Using marginal structural models to estimate the direct effect of adverse childhood social conditions on onset of heart disease, diabetes, and stroke

Racial Differences in Fatal Out-of-Hospital Coronary Heart Disease and the Role of Income in the Atherosclerosis Risk in Communities Cohort Study (1987 to 2017)

Black patients have higher incident fatal coronary heart disease (CHD) rates than do their White counterparts. Racial differences in out-of-hospital fatal CHD could explain the excess risk in fatal CHD among Black patients. We examined racial disparities in in- and out-of-hospital fatal CHD among participants with no history of CHD, and whether socioeconomic status might play a role in this association. We used data from the ARIC (Atherosclerosis Risk in Communities) study, including 4,095 Black and 10,884 White participants, followed between 1987 and 1989 until 2017. Race was self-reported. We examined racial differences in in- and out-of-hospital fatal CHD with hierarchical proportional hazard models. We then examined the role of income in these associations, using Cox marginal structural models for a mediation analysis. The incidence of out-of-hospital and in-hospital fatal CHD was 1.3 and 2.2 in Black participants, and 1.0 and 1.1 in White participants, respectively, per 1,000 person-years. The gender- and age-adjusted hazard ratios comparing out-of-hospital and in-hospital incident fatal CHD in Black with that in White participants were 1.65 (1.32 to 2.07) and 2.37 (1.96 to 2.86), respectively. The income-controlled direct effects of race in Black versus White participants decreased to 1.33 (1.01 to 1.74) for fatal out-of-hospital and to 2.03 (1.61 to 2.55) for fatal in-hospital CHD in Cox marginal structural models. In conclusion, higher rates of fatal in-hospital CHD in Black participants than in their White counterparts likely drive the overall racial differences in fatal CHD. Income largely explained racial differences in both fatal out-of-hospital CHD and fatal in-hospital CHD.

In utero Exposure to Maternal Diabetes and the Risk of Cerebral Palsy: A Population-based Cohort Study

BACKGROUND

Evidence on the effects of in utero exposure to maternal diabetes on cerebral palsy (CP) in offspring is limited. We aimed to examine the effects of pregestational (PGDM) and gestational diabetes (GDM) separately on CP risk and the mediating role of increased fetal size.

METHODS

In a population-based study, we included all live births in Ontario, Canada, between 2002 and 2017 followed up through 2018 (n = 2,110,177). Using administrative health data, we estimated crude and adjusted associations between PGDM or GDM and CP using Cox proportional hazards models to account for unequal follow-up in children. For the mediation analysis, we used marginal structural models to estimate the controlled direct effect of PGDM (and GDM) on the risk of CP not mediated by large-for-gestational age (LGA).

RESULTS

During the study period, 5,317 children were diagnosed with CP (187 exposed to PGDM and 171 exposed to GDM). Children of mothers with PGDM showed an increased risk (hazard ratio [HR]: 1.84 [95% confidence interval (CI): 1.59, 2.14]) after adjusting for maternal sociodemographic and clinical factors. We found no associations between GDM and CP (adjusted HR: 0.91 [0.77, 1.06]). Our mediation analysis estimated that LGA explained 14% of the PDGM-CP association.

CONCLUSIONS

In this population-based birth cohort study, maternal pregestational diabetes was associated with increased risk of CP, and the increased risk was not substantially mediated by the increased fetal size.

Associations between life-course household wealth mobility and adolescent physical growth, cognitive development and emotional and behavioral problems: A birth cohort in rural western China

Background

Parental household wealth has been shown to be associated with offspring health conditions, while inconsistent associations were reported among generally healthy population especially in low- and middle- income countries (LMICs). Whether the household wealth upward mobility in LMICs would confer benefits to child health remains unknown.

Methods

We conducted a prospective birth cohort of children born to mothers who participated in a randomized trial of antenatal micronutrient supplementation in rural western China. Household wealth were repeatedly assessed at pregnancy, mid-childhood and early adolescence using principal component analysis for household assets and dwelling characteristics. We used conditional gains and group-based trajectory modeling to assess the quantitative changes between two single-time points and relative mobility of household wealth over life-course, respectively. We performed generalized linear regressions to examine the associations of household wealth mobility indicators with adolescent height- (HAZ) and body mass index-for-age and sex z score (BAZ), scores of full-scale intelligent quotient (FSIQ) and emotional and behavioral problems.

Results

A total of 1,188 adolescents were followed, among them 59.9% were male with a mean (SD) age of 11.7 (0.9) years old. Per SD conditional increase of household wealth z score from pregnancy to mid-childhood was associated with 0.11 (95% CI 0.04, 0.17) SD higher HAZ and 1.41 (95% CI 0.68, 2.13) points higher FSIQ at early adolescence. Adolescents from the household wealth Upward trajectory had a 0.25 (95% CI 0.03, 0.47) SD higher HAZ and 4.98 (95% CI 2.59, 7.38) points higher FSIQ than those in the Consistently low subgroup.

Conclusion

Household wealth upward mobility particularly during early life has benefits on adolescent HAZ and cognitive development, which argues for government policies to implement social welfare programs to mitigate or reduce the consequences of early-life deprivations. Given the importance of household wealth in child health, it is recommended that socioeconomic circumstances should be routinely documented in the healthcare record in LMICs.

A Causal Mediation Analysis for Investigating the Effect of a Randomized Cash-Transfer Program in Nicaragua

Mediation analysis can be applied to data from randomized trials of health and social interventions to draw causal inference concerning their mechanisms. We used data from a cluster-randomized trial in Nicaragua, fielded between 2000 and 2002, to investigate whether the impact of providing access to a conditional cash-transfer program on child nutritional outcomes was mediated by child health check-ups and household dietary diversity. In a sample of 443 children 6-35 months old, we estimated the controlled direct (CDE) effect of random assignment on measured height-for-age z scores had we intervened so that all children received a health check-up and had the same level of household dietary diversity, using inverse-probability weighted marginal structural models to account for mediator-outcome confounding. Sensitivity analyses corrected the CDE for potential nondifferential error in the measurement of dietary diversity. Treatment assignment increased height-for-age z score by 0.37 (95% CI: 0.05, 0.69) standard deviations. The CDE was 0.20 (95% CI: -0.17, 0.57) standard deviations, suggesting nearly one-half of the program's impact on child nutrition would be eliminated had we intervened on these factors, although estimates were relatively imprecise. This study provides an illustration of how causal mediation analysis can be applied to examine the mechanisms of multifaceted interventions.

Maternal smoking during pregnancy, offspring smoking, adverse childhood events, and risk of major depression: a sibling design study

BACKGROUND

Evidence of a biologically plausible association between maternal smoking during pregnancy (MSP) and the risk of depression is discounted by null findings from two sibling studies. However, valid causal inference from sibling studies is subject to challenges inherent to human studies of MSP and biases particular to this design. We addressed these challenges in the first sibling study of MSP and depression conducted among adults past the peak age for the onset of depression, utilizing a prospectively collected and biologically validated measure of MSP and accounting for non-shared as well as mediating factors.

METHODS

We fit GEE binomial regression models to correct for dependence in the risk of depression across pregnancies of the same mother. We also fit marginal structural models (MSM) to estimate the controlled direct effect of MSP on depression that is not mediated by the offspring's smoking status. Both models allow the estimation of within- and between-sibling risk ratios.

RESULTS

The adjusted within-sibling risk ratios (RR_W) from both models (GEE: RR_W = 1.97, CI 1.16-3.32; MSM: RR_W = 2.08, CI 1.04-4.17) evinced an independent association between MSP and risk of depression. The overall effects from a standard model evinced lower associations (GEE: RR_T = 1.12, CI 0.98-1.28; MSM: RR_T = 1.18, CI 1.01-1.37).

CONCLUSIONS

Based on within-sibling information free of unmeasured shared confounders and accounting for a range of unshared factors, we found an effect of MSP on the offspring's risk of depression. Our findings, should they be replicated in future studies, highlight the importance of considering challenges inherent to human studies of MSP and affective disorders.

Childhood neighborhoods and health: Census-based neighborhood measures versus residential lived experiences

This study examines the impact of neighborhood disadvantage and neighborhood social connectedness during childhood on subsequent health status during early adulthood. We link longitudinal data from the Panel Study of Income Dynamics with Census data on children's surrounding neighborhoods. We estimate results with conventional linear regression and novel methods that better adjust for neighborhood selection processes. We find that neighborhood connectedness in childhood is protective against psychological distress in early adulthood, net of selection effects. However, greater connectedness exacerbates the risk of obesity within disadvantaged contexts for Black youth. Our results highlight a potential pathway for improving population health by investing in the social connectedness of neighborhoods alongside reducing structural inequalities.

Racial Disparities in Hospitalization Among Patients Who Receive a Diagnosis of Acute Coronary Syndrome in the Emergency Department

Background Timely hospitalization of patients who are diagnosed with an acute coronary syndrome (ACS) at the emergency department (ED) is a crucial step to lower the risk of ACS mortality. We examined whether there are racial and ethnic differences in the risk of being discharged home among patients who received a diagnostic code of ACS at the ED and whether having health insurance plays a role. Methods and Results We examined 51 022 910 discharge records of ED visits in Florida, New York, and Utah in the years 2008, 2011, 2014, and 2016/2017 using state-specific data from the Healthcare Cost and Utilization Project. We identified ED admissions for acute myocardial infarction or unstable angina using the International Classification of Diseases, Ninth Revision (ICD-9)/International Statistical Classification of Diseases, Tenth Revision (ICD-10) diagnostic codes. We used generalized estimating equation models to compare the risk of being discharged home across racial and ethnic groups. We used Poisson marginal structural models to estimate the mediating role of health insurance status. The proportion discharged home with a diagnostic code of ACS was 12% among Black patients, 6% among White patients, 9% among Hispanic patients, and 9% among Asian/Pacific Islander patients. The incidence risk ratio for being discharged home was 1.26 (95% CI, 1.18-1.34) in Black patients, 1.23 (95% CI, 1.15-1.32) in Hispanic patients, and 1.11 (95% CI, 0.93-1.31) in Asian/Pacific Islander patients compared with White patients. Race and ethnicity were marginally associated with discharge home via pathways not mediated by health insurance. Conclusions Racial and ethnic disparities exist in the hospitalization of patients who received a diagnostic code of ACS in the ED. Possible causes need to be investigated.

Early-life exposure to Chinese famine and stroke risk in mid- to late life: the mediating roles of cognitive function and depression

BACKGROUND

Limited research has examined the role that famine exposure plays in adulthood stroke risk. We aim to explore the causal implications of early exposure to the Great Chinese Famine on stroke risk and determine whether these associations were mediated by cognitive function, and depression.

METHODS

We sampled 12,681 individuals aged 45 years and older from the China Health and Retirement Longitudinal Study (CHARLS) and divided them into fetally exposed, childhood-exposed, adolescence/adulthood-exposed and unexposed groups. Stroke was defined by self- or proxy-reported physician diagnosis. Based on a counterfactual framework, marginal structural models were used to estimate the natural direct effect and the natural indirect effects through cognitive function and depression for causal inference.

RESULTS

We found that early-life exposure to Chinese famine was directly related to increased stroke risk in mid- to late life. Cognitive function and depression accounted for a greater part of the effect for childhood famine exposure, mediating 36.35% (95%CI: 14.19, 96.19%) of the overall association between famine exposure and incident stroke, than for the fetal, adolescence/adulthood famine exposure groups. However, the natural indirect effect through depression was not significant in the fetally exposed group. The results were robust in the sensitivity analysis of model specification and unobserved confounding.

CONCLUSIONS

Our findings are consistent with the latency, pathway, and accumulation models, supporting the life-course theory. Early stages of life exposed to the Chinese Famine were associated with higher risk of stroke in mid- to late life. Enhanced cognitive and depression interventions may reduce stroke risk in middle-aged and older Chinese adults who exposure to famine in early life.

Adverse Childhood Experiences in Patients With Neurologic Disease

Background and Objectives

To describe the prevalence of high adverse childhood experiences (ACEs) among neurology outpatients and determine their association with health care utilization rates and comorbid medical and psychiatric disease.

Methods

This was a cross-sectional study of adults seen for outpatient neurology follow-up at the University of Pennsylvania. Participants completed the ACE questionnaire and depression/anxiety screenings. Health care utilization metrics (emergency department [ED] visits, hospitalizations, and outpatient calls) were obtained for all participants. High ACE scores were defined as a score of ≥4. The prevalence of high ACE scores in our cohort was compared with US historical controls. Statistical associations were adjusted for age, sex, and race/ethnicity.

Results

One hundred ninety-eight patients were enrolled in the study. Neurology patients were more likely to have elevated ACE scores compared with US population estimates (23.7% vs 12.6%, p < 0.01). High ACE scores were associated with increased ED utilization (odds ratio [OR] = 21, 95% CI [5.8-76.0], p < 0.01), hospitalizations (OR = 5.2, 95% CI [1.7-15.0], p < 0.01), and telephone encounters (OR 3, 95% CI [1.1-8.2], p < 0.05). High ACEs were also associated with medical and psychiatric comorbidities (OR 5.8, 95% CI [2.0-17.0], p < 0.01 and OR 4.5, 95% CI [2.1-9.6], p < 0.01) and high depression and anxiety scores (OR = 6.9, 95% CI [2.8-17.0], p < 0.01, and OR = 4.3, [95% CI 1.7-11.0], p < 0.01).

Discussion

Patients with neurologic conditions are more likely to have high ACEs than the US population, which was associated with higher rates of health care utilization, increased number of medical and psychiatric comorbidities, and higher anxiety and depression scores. Addressing ACEs may be a way to improve the health outcomes of patients with neurologic conditions.

Marginal Structural Models for Life-Course Theories and Social Epidemiology: Definitions, Sources of Bias, and Simulated Illustrations

Social epidemiology aims to identify social structural risk factors, thus informing targets and timing of interventions. Ascertaining which interventions will be most effective and when they should be implemented is challenging because social conditions vary across the life course and are subject to time-varying confounding. Marginal structural models (MSMs) may be useful but can present unique challenges when studying social epidemiologic exposures over the life course. We describe selected MSMs corresponding to common theoretical life-course models and identify key issues for consideration related to time-varying confounding and late study enrollment. Using simulated data mimicking a cohort study evaluating the effects of depression in early, mid-, and late life on late-life stroke risk, we examined whether and when specific study characteristics and analytical strategies may induce bias. In the context of time-varying confounding, inverse-probability-weighted estimation of correctly specified MSMs accurately estimated the target causal effects, while conventional regression models showed significant bias. When no measure of early-life depression was available, neither MSMs nor conventional models were unbiased, due to confounding by early-life depression. To inform interventions, researchers need to identify timing of effects and consider whether missing data regarding exposures earlier in life may lead to biased estimates.

The role of ideation on the effect of an SBC intervention on consistent bed net use among caregivers of children under 5 years in Nigeria: a multilevel mediation analysis

Background

Malaria remains a significant public health challenge in Nigeria. Consistent bed net use (sleeping under a treated net every night) has been identified as a key malaria prevention behavior. This paper explores the relationship between mass media social and behavior change interventions, psychosocial factors, and consistent bed net use.

Methods

Data is from the endline survey of a USAID-funded social and behavior change communication campaign conducted from 2012 to 2017 across five states in Nigeria. The outcome measure was consistent bed net use, and the mediator variable was a composite measure called ideation from a set of psychosocial factors believed to influence bed net use. The independent variable was recall of malaria specific media messages. Multilevel mediation analysis explored if recall of malaria specific media messages had any effect on bed net related ideation and if this ideation had any effect on consistent net use.

Results

Respondents included in this study were on average aged 31 years, mostly married or cohabiting (97.5%) and female 75%. Four in 10 (39.7%) respondents were able to recall malaria specific messages. Respondents with low, moderate and high recall were 23, 32 and 80% more likely to have a higher ideational score in the emotional domain compared to those not able to recall. Respondents were more likely to have higher ideational scores in the cognitive domain if they had low (AOR = 1.26, 95% CI 1.15–1.38), moderate (AOR = 1.16, 95% CI 1.00–1.34) or high recall (AOR = 1.55, 95% CI 1.16–2.06), respectively compared to those with no recall. Similarly, respondents with low (AOR = 1.03, 95% CI .99–1.08), moderate (AOR = 1.15, 95% CI 1.08–1.23) and high (AOR = 1.15, 95% CI 1.01–1.30) recall were more likely to have a higher ideational score in the social domain compared to those with no recall. After adjusting for recall of media messages and other potential covariates, all three ideational domains also had a significant positive effect on consistent bed net use. For every unit increase in ideational score, the likelihood of reporting consistent bed net use increased by 5 to 10%. There was a significant indirect effect of recalling malaria specific messages on consistent bed net use through each of the ideational domains.

Conclusion

Access to a bed net is a critical first step in the process of bed net utilization. However, psychosocial factors e.g., emotional, cognitive, and social domains of ideation also play a major role in bed net use. Mass media SBC interventions could potentially influence bed net related ideation and consequently improve net use behavior. Future Social and behavior change interventions should employ approaches that improve these domains of ideation within their audiences in order to increase bed net utilization.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12889-021-11709-5.

Cohort and Period Effects as Explanations for Declining Dementia Trends and Cognitive Aging

Studies have reported that the age-adjusted incidence of cognitive impairment and dementia may have decreased over the past two decades. Aging is the predominant risk factor for Alzheimer's disease and related dementias and for neurocognitive decline. However, aging cannot explain changes in overall age-adjusted incidence of dementia. The objective of this position paper was to describe the potential for cohort and period effects in cognitive decline and incidence of dementia. Cohort effects have long been reported in demographic literature, but starting in the early 1980s, researchers began reporting cohort trends in cognitive function. At the same time, period effects have emerged in economic factors and stressors in early and midlife that may result in reduced cognitive dysfunction. Recognizing that aging individuals today were once children and adolescents, and that research has clearly noted that childhood cognitive performance is a primary determinant of old-age cognitive performance, this is the first study that proposes the need to connect known cohort effects in childhood cognition with differences in late-life functioning.

Adverse childhood experiences and adult cardiometabolic risk factors and disease outcomes: Cross-sectional, population-based study of adults in rural Uganda

Background

Cardiovascular diseases (CVD) pose a major threat to public health in sub-Saharan African communities, where the burden of these classes of illnesses is expected to double by 2030. Growing research suggests that past developmental experiences and early life conditions may also elevate CVD risk throughout the life course. Greater childhood stress and adversity are consistently associated with a range of adult CVDs and associated risk factors, yet little research exists on the long-term effects of early life stress on adult physical health outcomes, especially CVD risk, in sub-Saharan African contexts. This study aims to evaluate the associations between adverse childhood experiences and adult cardiometabolic risk factors and health outcomes in a population-based study of adults living in Mbarara, a rural region of southwestern Uganda.

Methods

Data come from an ongoing, whole-population social network cohort study of adults living in the eight villages of Nyakabare Parish, Mbarara. A modified version of the Adverse Childhood Experiences-International Questionnaire (ACEs) assessed past exposure to physical, emotional, and sexual adversity. Participants also took part in a health fair where medical histories on cardiometabolic risk factors and cardiovascular diseases were gathered. Multiple logistic regression models estimated the associations between ACEs and cardiometabolic risk factors and health outcomes.

Results

Data were available on 545 adults. The average number of ACEs was 4.9 out of a possible 16. The cumulative number of ACEs were associated with having a history of heart attack and/or heart failure (adjusted odds ratio (AOR) = 1.11, 95% confidence interval (CI) = 0.999-1.234, P = 0.051), but the estimated association was not statistically significant. ACEs did not have statistically significant associations with any others measures of adult cardiometabolic risk and CVD.

Conclusions

Adverse childhood experiences are not associated with a range of adult cardiometabolic risk factors and health outcomes in this sample of rural Ugandan adults. Further research in this sample is necessary to identify the pathways that may motivate these null relationship and possibly protect against adverse cardiometabolic and cardiovascular health outcomes.

Life-course pathways from childhood socioeconomic status to type 2 diabetes in mid-late Chinese adulthood

The relationship between childhood socioeconomic status (SES) and type 2 diabetes (T2D) remains inconclusive, and the pathways and mechanisms driving this relationship have yet to be clarified. This study aimed to examine the pathways linking childhood SES to T2D prevalence in mid-late adulthood in a low- and middle-income country. The incidence of T2D diagnosed in mid-late Chinese adulthood was assessed using self-reports from the Health and Retirement Longitudinal Study (CHARLS). Childhood SES was assessed by the education, occupation, survivorship of the parents and the financial situation of the family, whereas adulthood SES was assessed by education and wage. This study performed structural equation modeling to clarify the direct and indirect pathways from childhood SES to T2D via childhood health, childhood food shortage, adulthood SES and physical activity. A total of 15,132 participants were included, and the prevalence of T2D was 5.24%. This study found that childhood SES was directly associated with T2D in mid-late adulthood, the probability of developing T2D increased by 9.20% of the standard deviation for each decrease in standard deviation in childhood SES. Childhood SES was indirectly associated with T2D via adulthood SES, physical activity, childhood health and food shortage. Adulthood SES and physical activity mainly mediated the indirect pathway from childhood SES and T2D. This study showed direct and indirect pathways from disadvantaged childhood SES to increased risk of T2D in mid-late Chinese adulthood. Childhood SES, adulthood SES, physical activity, childhood health and food shortage were identified as life-course interventional targets that should be considered in the development of effective strategies to reduce the burden of T2D and SES-related health inequities in childhood.

Does the Temporal Pattern of Moving to a Higher-Quality Neighborhood Across a 5-Year Period Predict Psychological Distress Among Adolescents? Results From a Federal Housing Experiment

Using data from the Moving to Opportunity (MTO) experiment (1994-2002), this study examined how a multidimensional measure of neighborhood quality over time influenced adolescent psychological distress, using instrumental variable (IV) analysis. Neighborhood quality was operationalized with the independently validated 19-indicator Child Opportunity Index (COI), linked to MTO family addresses over 4-7 years. We examined whether being randomized to receive a housing subsidy (versus remaining in public housing) predicted neighborhood quality across time. Using IV analysis, we tested whether experimentally induced differences in COI across time predicted psychological distress on the Kessler Screening Scale for Psychological Distress (n = 2,829; mean β = -0.04 points (standard deviation, 1.12)). The MTO voucher treatment improved neighborhood quality for children as compared with in-place controls. A 1-standard-deviation change in COI since baseline predicted a 0.32-point lower psychological distress score for girls (β = -0.32, 95% confidence interval: -0.61, -0.03). Results were comparable but less precisely estimated when neighborhood quality was operationalized as simply average post-random-assignment COI (β = -0.36, 95% confidence interval: -0.74, 0.02). Effect estimates based on a COI excluding poverty and on the most recent COI measure were slightly larger than other operationalizations of neighborhood quality. Improving a multidimensional measure of neighborhood quality led to reductions in low-income girls' psychological distress, and this was estimated with high internal validity using IV methods.

Early Life Exposure to Food Contaminants and Social Stress as Risk Factor for Metabolic Disorders Occurrence?-An Overview

The global prevalence of obesity has been increasing in recent years and is now the major public health challenge worldwide. While the risks of developing metabolic disorders (MD) including obesity and type 2 diabetes (T2D) have been historically thought to be essentially driven by increased caloric intake and lack of exercise, this is insufficient to account for the observed changes in disease trends. Based on human epidemiological and pre-clinical experimental studies, this overview questioned the role of non-nutritional components as contributors to the epidemic of MD with a special emphasis on food contaminants and social stress. This overview examines the impact of early life adverse events (ELAE) focusing on exposures to food contaminants or social stress on weight gain and T2D occurrence in the offspring and explores potential mechanisms leading to MD in adulthood. Indeed, summing up data on both ELAE models in parallel allowed us to identify common patterns that appear worthwhile to study in MD etiology. This overview provides some evidence of a link between ELAE-induced intestinal barrier disruption, inflammation, epigenetic modifications, and the occurrence of MD. This overview sums up evidence that MD could have developmental origins and that ELAE are risk factors for MD at adulthood independently of nutritional status.

Is the effect of Mediterranean diet on hip fracture mediated through type 2 diabetes mellitus and body mass index?

BACKGROUND

We examined whether the inverse association between adherence to a Mediterranean diet and hip fracture risk is mediated by incident type 2 diabetes mellitus (T2DM) and body mass index (BMI).

METHODS

We included 50 755 men and women from the Cohort of Swedish Men and the Swedish Mammography Cohort who answered lifestyle and medical questionnaires in 1997 and 2008 (used for calculation of the Mediterranean diet score 9mMED; low, medium, high) and BMI in 1997, and incident T2DM in 1997-2008). The cumulative incidence of hip fracture from the National Patient Register (2009-14) was considered as outcome.

RESULTS

We present conditional odds ratios (OR) 9[95% confidence interval, CI) of hip fracture for medium and high adherence to mMED, compared with low adherence. The total effect ORs were 0.82 (0.71, 0.95) and 0.75 (0.62, 0.91), respectively. The controlled direct effect of mMED on hip fracture (not mediated by T2DM, considering BMI as an exposure-induced confounder), calculated using inverse probability weighting of marginal structural models, rendered ORs of 0.82 (0.72, 0.95) and 0.73 (0.60, 0.88), respectively. The natural direct effect ORs (not mediated by BMI or T2DM, calculated using flexible mediation analysis) were 0.82 (0.71, 0.95) and 0.74(0.61, 0.89), respectively. The path-specific indirect and partial indirect natural effects ORs (through BMI or T2DM) were close to 1.

CONCLUSIONS

Mediterranean diet has a direct effect on hip fracture risk via pathways other than through T2DM and BMI. We cannot exclude mediating effects of T2DM or BMI, or that their effects cancel each other out.

Social inequalities, debt, and health in the United States

Background

Household financial debt has more than tripled since the 1980s in the United States. The experience of indebtedness is socially structured and there is mounting evidence that debt is linked to decrements in health. However, it is unclear whether debt contributes to social disparities in health.

Objective

We examined whether household debt, measured by debt in excess of income and wealth, mediated education-based social inequalities in health, including cardiovascular risk factors (hypertension) and chronic conditions (diabetes, coronary heart disease, and psychiatric problems).

Method

We used longitudinal data from a sample of over 10,500 adults aged 18 years and older surveyed biennially between 1999 and 2015 as part of the Panel Study of Income Dynamics (PSID). We estimated the total effect of education on our health outcomes. To assess mediation by levels of household debt, we then estimated the controlled direct effect of education through pathways not mediated by levels of household debt, after accounting for lagged time-varying confounders and loss to follow-up using marginal structural models.

Results

Compared to respondents with at least a high school education, respondents with less than a high school education reported higher household debts in excess of income and wealth; they also reported a higher incidence of hypertension [risk ratio (RR) = 1.25, 95%CI = 1.13, 1.39), coronary heart disease (RR = 1.42, 95%CI: 1.25, 1.62), diabetes (RR = 1.50, 95%CI: 1.34, 1.68), and psychiatric problems (RR = 1.39, 95%CI: 1.24, 1.56). Compared to the total effects, the controlled direct effects of education on health were attenuated, particularly for death or first onset of hypertension and coronary heart disease, after fixing levels of household debt-to-income and debt-to-wealth.

Conclusion

Our results provide early evidence that household debt in excess of wealth partly mediates education-based inequalities in hypertension and coronary heart disease in the United States, with less consistent evidence for other chronic conditions.

The effect of early-life and adult socioeconomic position on development of lifestyle-related diseases

BACKGROUND

Early-life socioeconomic position (SEP) is associated with lifestyle-related diseases in adulthood. However, evidence is lacking on the extent to which adult SEP mediates this association.

METHODS

Time to either chronic obstructive pulmonary disease (COPD), cardiovascular disease or diabetes were assessed in the Danish population born between 1961 and 1971 (n = 793 674) from age 30 until 2015. Early-life position was assessed in 1981 (by parental) and again at age 30 (own) by four markers; income, occupation, education-divided into high, middle, low-and a combined score for all markers. Using a counterfactual approach, we estimated the total effect of early-life position on disease onset and the degree to which adult position mediated this effect.

RESULTS

Results of the time-to-event analysis showed a gradient of all early-life markers on the risk of developing all lifestyle-related diseases. Notably, comparing those in the lowest to the highest educational position, the hazard of COPD was 130% higher for women [hazard ratio = 2.30(95% confidence interval = 2.20-2.41)] and 114% higher for men [2.14 (2.05-2.25)]. About 67%(63-70%) of the effect of educational position was mediated through adult position for COPD, 55% for cardiovascular disease and 50% for diabetes. For the combined score 44, 29 and 33%, respectively, was mediated.

CONCLUSION

About one-tenth to two-thirds of the effect of early-life position is mediated by the position attained in adulthood. The degree mediated depend on the outcome investigated, gender and the social position marker used indicating that alternative pathways may play a key role in developing effective policies targeting early-life behaviours.

Maternal Education in Early Life and Risk of Metabolic Syndrome in Young Adult American Females and Males: Disentangling Life Course Processes Through Causal Models

BACKGROUND

Maternal education in a child's early life may directly affect the child's adult cardiometabolic health, but this is difficult to disentangle from biological, social, and behavioral life course processes that are associated with maternal education. These processes may also differ between males and females.

METHODS

Using data from the National Longitudinal Study of Adolescent to Adult Health (1995-2009) (N = 4,026 females and 3,192 males), we estimated sex-stratified associations between maternal attainment of less than high school (<HS), high school diploma (HS), or college degree (CD) at the respondent's birth and respondent's risk of metabolic syndrome (MetS); we used marginal structural models (MSM) to account for the influence of major life course risk factors, such as childhood maltreatment, adolescent overweight, adult education, household income, smoking, and physical activity, in mediating associations between maternal education and offspring MetS risk.

RESULTS

Each higher level of maternal education was associated with a 36% (Relative Risk = 0.64 [95% Confidence Interval (CI): 0.50-0.82]) reduced risk of MetS among females, but only 19% (RR = 0.81 [95% CI: 0.64-1.01]) reduction among males (P-value interaction < 0.05). Stronger inverse associations were also observed for waist circumference and glycated hemoglobin (HbA1c) among females compared with males (-5 cm vs. -2.4 cm and -1.5% vs. -1.0%, respectively).

CONCLUSION

High maternal education in early life was associated with a lower risk of MetS in young adulthood even after accounting for life course risk factors, particularly among females. Results were robust to altered model specifications.

Charting the life course: Emerging opportunities to advance scientific approaches using life course research

Life course research embraces the complexity of health and disease development, tackling the extensive interactions between genetics and environment. This interdisciplinary blueprint, or theoretical framework, offers a structure for research ideas and specifies relationships between related factors. Traditionally, methodological approaches attempt to reduce the complexity of these dynamic interactions and decompose health into component parts, ignoring the complex reciprocal interaction of factors that shape health over time. New methods that match the epistemological foundation of the life course framework are needed to fully explore adaptive, multilevel, and reciprocal interactions between individuals and their environment. The focus of this article is to (1) delineate the differences between lifespan and life course research, (2) articulate the importance of complex systems science as a methodological framework in the life course research toolbox to guide our research questions, (3) raise key questions that can be asked within the clinical and translational science domain utilizing this framework, and (4) provide recommendations for life course research implementation, charting the way forward. Recent advances in computational analytics, computer science, and data collection could be used to approximate, measure, and analyze the intertwining and dynamic nature of genetic and environmental factors involved in health development.

Psychophysiological Models to Identify and Monitor Elderly with a Cardiovascular Condition: The Added Value of Psychosocial Parameters to Routinely Applied Physiological Assessments

The steadily growing elderly population calls for efficient, reliable and preferably ambulant health supervision. Since cardiovascular risk factors interact with psychosocial strain (e.g., depression), we investigated the potential contribution of psychosocial factors in discriminating generally healthy elderly from those with a cardiovascular condition, on and above routinely applied physiological assessments. Fifteen elderly (aged 60 to 88) with a cardiovascular diagnosis were compared to fifteen age and gender matched healthy peers. Six sequential standardized lab assessments were conducted (one every two weeks), including an autonomic test battery, a 6-min step test and questionnaires covering perceived psychological state and experiences over the previous two weeks. Specific combinations of physiological and psychological factors (most prominently symptoms of depression) effectively predicted (clinical) cardiovascular markers. Additionally, a highly significant prognostic model was found, including depressive symptoms, recently experienced negative events and social isolation. It appeared slightly superior in identifying elderly with or without a cardiovascular condition compared to a model that only included physiological parameters. Adding psychosocial parameters to cardiovascular assessments in elderly may consequently provide protocols that are significantly more efficient, relatively comfortable and technologically feasible in ambulant settings, without necessarily compromising prognostic accuracy.

Life course trauma and muscle weakness in older adults by gender and race/ethnicity: Results from the U.S. health and Retirement Study

Muscle weakness, as measured by handgrip strength, is a primary determinant of physical functioning and disability. There is a high burden of muscle weakness in the United States with close to 50 percent of older Americans meeting criteria for clinical muscle weakness. While previous racial/ethnic disparities have been documented among older adults, the extent to which lifecourse trauma shapes muscle strength trajectories is unknown. Using U.S. Health and Retirement Study (N = 20,472, Mean Age = 63.8 years) data on grip strength (2006-2014, up to 3 assessments) and retrospectively reported traumatic events, we fit gender-stratified growth curve models to investigate whether traumatic events experienced across the lifecourse or at distinct sensitive periods (childhood, early/emerging adulthood or mid-life) predicted later-life trajectories of grip strength. There was no association between cumulative trauma and trajectories of grip strength and the main effects for the life stage models were largely null. However, among White women, our results suggest that traumatic events experienced during childhood (β = -0.012; 95% CI = -0.024, 0.0004) compared to middle adulthood are associated with faster declines in grip strength in later life. Traumatic events reported during childhood was related to a slower decline in grip strength over time among Hispanic women compared to that for White women (β = 0.086, 95% CI = 0.044, 0.128). Among Black men, the association between traumatic events during early/emerging adulthood and age-related declines in grip strength was stronger for Black men than for White men (interaction β = -0.070; 95% CI = -0.138, 0.001). Traumatic events experienced during distinct life stages may influence later life declines in grip strength and exacerbate racial inequalities in later life. This study addresses an important gap by investigating the life course social determinants of later life muscle strength, which is a key driver of physical functioning and mobility.

Time-varying Effects of Screen Media Exposure in the Relationship Between Socioeconomic Background and Childhood Obesity

BACKGROUND

We investigated to what extent social inequalities in childhood obesity could be reduced by eliminating differences in screen media exposure.

METHODS

We used longitudinal data from the UK-wide Millennium Cohort Study (n = 11,413). The study measured mother's educational level at child's age 5. We calculated screen media exposure as a combination of television viewing and computer use at ages 7 and 11. We derived obesity at age 14 from anthropometric measures. We estimated a counterfactual disparity measure of the unmediated association between mother's education and obesity by fitting an inverse probability-weighted marginal structural model, adjusting for mediator-outcome confounders.

RESULTS

Compared with children of mothers with a university degree, children of mothers with education to age 16 were 1.9 (95% confidence interval [CI] = 1.5, 2.3) times as likely to be obese. Those whose mothers had no qualifications were 2.0 (95% CI = 1.5, 2.5) times as likely to be obese. Compared with mothers with university qualifications, the estimated counterfactual disparity in obesity at age 14, if educational differences in screen media exposure at age 7 and 11 were eliminated, was 1.8 (95% CI = 1.4, 2.2) for mothers with education to age 16 and 1.8 (95% CI = 1.4, 2.4) for mothers with no qualifications on the risk ratio scale. Hence, relative inequalities in childhood obesity would reduce by 13% (95% CI = 1%, 26%) and 17% (95% CI = 1%, 33%). Estimated reductions on the risk difference scale (absolute inequalities) were of similar magnitude.

CONCLUSIONS

Our findings are consistent with the hypothesis that social inequalities in screen media exposure contribute substantially to social inequalities in childhood obesity.

Income at birth and tooth loss due to dental caries in adulthood: The 1982 Pelotas birth cohort

OBJECTIVE

To estimate the effect of income at birth on adulthood tooth loss due to dental caries in 539 adults from the 1982 Pelotas birth cohort.

METHODS

Family income was collected at birth. Tooth loss was clinically assessed when individuals were aged 31. Dental visit and oral hygiene at age 25 were considered mediators. Confounders included maternal skin color, and individual's skin color, sex, and income in adulthood. Marginal structural modeling was used to estimate the controlled direct effect of income at birth on tooth loss due to dental caries that was neither mediated by the use of dental service nor oral hygiene.

RESULTS

Forty-three percent of the individuals of low income at birth lost one/two teeth, and 23% lost three or more; among those non-poor, the prevalence was 30% and 14%, respectively. Poor individuals at birth had a 70% higher risk for missing teeth in adulthood than those non-poor. The risk of losing one/two (risk ratio 1.68) and three or more teeth (risk ratio 3.84) was also higher among those of low income at birth.

CONCLUSIONS

Economic disadvantage at birth had an effect on tooth loss due to dental caries at age 31 not mediated by individual risk factors.

Association between cumulative social risk, particulate matter environmental pollutant exposure, and cardiovascular disease risk

Background

Long-term exposure to pollution has been shown to increase risk of cardiovascular disease (CVD) and mortality, and may contribute to the increased risk of CVD among individuals with higher social risk.

Methods

Data from the community-based Heart Strategies Concentrating on Risk Evaluation (HeartSCORE) study were used to quantify Cumulative Social Risk (CSR) by assigning a score of 1 for the presence of each of 4 social risk factors: racial minority, single living, low income, and low educational status. 1-year average air pollution exposure to PM_2.5 was estimated using land-use regression models. Associations with clinical outcomes were assessed using Cox models, adjusting for traditional CVD risk factors. The primary clinical outcome was combined all-cause mortality and nonfatal CVD events.

Results

Data were available on 1933 participants (mean age 59 years, 66% female, 44% Black). In a median follow up time of 8.3 years, 137 primary clinical outcome events occurred. PM_2.5 exposure increased with higher CSR score. PM_2.5 was independently associated with clinical outcome (adjusted hazard ratio [HR]: 1.19 [95% CI: 1.00, 1.41]). Participants with ≥2 CSR factors had an adjusted HR of 2.34 (1.48–3.68) compared to those with CSR = 0. The association was attenuated after accounting for PM_2.5 (HR: 2.16; [1.34, 3.49]). Mediation analyses indicate that PM_2.5 explained 13% of the risk of clinical outcome in individuals with CSR score ≥ 2.

Conclusion

In a community-based cohort study, we found that the association of increasing CSR with higher CVD and mortality risks is partially accounted for by exposure to PM_2.5 environmental pollutants.

Associations between age and dyslipidemia are differed by education level: The Cardiovascular and Metabolic Diseases Etiology Research Center (CMERC) cohort

Background

Dyslipidemia is a multifactorial disorder, which arises from complex interactions among genetic and environmental risk factors. Previous studies have established the deteriorating effect of aging on lipid profiles. However, little is known about the role of education level, a stable marker of socioeconomic status, which reflect modifiability of lifestyle risk factors. Therefore, we examined the association between age and individual dyslipidemia parameter across education level among healthy, middle-aged Korean women.

Methods

From 2049 middle-aged women, education attainment was classified into completion of elementary school or below, middle school, high school, college or above. Dyslipidemia was assessed in adherence to the 2018 Korean Dyslipidemia Treatment Guideline. Multivariable logistic regression and generalized linear model tested for associations between age and dyslipidemia parameter across education level and other known risk factors, including menopause, obesity, and current drinking and smoking.

Results

In this cross-sectional analysis, the prevalence of each dyslipidemia parameter was significantly different by age and education level. The odds ratio (OR) for dyslipidemia was higher among participants who were older and had received higher education (OR = 2.31, p for interaction = 0.008) than younger and low education counterpart. The interaction between age and education level remained significant for hypercholesterolemia (p for interaction = 0.003) and hyper-LDL-cholesterolemia (p for interaction = 0.002).

Conclusions

Separate examination of individual dyslipidemia parameter indicated varying degree of interaction with age and education level. Such results imply that each type of lipid abnormality may arise from and be exacerbated by heterogeneous composition of biological and lifestyle risk factors, which may be reflected by education level.

Racial discrimination in medical care settings and opioid pain reliever misuse in a U.S. cohort: 1992 to 2015

BACKGROUND

In the United States whites are more likely to misuse opioid pain relievers (OPRs) than blacks, and blacks are less likely to be prescribed OPRs than whites. Our objective is to determine whether racial discrimination in medical settings is protective for blacks against OPR misuse, thus mediating the black-white disparities in OPR misuse.

METHODS

We used data from 3528 black and white adults in the Coronary Artery Risk Development in Young Adults (CARDIA) study, an ongoing multi-site cohort. We employ causal mediation methods, with race (black vs white) as the exposure, lifetime discrimination in medical settings prior to year 2000 as the mediator, and OPR misuse after 2000 as the outcome.

RESULTS

We found black participants were more likely to report discrimination in a medical setting (20.3% vs 0.9%) and less likely to report OPR misuse (5.8% vs 8.0%, OR = 0.71, 95% CI = 0.55, 0.93, adjusted for covariates). Our mediation models suggest that when everyone is not discriminated against, the disparity is wider with black persons having even lower odds of reporting OPR misuse (OR = 0.63, 95% CI = 0.45, 0.89) compared to their white counterparts, suggesting racial discrimination in medical settings is a risk factor for OPR misuse rather than protective.

CONCLUSIONS

These results suggest that racial discrimination in a medical setting is a risk factor for OPR misuse rather than being protective, and thus could not explain the seen black-white disparity in OPR misuse.

Adverse childhood experiences and bullying behaviours at work among workers in Japan

OBJECTIVES

To examine the relationship between adverse childhood experiences (ACEs), workplace bullying victimisation and bullying behaviours to subordinates among Japanese workers.

METHODS

We conducted an internet-based cross-sectional survey among workers who had enacted 0, 1 and ≥2 types of bullying behaviours that had been directed towards subordinates in the past 3 years (n=309 for each group, total N=927). We assessed ACEs with questionnaires about adverse experiences at home and bullying victimisation at school. The total and controlled direct effects of ACEs on the number of bullying behaviours to subordinates were estimated from a baseline-adjusted and a direct-effect marginal structural ordinal logistic model, respectively.

RESULTS

There was a positive dose-response association between the level of ACEs and the frequency of workplace bullying victimisation, as well as the number of bullying behaviours enacted at work after adjustment for sex, age and childhood socioeconomic status (both p<0.001). Workers in the highest tertile of ACEs compared with the lowest tertile had 3.15 (95% CI 2.20 to 4.50) times higher odds of having perpetrated more bullying behaviours at work. The magnitude of the effect was 2.57 (95% CI 1.70 to 3.90) via pathways not mediated by workplace bullying victimisation in a direct-effect marginal structural model.

CONCLUSIONS

People who had ACEs were at increased risk later in life of enacting bullying behaviours at work. Current findings may be useful to prevent bullying behaviours at work.

Is it possible to overcome the 'long arm' of childhood socioeconomic disadvantage through upward socioeconomic mobility?

OBJECTIVES

Socioeconomically disadvantaged children have worse adult health; we test if this 'long arm' of childhood disadvantage can be overcome through upward socioeconomic mobility in adulthood.

METHODS

Four SES trajectories (stable low, upwardly mobile, downwardly mobile and stable high) were created from median dichotomized childhood socioeconomic status (SES; childhood human and financial capital) and adult SES (wealth at age 67) from Health and Retirement Study respondents (N = 6669). Healthy ageing markers, in tertiles, were walking speed, peak expiratory flow (PEF), and grip strength measured in 2008 and 2010. Multinomial logistic regression models, weighted to be nationally representative, controlled for age, gender, race, birthplace, outcome year and childhood health and social capital.

RESULTS

Upwardly mobile individuals were as likely as the stable high SES group to be in the best health tertile for walking speed (OR = 0.81; 95% CI: 0.63, 1.05; P = 0.114), PEF (OR = 0.97; 95% CI: 0.78, 1.21; P = 0.810) and grip strength (OR = 0.97; 95%CI: 0.74, 1.27; P = 0.980).

DISCUSSION

Findings suggest the 'long arm' of childhood socioeconomic disadvantage can be overcome for these markers of healthy ageing through upward socioeconomic mobility.

How community resources mitigate the association between household poverty and the incidence of adverse childhood experiences

OBJECTIVES

To assess what proportion of the association between household low income and incidence of adverse childhood experiences (ACE) would be eliminated if all households had access to housing, transportation and childcare services, breastfeeding counselling, and parks.

METHODS

Using Growing Up in Scotland birth cohort data (N = 2816), an inverse probability-weighted regression-based mediation technique was applied to assess associations between low-income status (< £11,000 in 2004/5), resource access, and cumulative 8-year ACE incidence (≥ 1, ≥ 3 ACEs). Resource access was measured based on households' self-reported difficulties (yes/no) in accessing housing, transportation, childcare, and breastfeeding counselling, and park proximity (within 10 min from the residence).

RESULTS

The protective effects of resources were heterogeneous. Only access to transportation was associated with lower ACE incidence in both low- and higher-income households. If all had access to transportation, 21% (95% CI 3%, 41%) of the income-based inequality in incidence of 3 or more ACEs could be eliminated.

CONCLUSIONS

While second best to the elimination of child poverty, measures to improve families' access to community resources such as transportation may mitigate the effects of poverty on ACE incidence.

Association between adverse childhood experiences and adult diseases in older adults: a comparative cross-sectional study in Japan and Finland

OBJECTIVE

We aimed to examine the association between adverse childhood experiences (ACEs) and diseases in older adults in Japan and Finland.

DESIGN

Cross-sectional comparative study.

SETTING

Data from a gerontological study in Japan and two public health studies in Finland were evaluated.

PARTICIPANTS

A total of 13 123 adults (mean age, 69.5 years) from Japan and 10 353 adults (mean age, 64.4 years) from Finland were included in this study. Logistic regression was used to examine the association of each of, any of and the cumulative number of ACEs (parental divorce, fear of a family member and poverty in childhood; treated as ordered categorical variables) with poor self-rated health (SRH), cancer, heart disease or stroke, diabetes mellitus, smoking and body mass index. Models were adjusted for sex, age, education, marital status and working status.

RESULTS

Of the respondents, 50% of those in Japan and 37% of those in Finland reported having experienced at least one of the measured ACEs. Number of ACEs was associated with poor SRH in both countries, and the point estimates were similar (OR: 1.35, 95% CI: 1.25 to 1.46 in Japan; OR: 1.34, 95% CI: 1.27 to 1.41 in Finland). Number of ACEs was associated with the prevalence of cancer, heart disease or stroke, diabetes mellitus, current smoking and an increase in body mass index in both countries.

CONCLUSIONS

The association between ACEs and poor SRH, adult diseases and health behaviours was similar among older adults in both Japan and Finland. This international comparative study suggests that the impact of ACEs on health is noteworthy and consistent across cultural and social environments.

The Relationship between Income and Oral Health: A Critical Review

In this critical review, we summarized the evidence on associations between individual/household income and oral health, between income inequality and oral health, and income-related inequalities in oral health. Meta-analyses of mainly cross-sectional studies confirm that low individual/household income is associated with oral cancer (odds ratio, 2.41; 95% confidence interval [CI], 1.59-3.65), dental caries prevalence (prevalence ratio, 1.29; 95% CI, 1.18-1.41), any caries experience (odds ratio, 1.40; 95% CI, 1.19-1.65), tooth loss (odds ratio, 1.66; 95% CI, 1.48-1.86), and traumatic dental injuries (odds ratio, 0.76; 95% CI, 0.65-0.89). Reviews also confirm qualitatively that low income is associated with periodontal disease and poor oral health-related quality of life. Limited evidence from the United States shows that psychosocial and behavioral explanations only partially explain associations between low individual/household income and oral health. Few country-level studies and a handful of subnational studies from the United States, Japan, and Brazil show associations between area-level income inequality and poor oral health. However, this evidence is conflicting given that the association between area-level income inequality and oral health outcomes varies considerably by contexts and by oral health outcomes. Evidence also shows cross-national variations in income-related inequalities in oral health outcomes of self-rated oral health, dental care, oral health-related quality of life, outcomes of dental caries, and outcomes of tooth loss. There is a lack of discussion in oral health literature about limitations of using income as a measure of social position. Future studies on the relationship between income and oral health can benefit substantially from recent theoretical and methodological advancements in social epidemiology that include application of an intersectionality framework, improvements in reporting of inequality, and causal modeling approaches. Theoretically well-informed studies that apply robust epidemiological methods are required to address knowledge gaps for designing relevant policy interventions to reduce income-related inequalities in oral health.

A marginal structural model approach to analyse work-related injuries: an example using data from the health and retirement study

BACKGROUND

Biases may exist in the limited longitudinal data focusing on work-related injuries among the ageing workforce. Standard statistical techniques may not provide valid estimates when the data are time-varying and when prior exposures and outcomes may influence future outcomes. This research effort uses marginal structural models (MSMs), a class of causal models rarely applied for injury epidemiology research to analyse work-related injuries.

METHODS

7212 working US adults aged ≥50 years, obtained from the Health and Retirement Study sample in the year 2004 formed the study cohort that was followed until 2014. The analyses compared estimates measuring the associations between physical work requirements and work-related injuries using MSMs and a traditional regression model. The weights used in the MSMs, besides accounting for time-varying exposures, also accounted for the recurrent nature of injuries.

RESULTS

The results were consistent with regard to directionality between the two models. However, the effect estimate was greater when the same data were analysed using MSMs, built without the restriction for complete case analyses.

CONCLUSIONS

MSMs can be particularly useful for observational data, especially with the inclusion of recurrent outcomes as these can be incorporated in the weights themselves.

Does smoking during pregnancy mediate educational disparities in preterm delivery? Findings from three large birth cohorts

BACKGROUND

Socio-economic disparities in preterm delivery have often been attributed to socially patterned smoking habits. However, most existing studies have used methods that potentially give biased estimates of the mediating effect of smoking. We used a contemporary mediation approach to study to which extent smoking during pregnancy mediates educational disparities in preterm delivery.

METHODS

We performed a comparative analysis of data from three large birth cohort studies: the Danish National Birth Cohort (DNBC), the Dutch Generation R Study, and the Norwegian Mother and Child Cohort Study (MoBa). Risk of preterm delivery by maternal education is reported as risk differences and decomposed into a part explained by smoking and a part explained by other pathways.

RESULTS

Proportions of preterm singleton deliveries were 4.8%-4.9% in all three cohorts. Total effects of maternal education were 2.0 (95% confidence interval [CI] 1.4, 2.5), 3.2 (95% CI 0.8, 5.2) and 2.0 (95% CI 0.9, 3.0) excess preterm deliveries per 100 singleton deliveries in DNBC, Generation R and MoBa when comparing primary/lower secondary education to an academic degree or equivalent. Smoking mediated, respectively, 22%, 10% and 19% of the excess risk in the DNBC, Generation R and MoBa cohorts. Adjustment for potential misclassification of smoking only increased mediated proportions slightly.

CONCLUSIONS

Smoking during pregnancy explains part of educational disparities in preterm delivery, but the mediated proportion depends on the educational gradient in smoking, emphasising that educational disparities in preterm birth may be mediated by different risk factors in different countries.

State-level minimum wage and heart disease death rates in the United States, 1980-2015: A novel application of marginal structural modeling

Despite substantial declines since the 1960's, heart disease remains the leading cause of death in the United States (US) and geographic disparities in heart disease mortality have grown. State-level socioeconomic factors might be important contributors to geographic differences in heart disease mortality. This study examined the association between state-level minimum wage increases above the federal minimum wage and heart disease death rates from 1980 to 2015 among 'working age' individuals aged 35-64 years in the US. Annual, inflation-adjusted state and federal minimum wage data were extracted from legal databases and annual state-level heart disease death rates were obtained from CDC Wonder. Although most minimum wage and health studies to date use conventional regression models, we employed marginal structural models to account for possible time-varying confounding. Quasi-experimental, marginal structural models accounting for state, year, and state × year fixed effects estimated the association between increases in the state-level minimum wage above the federal minimum wage and heart disease death rates. In models of 'working age' adults (35-64 years old), a $1 increase in the state-level minimum wage above the federal minimum wage was on average associated with ~6 fewer heart disease deaths per 100,000 (95% CI: -10.4, -1.99), or a state-level heart disease death rate that was 3.5% lower per year. In contrast, for older adults (65+ years old) a $1 increase was on average associated with a 1.1% lower state-level heart disease death rate per year (b = -28.9 per 100,000, 95% CI: -71.1, 13.3). State-level economic policies are important targets for population health research.

Impact of childhood abuse on suicide-related behavior: Analysis using marginal structural models

BACKGROUND

Childhood abuse is associated with adult suicidal behaviors, partially mediated by mental disorders. However, the direct effect of childhood abuse not mediated by mental disorders is uncertain because the same risk factors serve as mediators and confounders of mental disorders and suicidal behaviors. The aim of the study was to estimate the direct effect of childhood abuse not mediated by mental disorders on suicidal behaviors using marginal structural models.

METHODS

We used cross-sectional data of Japanese adults in Tokyo and neighboring prefectures (The Japanese Study on Stratification, Health, Income, and Neighborhood). We developed a causal diagram of childhood abuse and suicidal behaviors, and defined exposures (childhood abuse), confounders (age, childhood social characteristics), mediators (mental disorders), risk factors (coping, smoking, alcohol consumption, education, physical health), and outcome (suicidal behaviors). We estimated the direct effect of childhood abuse according to sex using inverse-probability weighting at 2 points and compared to total and direct effects estimated by conventional regression models.

RESULTS

Of 1776 male and 2016 female participants, childhood abuse showed significant total effects on suicidal behaviors. Physical abuse was associated with suicidal ideation (risk ratio: males 2.11 [95% confidence interval: 1.59-2.82], females 2.15 [1.69-2.72]), suicidal plan (risk ratio: males 2.18 [1.21-3.92], females 2.14 [1.24-3.74]), and suicidal attempt (risk ratio: males 2.11 [1.14-5.10], females 4.79 [2.93-7.83]) through direct effect.

LIMITATIONS

Childhood abuse was measured according to self-report of the past experiences.

CONCLUSIONS

Our study suggests that childhood abuse is associated with adult suicidal behaviors through direct effects not mediated by mental disorders.

Joint Effect of Alcohol Consumption and Educational Level on Alcohol-related Medical Events: A Danish Register-based Cohort Study

BACKGROUND

Alcohol-related mortality is more pronounced in lower than in higher socioeconomic groups in Western countries. Part of the explanation is differences in drinking patterns. However, differences in vulnerability to health consequences of alcohol consumption across socioeconomic groups may also play a role. We investigated the joint effect of alcohol consumption and educational level on the rate of alcohol-related medical events.

METHODS

We pooled seven prospective cohorts from Denmark that enrolled 74,278 men and women age 30-70 years (study period, 1981 to 2009). We measured alcohol consumption at baseline using self-administrated questionnaires. Information on highest attained education 1 year before study entry and hospital and mortality data on alcohol-related medical events were obtained through linkage to nationwide registries. We performed analyses using the Aalen additive hazards model.

RESULTS

During follow-up (1,085,049 person-years), a total of 1718 alcohol-related events occurred. The joint effect of very high alcohol consumption (>21 [>28] drinks per week in women [men]) and low education on alcohol-related events exceeded the sum of their separate effects. Among men, we observed 289 (95% confidence interval = 123, 457) extra events per 100,000 person-years owing to education-alcohol interaction (P < 0.001). Similarly, among women, we observed 239 (95% confidence interval = 90, 388) extra events per 100,000 person-years owing to this interaction (P < 0.001).

CONCLUSIONS

High alcohol consumption is associated with a higher risk of alcohol-related medical events among those with low compared with high education. This interaction may be explained by differences in vulnerability and drinking patterns across educational groups.See video abstract at, http://links.lww.com/EDE/B267.

Socioeconomic Position and Age-Related Disparities in Regional Cerebral Blood Flow Within the Prefrontal Cortex

OBJECTIVE

Socioeconomic position (SEP) is associated with cerebrovascular health and brain function, particularly in prefrontal cortex and medial temporal lobe regions that exhibit plasticity across the life course. However, it is unknown whether SEP associates with resting cerebral blood flow (CBF), an indicator of baseline brain function, in these regions in midlife, and whether the association is (a) period specific, with independent associations for childhood and adulthood SEP, or driven by life course SEP, and (b) explained by a persistent disparity, widening disparity, or the leveling of disparities with age.

METHODS

To address these questions, we analyzed cerebral perfusion derived by magnetic resonance imaging in a cross-sectional study of healthy adults (N = 443) who reported on childhood and adult SEP. Main effects were examined as an index of persistent disparity and age by SEP interactions as reflecting widening or leveling disparities.

RESULTS

Stable high SEP across the lifespan was associated with higher global CBF and regional CBF (rCBF) in inferior frontal gyrus. However, childhood SEP was associated with rCBF in middle frontal gyrus, as moderated by age (β = 0.04, p = .035): rCBF was inversely associated with age only for those whose parents had a high school education or below. No associations were observed for the hippocampus or amygdala.

CONCLUSIONS

Life course SEP associations with rCBF in prefrontal cortex are suggestive of persistent disparities, whereas the age by childhood SEP interaction suggests that childhood disadvantage relates to a widening disparity, independent of global differences. These differential patterns in midlife may relate to disparities in later-life cerebrovascular and neurocognitive outcomes.

Heart Disease Death Rates Among Blacks and Whites Aged ≥35 Years - United States, 1968-2015

PROBLEM/CONDITION

Heart disease is the leading cause of death in the United States. In 2015, heart disease accounted for approximately 630,000 deaths, representing one in four deaths in the United States. Although heart disease death rates decreased 68% for the total population from 1968 to 2015, marked disparities in decreases exist by race and state.

PERIOD COVERED

1968-2015.

DESCRIPTION OF SYSTEM

The National Vital Statistics System (NVSS) data on deaths in the United States were abstracted for heart disease using diagnosis codes from the eighth, ninth, and tenth revisions of the International Classification of Diseases (ICD-8, ICD-9, and ICD-10) for 1968-2015. Population estimates were obtained from NVSS files. National and state-specific heart disease death rates for the total population and by race for adults aged ≥35 years were calculated for 1968-2015. National and state-specific black-white heart disease mortality ratios also were calculated. Death rates were age standardized to the 2000 U.S. standard population. Joinpoint regression was used to perform time trend analyses.

RESULTS

From 1968 to 2015, heart disease death rates decreased for the total U.S. population among adults aged ≥35 years, from 1,034.5 to 327.2 per 100,000 population, respectively, with variations in the magnitude of decreases by race and state. Rates decreased for the total population an average of 2.4% per year, with greater average decreases among whites (2.4% per year) than blacks (2.2% per year). At the national level, heart disease death rates for blacks and whites were similar at the start of the study period (1968) but began to diverge in the late 1970s, when rates for blacks plateaued while rates for whites continued to decrease. Heart disease death rates among blacks remained higher than among whites for the remainder of the study period. Nationwide, the black-white ratio of heart disease death rates increased from 1.04 in 1968 to 1.21 in 2015, with large increases occurring during the 1970s and 1980s followed by small but steady increases until approximately 2005. Since 2005, modest decreases have occurred in the black-white ratio of heart disease death rates at the national level. The majority of states had increases in black-white mortality ratios from 1968 to 2015. The number of states with black-white mortality ratios >1 increased from 16 (40%) to 27 (67.5%).

INTERPRETATION

Although heart disease death rates decreased both for blacks and whites from 1968 to 2015, substantial differences in decreases were found by race and state. At the national level and in most states, blacks experienced smaller decreases in heart disease death rates than whites for the majority of the period. Overall, the black-white disparity in heart disease death rates increased from 1968 to 2005, with a modest decrease from 2005 to 2015.

PUBLIC HEALTH ACTION

Since 1968, substantial increases have occurred in black-white disparities of heart disease death rates in the United States at the national level and in many states. These increases appear to be due to faster decreases in heart disease death rates for whites than blacks, particularly from the late 1970s until the mid-2000s. Despite modest decreases in black-white disparities at the national level since 2005, in 2015, heart disease death rates were 21% higher among blacks than among whites. This study demonstrates the use of NVSS data to conduct surveillance of heart disease death rates by race and of black-white disparities in heart disease death rates. Continued surveillance of temporal trends in heart disease death rates by race can provide valuable information to policy makers and public health practitioners working to reduce heart disease death rates both for blacks and whites and disparities between blacks and whites.

Posttraumatic stress disorder and mortality in VA patients with implantable cardioverter-defibrillators

BACKGROUND

The association between posttraumatic stress disorder (PTSD) and mortality in patients undergoing implantable cardioverter-defibrillator (ICD) placement has not been evaluated in US veterans.

HYPOTHESIS

PTSD in veterans with ICD is associated with increased mortality.

METHODS

We studied a retrospective cohort of 25 678 veterans who underwent ICD implantation between September 30, 2002, and December 31, 2011. Of these subjects, 3280 carried the diagnosis of PTSD prior to ICD implantation. Primary outcome was all-cause mortality between date of ICD implantation and end of follow-up (September 30, 2013). We used Cox proportional hazard models to compute multivariable adjusted hazard ratios with corresponding 95% confidence intervals for the relation between PTSD diagnosis and death following ICD placement.

RESULTS

During a mean follow-up of 4.21 ± 2.62 years, 11 015 deaths were reported. The crude incidence rate of death was 87.8 and 103.9/1000 person-years for people with and without PTSD, respectively. We did not find an association between presence of PTSD before or after ICD implantation and incident death when adjusted for multiple risk factors (hazard ratio: 1.003, 95% confidence interval: 0.948-1.061). In secondary analysis, no statistically significant association was found.

CONCLUSIONS

In this retrospective cohort study among more than 25 000 veterans undergoing ICD implantation, almost 13% had a diagnosis of PTSD. Subjects with PTSD were significantly younger, yet they had a higher incidence of coronary heart disease, major cardiac comorbidities, cancer, and mental health conditions. We found no association between presence of PTSD before or after ICD implantation and incident death when adjusting for all covariates.

Comparing Alternative Effect Decomposition Methods: The Role of Literacy in Mediating Educational Effects on Mortality

BACKGROUND

Inverse odds ratio weighting, a newly proposed tool to evaluate mediation in exposure-disease associations, may be valuable for a host of research questions, but little is known about its performance in real data. We compare this approach to a more conventional Baron and Kenny type of decomposition on an additive hazards scale to estimate total, direct, and indirect effects using the example of the role of literacy in mediating the effects of education on mortality.

METHODS

Health and Retirement Study participants born in the United States between 1900 and 1947 were interviewed biennially for up to 12 years (N = 17,054). Literacy was measured with a brief vocabulary assessment. Decomposition estimates were derived based on Aalen additive hazards models.

RESULTS

A 1 standard deviation difference in educational attainment (3 years) was associated with 6.7 fewer deaths per 1000 person-years (β = -6.7, 95% confidence interval [CI]: -7.9, -5.4). Of this decrease, 1.3 fewer deaths (β = -1.3, 95% CI: -4.0, 1.2) were attributed to the literacy pathway (natural indirect), representing 19% of the total effect. Baron and Kenny estimates were consistent with inverse odds ratio weighting estimates but were less variable (natural indirect effect: -1.2 [95% CI: -1.7, -0.69], representing 18% of total effect).

CONCLUSION

In a cohort of older Americans, literacy partially mediated the effect of education on mortality. See Video Abstract at http://links.lww.com/EDE/B78.

Short- and Long-Term Impacts of Neighborhood Built Environment on Self-Rated Health of Older Adults

Background and Objectives

Proximity to health care, healthy foods, and recreation is linked to improved health in older adults while deterioration of the built environment is a risk factor for poor health. Yet, it remains unclear whether individuals prone to good health self-select into favorable built environments and how long-term exposure to deteriorated environments impacts health. This study uses a longitudinal framework to address these questions.

Research Design and Methods

The study analyzes 3,240 Americans aged 45 or older from the Panel Study of Income Dynamics with good self-reported health at baseline, and follows them from 1999 to 2013. At each biennial survey wave, individual data are combined with data on services in the neighborhood of residence (defined as the zip code) from the Economic Census. The analysis overcomes the problem of residential self-selection by employing marginal structural models and inverse probability of treatment weights.

Results

Logistic regression estimates indicate that long-term exposure to neighborhood built environments that lack health-supportive services (e.g., physicians, pharmacies, grocery stores, senior centers, and recreational facilities) and are commercially declined (i.e., have a high density of liquor stores, pawn shops, and fast food outlets) increases the risk of fair/poor self-rated health compared to more average neighborhoods. Short-term exposure to the same environments as compared to average neighborhoods has no bearing on self-rated health after adjusting for self-selection.

Discussion and Implications

Results highlight the importance of expanding individuals' access to health-supportive services prior to their reaching old age, and expanding access for people unlikely to attain residence in service-dense neighborhoods.

The role of literacy in the association between educational attainment and depressive symptoms

There is a consistent association between education and depressive symptoms, but research on the mechanisms to explain this association remains limited. No study has formally evaluated the extent to which the association between education and depressive symptoms is mediated through a foundational skill such as literacy. Inverse odds ratio weighting (IORW) was used to estimate total, natural direct, and natural indirect effects in examining literacy as a mediator of the association between education and depressive symptoms. Health and Retirement Study participants born in the U.S. between 1900 and 1947 were interviewed biennially for up to 12 years (N = 16,718). Literacy was assessed with a brief vocabulary measure. Depressive symptoms were measured using the 8-item Centers for Epidemiologic Studies-Depression (CES-D) scale. Decomposition estimates were derived using regression analyses of repeated measures of depressive symptoms. Standard errors were obtained using a nonparametric bootstrap with the individual as the independent unit to account for dependence of observations within an individual. In a large cohort of older Americans, a one standard deviation difference in educational attainment (~ 3 years) was associated with a 0.35-point decrement in CES-D score (95% CI: -0.38, -0.32). This decrement represents a 0.22 standard deviation difference in depressive symptoms. Using IORW, the estimated effect of education on depressive symptoms mediated through literacy was -0.10 (95% CI: -0.18, -0.01), which represents 28% of the total effect. Education confers many benefits; as demonstrated by this study for depressive symptoms, one important benefit is literacy.

Maternal gestational weight gain and DNA methylation in young women: application of life course mediation methods

AIM

To investigate the role of maternal gestational weight gain (GWG) and prepregnancy BMI on programming offspring DNA methylation.

METHODS

Among 589 adult (age = 32) women participants of the Jerusalem Perinatal Study, we quantified DNA methylation in five candidate genes. We used inverse probability-weighting and parametric g-formula to estimate direct effects of maternal prepregnancy BMI and GWG on methylation.

RESULTS

Higher maternal GWG, but not prepregnancy BMI, was inversely related to offspring ABCA1 methylation (β = -1.1% per quartile; 95% CI: -2.0, -0.3) after accounting for ancestry, parental and offspring exposures. Total and controlled direct effects were nearly identical suggesting included offspring exposures did not mediate this relationship. Results were robust to sensitivity analyses for missing data and model specification.

CONCLUSION

We find some support for epigenetic programming and highlight strengths and limitations of these methods relative to other prevailing approaches.

Validation of a theoretically motivated approach to measuring childhood socioeconomic circumstances in the Health and Retirement Study

Childhood socioeconomic status (cSES) is a powerful predictor of adult health, but its operationalization and measurement varies across studies. Using Health and Retirement Study data (HRS, which is nationally representative of community-residing United States adults aged 50+ years), we specified theoretically-motivated cSES measures, evaluated their reliability and validity, and compared their performance to other cSES indices. HRS respondent data (N = 31,169, interviewed 1992–2010) were used to construct a cSES index reflecting childhood social capital (cSC), childhood financial capital (cFC), and childhood human capital (cHC), using retrospective reports from when the respondent was <16 years (at least 34 years prior). We assessed internal consistency reliability (Cronbach’s alpha) for the scales (cSC and cFC), and construct validity, and predictive validity for all measures. Validity was assessed with hypothesized correlates of cSES (educational attainment, measured adult height, self-reported childhood health, childhood learning problems, childhood drug and alcohol problems). We then compared the performance of our validated measures with other indices used in HRS in predicting self-rated health and number of depressive symptoms, measured in 2010. Internal consistency reliability was acceptable (cSC = 0.63, cFC = 0.61). Most measures were associated with hypothesized correlates (for example, the association between educational attainment and cSC was 0.01, p < 0.0001), with the exception that measured height was not associated with cFC (p = 0.19) and childhood drug and alcohol problems (p = 0.41), and childhood learning problems (p = 0.12) were not associated with cHC. Our measures explained slightly more variability in self-rated health (adjusted R² = 0.07 vs. <0.06) and number of depressive symptoms (adjusted R² > 0.05 vs. < 0.04) than alternative indices. Our cSES measures use latent variable models to handle item-missingness, thereby increasing the sample size available for analysis compared to complete case approaches (N = 15,345 vs. 8,248). Adopting this type of theoretically motivated operationalization of cSES may strengthen the quality of research on the effects of cSES on health outcomes.