Prevalence and clinical characteristics of individuals with newly detected lean diabetes in Tamil Nadu, South India: a community-based cross-sectional study

Background and objectives Lean diabetes is an entity that has been observed to be higher in Asian populations. The estimates of the burden of lean diabetes in India are mainly from hospital-based studies. This study reports the prevalence of lean diabetes among individuals with newly detected diabetes, from Vellore, Tamil Nadu, South India. Methods A cross-sectional WHO STEPS survey was conducted among adults aged 30-64 years, in one rural block and 48 urban wards, in Vellore. Physical and anthropometric parameters were assessed in addition to fasting lipid profile and plasma glucose. Newly detected diabetes was defined as fasting plasma glucose >= 126 mg/dl and lean diabetes as non-ketotic diabetes mellitus, without clinical features to suggest pancreatic diabetes, with a body mass index (BMI) <18.5 kg/m(2). Results Among 3445 rural and 2019 urban subjects, the proportion of lean diabetes among 280 subjects (146 rural, 134 urban) with newly detected diabetes was 5.5%, 95% CI: 1.7-9.3% (eight subjects) and 1.5%, 95% CI: 0-3.6% (two subjects), in the rural and urban areas respectively. The proportion of those with a normal BMI (18.5-22.9 kg/m(2)) was 25.3% and 18.7% in the rural and urban populations, while 69.2% and 79.9% had a BMI >= 23 kg/m(2). Those with lean diabetes were more likely to be older, illiterate, and involved in manual labor, than those with non-lean diabetes (p<0.05). Conclusion The prevalence of lean diabetes was low (5.5% of newly detected rural diabetes, 1.5% of newly detected urban diabetes) in Vellore, South India. Further documentation of the burden of this condition across India is needed to assess the public health implications for prevention and control.