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.

Background Hypertension, a critical risk factor for cardiovascular diseases, is found to cluster between spouses due to within-couple aggregation of antecedent environmental risk factors, either through assortative mating or cohabitation. However, majority of the evidence of spousal concordance of hypertension is from Caucasoid couples from western societies, whereas marriage, partner selection, and post-marital roles of husband and wives are very different in Indian society. Therefore, we aimed to comprehensively examine the phenomenon of spousal concordance of hypertension in Indian couples. Method Couples from Longitudinal Ageing Study in India Wave 1 (n = 10,994) and National Family Health Survey Round 5 (n = 52,026) represented 15 years + Indian spouses. Hypertension was defined when systolic and/or diastolic blood pressure was > 139 and > 89 mmHg respectively, and/or if the individual was previously diagnosed or on anti-hypertensive medication. Odds Ratios (OR) estimated the within-couple concordance of hypertension while adjusting for five environmental risk factors of hypertension: individual-level body mass index, education and caste, and household-level wealth and place of residence. Result OR marginally attenuated from 1.84 (95% Confidence Interval: 1.77, 1.92) to 1.75 (1.68, 1.83) after adjustment, signifying negligible explanation by environmental risk factors, and plausibility of “novel” risk factors. Concordance continued to weaken with age (OR: 2.25 (2.02, 2.52) in < 30 versus 1.36 (1.20, 1.53) in ≥ 60 years). Conclusion Our study underscores two critical knowledge gaps: first, the identity of “novel” risk factors of hypertension and second, the mechanism behind weakening of concordance with age. Future research should explore these novel risk factors rigorously and try to modify them. Also, primary healthcare policy of the country should focus on couples in addition to individuals for hypertension and cardiovascular disease screening and management.

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