Caste Differences in Hypertension Among Women in India: Diminishing Health Returns to Socioeconomic Status for Lower Caste Groups.

Introduction: The caste system is a relatively rigid system of social hierarchy in India. The caste membership defines one's access to resources and life opportunities. A growing body of research suggests that lower caste groups have an excess burden of morbidity and mortality in India. However, it is not clear as to what extent caste differences in health are conditioned by socioeconomic status (SES) indicators.
Purpose: This study examined the caste differences in hypertension and tested whether caste differences in hypertension are conditioned by education and household wealth in a representative sample of women in India.
Methods: This study used data from the National Family Health Survey (NFHS) 2015-2016, India. The analysis is based on a nationally representative sample of 648,064 adult women aged 15-49 years. We used logistic regression to examine whether the association between caste and hypertension varied by education and wealth index using interactions and controlling for potential confounders.
Results: The regression models suggest that scheduled tribes and non-caste members have the highest odds of hypertension compared with privileged upper caste members. Interaction models indicate complex intersections of caste, education, and wealth index. The predicted probabilities derived from these interaction models suggest that while SES indicators are inversely associated with the odds of hypertension, the inverse patterning was significantly weaker in other backward classes and more protective in non-caste members compared with upper caste. Additionally, caste difference in predictive risk of hypertension tends to diverge at the lower levels of SES and become narrower at the higher levels of SES.
Conclusions: These findings provide evidence of differential returns to SES and have implications for understanding the causes of SES patterning in health among disadvantaged caste groups in India.