Incidence and predictors of diabetes mellitus: A 7- year community cohort follow-up of urban, adult Sri Lankans

Background: There is limited data on the prevalence and outcome of prediabetes and the incidence of type 2 diabetes in South Asia. Objective: We conducted a prospective, community-based study involving a cohort of urban adults in Sri Lanka, with a seven-year follow-up period. 

Methods: Participants were selected using age-stratified random sampling, initially screened in 2007, and reevaluated in 2014. Structured interviews, anthropometric measurements, liver ultrasound, and biochemical and serological tests were performed on both occasions. 

Results: A total of 2985 individuals were recruited in 2007 [54.8% women, median age (IQR) 53(47–59)]; 737 had diabetes [baseline prevalence 24.7% (95%CI:23.1–26.2)] and 525 had prediabetes [baseline prevalence 17.9% (95%CI:16.2–19.6)]. In 2014, 2148(71.6%) persons attended follow-up [57.5% women; median (IQR) 60(54–66) years], which included 1650 who did not have diabetes in 2007. By 2014, 436/1650(27.6%) persons had developed new diabetes [annual incidence 3.9% (95%CI:3.0–4.9)]. Poisson regression analysis showed that prediabetes, central obesity, low HDL, and nonalcoholic fatty liver disease at baseline were significantly associated with new-onset diabetes. Of the 525 persons with prediabetes in 2007, 365(69.5%) were followed-up in 2014; 147/365(40.3%) remained in prediabetes, 201/365(55.1%) had progressed to diabetes, and 17/365(4.6%) had reverted to normoglycemia. The annual conversion rate of prediabetes to diabetes was 7.9%. An increase in waist circumference and low HDL levels from baseline predicted progression to diabetes. 

Conclusions: The presence of prediabetes, central obesity, low HDL, and nonalcoholic fatty liver disease at baseline predicted new-onset diabetes, whereas increase in waist circumference and low HDL predicted conversion of prediabetes to diabetes. Targeted lifestyle interventions are essential for individuals with metabolic risks to prevent future diabetes.