Characteristics of an adult population with newly diagnosed type 2 diabetes: the relation of obesity and age of onset.

OBJECTIVE

To determine whether adults diagnosed with type 2 diabetes at 18-44 years of age (early type 2 diabetes) have different metabolic profiles at diagnosis than adults diagnosed at > or =45 years of age (usual type 2 diabetes).

RESEARCH DESIGN AND METHODS

Within a health maintenance organization, we studied characteristics among 2,437 adults newly diagnosed with type 2 diabetes between 1996 and 1998 who had measured weight, HbA(1c), blood pressure, and cholesterol within 3 months of diagnosis. We abstracted clinical data from electronic medical records. We compared mean and proportional differences with parametric t tests and chi(2) analyses, respectively. We used multiple logistic regression to identify the factors independently associated with the onset group (early vs. usual type 2 diabetes).

RESULTS

There was an inverse linear relationship between BMI and age at diagnosis of type 2 diabetes (P < 0.001). On univariate analysis, adults with early type 2 diabetes were more obese (BMI 39 vs. 33 kg/m(2), P < 0.001), were more likely to be female (P = 0.04), had slightly worse glycemic control (HbA(1c) 7.7 vs. 7.5%, P = 0.03), had a higher prevalence of diastolic hypertension (37 vs. 26%, P < 0.001), despite a lower prevalence of systolic hypertension (34 vs. 55%, P < 0.001), and had an equally high rate of abnormal lipids (82 vs. 78%, P = 0.13) than adults with usual type 2 diabetes. BMI, female gender, cholesterol, and diastolic and systolic blood pressure remained independently associated with onset group at multivariate analysis.

CONCLUSIONS

Although both onset groups were on average obese, the inverse linear relationship of obesity and age of diabetes onset that we observed suggests that obesity is a continuous risk rather than a threshold risk for diabetes onset. Both onset groups had a high prevalence of cardiovascular disease risk factors.