Changes in BMI and weight before and after the development of type 2 diabetes.

OBJECTIVE: To examine weight changes occurring before and after the diagnosis of diabetes and the association of these changes with treatment and microvascular complications. RESEARCH DESIGN AND METHODS: We undertook an analysis of serial examinations conducted between 1965 and 2000 in residents of the Gila River Community in Central Arizona. Data were taken from 4,226 examinations of 816 individuals in whom diabetes developed over the course of a longitudinal study and who had undergone a nondiabetic examination within 4 years preceding diagnosis. We measured changes in BMI between examinations.
RESULTS: Before diagnosis of diabetes, there were steady gains in weight: mean BMI climbed between 0.43 and 0.71 kg/m(2) per year. After diagnosis, the weight gain declined, and weight loss was generally seen; the mean rate of change of BMI ranged between -0.61 and +0.22 kg/m(2) per year. When current treatment was considered, there was greater weight stability in individuals taking insulin compared with those not taking hypoglycemic medication. Medication was a statistically significant factor for change in weight for most of the time intervals analyzed. There was no statistically significant association with retinopathy or nephropathy.
CONCLUSIONS: Before development of diabetes, there was a progressive rise in weight, and after diagnosis, there was a tendency toward weight loss. Weight-loss interventions in individuals with diabetes will need to account for this tendency if they are to successfully modify the course of the disease.