GENDER, AUTOANTIBODIES, AND OBESITY IN NEWLY-DIAGNOSED DIABETIC-PATIENTS AGED 40-75 YEARS

OBJECTIVE - To evaluate the frequency of autoimmune markers (islet cel l 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 consecu tive patients (aged 40-75 years) with newly suspected diabetes diagnos ed during a 2-year period were studied. The diagnosis of newly discove red diabetes was confirmed in 203 patients. Gender, BMI, HbA(1c), fast ing C-peptide, ICA, and GADA were evaluated. The frequency of obesity was estimated using two different sets of criteria: 1) National Diabet es Data Group (NDDG) criteria, and 2) criteria based on a Swedish refe rence population. RESULTS - The annual incidence of diabetes was 106 p er 100,000 people. The incidence of diabetes in those patients who wer e 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 N IDDM 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 m ale preponderance was found among incident cases of diabetes in people aged 40-54 years. Autoimmune markers were detected in 10% of incident casts of diabetes in people aged 40-75 years. Using a conservative es timation, as many as 10 of 100,000 middle-aged and elderly subjects de veloped IDDM. The frequency of obesity in NIDDM was high but this was also the case in the reference population.