Early life socioeconomic position and mortality from cardiovascular diseases: an application of causal mediation analysis in the Stockholm Public Health Cohort

Intergenerational transmission of health inequalities: towards a life course approach to socioeconomic inequalities in health - a review

Adult health inequalities are a persistent public health problem. Explanations are usually sought in behaviours and environments in adulthood, despite evidence on the importance of early life conditions for life course outcomes. We review evidence from a broad range of fields to unravel to what extent, and how, socioeconomic health inequalities are intergenerationally transmitted.We find that transmission of socioeconomic and associated health (dis)advantages from parents to offspring, and its underlying structural determinants, contributes substantially to socioeconomic inequalities in adult health. In the first two decades of life-from conception to early adulthood-parental socioeconomic position (SEP) and parental health strongly influence offspring adult SEP and health. Socioeconomic and health (dis)advantages are largely transmitted through the same broad mechanisms. Socioeconomic inequalities in the fetal environment contribute to inequalities in fetal development and birth outcomes, with lifelong socioeconomic and health consequences. Inequalities in the postnatal environment-especially the psychosocial and learning environment, physical exposures and socialisation-result in inequalities in child and adolescent health, development and behavioural habits, with health and socioeconomic consequences tracking into adulthood. Structural factors shape these mechanisms in a socioeconomically patterned and time-specific and place-specific way, leading to distinct birth-cohort patterns in health inequality.Adult health inequalities are for an important part intergenerationally transmitted. Effective health inequality reduction requires addressing intergenerational transmission of (dis)advantage by creating societal circumstances that allow all children to develop to their full potential.

Intergenerational transmission of health inequalities: research agenda for a life course approach to socioeconomic inequalities in health

Explanations for socioeconomic inequalities in adult health are usually sought in behaviours and environments in adulthood. Yet, there is compelling evidence that the first two decades of life contribute substantially to both adult socioeconomic position (SEP) and adult health. This has implications for explanatory health inequalities research.We propose an analytical framework to advance research on the intergenerational transmission of health inequalities, that is, on intergenerational transmission of socioeconomic and associated health (dis)advantages at the family level, and its contribution to health inequalities at the population level. The framework distinguishes three transmission pathways: (1) intergenerational transmission of SEP, with effects on offspring health fully mediated by offspring SEP; (2) intergenerational transmission of health problems affecting SEP and (3) intergenerational transmission of both SEP and health, without a causal relationship between offspring adult SEP and health. We describe areas for future research along this framework and discuss the challenges and opportunities to advance this field.

Do health literacy, physical health and past rehabilitation utilization explain educational differences in the subjective need for medical rehabilitation? Results of the lidA cohort study

BACKGROUND

Medical rehabilitation can be helpful for maintaining workers' health and work ability. Its contribution to longer working lives is of high economic relevance in aging populations. In Germany, individuals must apply for rehabilitative measures themselves. Therefore, the subjective need for rehabilitation (SNR) is a prerequisite for rehabilitation access. A low education level is associated with poor health, lower health literacy and more frequent utilization of health services. In the present study, we investigated whether lower educational levels are also associated with a greater SNR and whether health literacy, past rehabilitation utilization and physical health play a mediating role in this path in older employees.

METHODS

3,130 socially insured older employees (born in 1959 or 1965) who participated in the German prospective lidA (leben in der Arbeit) cohort-study in 2011, 2014 and 2018 were included. A causal mediation analysis with an inverse odds weighting approach was performed with the SNR as the dependent variable; educational level as the independent variable; and health, health literacy and past rehabilitation utilization as the mediating variables. Sociodemographic variables were adjusted for.

RESULTS

The SNR was significantly greater in subjects with a low education level, poor physical health, inadequate health literacy and those who had utilized rehabilitation in the past. For health literacy, past rehabilitation utilization and physical health, a significant partial mediating effect on the SNR was found for employees with low compared to those with high education levels. However, the combined mediating effect of all the mediators was lower than the sum of their individual effects. Among those with medium or high education levels, none of the variables constituted a significant mediator.

CONCLUSIONS

The path between a low education level and a high SNR is mediated by inadequate health literacy, past rehabilitation utilization and poor physical health; these factors do not act independently of each other. Promoting health education may lower the SNR by improving physical health and health literacy. While improving physical health is beneficial for individuals, improved health literacy can be economically advantageous for the health system by reducing inappropriate expectations of rehabilitation benefits and subsequent applications for rehabilitation.

Does adult socioeconomic status mediate the relationship between adolescent socioeconomic status and adult quality of life?

Objective

This study aimed to determine the association between adolescent socioeconomic status (father's education and adolescent subjective socioeconomic status) and adult quality of life and the mediation roles of adult socioeconomic status, social capital and lifestyle (physical activity and exposure to smoke) among the "Tehran University of Medical Sciences Employees Cohort (TEC) Study" participants.

Method

Data of 4455 participants were derived from the Tehran University of Medical Sciences Employees Cohort (TEC) Study. In this study, the World Health Organization quality of life-BREF, the World Bank's Integrated and the International Physical Activity Questionnaire were used. Data were analyzed with structural equation modeling using SPSS Amos 24.0 program.

Results

The mean age of the participants was 42.31 years (SD: 8.37) and most of the subjects were female (60.7%). Correlation analysis results revealed that, quality of life had a significant and positive association with adolescent subjective socioeconomic status (r = 0.169, p < 0.01) and father's education (r = 0.091, p < 0.01). A mediation model testing the direct relationship between adolescent socioeconomic status and adult socioeconomic status and quality of life, showed a positive relationship between adolescent subjective socioeconomic status (β = 0.229, p < 0.001) and father's education (β = 0.443, p < 0.001) with adult socioeconomic status. Adult socioeconomic status was positively related to quality of life (β = 0.205, p < 0.001). Adult socioeconomic status mediated the relationship between adolescent subjective socioeconomic status (β = 0.047, p < 0.01) and father's education (β = 0.091, p < 0.01) with quality of life. While adult socioeconomic status fully mediated the relationship between the father's education and quality of life, it partially mediated the adolescent subjective socioeconomic status-quality of life association. Other variables such as social capital and lifestyle did not have mediator role in a mediation model.

Conclusion

This study provides the evidence for the role of adult socioeconomic status as a partial mediator between adolescent subjective socioeconomic status and quality of life. Therefore, there are several unknown mediators other than adult socioeconomic status that need to be explored in future studies.

Association of trauma, post-traumatic stress disorder and non-affective psychosis across the life course: a nationwide prospective cohort study

BACKGROUND

We aimed to examine the temporal relationships between traumatic events (TE), post-traumatic stress disorder (PTSD) and non-affective psychotic disorders (NAPD).

METHODS

A prospective cohort study of 1 965 214 individuals born in Sweden between 1971 and 1990 examining the independent effects of interpersonal and non-interpersonal TE on incidence of PTSD and NAPD using data from linked register data (Psychiatry-Sweden). Mediation analyses tested the hypothesis that PTSD lies on a causal pathway between interpersonal trauma and NAPD.

RESULTS

Increasing doses of interpersonal and non-interpersonal TE were independently associated with increased risk of NAPD [linear-trend incidence rate ratios (IRR)_adjusted = 2.17 [95% confidence interval (CI) 2.02-2.33] and IRR_adjusted = 1.27 (95% CI 1.23-1.31), respectively]. These attenuated to a relatively small degree in 5-year time-lagged models. A similar pattern of results was observed for PTSD [linear-trend IRR_adjusted = 3.43 (95% CI 3.21-3.66) and IRR_adjusted = 1.45 (95% CI 1.39-1.50)]. PTSD was associated with increased risk of NAPD [IRR_adjusted = 8.06 (95% CI 7.23-8.99)], which was substantially attenuated in 5-year time-lagged analyses [IRR_adjusted = 4.62 (95% CI 3.65-5.87)]. There was little evidence that PTSD diagnosis mediated the relationship between interpersonal TE and NAPD [IRR_adjusted = 0.92 (percentile CI 0.80-1.07)].

CONCLUSION

Despite the limitations to causal inference inherent in observational designs, the large effect-sizes observed between trauma, PTSD and NAPD in this study, consistent across sensitivity analyses, suggest that trauma may be a component cause of psychotic disorders. However, PTSD diagnosis might not be a good proxy for the likely complex psychological mechanisms mediating this association.

Is prosocial behaviour a missing link between green space quality and child health-related outcomes?

BACKGROUND

This study aimed to investigate prosocial behaviour-those behaviours that benefit others or enhance relationships with others-as a mediator of the associations between green space quality and child health-related outcomes (physical activity, mental health, and health-related quality of life (HRQOL)).

METHODS

This study involved data from 4983 children with 10-year follow-up (2004-2014) retrieved from the Longitudinal Study of Australian Children. Green space quality (the exposure), prosocial behaviour (the candidate mediator), and child health-related outcomes were assessed biennially based on caregiver reports. Causal mediation analysis was used, with four mediation models developed for each outcome.

RESULTS

Mediation by prosocial behaviour appeared in the late childhood mediation model with higher mediation proportions reported compared to models of earlier and middle childhood. Prosocial behaviour had moderate mediation consistency for the association between green space quality and physical activity enjoyment, but no mediation was evident for other physical activity variables. Prosocial behaviour had low mediation consistency for child mental health (internalising and externalising subscales). Similarly, low mediation consistency of prosocial behaviour was also evident for all HRQOL variables, such as physical, emotional, social, school functioning, psychosocial health, and total quality of life (QOL).

CONCLUSION

Prosocial behaviour partially mediated the association between green space quality and child health-related outcomes (physical activity enjoyment, mental health, and HRQOL). Improving the quality of neighbourhood green space that supports the development of prosocial behaviour may result in better child health-related outcomes. Other physical activity variables might not specifically relate to social interactions, and therefore, no mediation by prosocial behaviour was apparent.

Childhood Socioeconomic Position and Risk of Cardiovascular Disease in Adulthood: Systematic Review of Evidence From Low- and Middle-Income Countries

INTRODUCTION

Socioeconomic disadvantage in childhood is strongly associated with a higher risk of cardiovascular disease in high-income countries. However, the association in low- and middle-income countries, where childhood poverty remains prevalent, has not been reviewed.

METHODS

The authors systematically searched Embase, MEDLINE, and Global Health databases for articles on the association between childhood socioeconomic position and risk of cardiovascular disease in adulthood in low- and middle-income countries until September 2020. Outcomes included measures of cardiovascular disease, its subclinical markers (e.g., carotid intima-media thickness), and its major risk factors (e.g., hypertension, dyslipidemia, diabetes). Where available, associations were extracted before and after adjustment for socioeconomic position in adulthood. Results were synthesized qualitatively by outcome. The study protocol is registered on PROSPERO (CRD42018086984).

RESULTS

The search returned 3,568 unique abstracts, from which 29 eligible articles from 14 middle-income countries were identified, representing >150,000 participants. The most commonly reported outcomes were cardiovascular risk factors; very few studies reported prevalent measures of cardiovascular disease, and no studies reported cardiovascular disease incidence or mortality. Of the 46 reported associations between childhood socioeconomic position and risk of cardiovascular disease, 8 were inverse, 0 were positive, and 38 showed no clear evidence of association. All articles had high (16/29) or medium (13/29) risk of bias.

CONCLUSIONS

Current evidence from middle-income countries provides little support for an association between childhood socioeconomic position and risk of cardiovascular disease, and evidence from low-income countries is lacking. It would be premature to consider childhood poverty as a target for cardiovascular disease prevention in these settings.

Cross-sectional analysis of educational inequalities in primary prevention statin use in UK Biobank

Objective

Identify whether participants with lower education are less likely to report taking statins for primary cardiovascular prevention than those with higher education, but an equivalent increase in underlying cardiovascular risk.

Methods

Using data from a large prospective cohort study, UK Biobank, we calculated a QRISK3 cardiovascular risk score for 472 097 eligible participants with complete data on self-reported educational attainment and statin use (55% female participants; mean age 56 years). We used logistic regression to explore the association between (i) QRISK3 score and (ii) educational attainment on self-reported statin use. We then stratified the association between QRISK3 score and statin use, by educational attainment to test for interactions.

Results

There was evidence of an interaction between QRISK3 score and educational attainment. Per unit increase in QRISK3 score, more educated individuals were more likely to report taking statins. In women with ≤7 years of schooling, a one unit increase in QRISK3 score was associated with a 7% higher odds of statin use (OR 1.07, 95% CI 1.07 to 1.07). In women with ≥20 years of schooling, a one unit increase in QRISK3 score was associated with an 14% higher odds of statin use (OR 1.14, 95% CI 1.14 to 1.15). Comparable ORs in men were 1.04 (95% CI 1.04 to 1.05) for ≤7 years of schooling and 1.08 (95% CI 1.08, 1.08) for ≥20 years of schooling.

Conclusion

Per unit increase in QRISK3 score, individuals with lower educational attainment were less likely to report using statins, likely contributing to health inequalities.

Associations between family social circumstances and psychological distress among the university students of Bangladesh: To what extent do the lifestyle factors mediate?

BACKGROUND

While there is a growing body of empirical studies focusing on the social and behavioral predictors of psychological health, the mechanisms that may underlie the reported associations have not been adequately explored. This study aimed to examine the association of social and lifestyle factors with psychological distress, and the potential mediating role of the lifestyle factors in the estimated associations between social circumstances and psychological distress.

METHODS

A total of 742 tertiary level students (53% females) from a range of socio-economic backgrounds and multiple educational institutions participated in this cross-sectional study. The 12-items General Health Questionnaire (GHQ-12) was utilized for measuring psychological distress. Data related to students' socio-demographic characteristics, family social circumstances, and lifestyle factors were also collected. Modified Poisson regression analysis was used to estimate the risk ratios (RR) and their 95% confidence intervals (CI).

RESULTS

The multivariable regression analysis suggests heightened risks of psychological distress associated with low parental Socio-Economic Position (SEP) (RR: 1.36; 95% CI: 1.07, 1.76), childhood poverty (RR: 1.31; 95% CI: 1.11, 1.55), and living away from the family (RR: 1.28; 95% CI: 1.07, 1.54). Among the lifestyle factors, past smoking, physical inactivity, inadequate fruit intake, and poor sleep quality were strongly associated with psychological distress and these associations persisted when the family social circumstances and lifestyle factors were mutually adjusted for. The lifestyle factors did not considerably mediate the estimated associations between family social circumstances and psychological distress.

CONCLUSION

The social and lifestyle factors operated independently to increase students' risk of psychological distress. Accordingly, while promoting students' healthy lifestyles may reduce the overall burden of psychological distress, any equity initiative aiming to minimize the social inequalities in psychological health should be targeted to improving the living conditions in early life.

Early life programming of adult ischemic heart disease within and across generations: The role of the socioeconomic context

BACKGROUND

The developmental origins of ischemic heart disease (IHD) have been widely documented but little is known about their persistence across more than one generation. This study aimed to investigate whether the effects of early life disadvantages on adult IHD have changed between generations and are mediated by adult socioeconomic circumstances, and further explore the transgenerational effects of grandparental and parental exposures to disadvantaged circumstances on adult offspring's IHD.

METHODS

We used register-based data from the Uppsala Multigenerational Study, Sweden. The study populations were the parents born 1915-1929 and their offspring born 1932-1972 with available obstetric data. The offspring were further linked to grandparents who had their socioeconomic and demographic data recorded. The outcome was incident IHD assessed at ages 32-75 during a follow-up from January 1, 1964 till December 31, 2008. The exposures included birthweight standardized-for-gestational age, ponderal index, gestational length, and parental socioeconomic position (SEP). Education and income were analyzed as mediators. Potential transgenerational associations were explored by linking offspring IHD to parents' standardized birthweight and gestational length, grandparental SEP, and to grandmothers' age, parity, and marital status at parental birth. All associations were examined in Cox proportional hazard regression models.

RESULTS

Lower standardized birthweight and lower parental SEP were found to be associated with higher IHD rates in both generations, with no evidence of effect modification by generation. Education and income did not mediate the association between standardized birthweight and IHD. Disadvantaged grandparental SEP, younger and older childbearing ages of grandmothers, and paternal preterm birth affected offspring's IHD independent of parental education, income, or IHD history.

CONCLUSIONS

The findings point to similar magnitudes of IHD inequalities by early life disadvantages across two historical periods and the existence of transgenerational effects on IHD. Epigenetic dysregulation involving the germline is a plausible candidate mechanism underlying the transgenerational associations that warrant further research.

Preeclampsia Mediates the Association between Advanced Maternal Age and Adverse Pregnancy Outcomes: A Structural Equation Modeling Approach

BACKGROUND

Advanced maternal age (AMA) is considered a risk factor associated with preeclampsia and adverse pregnancy outcomes. We aimed to assess the mediating role of preeclampsia between AMA and adverse pregnancy outcomes.

METHODS

A sample of 14646 pregnant women from the tertiary hospital of Hubei Province, China, during the years 2011-2017 were included in this study. Pregnant women were divided into 4 groups according to their age at delivery. Mediated effect of preeclampsia with relation to AMA and adverse pregnancy outcomes was measured using structural equation modeling.

RESULTS

Women in the highest age group were significantly associated with preterm delivery [RR 1.37 (95% CI 1.24 - 1.49)] and low birth weight [RR 1.28 (95% CI 1.11 - 1.45)] compared with women in the lowest age group. The indirect effect (mediated effect) of AMA on preterm delivery and low birth weight mediated by preeclampsia was [β 0.053 (95% CI: 0.047, 0.060)], and [β 0.045 (95% CI: 0.038, 0.052)], respectively. The estimated mediation proportion of the effect of AMA due to mediated effect of preeclampsia was (35.5%) for pre-term delivery and (23.5%) for low birth weight.

CONCLUSION

Preeclampsia partially mediates the association between AMA and adverse pregnancy outcomes.