Obesity and Bone Loss

Contrary to popular opinion, greater body fat is linked to lower bone mineral density (BMD), not greater density, particularly in men. This benefit was though to be from effects of weight-bearing on the skeleton and hormonal factors linked to body fat. Investigator’s study published in J Clin Endocrinol Metab. 2022 Feb 10 found otherwise.

“While higher body mass index (BMI) is general associated with higher bone density, our study demonstrates that lean and fat mass affect bone density differently and that obesity is not a guarantee against osteoporosis,” Rajesh K Jain, MD of the University of Chicago says. In this study, participants were grouped in sex specific quartiles according to lean mass index (LMI; lean mass divided by height squared) and fat mass index (FMI; fat mass divided by height squared). It was found that lean body mass had a positive effect on bone density whereas fat mass had a negative effect.

Clinicians have no good way of measuring body composition in an office setting, therefore, patients with obesity should undergo recommended bone density screening, especially if other risk factors exists such as diabetes, previous fractures/family history of fractures and older age.

Bottom line is that if you are obese, don’t have false reassurances that you may be protected from fragility fractures…… be your own advocate!

Source: Clinical Endocrinology News, Vol. 17.No 3. March 2022