Etiopathological differentiation of diabetes mellitus in lean, young adults

Classification of diabetes mellitus (DM) into type 1 or type 2 is difficult in lean, young individuals. We studied the β-cell function, insulin resistance (IR) and autoimmunity in young patients with recent onset DM.

In this cross-sectional study, we included patients (age below 35 years) with recent onset DM (<6 months) and normal body weight for evaluation. The detailed clinical examination was done to identify markers of IR. Autoimmune DM was diagnosed using glutamic acid decarboxylase 65 (GAD₆₅), insulin autoantibody (IAA) and islet cell antibody (ICA). Homeostasis model assessment (HOMA) models of HOMA-B and HOMA- IR were used for estimation of β-cell function and IR respectively. The patients were divided into four groups based on, the autoimmunity (A) and ketosis (K) as group 1 (A+K), group 2 (A-K+), group 3 (A+K-) and group 4 (A-K-). Appropriate statistical tests +)were used to analyze the results.

The study population (n=75, all males) had a mean age of 28.9±4.3years, body mass index 20.6±1.9kg/m², fasting plasma glucose 177.1±31.4mg/dl and HbA1c of 9.9±2.1% at presentation. The number of patients in groups 1 to 4 are 8, 5, 10 and 52 respectively (p<0.0001). HOMA-IR was higher in groups 2 and 4 (4.1±1.3, 3.6±1.1 respectively), whereas HOMA-B was higher in group 4 (3.6±1.5) alone (p=0.0005).

Type 2 DM is the most common etiology even in young, lean adults in India. Further studies with large numbers are required to confirm our findings.