Dietary pattern and bone density changes in elderly women: a longitudinal study.

OBJECTIVE

Few data are available on the effect of the diet in general on bone health. The objective of this study was to identify dietary patterns and to evaluate the association between such patterns and bone mineral density (BMD) changes over time.

METHODS

We analyzed a sample of women aged ≥65 years participating in the InCHIANTI Study. BMD was evaluated using computed tomography of the tibia and nutritional intake using the EPIC questionnaire. We used a cluster analysis to identify patterns of dietary intake. The clusters were compared with respect to nutritional intake; risk factors for osteoporosis; comorbidity; total, trabecular, and cortical BMD; and BMD changes over 6 years.

RESULTS

The sample size was 434, with a mean age of 75.2 years (SD, 7.01 years; range, 65-94 years). Based on dietary variables, 2 clusters were identified with a marked difference in energy intake (30 kcal/kg of ideal body weight [IBW] in cluster 1 vs 44 kcal/kg IBW in cluster 2). We found no meaningful differences between clusters with regard to nondietary risk factors for osteoporosis, BMD measured at baseline, and changes in BMD over the 6-year follow-up; cluster 2 showed a greater increase in cortical BMD (+30.2 mg/cm(3) vs +16.7 mg/cm(3)). Members of cluster 2 were less likely to have a lower cortical BMD increase (adjusted odds ratio, 0.452; 95% confidence interval, 0.215-0.950).

CONCLUSIONS

Cortical BMD increases more in participants eating a diet exceeding the RDA for macronutrients. Cortical BMD may be more sensitive to diet and dietary interventions than trabecular bone.