Normalising BMI in youth may lower risk of progressing to type 1 diabetes, study suggests

Research from TrialNet indicates that restoring BMI to a healthy range in overweight or obese children and adolescents with early-stage type 1 diabetes could reduce their likelihood of disease progression, highlighting weight management as a modifiable factor in disease risk.

Researchers analysing data from TrialNet say that people with early-stage type 1 diabetes who were overweight or obese were less likely to progress to full clinical disease if their body mass index returned to the normal range. The study, published in Diabetes Care, followed 833 children and adults with islet autoantibodies and found that nearly 27% reached a healthy BMI during follow-up. Those who did so had a substantially lower risk of developing stage 3 type 1 diabetes than participants who remained above the healthy range.

Maria J. Redondo, a professor of paediatrics at Texas Children’s Hospital and Baylor College of Medicine, said the association was strongest in younger patients. Speaking to Healio, she said the finding suggests excess weight may be a modifiable contributor to disease progression, although the research cannot prove that weight normalisation itself prevents type 1 diabetes. The data showed a lower risk of progression among children and males, with the most striking benefit seen in boys younger than 12 and in girls aged 12 to 18.

The study also found that reaching a normal BMI was linked with a reduced risk of advancing from stage 1 to stage 2 disease and from stage 2 to stage 3. In other words, the association was not confined to a single step in the disease process. In adults and females overall, however, the relationship was not seen consistently, underlining that the effect may vary by age and sex.

The findings fit with earlier research suggesting that body size in childhood can influence later type 1 diabetes risk. A 2022 study in Nature Communications reported that larger childhood body size increased the likelihood of developing the disease, while other research has shown that children with type 1 diabetes can often maintain good metabolic control without excess weight gain during treatment. Taken together, the evidence points to weight trajectory as an important factor to monitor in people at risk, even as Redondo stressed that normalising BMI in a growing child does not necessarily mean losing weight.