Changes in body mass index and three-year incidence of overweight/obesity among urban women aged 30–40 years in Vellore, Tamil Nadu, India: A non-concurrent cohort study

Abstract

ABSTRACT Background: Although studies often report the prevalence of obesity, community-based studies reporting the incidence of overweight or obesity in India are scarce. Such incidence data are crucial for improving projections about the future burden of obesity. Methods: A non-concurrent follow-up study was done in 2015 in urban Vellore, Tamil Nadu, among two groups of women aged 30-40 years, with body mass index (BMI) <25 kg/m2 (normal) and BMI ≥25 kg/m2 (overweight/obese) in 2012, to assess changes in BMI. The sampling frame consisted of 473 women: 209 women with BMI <25 kg/m2, and 264 women with BMI ≥25 kg/m2, who were part of a cross-sectional survey in 2012. A randomly selected list of 370 women (80% of the original cohort) was used to trace the women. Measurements at follow-up included weight, height, dietary and other risk factors. Results: Of 370 women, 170 (45.9%) were followed up at the end of three years, which included 82 with BMI <25 kg/m2 and 88 with BMI >25 kg/m2. The incidence of overweight (BMI ≥25 kg/m2) in three years, was 29.2% (24/82), among women with a normal BMI (<25 kg/m2) in 2012. Among the 88 women who were overweight/obese in 2012, there was no regression to normal BMI within the three years of follow-up. There was an association between the incidence of overweight and the intake of carbohydrates (adjusted odds ratios (AORs): 3, 95% confidence interval (CI): 1.04 to 8.63) and protein intake (AOR: 20.0, 95% CI:2.5 to 158.3). Conclusions: This study found an incidence of nearly one-third (29.2%) of developing high BMI (≥25.0 kg/m2) in 30-40-year-old urban women from Vellore, implying a rapid increase in overweight and obesity among young women.