1675-P: Does Intensification of Insulin Therapy Lead to Increased Body Fat among Youth and Young Adults with Type 1 Diabetes (T1D)?

Intensive insulin therapy may have the unintended consequence of increased adiposity, contributing to the high prevalence of overweight and obesity in people with T1D.

We examined the longitudinal association of insulin intensification with estimated body fat percentage (eBFP) among 746 individuals with T1D (age 10-21 years at initial visit) in the SEARCH for Diabetes in Youth study.

eBFP was calculated using validated, published sex and race/ethnic specific formulae incorporating age and anthropometrics. Insulin intensification was defined as more intense, less intense or no change, in which “more intense” was an increased number of injections or addition of long-acting insulin, or a change from injections to an insulin pump. Sex-specific, linear mixed effects models used continuous eBFP at each available visit (baseline, and 1-4 follow-up visits; median T1D duration at the last visit, 8 years). Interaction terms between time and insulin intensification relative to change in eBFP tested the study hypothesis.

Mean diagnosis age was 12.7 years ± 2.5, 47% were female, 80% non-Hispanic white. At baseline, mean BMIz score was 0.51 ± 0.93, with 32% overweight or with obesity. Although BMIz and weight status did not differ by sex, eBFP was significantly higher in females compared to males (32.4% ± 5.3 and 25.3% ± 5.9 respectively; p<0.0001). After adjustment for age at diagnosis, study site, and sociodemographic factors, there was a statistically significant increase in eBFP over time for females (4.8% over the median duration of 8 years) and a statistically significant decrease for males (1.6% over the median duration of 8 years). For females, this increase was 2.2% greater over the median duration of 8 years for more intense compared to less intense therapy (p=0.0009). Rates of change in eBFP did not depend on insulin intensification for males (p=0.09). Further work may determine metabolic and behavioral drivers of this unintended increase in eBFP, particularly among females with T1D.