Childhood family background and mortality differences by income in adulthood: fixed-effects analysis of Finnish siblings

Parental income gradients in child and adolescent mortality: Norwegian trends over half a century

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.

Socioeconomic inequalities in cardiovascular disease: a causal perspective

Socioeconomic inequalities in cardiovascular disease (CVD) persist in high-income countries despite marked overall declines in CVD-related morbidity and mortality. After decades of research, the field has struggled to unequivocally answer a crucial question: is the association between low socioeconomic position (SEP) and the development of CVD causal? We review relevant evidence from various study designs and disciplinary perspectives. Traditional observational, family-based and Mendelian randomization studies support the widely accepted view that low SEP causally influences CVD. However, results from quasi-experimental and experimental studies are both limited and equivocal. While more experimental and quasi-experimental studies are needed to aid causal understanding and inform policy, high-quality descriptive studies are also required to document inequalities, investigate their contextual dependence and consider SEP throughout the lifespan; no simple hierarchy of evidence exists for an exposure as complex as SEP. The COVID-19 pandemic illustrates the context-dependent nature of CVD inequalities, with the generation of potentially new causal pathways linking SEP and CVD. The linked goals of understanding the causal nature of SEP and CVD associations, their contextual dependence, and their remediation by policy interventions necessitate a detailed understanding of society, its change over time and the phenotypes of CVD. Interdisciplinary research is therefore key to advancing both causal understanding and policy translation.

Pathways from Childhood Economic Conditions to Adult Mortality in a 1953 Stockholm Cohort: The Intermediate Role of Personal Attributes and Socioeconomic Career

Although both childhood and adult economic conditions have been found to be associated with mortality, independently or in combination with each other, less is known about the role of intermediate factors between these two life stages. This study explores the pathways between childhood economic conditions and adult mortality by taking personal attributes as well as adult socioeconomic career into consideration. Further, we investigate the role of intergenerational income mobility for adult mortality. We used data from a prospective cohort study of individuals that were born in 1953 and residing in Stockholm, Sweden, in 1963 who were followed for mortality between 2002 and 2021 (n = 11,325). We fit Cox proportional hazards models to assess the association of parental income, cognitive ability, social skills, educational attainment, occupational status, and adult income with mortality. The income mobility is operationalized as the interaction between parental and adult income. Our results show that the association between parental income and adult mortality is modest and largely operates through cognitive ability and adult educational attainment. However, our results do not provide support for there being an effect of intergenerational income mobility on adult mortality. In a Swedish cohort who grew up in a comparatively egalitarian society during the 1950s and 1960s, childhood economic conditions were found to play a distinct but relatively small role for later mortality.

Height and marital outcomes in the Netherlands, birth years 1841-1900

Adult body height appears to be significantly associated with marital outcomes: taller men across contexts have been found to be more likely to be married, and more likely to be married at younger ages. We are interested in exploring both outcomes individually and simultaneously, while using an unique, individual-level dataset of Dutch men and their brothers born between 1841 and 1900. To do so, we exploit survival models and cure models. While survival models yield a single estimate for the hazard (or age at) marriage, cure models yield two: one for the likelihood of marriage, and one for the hazard of first marriage. Cure models thus account for selection into marriage, while survival models do not. We find that, in the survival analyses, being in the shortest 20 % of heights is associated with later ages of marriage, relative to being average height. However, when we account for selection into marriage with cure models, we find that height is no longer associated with age at marriage. Instead, we see that height is associated with the likelihood of being married, with being in the bottom 20 % of heights associated with a 56.1 % decreased likelihood of being married, relative to being average height. We therefore conclude that height may be a gatekeeper for access to marriage, but it appears that other factors - likely related to the ability to set up an independent household - are more important in determining the timing of marriage for our research population.

The changing contribution of childhood social characteristics to mortality: a comparison of Finnish cohorts born in 1936-50 and 1961-75

Background

Life course epidemiology suggests that early life circumstances affect adult mortality, but most of the evidence is based on cohorts born in the beginning of the 20th century. It remains unclear whether and how the influences of early life circumstances on mortality have changed in later birth cohorts.

Methods

Analyses rely on 10% register-based samples of households drawn from the 1950 and the 1975 Finnish censuses, with consistent follow-up of socioeconomic and housing-related characteristics and early mid-life mortality (at ages 30–55 years). We estimate survival models for the associations between childhood circumstances and all-cause, internal and external mortality for cohorts born in 1936–50 and 1961–75 adjusting for attained social characteristics. We estimate sibling intraclass correlations as summary measures of all early life and familial influences.

Results

Adverse childhood social circumstances were typically associated with about 10–30% excess cause-specific mortality. These associations were almost fully attenuated by adjustment for achieved later life social characteristics. Early life influences have grown over time for mortality from external causes, particularly as related to home ownership and family type. Differentials have remained stable for internal causes. The intraclass correlations further confirmed the increasing association of early life circumstances on external-cause mortality.

Conclusions

Our analyses show that the associations between childhood characteristics and mid-life mortality are substantial and almost fully mediated by achieved adult social characteristics. The increase in the contribution of childhood circumstances to mid-life mortality is driven by ever stronger associations with external causes of death.

Accumulated Disadvantage over the Lower Secondary School Years in Helsinki Metropolitan Area, Finland

Accumulated disadvantage (AD) is conceptualised here as an agglomeration of unfavourable or prejudicial conditions which in adolescence may compromise the progress to further education or future life chances. There are several theories on AD, suggesting, e.g., (1) an increase of AD by age and (2) trajectories (previous disadvantage predicts later disadvantage). Social pathways theory suggests that (3) a third factor (e.g., socioeconomic position, SEP) mediates or moderates the association between early and later disadvantage, while other theories imply (4) polarisation (a strengthening association between AD and SEP by age) or (5) equalisation (a weakening of association between AD and SEP). We apply these theories to longitudinal data of 7th graders (13 years, N = 5742), followed until the end of the 9th grade. Five dimensions of disadvantage were health (poor self-rated health), social behaviour (poor prosocial behaviour), normative (conduct disorders), educational (poor academic achievement), and economic (parental unemployment). The results show that the prevalence of AD increased over the follow-up as most indicators of disadvantage elevated. AD at the 7th grade predicted later AD, as did the SEP of the students. Moderation of AD by SEP was also observed. The study corroborates with hypotheses on increase of AD, trajectory, and social pathways but no signs of polarisation or equalisation were observed.

Life expectancy and parental education

This study analyses the relationship between life expectancy and parental education. Based on data from the German Socio-Economic Panel Study and survival analysis models, we show that maternal education is related to children's life expectancy - even after controlling for children's own level of education. This applies equally to daughters and sons as well as to children's further life expectancies examined at age 35 to age 65. This pattern is more pronounced for younger cohorts. In most cases, the education of the father is not significantly related to children's life expectancy. Neither the vocational training nor the occupational position of the parents in childhood, which both correlate with household income, can explain the connection. The health behaviour of the children and the health accumulated over the life course appear as important channels. This study extends the previous literature that focused mostly on the relationship between individuals' own education and their life expectancy. It implies that the link between education and life expectancy is substantially stronger and that returns to education are higher if the intergenerational component is considered.

The importance of early life family factors in the association between cardiovascular risk factors and early cardiovascular mortality

Objective

To explore the importance of early life factors shared by siblings, such as parental socioeconomic position, parental practices, housing and neighbourhood, for the association between cardiovascular disease (CVD) risk factors and mortality from CVD, ischaemic heart disease (IHD) and cerebrovascular disease.

Methods

Norwegian health surveys (1974–2003) were linked with data from the Norwegian Family Based Life Course Study and the Cause of Death Registry. Participants with at least one full sibling among survey participants (n=2 71 643) were included. Data on CVD risk factors, body mass index (BMI), height, systolic blood pressure (SBP) and total cholesterol (TC) were stratified into ‘low’, ‘medium’ and ‘high’ risk, and smoking to ‘daily smoking’ and ‘not daily smoking’.

Results

Mean age of participants was 41 years, mean follow-up time was 19 years and during follow-up 2512 died from CVD. For each category of increased risk factor level, the per step HR of CVD mortality was increased by 1.91 (95% CI 1.78 to 2.05) for SBP, 1.67 (1.58 to 1.76) for TC, 1.44 (1.36 to 1.53) for BMI, 1.26 (1.18 to 1.35) for height and 2.89 (2.66 to 3.14) for smoking. In analyses where each sibship (groups of full siblings) had a group-specific baseline hazard, these associations were attenuated to 1.74, 1.51, 1.29, 1.18 and 2.63, respectively. The associations between risk factors and IHD mortality followed the same pattern.

Conclusion

Early life family factors explained a small part of the association between risk factors and mortality from CVD and IHD in a relatively young sample.

Educational differences in cardiovascular mortality: The role of shared family factors and cardiovascular risk factors

AIMS

To explore the confounding effects of early family factors shared by siblings and cardiovascular risk factors in midlife on the educational differences in mortality from cardiovascular disease (CVD).

METHODS

Data from national and regional health surveys in Norway (1974-2003) were linked with data from the Norwegian Family Based Life Course Study, the National Educational Registry and the Cause of Death Registry. The study population consisted of participants with at least one full sibling among the health survey participants ( n=271,310). Data were available on CVD risk factors, including weight, height, blood pressure, total cholesterol and smoking.

RESULTS

The hazards ratio (HR) of CVD mortality was 3.44 (95% confidence interval (CI) 2.98-3.96) in the lowest educational group relative to the highest. The HRs were little altered in the within-sibship analyses. Adjusted for risk factors, the HR for CVD mortality in the cohort analyses was 2.05 (CI 1.77-2.37) in the lowest educational group relative to the highest. The respective HR in the within-sibship analyses was 2.46 (CI 1.48-2.24).

CONCLUSIONS

Using a sibling design, we did not find that the association between education and CVD mortality was confounded by early life factors shared by siblings, but it was explained to a large extent by CVD risk factors. These results suggest that reducing levels of CVD risk factors could have the greatest effect on mortality in less well-educated people.