Mortality in Adult Offspring of Immigrants: A Swedish National Cohort Study

BackgroundHigher risks of psychiatric disorders and lower-than-average subjective health in adulthood have been demonstrated in offspring of immigrants in Sweden compared with offspring of native Swedes, and linked to relative socioeconomic disadvantage. The present study investigated mortality rates in relation to this inequity from a gender perspective.MethodsWe used data from national registers covering the entire Swedish population aged 18-65 years. Offspring of foreign-born parents who were either Swedish born or had received residency in Sweden before school age (<7 years) were defined as “offspring of immigrants.” We used Cox regression models to examine the association between parental country of birth and mortality between 1990 and 2008, with adjustment for education, income, age and family type.ResultsMale offspring of immigrants from the Middle East (HR:2.00, CI:1.66-2.26), other non-European countries (HR:1.80, CI:1.36-2.36) and Finland (HR:1.56, CI:1.48-1.65) showed an age-adjusted excess mortality risk from all causes of death when compared to offspring with Swedish-born parents. Income, but not education, greatly attenuated these increased mortality risks. No excess mortality rates were found among female offspring of immigrants, with the exception of external cause of death among offspring of Finnish immigrants.ConclusionThe study demonstrates high mortality rates in male offspring of immigrants from Finland and non-European countries that are associated with economic, but not educational, disadvantage. No increased mortality rates were found among female offspring of immigrants. Future studies are needed to explain this gender differential and why income, but not education, predicts mortality in male offspring of immigrants.     

Paternal investment and status-related child outcomes: timing of father's death affects offspring success

Recent work in human behavioural ecology has suggested that analyses focusing on early childhood may underestimate the importance of paternal investment to child outcomes since such investment may not become crucial until adolescence or beyond. This may be especially important in societies with a heritable component to status, as later investment by fathers may be more strongly related to a child's adult status than early forms of parental investment that affect child survival and child health. In such circumstances, the death or absence of a father may have profoundly negative effects on the adult outcomes of his children that cannot be easily compensated for by the investment of mothers or other relatives. This proposition is tested using a multigenerational dataset from Bangalore, India, containing information on paternal mortality as well as several child outcomes dependent on parental investment during adolescence and young adulthood. The paper examines the effects of paternal death, and the timing of paternal death, on a child's education, adult income, age at marriage and the amount spent on his or her marriage, along with similar characteristics of spouses. Results indicate that a father's death has a negative impact on child outcomes, and that, in contrast to some findings in the literature on father absence, the effects of paternal death are strongest for children who lose their father in late childhood or adolescence.     

Parental mortality rates in a western country after the death of a child: assessment of the role of the child's sex

Background: Loss of a child has been associated with elevated mortality rates in parents. Studies that focus on the influence of the child's sex on parental mortality are sparse.Objective: The main objective of the present study was to reevaluate the combined impact of the parents' and child's sex within a larger sample and focus on adverse health effects as an objective measure of possible long-term effects of maladaptive grief reactions.Methods: For the time period between 1980 and 1996, all children in Denmark who died before 18 years of age were identified. Parents who had lost a child were identified as the bereaved (exposed) group. Mortality rates of parents within the same-sex parent-child dyad were compared with mortality rates of parents within the opposite-sex parent-child dyad. Separate analyses were performed for bereaved fathers and for bereaved mothers, and additional analyses were conducted to examine the sole effect of the child's sex, irrespective of parental gender. A Cox proportional hazards regression model was used to estimate the hazard ratios (HRs) with 95% CIs.Results: The study population consisted of 21,062 parents (mean age at entry, 32 years; 11,221 mothers, 9841 fathers). Bereaved parents who had lost a child of the same sex had similar overall mortality as bereaved parents who had lost a child of the opposite sex (HR = 1.02; 95% CI, 0.85–1.22). Similar findings were observed for mortality due to natural death (HR = 0.96; 95% CI, 0.78–1.18) or mortality due to unnatural death (HR = 1.22; 95% CI, 0.84–1.77). Bereaved fathers who had lost a son had similar mortality as those bereaved by the death of a daughter (HR = 1.10; 95% CI, 0.86–1.40). Bereaved mothers who had lost a daughter had similar mortality as those bereaved by the death of a son (HR = 0.93; 95% CI, 0.70–1.22). Bereaved parents who had lost a son had mortality rates similar to those who had lost a daughter (HR = 1.09; 95% CI, 0.91–1.31). The interactions between grouping variable and sex of parents were not significant, indicating that the differential effect of losing a child based on sex of the child was not greater for fathers than for mothers.Conclusions: The results of this study revealed no significant effect of sex of the deceased child on mortality in these bereaved parents. The results might differ if this study was replicated in a population with a different grief culture and, more importantly, different gender schemas.     

Mortality after Parental Death in Childhood: A Nationwide Cohort Study from Three Nordic Countries

Background

Bereavement by spousal death and child death in adulthood has been shown to lead to an increased risk of mortality. Maternal death in infancy or parental death in early childhood may have an impact on mortality but evidence has been limited to short-term or selected causes of death. Little is known about long-term or cause-specific mortality after parental death in childhood.

Methods and Findings

This cohort study included all persons born in Denmark from 1968 to 2008 (n = 2,789,807) and in Sweden from 1973 to 2006 (n = 3,380,301), and a random sample of 89.3% of all born in Finland from 1987 to 2007 (n = 1,131,905). A total of 189,094 persons were included in the exposed cohort when they lost a parent before 18 years old. Log-linear Poisson regression was used to estimate mortality rate ratio (MRR). Parental death was associated with a 50% increased all-cause mortality (MRR = 1.50, 95% CI 1.43–1.58). The risks were increased for most specific cause groups and the highest MRRs were observed when the cause of child death and the cause of parental death were in the same category. Parental unnatural death was associated with a higher mortality risk (MRR = 1.84, 95% CI 1.71–2.00) than parental natural death (MRR = 1.33, 95% CI 1.24–1.41). The magnitude of the associations varied according to type of death and age at bereavement over different follow-up periods. The main limitation of the study is the lack of data on post-bereavement information on the quality of the parent-child relationship, lifestyles, and common physical environment.

Conclusions

Parental death in childhood or adolescence is associated with increased all-cause mortality into early adulthood. Since an increased mortality reflects both genetic susceptibility and long-term impacts of parental death on health and social well-being, our findings have implications in clinical responses and public health strategies. Please see later in the article for the Editors'' Summary     

Childhood Household Dysfunction,Social Inequality and Alcohol Related Illness in Young Adulthood. A Swedish National Cohort Study

The aim of this paper is to estimate the cumulative effect of childhood household dysfunction (CHD) on alcohol related illness and death later in life and to test the interaction between CHD and socioeconomic background. The study utilised Swedish national registers including data of a Swedish national cohort born 1973–82 (n = 872 912), which was followed from age 18 to 29–40 years. Cox regression analyses were used to calculate hazard ratios (HR) for alcohol related illness or death in young adulthood. The CHD measure consisted of seven indicators: parental alcohol/drug misuse, mental health problems, criminality, death, divorce, social assistance, and child welfare interventions. Childhood socioeconomic position (SEP) was indicated by parental occupational status. Outcomes were alcohol related inpatient hospital care, specialised outpatient care or deaths. Using the highest socioeconomic group without CHD experience as a reference, those in the same socioeconomic group with one indicator of CHD had HRs of 2.1 [95% CI: 1.7–2.5], two CHD indicators 5.6 [4.4–7.1], three or more indicators 9.4 [7.1–12.4] for retrieving inpatient care. Socioeconomic disadvantage further increased the risks–those with low socioeconomic background and three CHD indicators or more had a HR of 12.5 [10.9–14.3]. Testing for interaction suggests that the combined HRs deviates from additivity [Synergy index: 1.6, 95% CI: 1.4–1.9]. The results for outpatient care were similar, but not as pronounced. In conclusion, this Swedish national cohort study shows that childhood household dysfunction is strongly and cumulatively associated to alcohol related illness later in life and that it interacts with socioeconomic disadvantage.     

Email submissions from outside the United Kingdom

ObjectivesTo identify whether psychiatric disturbance in parentally bereaved children and surviving parents is related to service provision.DesignProspective case-control study.SettingTwo adjacent outer London health authorities. Participants45 bereaved families with children aged 2 to 16 years.ResultsParentally bereaved children and surviving parents showed higher than expected levels of psychiatric difficulties. Boys were more affected than girls, and bereaved mothers had more mental health difficulties than bereaved fathers. Levels of psychiatric disturbance in children were higher when parents showed probable psychiatric disorder. Service provision related to the age of the children and the manner of parental death. Children under 5 years of age were less likely to be offered services than older children even though their parents desired it. Children were significantly more likely to be offered services when the parent had committed suicide or when the death was expected. Children least likely to receive service support were those who were not in touch with services before parental death.ConclusionsService provision was not significantly related to parental wishes or to level of psychiatric disturbance in parents or children. There is a role for general practitioners and primary care workers in identifying psychologically distressed surviving parents whose children may be psychiatrically disturbed, and referring them to appropriate services.

Key messages

• Parentally bereaved children show high levels of psychological disturbance, with boys being more vulnerable than girls
• Surviving mothers show more psychiatric morbidity than surviving fathers
• Psychological distress in bereaved parents is associated with psychological difficulties in their children
• Service provision for bereaved children is not determined by mental health difficulties in either parents or children, or by parental wishes; it is influenced only by the manner of parental death and the age of the child
• The mismatch between need and service provision indicates a role for general practitioners and primary care workers in identifying distressed or disturbed families in need of public or voluntary service help

     

War and Bereavement: Consequences for Mental and Physical Distress

Background

Little is known about the long-term impact of the killing of a parent in childhood or adolescence during war on distress and disability in young adulthood. This study assessed current prevalence rates of mental disorders and levels of dysfunction among young adults who had lost their father due to war-related violence in childhood or adolescence.

Methods

179 bereaved young adults and 175 non-bereaved young adults were interviewed a decade after experiencing the war in Kosovo. Prevalence rates of Major Depressive Episode (MDE), anxiety, and substance use disorders, and current suicide risk were assessed using the Mini–International Neuropsychiatric Interview. The syndrome of Prolonged Grief Disorder (PGD) was assessed with the Prolonged Grief Disorder Interview (PG-13). Somatic symptoms were measured with the Patient Health Questionnaire. General health distress was assessed with the General Health Questionnaire.

Findings

Bereaved participants were significantly more likely to suffer from either MDE or any anxiety disorder than non-bereaved participants (58.7% vs. 40%). Among bereaved participants, 39.7% met criteria for Post-Traumatic Stress Disorder, 34.6% for PGD, and 22.3% for MDE. Bereaved participants with PGD were more likely to suffer from MDE, any anxiety disorder, or current suicide risk than bereaved participants without PGD. Furthermore, these participants reported significantly greater physical distress than bereaved participants without PGD.

Conclusion

War-related loss during middle childhood and adolescence presents significant risk for adverse mental health and dysfunction in young adulthood in addition to exposure to other war-related traumatic events. Furthermore, the syndrome of PGD can help to identify those with the greatest degree of distress and dysfunction.     

Childhood predictors of late‐life diabetes: The case of Mexico

Abstract

We investigated the interplay between characteristics of early childhood circumstances and current socioeconomic conditions and health, focusing specifically on diabetes in mid and late life in Mexico. The analysis used data from the 2001 Mexican Health and Aging Study (MHAS), a large nationally representative study of Mexicans born before 1950. We analyzed the extent to which childhood conditions, such as exposure to infectious diseases, a poor socioeconomic environment, and parental education, affect the risk of diabetes in later life. Our results indicate that individuals age 50 and older who experienced serious health problems before age 10 have a higher risk of having late‐life diabetes. There is a significant inverse relationship between maternal education and diabetes in late life of adult offspring. Individuals with better educated mothers have a lower risk of being diabetic after age 50. This relationship remains after controlling for other childhood and adult risk factors.     

Socioeconomic status during childhood and health status in adulthood: the Wrocław growth study

It has been widely observed that socioeconomic status (SES) is associated with frequency of cardiovascular disease. Both men and women of low socioeconomic position have increased risk of cardiovascular disease morbidity and premature death. In this study the relationship between SES in childhood, and health status at the age of 50 years was examined. Socioeconomic status in childhood was measured using objective (father's educational level and number of children in the family) and subjective (self-assessed SES in childhood declared in early adulthood) indicators. Data from the Wroclaw Growth Study were completed when subjects were 50 years old, and information concerning health status was added. The results indicated that the objective, universally used measures of SES in childhood such as father's educational level and size of family did not show any essential relationships with health outcomes in adulthood, both for men and women. By contrast, retrospective, self-assessed SES (as better, average or worse as compared with peers) in childhood was significantly associated with the appearance of cardiovascular disease among women aged 50 years. Women who at the beginning of their adult life declared better socioeconomic condition in childhood were significantly healthier at the age of 50 years (OR=3.43; p=0.02). Moreover, this appeared to be independent of BMI, SES and life-style in adulthood. For men, retrospective self-assessed SES showed no relation to health status at the age of 50 years. The gender differences in the relationships between self-assessed SES in childhood and health status in adulthood are explained by possible selective premature mortality among men from lower childhood SES and/or sex differences in cognitive abilities.     

Socioeconomic inequalities in prevalence and development of multimorbidity across adulthood: A longitudinal analysis of the MRC 1946 National Survey of Health and Development in the UK

BackgroundWe aimed to estimate multimorbidity trajectories and quantify socioeconomic inequalities based on childhood and adulthood socioeconomic position (SEP) in the risks and rates of multimorbidity accumulation across adulthood.Methods and findingsParticipants from the UK 1946 National Survey of Health and Development (NSHD) birth cohort study who attended the age 36 years assessment in 1982 and any one of the follow-up assessments at ages 43, 53, 63, and 69 years (N = 3,723, 51% males). Information on 18 health conditions was based on a combination of self-report, biomarkers, health records, and prescribed medications. We estimated multimorbidity trajectories and delineated socioeconomic inequalities (based on childhood and adulthood social class and highest education) in multimorbidity at each age and in longitudinal trajectories.Multimorbidity increased with age (0.7 conditions at 36 years to 3.7 at 69 years). Multimorbidity accumulation was nonlinear, accelerating with age at the rate of 0.08 conditions/year (95% CI 0.07 to 0.09, p < 0.001) at 36 to 43 years to 0.19 conditions/year (95% CI 0.18 to 0.20, p < 0.001) at 63 to 69 years. At all ages, the most socioeconomically disadvantaged had 1.2 to 1.4 times greater number of conditions on average compared to the most advantaged. The most disadvantaged by each socioeconomic indicator experienced an additional 0.39 conditions (childhood social class), 0.83 (adult social class), and 1.08 conditions (adult education) at age 69 years, independent of all other socioeconomic indicators. Adverse adulthood SEP was associated with more rapid accumulation of multimorbidity, resulting in 0.49 excess conditions in partly/unskilled compared to professional/intermediate individuals between 63 and 69 years. Disadvantaged childhood social class, independently of adulthood SEP, was associated with accelerated multimorbidity trajectories from age 53 years onwards.Study limitations include that the NSHD cohort is composed of individuals of white European heritage only, and findings may not be generalizable to the non-white British population of the same generation and did not account for other important dimensions of SEP such as income and wealth.ConclusionsIn this study, we found that socioeconomically disadvantaged individuals have earlier onset and more rapid accumulation of multimorbidity resulting in widening inequalities into old age, with independent contributions from both childhood and adulthood SEP.

Amal Khanolkar and co-workers study associations between multimorbidity and socioeconomic position in the UK.     

Parental Socioeconomic Status,Childhood Asthma and Medication Use – A Population-Based Study

Background

Little is known about how parental socioeconomic status affects offspring asthma risk in the general population, or its relation to healthcare and medication use among diagnosed children.

Methods

This register-based cohort study included 211,520 children born between April 2006 and December 2008 followed until December 2010. Asthma diagnoses were retrieved from the National Patient Register, and dispensed asthma medications from the Prescribed Drug Register. Parental socioeconomic status (income and education) were retrieved from Statistics Sweden. The associations between parental socioeconomic status and outcomes were estimated by Cox proportional hazard regression.

Results

Compared to the highest parental income level, children exposed to all other levels had increased risk of asthma during their first year of life (e.g. hazard ratio, HR 1.19, 95% confidence interval, CI 1.09–1.31 for diagnosis and HR 1.17, 95% CI 1.08–1.26 for medications for the lowest quintile) and the risk was decreased after the first year, especially among children from the lowest parental income quintile (HR 0.84, 95% CI 0.77–0.92 for diagnosis, and HR 0.80, 95% CI 0.74–0.86 for medications). Further, compared to children with college-educated parents, those whose parents had lower education had increased risk of childhood asthma regardless of age. Children with the lowest parental education had increased risk of an inpatient (HR 2.07, 95% CI 1.61–2.65) and outpatient (HR 1.32, 95% CI 1.18–1.47) asthma diagnosis. Among diagnosed children, those from families with lower education used fewer controller medications than those whose parents were college graduates.

Conclusions

Our findings indicate an age-varying association between parental income and childhood asthma and consistent inverse association regardless of age between parental education and asthma incidence, dispensed controller medications and inpatient care which should be further investigated and remedied.     

Early-Life Socioeconomic Status and Adult Physiological Functioning: A Life Course Examination of Biosocial Mechanisms

A growing literature has demonstrated a link between early-life socioeconomic conditions and adult health at a singular point in life. No research exists, however, that specifies the life course patterns of socioeconomic status (SES) in relation to the underlying biological processes that determine health. Using an innovative life course research design consisting of four nationally representative longitudinal datasets that collectively cover the human life span from early adolescence to old age (Add Health, MIDUS, NSHAP, and HRS), we address this scientific gap and assess how SES pathways from childhood into adulthood are associated with biophysiological outcomes in different adult life stages. For each dataset, we constructed standardized composite measures of early-life SES and adult SES and harmonized biophysiological measurements of immune and metabolic functioning. We found that the relative importance of early-life SES and adult SES varied across young, mid, and late adulthood, such that early-life SES sets a life course trajectory of socioeconomic well-being and operates through adult SES to influence health as adults age. We also documented evidence of the detrimental health effects of downward mobility and persistent socioeconomic disadvantage. These findings are the first to specify the life course patterns of SES that matter for underlying biophysiological functioning in different stages of adulthood. The study thus contributes new knowledge critical for improving population health by identifying the particular points in the life course at which interventions might be most effective in preventing disease and premature mortality.     

Associations of parental depression during adolescence with cognitive development in later life in China: A population-based cohort study

BackgroundPrior research has underscored negative impacts of perinatal parental depression on offspring cognitive performance in early childhood. However, little is known about the effects of parental depression during adolescence on offspring cognitive development.Methods and findingsThis study used longitudinal data from the nationally representative China Family Panel Studies (CFPS). The sample included 2,281 adolescents aged 10–15 years (the median age was 13 years with an interquartile range between 11 and 14 years) in 2012 when their parents were surveyed for depression symptoms with the 20-item Center for Epidemiologic Studies Depression Scale (CES-D). The sample was approximately balanced by sex, with 1,088 females (47.7%). We examined the associations of parental depression in 2012 with offspring cognitive performance (measured by mathematics, vocabulary, immediate word recall, delayed word recall, and number series tests) in subsequent years (i.e., 2014, 2016, and 2018) using linear regression models, adjusting for various offspring (i.e., age, sex, and birth order), parent (i.e., parents’ education level, age, whether living with the offspring, and employment status), and household characteristics (i.e., place of residence, household income, and the number of offspring). We found parental depression during adolescence to be significantly associated with worse cognitive performance in subsequent years, in both crude and adjusted models. For example, in the crude models, adolescents whose mothers had depression symptoms in 2012 scored 1.0 point lower (95% confidence interval [CI]: −1.2 to −0.8, p < 0.001) in mathematics in 2014 compared to those whose mothers did not have depression symptoms; after covariate adjustment, this difference marginally reduced to 0.8 points (95% CI: −1.0 to −0.5, p < 0.001); the associations remained robust after further adjusting for offspring earlier cognitive ability in toddlerhood (−1.2, 95% CI: −1.6, −0.9, p < 0.001), offspring cognitive ability in 2012 (−0.6, 95% CI: −0.8, −0.3, p < 0.001), offspring depression status (−0.7, 95% CI: −1.0, −0.5, p < 0.001), and parents’ cognitive ability (−0.8, 95% CI: −1.2, −0.3, p < 0.001). In line with the neuroplasticity theory, we observed stronger associations between maternal depression and mathematical/vocabulary scores among the younger adolescents (i.e., 10–11 years) than the older ones (i.e., 12–15 years). For example, the association between maternal depression and 2014 vocabulary scores was estimated to be −2.1 (95% CI: −2.6, −1.6, p < 0.001) in those aged 10–11 years, compared to −1.2 (95% CI: −1.6, −0.8, p < 0.001) in those aged 12–15 years with a difference of 0.9 (95% CI: 0.2, 1.6, p = 0.010). We also observed a stronger association of greater depression severity with worse mathematical scores. The primary limitations of this study were the relatively high attrition rate and residual confounding.ConclusionsIn this study, we observed that parental depression during adolescence was associated with adverse offspring cognitive development assessed up to 6 years later. These findings highlight the intergenerational association between depression in parents and cognitive development across the early life course into adolescence.

In this cohort study, Zhihui Li and colleagues explore associations between parental depression and offspring cognitive development up to six years later.     

Canadian Indian mortality during the 1980s

Abstract

This study concerns itself with an investigation of general and cause‐specific mortality differentials between Canadian Registered Indians (a subset of all aboriginals) and the larger Canadian population over two points in time, 1981 and 1991. Multivariate analyses are executed separately across four segments of the life cycle: adulthood, infancy, early childhood and late childhood. With respect to adults, Indians share relatively high rates of suicide, homicide and accidental causes of death; over time, their conditional risks of death due to cancer and circulatory afflictions have gone up significantly. Mortality disadvantages for the Indians are also pronounced in infancy, early childhood (ages 1–4) and late childhood (ages 5–14). Suicide, accidents, and violence constitute serious problems among 5–14 year olds, while infectious/parasitic, respiratory and circulatory complications, plus accidents and violence, are principle killers in infancy. For children aged 1–4, respiratory problems and accidents/violence are prime causes of premature death. This less‐than‐optimal mortality profile is reflective of persistent problems associated with prolonged socioeconomic marginalization. The temporal pattern of change in chronic/degenerative disease mortality among adult Indians suggests a movement of this population toward a mature stage of epidemiological transition.     

Cognitive function in adolescence and the risk for premature diabetes and cardiovascular mortality in adulthood

Background

Epidemiological studies have demonstrated a relationship between cognitive function in youth and the future risk of death. Less is known regarding the relationship with diabetes related death. This study assessed the relationship between cognitive function in late adolescence and the risk for diabetes, cardiovascular- (CVD) and all-cause mortality in adulthood.

Methods

This retrospective study linked data from 2,277,188 16–19 year olds who had general intelligence tests (GIT) conducted during pre-military recruitment assessment with cause of death as coded by the Israel Central Bureau of Statistics. The associations between cognitive function and cause-specific mortality were assessed using Cox models.

Results

There were 31,268 deaths that were recorded during 41,916,603 person-years of follow-up, with a median follow-up of 19.2 (IQR 10.7, 29.5) years. 3068, 1443, 514 and 457 deaths were attributed to CVD, CHD, stroke, and diabetes, respectively. Individuals in the lowest GIT vs. highest GIT quintiles in unadjusted models had the highest risk for all-cause mortality (HR 1.84, 95% CI 1.78, 1.91), total CVD (HR 3.32, 95% CI 2.93, 3.75), CHD (HR 3.49 95% CI 2.92, 4.18), stroke (HR 3.96 95% CI 2.85, 5.5) and diabetes-related (HR 6.96 95% CI 4.68, 10.36) mortality. These HRs were attenuated following adjustment for age, sex, birth year, body-mass index, residential socioeconomic status, education and country of origin for all-cause (HR 1.23, 95% CI 1.17, 1.28), CVD (HR 1.76, 95% CI 1.52, 2.04), CHD (HR 1.7 95% CI 1.37, 2.11), stroke (HR 2.03, 95% CI 1.39, 2.98) and diabetes-related (HR 3.14 95% CI 2.00, 4.94) mortality. Results persisted in a sensitivity analyses limited to participants with unimpaired health at baseline and that accounted competing risk.

Conclusions

This analysis of over 2 million demonstrates a strong relationship between cognitive function at youth and the risk for diabetes, all-cause and CVD-related mortality independent of adolescent obesity.

     

Polygenic and socioeconomic risk for high body mass index: 69 years of follow-up across life

Genetic influences on body mass index (BMI) appear to markedly differ across life, yet existing research is equivocal and limited by a paucity of life course data. We thus used a birth cohort study to investigate differences in association and explained variance in polygenic risk for high BMI across infancy to old age (2–69 years). A secondary aim was to investigate how the association between BMI and a key purported environmental determinant (childhood socioeconomic position) differed across life, and whether this operated independently and/or multiplicatively of genetic influences. Data were from up to 2677 participants in the MRC National Survey of Health and Development, with measured BMI at 12 timepoints from 2–69 years. We used multiple polygenic indices from GWAS of adult and childhood BMI, and investigated their associations with BMI at each age. For polygenic liability to higher adult BMI, the trajectories of effect size (β) and explained variance (R²) diverged: explained variance peaked in early adulthood and plateaued thereafter, while absolute effect sizes increased throughout adulthood. For polygenic liability to higher childhood BMI, explained variance was largest in adolescence and early adulthood; effect sizes were marginally smaller in absolute terms from adolescence to adulthood. All polygenic indices were related to higher variation in BMI; quantile regression analyses showed that effect sizes were sizably larger at the upper end of the BMI distribution. Socioeconomic and polygenic risk for higher BMI across life appear to operate additively; we found little evidence of interaction. Our findings highlight the likely independent influences of polygenic and socioeconomic factors on BMI across life. Despite sizable associations, the BMI variance explained by each plateaued or declined across adulthood while BMI variance itself increased. This is suggestive of the increasing importance of chance (‘non-shared’) environmental influences on BMI across life.     

Early-life conditions and age at first pregnancy in British women

There is growing evidence that the reproductive schedules of female mammals can be affected by conditions experienced during early development, with low parental investment leading to accelerated life-history strategies in the offspring. In humans, the relationships between early-life conditions and timing of puberty are well studied, but much less attention has been paid to reproductive behaviour. Here, we investigate associations between early-life conditions and age at first pregnancy (AFP) in a large, longitudinally studied cohort of British women (n = 4553). Low birthweight for gestational age, short duration of breastfeeding, separation from mother in childhood, frequent family residential moves and lack of paternal involvement are all independently associated with earlier first pregnancy. Apart from that of birthweight, the effects are robust to adjustment for family socioeconomic position (SEP) and the cohort member's mother's age at her birth. The association between childhood SEP and AFP is partially mediated by early-life conditions, and the association between early-life conditions and AFP is partially mediated by emotional and behavioural problems in childhood. The overall relationship between early-life adversities and AFP appears to be approximately additive.     

Psychological Stress and Hospitalization for Childhood Asthma-a Nationwide Cohort Study in Two Nordic Countries

Objective

Exposures to psychological stress in early life may contribute to the development or exacerbation of asthma. We undertook a cohort study based on data from several population-based registers in Denmark and Sweden to examine whether bereavement in childhood led to increased asthma hospitalization.

Methods

All singleton children born in Denmark during 1977-2008 and in Sweden during 1973-2006 were included in the study (N=5,202,576). The children were followed from birth to the date of first asthma hospitalization, emigration, death, their 18^th birthday, or the end of study (31 December 2007 in Sweden and 31 December 2008 in Denmark), whichever came first. All the children were assigned to the non-bereaved group until they lost a close relative (mother, father or a sibling), from when they were included in the bereaved group. We evaluated the hazard ratio (HR) of first hospitalization for asthma in bereaved children using Cox proportional hazards regression models, compared to those who were in the non-bereaved group. We also did a sub-analysis on the association between bereavement and first asthma medication.

Results

A total of 147,829 children were hospitalized for asthma. The overall adjusted HR of asthma hospitalization in bereaved children was 1.10 (95% confidence interval (CI): 1.04-1.16), compared to non-bereaved children. The risk of asthma hospitalization was increased in those who lost a close relative at age of 14-17 years (HR=1.54, 95% CI: 1.23-1.92), but not in younger age groups. The association between bereavement and asthma hospitalization did not change over time since bereavement. In the sub-analysis in singleton live births during 1996-2008 recorded in the DMBR, bereavement was associated with a lower use of asthma medication (HR=0.87, 95% CI: 0.80-0.95).

Conclusions

Our data suggests that psychological stress following bereavement in late adolescence is associated with an increased risk of asthma hospitalization or lowers the threshold for asthma hospitalization.