Intentional weight loss has been shown to increase bone loss short term but the long-term effects are not known. Data from the Look AHEAD clinical trial shows that a long term intentional weight loss intervention was associated with greater bone loss at the hip in men.

Purpose

Intentional weight loss has been shown to increase bone loss short term and increase frailty fracture risk, but the long-term effects on bone mineral density (BMD) are not known.

Methods

Data from a subgroup from the Look AHEAD (LA) multicenter, randomized clinical trial was used to evaluate whether a long term intentional weight loss intervention would increase bone loss. In a preplanned substudy, BMD was assessed at 5 of the 16 LA clinical centers using dual-energy X-ray absorptiometry at baseline, year 8, and the observational visit 12.6-16.3 years after randomization (year 12-16).

Results

At year 8, bone density loss (%) was greater in the Intensive Lifestyle Intervention (ILI) group compared with the control group (DSE) for the femoral neck (p = 0.0122) but this finding was not observed at the year 12-16 visit. In analyses stratified by gender, bone density loss (%) was greater at the total hip for men in the ILI group than the DSE group at both the year 8 and year 12-16 visits (year 8 p = 0.0263 and year 12-16 p = 0.0062). This finding was not observed among women.

Conclusion

Long term intentional weight loss was associated with greater bone loss at the hip in men. These results taken with the previously published Look AHEAD data from the entire clinical trial showing increased frailty fracture risk with weight loss in the ILI group suggest that when intentional weight loss is planned, consideration of bone density preservation and fracture prevention strategies is warranted.

Trial registration

Clinicaltrials.gov Identifier: NCT00017953. June 21, 2001.

Objective

We aimed to identify factors that are independently associated with the metabolic clearance rate of insulin (MCRI) and to examine the association of MCRI with incident type 2 diabetes in nondiabetic Hispanics and African Americans.

Research design and methods

We investigated 1,116 participants in the Insulin Resistance Atherosclerosis Study (IRAS) Family Study with baseline examinations from 2000 to 2002 and follow-up examinations from 2005 to 2006. Insulin sensitivity (S(I)), acute insulin response (AIR), and MCRI were determined at baseline from frequently sampled intravenous glucose tolerance tests. MCRI was calculated as the ratio of the insulin dose over the incremental area under the curve of insulin. Incident diabetes was defined as fasting glucose ≥126 mg/dL or antidiabetic medication use by self-report.

Results

We observed that S(I) and HDL cholesterol were independent positive correlates of MCRI, whereas fasting insulin, fasting glucose, subcutaneous adipose tissue, visceral adipose tissue, and AIR were independent negative correlates (all P < 0.05) at baseline. After 5 years of follow-up, 71 (6.4%) participants developed type 2 diabetes. Lower MCRI was associated with a higher risk of incident diabetes after adjusting for demographics, lifestyle factors, HDL cholesterol, indexes of obesity and adiposity, and insulin secretion (odds ratio 2.01 [95% CI 1.30-3.10], P = 0.0064, per one-SD decrease in loge-transformed MCRI).

Conclusions

Our data showed that lower MCRI predicts the incidence of type 2 diabetes.