Life-course Socioeconomic Position Research Articles

Can Social Mobility Impact Frailty Trajectories of Chinese Adults in Later Life? A Nationwide Longitudinal Study.

Evidence remains unclear on the impact of life-course socioeconomic position (SEP) mobility on frailty trajectories in later life. We aim to examine the longitudinal effects of social mobility on frailty trajectories among Chinese middle-aged and older populations. A total of 13239 participants aged 45 and older from the 2011-2018 China Health and Retirement Longitudinal Study were analyzed. Based on changes in SEP from childhood to adulthood, 5 patterns of social mobility were established. A 32-item deficit cumulative frailty index (FI) was developed to evaluate frailty trajectories at each follow-up. Linear mixed-effects models were used to examine the longitudinal association of the 5 social mobility patterns with the frailty trajectory. The trajectory of late-life FI increased across all 5 social mobility groups during the follow-up. The FI trajectory had the largest disparity between stable high SEP and stable low SEP, with a faster increase in FI of 0.489 (95% confidence interval [CI]: 0.327-0.650, p < .001) in the stable low versus stable high SEP group. The FI trajectories of individuals in the upward and downward mobility groups fall between those in the stable high SEP and low SEP groups. Specifically, compared to the stable high SEP group, the increase in FI was 0.229 (95% CI: 0.098-0.360, p = .001) faster in the downward mobility group, and 0.145 (95% CI: 0.017-0.273, p = .03) faster in the upward mobility group. The impact of social mobility on frailty trajectories was more pronounced among middle-aged adults and women. These findings emphasize that policies to identify vulnerable populations and reduce frailty inequalities should focus on the socioeconomic environment across the life course, with particular attention paid to those with consistently low SEP and downward mobility.

Life-Course Socioeconomic Position and Mild Cognitive Impairment in Midlife: Evidence from the 1958 British Birth Cohort

BackgroundDementia has been the leading cause of death in the UK since 2015. Increasing evidence supports an association between socioeconomic position (SEP) and dementia onset in later life. However, limited studies have examined how life-course SEP influences the development of mild cognitive impairment (MCI), an intermediate state potentially preceding dementia. Therefore, the present study aims to examine the relationship between life-course SEP and MCI amongst adults aged 50 years in Great Britain.MethodsWe employed data from the National Child Development Study (NCDS), also known as the 1958 British Birth Cohort, to determine the associations between SEP and MCI in 6590 participants. We categorised life-course measures of SEP as stable high/low or moving upward/downward over the life course. We assessed MCI at age 50 using one standard deviation below the averaged combined scores from all cognitive tests available. We then used binary logistic regression to estimate the longitudinal associations between life-course SEP and MCI.ResultsRelative to those of a high SEP across the life course, participants who moved upward, downward, or remained at a low SEP were significantly associated with 25% (95% CI 1.02–1.54, p = 0.035), 70% (95% CI 1.27–2.27, p < 0.001), and 85% (95% CI 1.50–2.29, p < 0.001), respectively, higher odds of MCI, independent of all selected covariates.ConclusionsLower life-course SEP was associated with significantly higher odds of MCI onset in middle life within the NCDS cohort. Public health policies targeting cognitive impairment should encompass a life-course approach to reduce socioeconomic inequalities.

Association Between Trajectory of Socioeconomic Position and Regional Brain Volumes Related to Dementia: Results From the NEIGE Study.

Low socioeconomic position (SEP) has been linked to an increased risk of dementia. However, little is known about the association between SEP trajectory and regional brain volumes related to dementia. A random sample of community-dwelling older adults (n = 428, age = 73.1±5.5) living in Tokamachi City (Niigata Prefecture, Japan) without medical histories of dementia, Parkinson's disease, and depression who underwent automated assessment of brain volumes on magnetic resonance imaging and responded to a self-administered questionnaire survey in 2017. We measured SEP in childhood (household SEP at age 15), young adulthood (education), mid-adulthood (the longest occupation), and late adulthood (current wealth), and further performed group-based trajectory analysis to identify lifetime trajectory patterns on SEP. Multivariate regression models were employed to investigate the association between SEP trajectories and 4 regional brain volumes related to the development of Alzheimer's disease (ie, entorhinal cortex, hippocampus, amygdala, and the parahippocampus), the most common type of dementia. We found 3 distinct SEP trajectories (stable middle class [68%], downward [23%], and upward [9%]). Compared to those who experienced stable middle class, older adults who experienced the upward SEP mobility had significantly larger hippocampus (β: 213.2, 95% confidence interval: 14.7, 411.8). On the other hand, older adults who experienced downward SEP mobility showed no significant differences in any of the 4 brain structural volumes. Our findings indicate that upward life-course SEP mobility is associated with larger volumes of hippocampus in old age. SEP trajectory may offer us a useful lens to enhance our understanding of the etiology of dementia.

Life-course social disparities in body mass index trajectories across adulthood: cohort study evidence from China health and nutrition survey

BackgroundThe social disparities in obesity may originate in early life or in adulthood, and the associations of socioeconomic position (SEP) with obesity could alter over time. It is unclear how lifetime-specific and life-course SEP influence adult obesity development in China.MethodsBased on the China Health and Nutrition Survey (CHNS), three SEP-related indicators, including the father’s occupational position and the participant’s education and occupational position, were obtained. The life-course socioeconomic changes and a cumulative SEP score were established to represent the life-course SEP of the participants in the study. The growth mixture modeling was used to identify BMI trajectories in adulthood. Multinomial logistic regression was adopted to assess the associations between SEP and adult BMI trajectories.ResultsA total of 3,138 participants were included in the study. A positive correlation was found between the paternal occupational position, the participants’ occupational position, education, and obesity in males, whereas an inverse correlation was observed among females. Males who experienced social upward mobility or remained stable high SEP during the follow-up had 2.31 and 2.52-fold risks of progressive obesity compared to those with a stable-low SEP. Among females, stable high SEP in both childhood and adulthood was associated with lower risks of progressive obesity (OR = 0.63, 95% CI: 0.43–0.94). Higher risks of obesity were associated with the life-course cumulative SEP score among males, while the opposite relationship was observed among females.ConclusionsThe associations between life-course SEP and BMI development trajectories differed significantly by gender. Special emphasis should be placed on males experiencing upward and stable high socioeconomic change.

Childhood and Life-Course Socioeconomic Position and Cognitive Function in the Adult Population of the Hispanic Community Health Study/Study of Latinos.

The Hispanic/Latino population experiences socioeconomic adversities across the lifespan and is at greater risk of cognitive impairment, yet little is known about the role of life-course socioeconomic position (SEP) in cognitive function in this population. Using baseline data (2008-2011) from adults (aged 45-74 years) of the Hispanic Community Health Study/Study of Latinos, we assessed the association between childhood SEP and socioeconomic mobility with cognitive function, and whether this association was mediated by midlife SEP. Childhood SEP was assessed using parental education. An index combining participants' education and household income represented midlife SEP. Socioeconomic mobility was categorized as stable low, downward or upward mobility, and stable high-SEP. Cognitive function measures were modeled using survey linear regression with inverse-probability weighting, accounting for covariates. We used mediation analysis to estimate the indirect effect of childhood SEP on cognition through midlife SEP. High childhood SEP was associated with global cognition in adulthood (coefficient for parental education beyond high school vs. less than high school = 0.26, 95% confidence interval: 0.15, 0.37). This association was partially mediated through midlife SEP (indirect effect coefficient = 0.16, 95% confidence interval: 0.15, 0.18). Low SEP through the life course was associated with the lowest cognitive function. This study provides evidence that life-course SEP influences cognitive performance in adulthood.

Life-Course Mobility in Socioeconomic Position and High Depressive Symptoms Among Young Black Women: The SELF Study.

Current literature on the association between mobility in socioeconomic position (SEP) and depression demonstrates mixed findings, with variation in the benefits of upward SEP by racial group and ethnic background. No study has examined life-course SEP mobility and depressive symptoms among Black women in the United States. Our cohort included 1,612 Black women enrolled in the Study of Environment, Lifestyle and Fibroids between 2010 and 2012 and followed for 5years. We used data on socioeconomic indicators at childhood and adulthood and used latent class analysis to create a life-course SEP mobility measure (persistently low, downward, upward, and persistently high). Using the 11-item Center for Epidemiologic Studies Depression Scale (CES-D), we assessed high (≥9) versus low depressive symptoms. Multivariable log risk models were used to produce risk ratios (RRs) and 95% confidence intervals (CIs). Of the participants, 37% had high depressive symptoms. Persistently low (RR, 1.56; 95% CI, 1.31-1.86) and downward (RR, 1.36; 95% CI, 1.14-1.63) SEP mobility was associated with high depressive symptoms after adjustment for age, adult social support, and marital status. There was evidence of an effect measure modification by adult social support, with a stronger association among those who reported high adult social support compared with low adult social support. These findings suggest directing mental health resources to people experiencing low SEP at any stage in life, especially those with low SEP in adulthood, to aid in the management of depressive symptoms.

Abstract P655: Childhood and Lifecourse Socioeconomic Position and Cardiovascular Health in Hispanic/Latino Adults of the Hispanic Community Health Study/Study of Latinos

Introduction: The Hispanic/Latino population experiences extensive socioeconomic adversity across the lifespan. Yet little is known about the role of lifecourse socioeconomic position (SEP) on cardiovascular health (CVH) in this population. Hypothesis: Childhood and adulthood SEP as well as socioeconomic mobility are associated with changes in CVH over time in Hispanic/Latino adults. Methods: We used longitudinal data (N = 14,604) from the Hispanic Community Health Study/Study of Latinos (HCHS/SOL), a population-based cohort study conducted in four major U.S cities. We determined childhood SEP using participant-reported parental education classified as No schooling; Elementary, middle, or high school; and more than high school (HS). Adulthood SEP was determined through an index with a score ranging from 0 to 9 combining participants’ education, occupation, annual household income, and assets, and classified as low (0), middle (1-4), and high SEP (5-9). Using childhood and adulthood SEP, we classified participants into socioeconomic mobility categories (e.g., persisting low, downward, or upward mobility, etc.). Using the four-health metrics of the American Heart Association “Life’s Essential 8” (i.e., body mass index, non-HDL cholesterol, fasting blood glucose or HbA1c, and blood pressure) we built a score of ideal CVH ranging from 0 to 100. CVH was assessed at baseline and at the 6-year follow-up. Since changes in CVH over time differed by CVH at baseline, we conducted linear mixed effects models stratifying by CVH at baseline, with random intercept and slope, adjusting for age, sex, Hispanic/Latino background, study center, U.S or foreign-born, years in the U.S, as well as baseline health insurance, diet, physical activity, hours of sleep per night, smoking, alcohol consumption, and antihypertensive and cholesterol medication use. Results: 8% of parents did not have any formal education, 11% of the population had low SEP in adulthood, and 37% showed upward socioeconomic mobility. Among those with low (CVH score &lt;50) and moderate to high (CVH score 50-100) baseline CVH, there was no association between childhood SEP and CVH at baseline. However, among those with moderate to high baseline CVH, high childhood SEP was associated with greater CVH over time (Coefficient for &gt;HS: 0.24, 95% CI: 0.00, 0.47). There was no longitudinal association among those with low baseline CVH. High adulthood SEP was associated with greater CVH at baseline for those with low (Coefficient: 2.55 95% CI: 1.25, 3.85) and moderate to high CVH (Coefficient: 1.36 95% CI: 0.09, 2.62). However, it was not associated with changes in CVH. Socioeconomic mobility was associated with greater baseline CVH as well as with improvements in CVH over time. Conclusion: Among Hispanic/Latino population with high initial CVH, high childhood SEP and socioeconomic mobility were associated with better CVH over time.

Socioeconomic position over the life course and impaired lung function of older adults in Central and Eastern Europe: the HAPIEE study

BackgroundSocial differences in lung functioning have been reported, but the role of socioeconomic position (SEP) at different stages of life is less well understood, particularly in Central and Eastern Europe....

Association between socioeconomic position trajectories and frailty among elderly people in Taiwan

This study examined the association between socioeconomic position (SEP) trajectories and frailty in the elderly population in Taiwan. We used data from people aged 53 years and over (n = 1284) collected from wave two of the Social Environment and Biomarkers of Aging Study. Frailty was identified using the modified Fried criteria, with the scores combined to use to categorize participants as frail (score = 3-5), prefrail (score = 1 or 2) and robust (score = 0). We applied a group-based person-centered trajectory model to identify four types of SEP trajectories (low-low, 19.2%; high-low 12.5%; low-high, 35.4%; and high-high, 32.9%) to describe the social mobility patterns in the participants' lives from childhood to older age. The mean age of the study population was 65.30 ± 8.94 years, and 47.39% of the participants were women. The prevalence of frailty was 18.39%. The low-low, high-low, low-high, and high-high SEP trajectory groups were represented by 37.92%, 24.93%, 15.43%, and 7.91%, respectively, of the study population. We used multinomial logistic regression models to evaluate the association between SEP and the risk of frailty. Compared with the low-low SEP trajectory group, the high-high SEP trajectory group was significantly associated with a lower prevalence of frail and pre-frail (odds ratios 0.17 and 0.36; 95% confidence interval 0.08–0.34 and 0.21-0.61). Our results suggest that a disadvantaged life-course SEP is associated with increased risks of frailty in older age. Avoiding that unfavourable SEP trajectories over the life course translate into an increased probability of frailty is key to reducing health inequalities in elderly populations.

Lifecourse socioeconomic position and cohort differences in health expectancy in Australia: a longitudinal cohort study

There is a need to know how changes in health expectancy differ for population subgroups globally. The aim of this study was to estimate 10-year trends in health expectancies by individual markers of socioeconomic position from three points over the lifecourse, evaluating how compression and expansion of morbidity have varied within a national population. We analysed data from two cohorts of the Household Income and Labour Dynamics in Australia survey. The cohorts were followed annually from 2001 to 2007 (n=4720; baseline age range 50-100 years) and 2011 to 2017 (n=6632; baseline age range 50-99 years). Health expectancies were estimated at age 65 years for four outcomes reflecting activity limitations, disability, perceived health, and mental health. Cohort differences were compared by gender, age left school, occupational prestige, and housing tenure. Women with low socioeconomic position were the only group with no improvements in life expectancy across the two cohorts. Among men with low education and all women gains in life expectancy comprised entirely of years lived with global activity limitations. Compression of years lived with severe-disability, poor self-rated health, and poor mental health was most consistently observed for men and women with high education and home ownership. Occupational prestige did not greatly differentiate cohort differences in health expectancies. Over the past two decades in Australia, social disparities in health expectancies have at least been maintained, and have increased for some outcomes. Equitable gains in health expectancies should be a major public health goal, and will help support sustainable health and social care systems. Australian Research Council.

Individual Life-Course Socioeconomic Position and Hearing Aid Use in the Atherosclerosis Risk in Communities Study.

To measure the association between individual life-course socioeconomic position (SEP) and hearing aid use, we examined childhood and adulthood socioeconomic variables collected at the Atherosclerosis Risk in Communities (ARIC) study baseline visit (1987-1989)/Life Course Socioeconomic Status study (2001-2002) and hearing aid use data collected at visit 6 (2016-2017). ARIC is a prospective cohort study of older adults (45-64 years) recruited from 4 U.S. communities. This analysis included a subset of 2 470 participants with hearing loss at visit 6 (≥25 decibels hearing level [dB HL] better-ear) with complete hearing aid use data. Childhood SEP variables included parental education, parental occupation, and parental home ownership. Young and older adulthood SEP variables included income, education, occupation, and home ownership. Each life epoch was assigned a score ranging from 0 to 5 and then summed to calculate the individual cumulative SEP score. Multivariable-adjusted logistic regression was used to estimate the association between individual cumulative SEP and hearing aid use. Missing SEP scores were imputed for participants with incomplete socioeconomic data. Of the 2 470 participants in the analytic cohort (median [interquartile interval] age 79.9 [76.7-84.0], 1 330 [53.8%] women, 450 [18.2%] Black), 685 (27.7%) participants reported hearing aid use. Higher cumulative SEP was positively associated with hearing aid use (odds ratio [OR] = 1.09, 95% confidence interval [CI]: 1.04-1.14), and slightly stronger for childhood (OR = 1.09, 95% CI: 1.00-1.20) than older adulthood SEP score (OR = 1.06, 95% CI: 0.95-1.18). In this community-based cohort of older adults with hearing loss, higher individual life-course SEP was positively associated with hearing aid use.

Lifecourse socioeconomic position and diabetes incidence in the REasons for Geographic and Racial Differences in Stroke (REGARDS) study, 2003 to 2016

Low socioeconomic position (SEP) across the lifecourse is associated with Type 2 diabetes (T2DM). We examined whether these economic disparities differ by race and sex. We included 5448 African American (AA) and white participants aged ≥45 years from the national (United States) REasons for Geographic and Racial Differences in Stroke (REGARDS) cohort without T2DM at baseline (2003–07). Incident T2DM was defined by fasting glucose ≥126 mg/dL, random glucose ≥200 mg/dL, or using T2DM medications at follow-up (2013–16). Derived SEP scores in childhood (CSEP) and adulthood (ASEP) were used to calculate a cumulative (CumSEP) score. Social mobility was defined as change in SEP. We fitted race-stratified logistic regression models to estimate the association between each lifecourse SEP indicator and T2DM, adjusting for covariates; additionally, we tested SEP-sex interactions. Over a median of 9.0 (range 7–14) years of follow-up, T2DM incidence was 167.1 per 1000 persons among AA and 89.9 per 1000 persons among white participants. Low CSEP was associated with T2DM incidence among AA (OR = 1.61; 95%CI 1.05–2.46) but not white (1.06; 0.74–2.33) participants; this was attenuated after adjustment for ASEP. In contrast, low CumSEP was associated with T2DM incidence for both racial groups. T2DM risk was similar for stable low SEP and increased for downward mobility when compared with stable high SEP in both groups, whereas upward mobility increased T2DM risk among AAs only. No differences by sex were observed. Among AAs, low CSEP was not independently associated with T2DM, but CSEP may shape later-life experiences and health risks.

Why Are Inequalities in Disability-Free Life Expectancy by Socioeconomic Position Widening?

Life expectancy has increased over previous decades, but several countries are seeing widening inequalities in disability-free life expectancy (DFLE) by socioeconomic position (SEP). In this symposium we address three unanswered questions.1. Do DFLE trends differ for SEP groups, and which of the underlying transitions (incidence, recovery, death when disability-free, death when already disabled) explains the differences?2. Do DFLE trends by SEP depend on when in the life-course SEP is measured (early life - education, mid-life - occupational status or late-life - material disadvantage)?3. How much does multi-morbidity contribute to differing trends in DFLE by SEP, since multi-morbidity is more prevalent in low SEP groups? To answer these questions, we use unique longitudinal studies of older people across different generations in two countries: the UK (Cognitive Function and Ageing Studies – CFAS I and II) and Australia (Household, Income and Labour Dynamics in Australia – HILDA). The first presentation sets the scene with findings from a systematic review of worldwide trends in life and healthy life expectancy by SEP. Presentations two and three examine the first question using DFLE at age65 by SEP defined by late-life disadvantage in CFAS (1991-2011), followed by HILDA (2001-2017). The fourth presentation investigates the effect of different life-course measures of SEP using HILDA. The final presentation from CFAS examines the third question. This symposium increases our understanding of how and why inequalities in DFLE by SEP are changing with the goal of achieving healthy ageing for all.

Nativity differences in lifecourse socioeconomic position and late‐life cognition among KHANDLE participants

AbstractBackgroundSocioeconomic position (SEP) in childhood and adulthood is associated with late‐life cognition. Less is known about how SEP changes may be associated with late‐life cognition in diverse cohorts.MethodsThe Kaiser Healthy Aging and Diverse Life Experiences Study (KHANDLE) is a cohort of community‐dwelling Kaiser Permanente members who reside in the San Francisco Bay area and Sacramento valley (n=1,708; Asians (24%), Blacks (26%), Latinos (20%) and Whites (30%)). KHANDLE aims to evaluate how lifecourse and sociocultural factors influence late‐life brain health and cognitive decline and contribute to race/ethnic disparities. We used linear regression to test the association between lifecourse SEP trajectories and late‐life cognition and tested if these associations differed by US vs. foreign nativity. Childhood SEP is a composite of parents’ education (≥HS vs. &lt;HS), childhood hunger, and self‐reported family financial status. Adult SEP included participants’ education (≥HS vs. &lt;HS), late‐life low income status (e.g. qualified for low‐income welfare programs), and self‐reported social status. Participants were classified as having consistently high SEP (HH), low childhood/high adult SEP (LH), high childhood/low adult SEP (HL), or consistently low SEP (LL). Executive function, semantic memory and verbal episodic memory measured with the Spanish and English Neuropsychological Assessment Scales (SENAS) were z‐standardized and averaged for overall cognition. Pooled analyses adjusted for age, race/ethnicity, gender, and foreign nativity.ResultsOverall, participants classified as LH did not differ from HH (ref.) in any cognitive domain, while those classified as HL and LL had lower cognition than HH in all domains (see table). We observed a significant interaction of US vs. foreign birth and lifecourse SES trajectory for semantic memory (p=0.01), but no other domain. Stratified analyses demonstrated a similar pattern to pooled. However, foreign‐born participants HL participants had significantly lower overall cognition (p=0.03), and verbal memory (p=0.02) than US‐born HL participants. By contrast, foreign‐born LH participants performed significantly better than US‐born LH in semantic memory (p=0.01).ConclusionsThose with high Adult SEP had the best cognitive function, regardless of childhood SEP or nativity. In some measures of cognition, foreign‐born HL participants performed worse than US‐born, while foreign‐born LH performed better.

The impact of lifecourse socio-economic position and individual social mobility on breast cancer risk

BackgroundWomen with an advantaged socioeconomic position (SEP) have a higher risk of developing breast cancer (BC). The reasons for this association do not seem to be limited to reproductive factors and remain to be understood. We aimed to investigate the impact of lifecourse SEP from childhood and social mobility on the risk of BC considering a broad set of potential mediators.MethodsWe used a discovery-replication strategy in two European prospective cohorts, E3N (N = 83,436) and EPIC-Italy (N = 20,530). In E3N, 7877 women were diagnosed with BC during a median 24.4 years of follow-up, while in EPIC-Italy, 893 BC cases were diagnosed within 15.1 years. Hazard ratios (HR) were estimated using Cox proportional hazard models on imputed data.ResultsIn E3N, women with higher education had a higher risk of BC (HR [95%CI] = 1.21 [1.12, 1.30]). This association was attenuated by adjusting for reproductive factors, in particular age at first childbirth (HR[95%CI] = 1.13 [1.04, 1.22]). Health behaviours, anthropometric variables, and BC screening had a weaker effect on the association. Women who remained in a stable advantaged SEP had a higher risk of BC (HR [95%CI] = 1.24 [1.07; 1.43]) attenuated after adjustment for potential mediators (HR [95%CI] = 1.13 [0.98; 1.31]). These results were replicated in EPIC-Italy.ConclusionsThese results confirm the important role of reproductive factors in the social gradient in BC risk, which does not appear to be fully explained by the large set of potential mediators, including cancer screening, suggesting that further research is needed to identify additional mechanisms.

Exploring the relation between socioeconomic position and DNA methylation in a European population

Abstract Background Previous investigations have reported that adverse socioeconomic circumstances across the life-course lead to the alteration of major biological processes, eventually resulting in a higher disease risk and premature death. In particular, a low life-course socioeconomic position (SEP) has been associated with a modified epigenetic signature of loci involved in inflammation, the physiological response to stress, and other regulatory processes. Methods In this study, we investigated the association between nine indicators of SEP across the life-course and the differential methylation of 451'000 genome-wide CpG markers, using data from 690 adults included in a Swiss population-based study. We further examined the interrelations between the SEP-related CpGs, and the biological pathways in which the identified markers are involved. Results Three SEP indicators in adulthood were associated the differential methylation of 161 genome-wide CpG markers, whereby 156 CpGs were less methylated in people with low versus high SEP. Among the identified CpGs, a substantial proportion of markers were no longer associated with SEP upon accounting for health behaviors and cardiometabolic disorders. In addition, the identified CpGs were found to be involved in immune, inflammatory, and cancer-related processes. Conclusions Our results support the hypothesis that adverse socioeconomic circumstances may lead to the dysregulation of inflammatory processes, eventually resulting in the occurrence of serious chronic conditions such as atherosclerosis, diabetes, or cancer. Key messages Socioeconomic position is a major determinant of health-related outcomes. Epigenetic modifications may constitute a biological mechanism through which socioeconomic circumstances affect health.

Education across the life-course and hypertension in adults from Southern Brazil.

The present study examines the association between life-course socioeconomic position (SEP) and hypertension (SAH), focusing on the health impacts of childhood SEP (SEPc), adult SEP (SEPa), as well as SEP mobility. Data from the Brazilian EpiFloripa Cohort Study (n = 1,720; 56% women; 55% <= 30 years) were analyzed. SAH was determined by the average of two measures of systolic and diastolic blood pressure, previous medical diagnosis or use of anti-hypertensive medication (43% of the sample was hypertensive). The main independent variables were: SEPa - participants' level of education; SEPc - parental educational attainment; and SEP mobility - the socio-economic trajectories from SEPc to SEPa. Five logistic regressions models were adjusted for sex, age or income, and were compared among each other. High SEPa was associated with a 37% reduction in the odds of SAH compared to low SEPa. High SEP over the life course was associated with 34-37% lower odds of SAH compared to persistent low SEP. Mobility models explained more of the outcome variance than the sensitive period model. The results reinforce the importance of education in the risk of SAH and the relevance of a socioeconomic mobility approach for the analysis of social inequalities in health.

INTEGRATIVE ANALYSIS OF ALZHEIMER’S DISEASE GWAS TO DEVELOP A NEW POLYGENIC PREDICTOR AND TEST BIOSOCIAL ETIOLOGY

Alzheimer’s disease (AD) has genetic and environmental causes and etiology is thought to reflect interplay among these factors. A barrier to integration of genetic and environmental etiologic factors in research to inform prevention and intervention is poor understanding of AD genetics beyond APOE4. We used the new Genomic SEM methodology to conduct integrative analysis of results from several AD genome-wide association studies (GWAS), including brain-imaging and autopsy AD GWAS, to derive a novel, polygenic genetic predictor of AD. We applied this polygenic predictor in the US Health and Retirement Study to test associations with (1) cognitive aging measured from repeated-measures longitudinal cognitive-test data; and (2) blood-chemistry-based biological age algorithms. In further exploratory analysis, we tested if risk measured by the novel AD polygenic predictor was correlated with and/or buffered by a known environmental factor influencing AD etiology, life-course socioeconomic position. Results map new directions for biosocial AD research.

INEQUALITIES IN FRAILTY BY SOCIO-ECONOMIC POSITION: IT’S ALL IN THE TIMING

A number of studies have found that higher socio-economic position (SEP) appears protective of becoming frail. However, not only can SEP be defined in early, mid or late life, by education, occupational status or income/material disadvantage respectively, but frailty may occur in the young old as well as the very old. Do the same measures of SEP reflect inequalities in frailty in the young old as the very old? Does it matter when in the lifecourse SEP is measured? Have inequalities in frailty between SEP groups changed across the generations of older people? We seek to answer such questions from cohorts across the spectrum of later life. The first presentation, from the 1958 British Birth Cohort Study, examines the association between early-life SEP and frailty at age 50 and whether this association is due to continued disadvantage into mid-life. The second presentation moves to very old age, examining the role of early, mid and late life disadvantage on the progression of frailty between ages 85 and 90 in the Newcastle 85+ cohort. The third presentation, based on the electronic health records of adults aged 75 years and over in England, focuses on whether SEP modifies frailty trajectories in the last year of life. The final presentation examines whether SEP inequalities in frailty have changed over different generations of older people, and utilises data from the Cognitive Function and Ageing Studies. Together these presentations increase understanding of which SEP groups should be targeted for interventions to reduce frailty throughout later life.

Differential impact of socioeconomic position across life on oral cancer risk in Kerala, India: An investigation of life-course models under a time-varying framework.

The incidence of oral cancer has been rapidly increasing in India, calling for evidence contributing to a deeper understanding of its determinants. Although disadvantageous life-course socioeconomic position (SEP) is independently associated with the risk of these cancers, the explanatory mechanisms remain unclear. Possible pathways may be better understood by testing which life-course model most influences oral cancer risk. We estimated the association between life-course SEP and oral cancer risk under three life-course models: critical period, accumulation and social mobility. We recruited incident oral cancer cases (N=350) and controls (N=371) frequency-matched by age and sex from two main referral hospitals in Kozhikode, Kerala, India, between 2008 and 2012. We collected information on childhood (0-16years), early adulthood (17-30years) and late adulthood (above 30years) SEP and behavioural factors along the life span using interviews and a life-grid technique. Odds ratios (OR) and 95% confidence intervals (CI) were estimated for the association between life-course SEP and oral cancer risk using inverse probability weighted marginal structural models. Relative to an advantageous SEP in childhood and early adulthood, a disadvantageous SEP was associated with oral cancer risk [(OR=2.76, 95% CI: 1.99, 3.81) and (OR=1.84, 95% CI: 1.21, 2.79), respectively]. In addition, participants who were in a disadvantageous (vs advantageous) SEP during all three periods of life had an increased oral cancer risk (OR=4.86, 95% CI:2.61, 9.06). The childhood to early adulthood social mobility model and overall life-course trajectories indicated strong influence of exposure to disadvantageous SEP in childhood on the risk for oral cancer. Using novel approaches to existing methods, our study provides empirical evidence that disadvantageous childhood SEP is critical for oral cancer risk in this population from Kerala, India.