Obesity and Bone Density: What Is the Relationship?

Although obesity was found to be associated with favorable bone microarchitecture in a recent study, the relationship was no sustained following the normalization of parameters for body weight.

“Low body mass index (BMI) is an established risk factor for fractures in postmenopausal women but the interaction of obesity with bone microarchitecture is not fully understood,” the researchers explained.

They sought to examine the relationship between bone microarchitecture and fat mass, as well as areal bone mineral density (aBMD) in relation to BMI categories using data from 491 participants in the UK arm of the Global Longitudinal Study of Osteoporosis in Women.

The women underwent high-resolution peripheral quantitative computed tomography (HRpQCT) scans of the radius and tibia as well as DXA scans of their full body, proximal femur, and lumbar spine. The researchers employed linear regression to examine the relationship between BMI category and HRpQCT and DXA aBMD parameters.

Overall, significant increasing trends according to BMI category were observed in aBMD of whole body, hip, femoral neck, and lumbar spine; cortical area, thickness and volumetric density, and volumetric density and separation at the radius and tibia. When normalized for body weight, HRpQCT and DXA aBMD parameters were found to decrease with increases in BMI.

“Significant trends in HRpQCT parameters suggested favorable bone microarchitecture at the radius and tibia with increasing BMI but these were not proportionate to increased weight,” the researchers concluded.

—Michael Potts

Reference:

Litwic AE, Westbury LD, Ward K, Cooper C, Dennison EM. Adiposity and bone microarchitecture in the GLOW study. Published online September 19, 2020. Osteoporos Int. Doi: 10.1007/s00198-020-05603-w