Body-mass index (BMI) is a proxy for fat accumulation in the body. Asian populations experience increased diabetes and cardiovascular diseases risks at lower BMI than the WHO recommended cut-off for overweight (25 - 29.9 kg/m2) and obesity (>30 kg/m2). Bangladesh guideline follows BMI 18.5 - 24.9 kg/m2 for normal weight. This study aims at quantifying hypertension and type 2 diabetes risk in Bangladeshi adults with moderately increased BMI (23.0-24.9 kg/m2) i.e. those who are “at risk of overweight”.
Data from the most recent Bangladesh Demographic and Health Survey (BDHS 2011) were analysed. BMI, blood pressure, blood sugar and related information were collected from a nationally representative sample of 7,433 adults, aged ≥ 35 years. Modified Poisson regression models with robust error variance were used to calculate adjusted relative risk (ARR) for HTN or T2DM by BMI categories, with BMI 18.5 - 22.9 as the reference.
About 45% of Bangladeshi adults in this nationally representative population had BMI within 18.5 - 22.9 kg/m2. About one-in-four (25%) had BMI ≥ 23 including 2% with BMI > 30.0 (obese). About 12% of Bangladeshi adults, both male and female, had BMI within 23.0-24.9 kg/m2 (moderately increased), and showed increased hypertension (ARR 1.55-1.77) and diabetes risk (ARR 1.54-1.93), compared to the reference group (18.5 - 22.9 kg/m2). Apart from BMI, increased age (≥ 56 years), higher wealth and education were associated with increased hypertension and diabetes risks.
Our findings support the recommendation that calls for setting optimum BMI for Asian populations to 18.5-23.0 kg/m2 for health promotion and public health interventions such as leisure time physical activity. WHO cut-offs for overweight (BMI 25.0-29.9 kg/m2) should be used to facilitate international comparisons. Future studies may explore BMI cut-offs when risk of malnutrition- related illnesses converts to risk of chronic disease for Asian populations.