater decrease in PGCMS. A higher baseline PGCMS score did not attenuate the adverse effect negative life events had on morale. CONCLUSION: Morale seemed to be mainly stable in a five-year follow-up of very old people. It seems, nonetheless, that individuals are affected by negative life events, regardless of level of morale. Preventing negative life events and supporting individuals who experience multiple negative life events could have important implications for the care of very old people.

Experience of sibling death in childhood and risk of psychiatric care in adulthood: a national cohort study from Sweden.

Studies have found that sibling loss is associated with an increased risk of death from external causes (i.e. suicides, accidents and homicides). Increased psychiatric health problems following bereavement could underlie such an association. We studied the influence of sibling loss during childhood on psychiatric care in young adulthood, adjusting for psychosocial covariates shared by siblings in childhood. A national cohort born in Sweden in 1973-1982 (N = 701,270) was followed prospectively until 2013. Cox proportional hazards models were used to analyse the association between sibling loss during childhood and psychiatric inpatient and outpatient care identified by the Hospital Discharge Register. After adjustment for confounders, the HRs of psychiatric care in men who experienced sibling loss were 1.17 (95% CI 1.07-1.27) while the associations turned non-significant in women after adjustment for family-related psychosocial covariates, HR 1.07 (95% CI 0.99-1.16). An increased risk was found in men bereaved in early childhood (1.22 95% CI 1.07-1.38) and adolescence (1.27 95% CI 1.08-1.48). Among women, loss of a sibling during adolescence was significantly associated with psychiatric care (1.19 95% CI 1.03-1.36). Increased psychiatric health problems following bereavement could underlie the previously found association between sibling loss and mortality from external causes. Family-related psychosocial conditions shared by siblings in childhood may account for the association between sibling death and psychiatric care in adulthood.

Mortality after the death of a parent in adulthood: a register-based comparison of two ethno-linguistic groups.

BACKGROUND: Most research on parental bereavement and health have analysed health consequences of parental loss in childhood, while collateral health in adulthood has been less studied. METHODS: Using register-based population data from Finland, we analyse adult offspring aged 18-50 years with discrete-time hazard models that adjust for offspring and parental socioeconomic and demographic characteristics. In focus are adult children whose parents were alive and lived together at the beginning of the observation period. We compare two culturally distinct but otherwise similar ethno-linguistic groups, Finnish speakers and Swedish speakers. RESULTS: The results suggest that bereaved men have an approximately 30% higher death risk than non-bereaved men, while there is practically no difference in women. Associations between parental and child deaths are, as expected, stronger for concordant causes of death than for discordant causes of death. However, some associations for discordant causes of death remain, which may indicate causality. Among Swedish speakers, who have notably higher family stability than Finnish speakers, the death of one or both parents shows a stronger association with own mortality. CONCLUSIONS: The estimated associations found are generally larger than in the neighbouring country Sweden, which may be due to a stronger obedience to traditional family values and patriarchal family roles in Finland. These findings suggest that the association between parental death and mortality in adult offspring may depend on the societal context as well as on cultural practices. These factors should be increasingly acknowledged in future studies on collateral health.

Divorce and parity progression following the death of a child: A register-based study from Finland.

Most studies that have examined whether a child's death influences parental relationship stability have used small-scale data sets and their results are inconclusive. A likely reason is that child loss affects not only the risk of parental separation, but also the risk of having another child. Hence parity progression and separation must be treated as two competing events in relation to child loss. The analysis in this paper used Finnish register data from 1971 to 2003, covering over 100,000 married couples whose durations of both first marriage and parenthood could be observed. We ran parity-specific Cox regressions in which process time started from the birth of each additional child. All marriages included women of childbearing age, none of whom had experienced any child death on entering the analysis. We find that child loss only modestly influences the divorce risk, whereas its effect on the risk of parity progression is considerable.

Experience of Sibling Death in Childhood and Risk of Death in Adulthood: A National Cohort Study From Sweden.

Although there is some evidence of an association between loss of a sibling in adulthood and subsequent mortality, there have been no previous studies in which investigators have examined whether the death of a sibling in childhood is associated with adult mortality using total population data. Data on a national cohort born in Sweden in 1973-1982 (n = 717,723) were prospectively collected from the Cause of Death Register until 2013 (i.e., from the ages of 18 years to 31-40 years). Cox proportional hazards models were used to analyze the association between sibling loss during childhood and death in young adulthood. After adjustment for sociodemographic confounders and parental psychosocial covariates, the hazard ratio for all-cause mortality in bereaved siblings versus nonbereaved siblings was 1.39 (95% confidence interval: 1.14, 1.69). Risks were more pronounced for those who lost a noninfant sibling (i.e., >1 year of age) (hazard ratio = 1.53, 95% confidence interval: 1.18, 1.95) and those who lost a sibling in adolescence (i.e., between the ages of 12 and 18 years) (hazard ratio = 1.71, 95% confidence interval: 1.24, 2.35). Excess mortality risk was found for concordant causes of death (i.e., siblings dying from the same causes) but not for discordant causes.

Assessment of educational misclassification in register-based data on Finnish immigrants in Sweden.

AIM: In population registers, information on completed schooling is either missing or misclassified for a large proportion of newly arrived immigrants. It is unclear how quickly the information is updated and whether misclassification, i.e., that the wrong level of education is recorded, biases empirical estimates. METHODS: We use unique linked Swedish and Finnish register data to determine the extent of such mismeasurement. By running logistic regressions on zero earnings, we also illustrate how mismeasurement might influence the estimated effects of education on health or labour market outcomes. RESULTS: We find a considerable bias in estimates based on Swedish records of educational attainment during immigrants' first few years in the country. Misclassification is additionally very common, even when information on educational attainment exists. CONCLUSIONS: These findings suggest that research and policies using recently arrived immigrants' completed schooling as a determinant of socioeconomic integration need to be interpreted with care.

Testing the anniversary reaction: causal effects of bereavement in a nationwide follow-up study from Sweden.

Lingering grief associated with the death of a loved one has been hypothesized to precipitate acute health events among survivors on anniversary dates. We sought to study excess mortality risk in parents around the death date and birth date of a deceased child as an indication of a "bereavement effect". We conducted a population based follow-up study using Swedish registries including links between children and parents. All biological and Swedish-born parents who experienced the death of a minor child born were observed during the period 1973-2008 (n = 48,666). An increased mortality risk was found during the week of a child's death among mothers who lost a child aged 0-17 years (SMRR = 1.46, 95% CI 0.98-2.17). The association was stronger among mothers who lost a child aged 1-17 years (SMRR = 1.89, 95% CI 0.97-3.67) as compared to those who lost an infant (SMRR = 1.29, 95% CI 0.78-2.12). Cardiovascular diseases and suicides were overrepresented as causes of death in mothers who died around the anniversary. We found no significant increase in the mortality risk around the date of child's birth, nor any suggestion of excess mortality risk among fathers, but rather a depression of paternal death (SMRR = 0.60, 95% CI 0.34-1.03). Our study indicates an anniversary reaction among mothers who lost a young child. These results suggest that bereavement per se could have an effect on health and mortality which should be acknowledged by public health professionals working with bereaved people.

Birth order and suicide in adulthood: evidence from Swedish population data.

Each year, almost 1 million people die from suicide, which is among the leading causes of death in young people. We studied how birth order was associated with suicide and other main causes of death. A follow-up study based on the Swedish population register was conducted for sibling groups born from 1932 to 1980 who were observed during the period 1981-2002. Focus was on the within-family variation in suicide risk, meaning that we studied sibling groups that consisted of 2 or more children in which at least 1 died from suicide. These family-fixed effects analyses revealed that each increase in birth order was related to an 18% higher suicide risk (95% confidence interval (CI): 1.14, 1.23, P = 0.000). The association was slightly lower among sibling groups born in 1932-1955 (hazard ratio = 1.13, 95% CI: 1.06, 1.21, P = 0.000) than among those born in 1967-1980 (hazard ratio = 1.24, 95% CI: 0.97, 1.57, P = 0.080). Further analyses suggested that the association between birth order and suicide was only modestly influenced by sex, birth spacing, size of the sibling group, own socioeconomic position, own marital status, and socioeconomic rank within the sibling group. Causes of death other than suicide and other external causes were not associated with birth order.

"The psychological skeleton in the closet": mortality after a sibling's suicide.

PURPOSE: To study the association between loss of an adult sibling due to suicide and mortality from various causes up to 18 years after bereavement. METHODS: We conducted a follow-up study between 1981 and 2002, based on register data representing the total population of Swedes aged 25-64 years (n = 1,748,069). RESULTS: An elevated mortality rate from all causes was found among men (RR 1.26; 95 % CI: 1.14-1.40) and women (1.27; 1.11-1.45) who had experienced a sibling's suicide. The standardized rate ratio of suicide of bereaved to non-bereaved persons was 2.46 (1.86-3.24) among men and 3.25 (2.28-4.65) among women. We also found some indications of an interrelation between sibling suicide and subsequent deaths from external causes other than suicide in men (1.77; 1.34-2.34) and deaths from cardiovascular disease in women (1.37; 0.99-1.91). An elevated all-cause mortality rate was found after the first year of bereavement in men, while bereaved women experienced higher mortality rates during the first 2 years and after 5 years of bereavement. CONCLUSIONS: Our study provides support for adverse health effects among survivors associated with sibling loss due to suicide. Sibling suicides were primarily associated with suicide in bereaved survivors, although there was an increased mortality rate from discordant causes, which strengthens the possibility that the observed associations might not be entirely due to shared genetic causes.

First Partner Choice in a Native Minority: The Role of Own and Parental Ethnolinguistic Affiliation.

Despite increasing diversity within many societies, ethnically endogamous unions remain common. In contexts where one ethnic minority has lived alongside the majority for centuries, understanding who partners with whom is central to understanding how ethnic boundaries are maintained or dissolved. This study examines the role of own and parental ethnolinguistic affiliation for the first partner choice in Finland. We provide a unique test of the relevance of ethnic endogamy across two generations, in a context where both groups are native, but one (Finnish speakers) overwhelmingly outnumbers the other (Swedish speakers). Using register data on the total population, we examine how a person's ethnolinguistic affiliation and background affect the choice of the first cohabiting partner in terms of the partner's ethnolinguistic affiliation and background. We apply discrete-time competing risk models for men and women born 1970-1983. Results indicate that Swedish-registered individuals with two Swedish-registered parents are, by far, the most likely to partner with another Swedish-registered person with endogamous background. Partnering with a Swedish-registered person with exogamous background is most likely among individuals who themselves come from mixed unions. Patterns are remarkably consistent across gender, and adjustments for education and residential area only marginally alter the results.

Religion and Fertility: A Longitudinal Register Study Examining Differences by Sex, Parity, Partner's Religion, and Religious Conversion in Finland.

We use longitudinal data on religious affiliation in Finland to examine childbearing behavior. All analyses are based on detailed fertility information from the Finnish national register of each person's religious denomination for men and women born in 1956-1975. We identify higher fertility according to parity among members of the Evangelical Lutheran state church and other Protestant churches, and lower fertility among individuals with no religious affiliation. Most other religious groups-Orthodox Christians, Jews, Muslims, and adherents of Eastern religions-have intermediate levels of fertility. We also find that religious converts, that is, those observed with more than one religious denomination over their life course, typically are similar to the non-converts of the group they convert to, though with more distinct deviations from the Finnish population. Women show larger differences by religious affiliation than men. We find the largest differences across religions when we examine the proportion of childless men and women. Overall, differences between religious groups are rather modest, and childbearing patterns are quite similar. Our results provide, to our knowledge, the first examination of religion and fertility using national-level longitudinal data.

Religion and mental health in young adulthood: a register-based study on differences by religious affiliation in sickness absence due to mental disorders in Finland.

BACKGROUND: Religiosity and spirituality are known to be positively correlated with health. This is the first study to analyse the interrelation between religious denomination and sickness absence due to mental disorders using population register data with detailed ICD codes. METHODS: The follow-up study was based on the entire population born in Finland between 1984 and 1996 (N=794 476). Each person was observed from age 20 over the period from 2004 to 2018. Cox proportional hazards models were applied to analyse the association between religious denomination and first-time sickness allowance receipts for any cause and mental disorder. Mental disorders were categorised as severe mental illness (F20-F31), depression (F32-F33), anxiety (F40-F48) and any other mental disorder (all other F codes). Men and women were analysed separately. RESULTS: The differences in sickness absence due to mental disorder were substantial between religious affiliations. Compared with members of the Evangelical Lutheran state church, the relative hazard for mental disorders among non-affiliated women was 1.34 (95% CI 1.30 to 1.39), while that among women with other religions was 1.27 (95% CI 1.19 to 1.35), after adjusting for own and parental characteristics. The corresponding numbers for men were 1.45 (95% CI 1.39 to 1.50) and 1.42 (95% CI 1.30 to 1.54), respectively. The gradient was larger for severe mental illness and depression than for anxiety and other mental disorders. For any cause of sickness absence, there was no difference between Lutherans, non-affiliated individuals and those with other religions. CONCLUSIONS: Epidemiologists and public health practitioners should further examine the association between mental disorders and church membership using administrative registers.

Invited commentary: birth order and suicide in a broader context.

In this issue of the Journal, Bjørngaard et al. give us new insights into the etiology of mental health by studying birth order and suicide risk (Am J Epidemiol. 2013;177(7):638-644). Although the authors provided empirical evidence that each increase in birth order (i.e., from first-born to second-born, second-born to third-born, etc.) is associated with a 46% higher suicide risk, they gave us very little information on the likely explanations. In our commentary, we draw attention to the possible mechanisms underlying a causal relationship between birth order and suicide. Given that Norway is one of the richest countries in the world, the findings of Bjørngaard et al. in a Norwegian cohort also call for a discussion of whether their results are representative of other societies that are similar or dissimilar with respect to economic institutions, social conditions, and political environment. We suggest that there are several plausible mechanisms to explain higher suicide rates among later-born children, but other mechanisms might also operate in the opposite direction, that is, have beneficial outcomes among later-born children. Specifically, there are reasons to expect a different relationship between birth order and psychiatric outcomes in poorer societal contexts.

Who Migrates and Who Returns in a Context of Free Mobility? An Analysis of the Reason for Migration, Income and Family Trajectories.

The establishment of free mobility in Europe has lowered barriers to movement and given rise to diversity in migration and integration patterns. However, in part due to data constraints, it is difficult to study migration motives, integration and return migration together. Using linked Finnish and Swedish register data covering the period 1988-2005, we address these processes within the same framework and study how the reason for migration and trajectories at the destination relate to return migration. In particular, we assess the migration motives of 13,948 Finnish migrants in Sweden using pre- and post-migration information. Finland and Sweden have been part of the common Nordic labour market since 1954, which has allowed Nordic citizens to move without barriers between the two countries. We also study how income trajectories and trajectories of family formation differ across the assessed motives, and analyse how return migration risks are shaped by the motive and by trajectories of income and family formation. Results reveal that labour and tied migrants are initially more likely to have family abroad than student migrants. Student migrants instead continue their education and experience a steeper income increase. The income of student migrants eventually catches up and surpasses that of labour migrants. Return migration risks are shaped by trajectories at the destination, but also by the initial migration motive. These findings underline the importance of assessing diversity across migrants to gain a better understanding of how different migrant groups fare in the destination country and how this relates to subsequent moves.

Birth order and sickness absence: Register-based evidence from Finland.

BACKGROUND: In working ages, sickness absence is strongly related to persons' health condition. We studied how birth order was associated with receipt of sickness allowance, distinguishing between mental disorders, musculoskeletal disorders and injuries. METHODS: A follow-up study based on the entire Finnish population was conducted for sibling groups born 1969-1982, in which each sibling was observed from age 35 years in the period 2004-2018. Focus was on within-family variation in first-time sickness allowance receipt. RESULTS: Results of stratified Cox regressions revealed that each increase in birth order was associated with a slightly higher risk of sickness absence from any cause. For mental disorders, associations were stronger; the hazard ratio as compared to first borns was 1.03 (95% CI: 0.98-1.08) of second borns, 1.10 (0.99-1.22) of third borns, and 1.52 (1.25-1.85) of fourth or higher borns. Corresponding numbers for musculoskeletal disorders were 1.12 (1.07-1.17), 1.19 (1.09-1.30) and 1.15 (0.96-1.38), and for injuries 1.06 (1.01-1.12), 1.09 (1.21-1.14) and 0.96 (0.77-1.20), respectively. CONCLUSIONS: Birth order effects were generally stronger for women than men, and to some extent influenced by educational level, occupation, income, and family composition. Possible latent mechanisms behind the associations may relate to within-family dynamics at childhood.

Suicide Around the Anniversary of a Parent's Death in Sweden.

Importance: Bereavement following parental death experienced in adulthood may be associated with suicide over many years, but this risk has received scant attention. Objective: To investigate whether the risk of suicide increases among adult children around the anniversary of a parent's death. Design, Setting, and Participants: This case-crossover study used Swedish register-based longitudinal data from 1990 to 2016, based on the entire national population. Participants included all adults aged 18 to 65 years who experienced parental death and subsequently died by suicide. Conditional logistic regression was used to quantify the association between the anniversary (or preanniversary and postanniversary periods) and suicide, controlling for time-invariant confounding. All analyses were stratified by sex of the offspring. The analyses were also stratified by the sex of the deceased parent, time since parental death, age, and marital status. Data analyses were performed in June 2022. Exposures: Anniversary of a parent's death (or preanniversary and postanniversary periods). Main Outcomes and Measures: Suicide. Results: Of 7694 individuals who died by suicide (76% intentional self-harm), 2255 (29%) were women, and the median (IQR) age at suicide was 55 (47-62) years. There was evidence of an anniversary reaction among women, with a 67% increase in the odds of suicide when exposed to the period from the anniversary to 2 days after the anniversary, compared with when not being exposed (odds ratio [OR], 1.67; 95% CI, 1.07-2.62). The risk was particularly pronounced among maternally bereaved women (OR, 2.29; 95% CI, 1.20-4.40) and women who were never married (OR, 2.08; 95% CI, 0.99-4.37), although the latter was not statistically significant. An increased risk of suicide from the day before up to the anniversary was observed among women bereaved between the ages of 18 and 34 years (OR, 3.46; 95% CI, 1.14-10.56) and between the ages of 50 and 65 years (OR, 2.53; 95% CI, 1.04-6.15). Men had an attenuated suicide risk for the period from the day before up to the anniversary (OR, 0.57; 95% CI, 0.36-0.92). Conclusions and Relevance: These findings suggest that the anniversary of a parent's death is associated with an increased suicide risk among women. Women bereaved at younger or older ages, those who were maternally bereaved, and those who never married appeared to be particularly vulnerable. Families and social and health care professionals need to consider anniversary reactions in suicide prevention.