High Levels of Body Fat Linked to Increased Osteoporosis Risk in Men

Using data from NHANES, researchers at the University of Chicago provide insight into associations of fat mass index and lean mass index on bone mineral density and how sex influences these associations.

Men with high levels of body fat could be at an increased risk of osteoporosis, according to the results of a recent study.

An analysis of data from more than 10,000 participants within the National Health and Nutrition Examination Survey (NHANES) from 2011-2018, results of the study suggest every 1 kg/m2 increase in lean mass index was associated with a 0.19 increase in T-score while every 1 kg/m2 increase in fat mass index was associated with a 0.10 decrease in T-score.

“We found that higher fat mass was related to lower bone density, and these trends were stronger in men than women,” said Rajesh K. Jain, MD, of University of Chicago Medicine, in a statement. “Our research suggests that the effect of body weight depends on a person's makeup of lean and fat mass, and that high body weight alone is not a guarantee against osteoporosis.”

As part of NHANES, a subset of patients aged 8-59 years of age underwent total body DXA with Hologic Discovery model A densitometers. All scans were reviewed for accuracy by the University of California San Francisco. For the current analysis, investigators restricted their study cohort to those aged 20 years and older.

In total, investigators identified 10,814 subjects with total body BMD and body composition data for inclusion in their analyses. Linear regression models were used to assess associations of lean mass index and fat mass index with BMD T-score. Investigators noted these models controlled for age, gender, race/ethnicity, height, and smoking status.

Of the 10,814 included in the study, 3248 had obesity, 771 had severe obesity, and 6795 had no obesity. Investigators pointed out those without obesity were younger and less ethnically diverse than those with obesity and with severe obesity. Additionally, those without obesity had a lower total body BMD than those with obesity and with severe obesity.

In multivariable modeling, results suggested every 1 kg/m2 increase in lean mass index was associated with a 0.19 higher T-score and every 1 kg/m2 increase in fat mass index was associated with a 0.10 reduction in T-score (P <.001 for both). Further analysis stratified by sex indicated the negative effect of fat mass index on T-score was stronger among men than women. Specifically, every 1 kg/m2 increase in fat mass index was associated with a 0.08 reduction in T-score among women versus a 0.13 reduction in T-score among men (P for interaction <.001), with this effect most evident among those in the highest quartile.

When assessing the influence of race/ethnicity, results indicated only Mexican Americans had a slightly less positive effect of lean mass index than Whites. No other interactions were observed between race/ethnicity and lean mass index or fat mass index.

“Health care providers should consider osteoporosis screening for patients with high body weight, especially if they have other risk factors like older age, previous fracture, family history, or steroid use,” Jain added.

This study, “Fat Mass Has Negative Effects on Bone, Especially in Men: A Cross-Sectional Analysis of NHANES 2011-2018,” was published in the Journal of Clinical Endocrinology & Metabolism.