Intergenerational hypertension transmission before and after South Africa's democratic transition

Apartheid's structural violence produced profound cardiovascular inequalities among Black South Africans through processes that accelerate biological aging ("weathering") and transmit health disadvantage across successive generations. Whether South Africa's 1994 political transition interrupted this intergenerational transmission remains unknown. This study tests whether parent-to-offspring hypertension transmission weakened among cohorts born after apartheid's end, using the 1994 transition as a natural experiment.

This study analyzed 30,438 parent-offspring dyads from five waves (2008-2017) of South Africa's National Income Dynamics Study, representing 11,655 unique offspring aged 18 years and older. Hypertension was defined as blood pressure ≥140/90mmHg or use of antihypertensive medication. Logistic regression models with offspring-clustered standard errors estimated transmission strength by birth cohort (born before 1960; born 1960-1993; born 1994 or later), testing whether socioeconomic factors (education, income, province) attenuated parent-offspring associations.

Parent-offspring hypertension transmission remained strong after adjusting for demographics and socioeconomic factors (OR = 1.83, 95% CI: 1.71-1.95). Transmission strength was statistically invariant across birth cohorts, with no significant weakening among those born after 1994 (OR = 1.63) compared with those born during the apartheid era (OR = 1.83). Socioeconomic controls produced minimal attenuation (a 7% reduction), suggesting that biological embedding predominates over structural persistence. Cohort-invariant transmission persisted among Black Africans (OR = 1.77) and Coloureds (OR = 2.05), with birth cohort interactions failing to reach statistical significance in both groups.

Political liberation dismantled apartheid's legal structures but failed to interrupt intergenerational cardiovascular transmission. The "Born Free" generation inherits hypertension vulnerability at rates indistinguishable from apartheid-era cohorts despite improved socioeconomic conditions. This persistence suggests that biological embedding mechanisms transcend political change, requiring interventions that target both structural conditions and biological pathways.