Weight Loss Linked to Changes in Bone Mass

Weight loss and glucose metabolism may influence bone marrow fat, which, in turn, may influence bone mineral density (BMD), according to the findings of a recent study.

The study included 30 women with obesity who underwent Roux-en-Y gastric bypass (RYGB) surgery. BMD was measured using dual energy X-ray absorptiometry (DXA) and quantitative computed tomography (QCT) before and 6 months after RYGB, and vertebral marrow fat content was measured using magnetic resonance spectroscopy. Participants were stratified by diabetes status.
_______________________________________________________________________________________________________________________________
RELATED CONTENT
Study Examines the Effects of Inflammatory Diet on Risk of Bone Mineral Density Loss
One Minute of Running a Day Could Improve Bone Health
_______________________________________________________________________________________________________________________________
After RYGB, all participants experienced a dramatic decline in total body fat.

At baseline, women with higher marrow fat had lower BMD. The effects of RYGB on marrow fat differed by diabetes status, with women without diabetes experienced no significant mean change in marrow fat. However, those who lost more total body fat were more likely to experience increases in marrow fat. Women with diabetes experienced a mean marrow fat change of –6.5%, and those with greater improvements in hemoglobin A1c experienced decreases in marrow fat.

Increases in IGF-1, which is a potential mediator in the bone marrow fat and bone mineral density relationship, were associated with marrow fat declines. In addition, spinal volumetric BMD decreased by 6.4% ± 5.9% and femoral neck areal BMD decreased by 4.3% ± 4.1%.

Marrow fat was negatively associated with BMD changes, where participants who experienced increases in marrow fat had more BMD loss at the spine and femoral neck. This association was independent of age and menopause.

“Our findings suggest that glucose metabolism and weight loss may influence marrow fat behavior, and marrow fat may be a determinant of bone metabolism,” the researchers concluded.

—Melissa Weiss

Reference:

Kim TY, Schwartz AV, Li X, et al. Bone marrow fat changes after gastric bypass surgery are associated with loss of bone mass [published online August 9, 2017]. JBMR. DOI: 10.1002/jbmr.3212.