Income-based inequalities in risk factors of NCDs and inequities of preventive care services amongst 202,682 adults: a cross-sectional study of South Asia Biobank

Abstract Background There is scant research examining income-based inequalities in risk factors of non-communicable diseases (NCDs) and inequities of preventive care services across the South Asian population. Methods We conducted a cross-sectional study of 202,682 adults aged 18 or above in four South Asian countries: Bangladesh, India, Pakistan, and Sri Lanka. We combined South Asia Biobank (SAB) surveillance data with environmental mapping exposure and 24-h dietary recall to estimate income-based inequalities using concentration curves and concentration indices (CI) that measure the magnitude and directional inequality effects. We also computed the horizontal inequity index (HII) for need-standardised healthcare utilisation and advice by measuring the extent to which the distribution of health promotion advice matches the distribution of diet-related risk factor variables across the income distribution. We reported concentration index coefficients and standard errors. Results Inequalities in exposure and diet-related risk factors of NCDs were observed. Underweight was concentrated amongst the poor (CI = − 0.16, SE = 0.005, p < 0.001), while overweight and obesity were concentrated amongst the rich (CI = 0.11, SE = 0.003, p < 0.001). Non-recommended intake of fats (CI = 0.04, SE = 0.003, p < 0.001) and carbohydrates were concentrated amongst the rich (CI = 0.05, SE = 0.003, p < 0.001), while non-recommended intake of free sugars (CI = − 0.05, SE = 0.004, p < 0.001) and fruits and vegetables amongst the poor (CI = − 0.07, SE = 0.005, p < 0.001). Exposure to unhealthy outlets was concentrated amongst the rich (CI = 0.02, SE = 0.002, p < 0.001). There were persistent and pro-rich inequities in healthcare utilisation (HII = 0.02, SE = 0.002, p < 0.001) and advice for salt reduction (HII = 0.02, SE = 0.004, p < 0.001), fat reduction (HII = 0.02, SE = 0.004, p < 0.001), healthy weight (HII = 0.03, SE = 0.006, p < 0.001), and fruits and vegetables consumption (HII = 0.04, SE = 0.004, p < 0.001). Conclusions These findings indicate the need to address and mitigate income-based inequalities in diet-related risk factors of NCDs and underscore the need of policies directed at mitigating NCDs risk exposure and achieving improved and equitable access to healthcare.