Changes in asset-based wealth across the life course in birth cohorts from five low- and middle-income countries

Lower Socioeconomic Status Predicts Increased Proinflammatory Signaling in Late Pregnancy: Evidence From a Filipino Cohort

OBJECTIVES

Maternal socioeconomic status (SES) is an important predictor of adverse birth outcomes and postnatal health across global populations. Chronic inflammation is implicated in cardiometabolic disease risk in high-income contexts and is a potential pathway linking maternal adversity to offspring health trajectories. To clarify how socioeconomic inequality shapes pregnancy inflammation in middle-income settings, we investigated SES as a predictor of inflammatory cytokines in late gestation in a sample from the Cebu Longitudinal Health Nutrition Survey in Cebu, Philippines.

METHODS

We used multiple regression to evaluate maternal SES, reflected in household assets, as a predictor of general inflammation (C-reactive protein), inflammatory cytokines (interleukin-6, interleukin-10), and inflammatory balance (n = 407). Inflammatory markers were measured at 29.9 weeks gestation in dried blood spots, and a measure reflecting relative balance of IL6 and IL10 was calculated to capture pro- versus anti-inflammatory skewed immune profiles.

RESULTS

Greater household assets significantly predicted lower IL6 concentration (p <  0.001), with a trend toward lower IL6 relative to IL10 (p = 0.084). C-reactive protein and IL10 were not individually related to SES.

CONCLUSIONS

The inverse relationship between SES and pregnancy inflammation in Cebu is consistent with results from high-income settings. These findings further highlight the influence of socioeconomic conditions on immune regulation during pregnancy. Given the evidence that gestational inflammation impacts offspring fetal growth, our results suggest that social and economic effects on immune function may be an important pathway for the intergenerational transmission of health disparities.

Intimate partner violence, depression, and chronic low-grade inflammation among middle-aged women in Cebu, Philippines

OBJECTIVES

Recent discussions in human biology have highlighted how local ecological contexts shape the relationship between social stressors and health across populations. Chronic low-grade inflammation has been proposed as a pathway linking social stressors to health, with evidence concentrated in high-income Western contexts. However, it remains unclear whether this is an important pathway in populations where prevalence is lower due to lower adiposity and greater infectious exposures. To investigate this further, we tested associations between multiple types of intimate partner violence (IPV), a highly prevalent stressor and health crisis globally, and C-reactive protein (CRP), a commonly used measure of chronic low-grade inflammation, in Cebu, Philippines. For reference, we compared results for CRP to depression, a well-established and consistently observed health outcome of IPV.

METHODS

Data came from 1601 currently partnered women (ages 35-69 years) as part of the Cebu Longitudinal Health and Nutrition Survey. IPV exposures included physical, emotional, and controlling behavior. Depression scores were measured using a modified version of the Center for Epidemiologic Studies-Depression Scale for this population, whereas plasma CRP was measured from overnight-fasted morning blood samples.

RESULTS

All three types of IPV were associated with a higher depression score. However, none of the IPV measures were associated with CRP. In a post hoc interaction test, emotional IPV became positively associated with CRP as waist circumference increased above the mean.

CONCLUSIONS

Our results suggest a complex relationship between social stressors and chronic low-grade inflammation, which is likely dependent on the population-specific context of lifestyle and environmental factors.

Socioeconomic status is negatively associated with immunosenescence but positively associated with inflammation among middle-aged women in Cebu, Philippines

BACKGROUND

Socioeconomic status (SES) gradients in health are well-documented, and while biological pathways are incompletely understood, chronic inflammation and accelerated immune aging (immunosenescence) among lower SES individuals have been implicated. However, previous findings have come from samples in higher income countries, and it is unclear how generalizable they are to lower- and middle-income countries (LMIC) with different infectious exposures and where adiposity-an important contributor to chronic inflammation-might show different SES patterning. To address this gap, we explored associations between SES and inflammation and immunosenescence in a sample of women in Cebu, Philippines.

METHODS

Data came from the mothers of the Cebu Longitudinal Health and Nutrition Survey birth cohort (mean age: 47.7, range: 35-69 years). SES was measured as a combination of annual household income, education level, and assets. Chronic inflammation was measured using C-reactive protein (CRP) in plasma samples from 1,834 women. Immunosenescence was measured by the abundance of exhausted CD8T (CD8 + CD28-CD45RA-) and naïve CD8T and CD4T cells, estimated from DNA methylation in whole blood in a random subsample of 1,028. Possible mediators included waist circumference and a collection of proxy measures of pathogen exposure.

RESULTS

SES was negatively associated with the measures of immunosenescence, with slight evidence for mediation by a proxy measure for pathogen exposure from the household's drinking water source. In contrast, SES was positively associated with CRP, which was explained by the positive association with waist circumference.

CONCLUSIONS

Similar to higher income populations, in Cebu there is an SES-gradient in pathogen exposures and immunosenescence. However, lifestyle changes occurring more rapidly among higher SES individuals is contributing to a positive association between SES and adiposity and inflammation. Our results suggest more studies are needed to clarify the relationship between SES and inflammation and immunosenescence across LMIC.

Conditional wealth to estimate association of wealth mobility with health and human capital in low- and middle-income country cohorts

Temporally harmonized asset indices allow the study of changes in relative wealth (mean, variance, social mobility) over time and its association with adult health and human capital in cohort studies. Conditional measures are the unexplained residuals of an indicator regressed on its past values. Using such measures, previously used to study the relative importance of key life stages for anthropometric growth, we can identify specific life stages during which changes in relative wealth are important for adult health in longitudinal studies. We discuss the assumptions, strengths and limitations of this methodology as applied to relative wealth. We provide an illustrative example using a publicly-available longitudinal dataset and show how relative wealth changes at different life stages are differentially associated with body mass index in adulthood.

Assessing comparative asset-based measures of material wealth as predictors of physical growth and mortality

Social scientists and policymakers have increasingly relied on asset-based indices of household wealth to assess social disparities and to identify economically vulnerable populations in low- and middle-income countries. In the last decade, researchers have proposed a number of asset-based measures that permit global comparisons of household wealth across populations in different countries and over time. Each of these measures relies on different assumptions and indicators, and little is known about the relative performance of these measures in assessing disparities. In this study, we assess four comparative, asset-based measures of wealth-the Absolute Wealth Estimate (AWE), the International Wealth Index (IWI), the Comparative Wealth Index (CWI), and the "Standard of Living" portion of the Multi-Dimensional Poverty Index (MPI), along with a variable measuring television ownership-and compare how well each predicts health related variables such as women's BMI, children's height-for-age Z scores, and infant mortality at the household and survey level. Analyzing data from over 300 Demographic and Health surveys in 84 countries (n = 2,304,928 households), we found that AWE, IWI, CWI, MPI are all highly correlated (r = 0.7 to 0.9). However, IWI which is based on a common set of universally weighted indicators, typically best accounts for variation in all three health measures. We discuss the implications of these findings for choosing and interpreting these measures of wealth for different purposes.

Subjective social status is associated with happiness but not weight status or psychological distress: An analysis of three prospective birth cohorts from low- and middle-income countries

BACKGROUND

Subjective social status (SSS, perception of social position relative to a frame of reference) has been associated with physical, mental and socio-emotional wellbeing. However, these associations may be susceptible to unmeasured confounding by life course objective socio-economic position (SEP; such as wealth, education and employment) and life satisfaction.

PURPOSE

To estimate the association of position on ladders of perceived community respect and perceived economic status with weight, distress and wellbeing, independent of objective SEP in cohorts from three low and middle-income countries.

METHODS

We used data from birth cohorts in Guatemala (n = 1258), Philippines (n = 1323) and South Africa (n = 1393). We estimated the association of perceived community respect and perceived economic status with body mass index (kg/m²), the World Health Organization's Self-Reported Questionnaire-20 (SRQ-20) for psychological distress, and Lyubomirsky's Subjective Happiness Scale. We estimated these associations using robust linear regression models adjusting for indicators of life course objective SEP, early life characteristics, adult covariates, and life satisfaction.

RESULTS

Participants in South Africa (age 27-28y) rated themselves higher on average for both the respect (7 vs 5 in Guatemala and 6 in Philippines) and economic (5 vs 3 in Guatemala and 4 in Philippines) ladder measures. Position on neither community respect nor economic ladders were associated with BMI or psychological distress. Higher position on community respect (Guatemala: 0.03, 95%CI: 0.01, 0.04; Philippines: 0.03, 95% CI: 0.02, 0.05; South Africa: 0.07, 95%CI: 0.04, 0.09) and economic (Guatemala: 0.02, 95%CI: 0, 0.04; Philippines: 0.04, 95%CI: 0.02, 0.07; South Africa: 0.07, 95%CI: 0.04, 0.10) ladders were associated with greater happiness.

CONCLUSIONS

Subjective social status showed small but consistent associations with happiness in birth cohorts independent of life-course SEP.