Gender difference in prevalence of hypertension among Indians across various age-groups: a report from multiple nationally representative samples.

BACKGROUND

Prevalence of hypertension increases with age, but there is a general perception in India that women are less affected at every stage of life, although empiric evidence hardly exists regarding gender difference in hypertension in Indians of different ages. Therefore, we aimed to examine the gender difference in hypertension among Indians across various age-groups; and the contribution of variation in body mass index (BMI) to this difference.

METHODS

Data were analysed after combining National Family Health Survey 4 (n = 294,584 aged 35-49 years) and Study of Ageing and Health wave 2 (n = 7118 aged 50 + years) datasets (NFHS-SAGE). Longitudinal Ageing Study of India (LASI) dataset (n = 65,900 aged > 45years) was analysed to replicate the results. Hypertension was defined if systolic and diastolic blood pressure was > 89 and/or > 139 respectively and/or if there was a history of anti-hypertensive medication. Descriptive summaries were tabulated and plotted to examine the gender difference in hypertension in various age-groups (35-39,40-44, 45-49, 50-54, 55-59, 60-64, 65-69, ≥ 70). Odds Ratios (ORs) from logistic regression models estimated the age gradient of hypertension and their male-female difference, adjusted for Body Mass Index (BMI).

RESULTS

Males had a higher prevalence of hypertension up to 50 years; after that, females had higher rates. The estimates of age gradient, expressed as ORs, were 1.02 (1.02, 1.02) in males versus 1.05(1.05, 1.06) in females (p < 0.001) in NFHS-SAGE and 1.01(1.01, 1.02) in males versus 1.04(1.03, 1.04)in females (p < 0.001) in LASI;these differences marginally changed after adjustment with BMI.

CONCLUSION

This is perhaps the first study to comprehensively demonstrate that cardio-metabolic risk in Indian females surpasses males after 50 years of age, "busting the myth" that Indian females are always at much lower risk than males; and this evidence should inform the Indian healthcare system to prioritise older women for screening and treatment of hypertension.