Researchers compared weight gain in patients receiving intensive (INT) and conventional (CONV) type 1 diabetes treatment vs a population without diabetes, and they found that greater weight gain associated with INT therapy happened in two stages, resulted in similar or greater obesity rates relative to controls after 2 years and was mainly altered by glucose control and family history, supportive of a therapeutic-genetic impact on weight trajectories.

• This study comprised males and females of 18 years and older in the Diabetes Control and Complications Trial (DCCT) randomized to INT (n = 562) or CONV (n = 568) as well as a prospective, observational cohort without diabetes from the Coronary Artery Development in Young Adults (CARDIA, controls) study (n = 2,446).

• Annual weight gain conferred by INT peaked 1.3 years post-initiation and was found to be greater than both CONV and controls prior to and after this peak.

• INT was associated with a lower prevalence of obesity at baseline than controls; the prevalence was similar to controls at 2 years and surpassed controls by 5 years.

• At all time points, obesity rates with CONV continued to be below controls.

• In the DCCT, greater annual weight gain was identified to be linked with lower hemoglobin A1c, higher insulin dose and family history of type 2 diabetes.