Does diet affect bone mineral density?
Analysis of data from the Women’s Health Initiative (WHI) suggests that eating an inflammatory diet may affect some women’s risk of bone loss and hip fracture. The findings, which do not prove causality, were published in The Journal of Bone and Mineral Research.
For the study, researchers from Ohio State University evaluated the association between dietary inflammatory index (DII) and risk of hip, lower-arm and total fracture using longitudinal data from WHI. The researchers also looked at changes in bone mineral density (BMD) and DII scores.
The DII is a measure of the inflammatory potential of diet and takes into consideration 28 factors such as energy, carbohydrate, protein, total fat, alcohol, fiber, cholesterol, saturated fat, mono-unsaturated fat, and poly-unsaturated fat. DII scores were calculated from baseline food frequency questionnaires (FFQ) completed by 160,191 WHI participants with a mean age of 63 who had no history of hip fracture at study enrollment. A DII change score was calculated using Year 3 FFQs.
Multivariable Cox proportional hazard models were used to compute hazard ratios (HR) for fractures and stratified by age and race/ethnicity. Pair-wise comparisons of changes in hip BMD, measured by dual-energy X-ray absorptiometry from baseline and years 3 and 6 were analyzed by quartile of baseline DII scores in a subgroup of 10,290 women.
Over 3 years, the authors found that mean DII scores improved significantly (P<0.01) but the change was not associated with fracture risk. Baseline DII score was only associated with hip fracture risk in younger white women (HR QR: 1.48; 95% confidence interval [CI] 1.09, 2.01; P=0.01). By Year 6, women the least inflammatory DII scores had less loss of hip BMD (P=0.01) despite lower baseline hip BMD in comparison with women with the most inflammatory DII scores.
A less inflammatory dietary pattern, the researchers concluded, was associated with less BMD loss in postmenopausal women. A more inflammatory diet was associated with increased hip fracture risk only in white women younger than age 63.