(P13-20-26) Lean Mass Change During the Look AHEAD Behavioral Lifestyle Intervention Does Not Impede Ability to Sustain Long-Term Reductions in Fat Mass or Improved Glucose Homeostasis

Objectives: To determine the impact of non-bone lean mass change during 1 year of the Look AHEAD intensive lifestyle intervention (ILI) in adults with type 2 diabetes (T2DM) on reduced weight maintenance and improved glucose homeostasis at years 4 and 8, independent of changes in fat mass and other covariates.

Methods: Look AHEAD participants assigned to ILI with body composition from dual energy x-ray absorptiometry were included (n= 497). Missing data was addressed using 20 imputed datasets, generated from classification and regression trees for all variables. Pooled estimates were derived from logistic and multiple regressions estimating the impact of non-bone lean mass loss over 1 year on change in HbA1c, medication use, total, fat, and lean mass from 1 year to follow-up at years 4 and 8. Fat mass and medication changes during year 1, age, sex, and baseline values for the outcome variable were included as covariates in models. Sensitivity analyses determined whether weight lost during year 1 (5, 7, and 10% of total body mass) impacted the relationship between lean mass change and outcomes.<

Results: Participants at baseline: 42% female, 75% white, average: age 58.7 years, BMI of 35.3 kg/m², duration of diabetes since diagnosis of 5 years, HbA1c of 7.1%, 87% taking blood glucose regulating medications and 15% taking regular insulin. Following the ILI, 9.1% of total body mass was lost (62.8% fat and 28.1% lean mass), HbA1c decreased by 0.6% (mean at year 1= 6.5%) and majority had no changes in medications (~90%). Participants who dropped out by year 4 had significantly smaller changes in total body mass and fat mass and HbA1c after ILI-Year 1, with no differences between dropouts and completers at year 8. At 4- and 8-year follow-ups, changes in lean mass after 1-year ILI were not associated with HbA1c or medication changes. Greater lean mass loss during the intervention predicted greater total body mass (β= -0.3 to -0.5, standard error= 0.1 to 0.2) and lean mass (β= -0.4 to -0.5; standard error= 0.1) regain at both timepoints, but was not associated with fat mass change.

Conclusions: Lean mass loss from a 1-year intervention did not impede long-term reductions in glucose homeostasis and fat mass, including those losing up to 10% weight.

Funding Sources: Supported in part by the NIH, including NIDDK and a T32 Fellowship.