Gender, Autoantibodies, and Obesity in Newly Diagnosed Diabetic Patients Aged 40–75 Years

Abstract

OBJECTIVE To evaluate the frequency of autoimmune markers (islet cell antibodies [ICA] and glutamic acid decarboxylase antibodies [GADA]) and clinical features in newly diagnosed people with diabetes aged 40–75 years. RESEARCH DESIGN AND METHODS Two hundred fifty-nine consecutive patients (aged 40–75 years) with newly suspected diabetes diagnosed during a 2-year period were studied. The diagnosis of newly discovered diabetes was confirmed in 203 patients. Gender, BMI, HbAic, fasting C-peptide, ICA, and GADA were evaluated. The frequency of obesity was estimated using two different sets of criteria: 1) National Diabetes Data Group (NDDG) criteria, and 2) criteria based on a Swedish reference population. RESULTS The annual incidence of diabetes was 106 per 100,000 people. The incidence of diabetes in those patients who were 40–54 years old was significantly higher in men than in women (odds ratio: 2.16; P = 0.001). ICA were detected in 16 of 203 patients (8%), whereas 17 of 203 patients (8%) were GADA+; 10 of 203 (5%) patients were positive for both ICA and GADA. Among the 203 diabetic patients, 19 (9.4%) were classified as having IDDM, giving an IDDM incidence of 10 per 100,000 people aged 40–75 years. The frequency of obesity in NIDDM was high but varied with its definition; the frequency of obesity was highest (P < 0.001) when NDDG criteria, and not Swedish reference values, were used (57 of 75 [76%] vs. 40 of 75 [53%] for women and 66 of 109 [61%] vs. 45 of 109 [41%] for men). CONCLUSIONS A striking male preponderance was found among incident cases of diabetes in people aged 40–54 years. Autoimmune markers were detected in 10% of incident cases of diabetes in people aged 40–75 years. Using a conservative estimation, as many as 10 of 100,000 middle-aged and elderly subjects developed IDDM. The frequency of obesity in NIDDM was high but this was also the case in the reference population.