Secular trends in the prevalence of diabetes and prediabetes among the rural population of South India

Objective: This study aimed to assess the secular trends in the prevalence of diabetes and pre-diabetes from two cross-sectional studies done 11 years apart, in rural Tamil Nadu. 

Methods: The Telemedicine PRoject for screENing Diabetes and its complications in rural Tamil Nadu(TREND) study is a cross-sectional survey that screened 14,117 individuals aged ≥ 18 years between 2018–2021. TREND was conducted in 30 villages of Chengalpattu/Kancheepuram districts of Tamil Nadu in Southern India. The prevalence of diabetes and prediabetes was compared with an earlier study the Chunampet Rural Diabetes Prevention Project(CRDPP) which screened 23,380 individuals aged ≥ 20 years between 2006–2010 using similar methodology, in 42 villages in the same area. Diabetes and prediabetes were diagnosed using the WHO criteria. 

Results: Individuals screened in TREND were significantly older (43.7 ± 14.5 vs.40.5 ± 15.2 years) and had higher BMI (23 ± 5 vs.21.4 ± 4.1) compared to CRDPP participants. The age and gender adjusted prevalence of diabetes increased from 5.3% to 13.7% (158.5% increase) during this 11-year period. There was a significant increase in prevalence of both self-reported diabetes (3.8% to 9.7%) and newly diagnosed diabetes (1.5% to 4.0%), but a decrease in prevalence of prediabetes from 16.7% to 8.4% (49.7% decrease) during the 11-year period. Age, male sex, BMI, formal education, occupations other than agriculture, family history of diabetes, and systolic blood pressure were significant predictors of diabetes. 

Conclusions: The prevalence of diabetes among adults in rural south India has dramatically increased while that of prediabetes, has decreased, over a 11-year period. The decrease in prevalence of prediabetes might suggest a future slowing down of the epidemic.