Objective: The present study examined the association between body composition measurements, using dual-energy x-ray absorptiometry and anthropometry, with serum 25-hydroxyvitamin D levels in nonosteoporotic, postmenopausal women.
Methods: Serum 25-hydroxyvitamin D, intact parathyroid hormone, insulin-like growth factor I levels, dual-energy x-ray absorptiometry measurements of fat and fat-free mass, anthropometric and handgrip strength measurements, dietary intake estimations, ultraviolet B radiation exposure, and physical activity levels were collected from 112 nonosteoporotic, postmenopausal women (age, 60.3 ± 5.0 y; body mass index, 29.5 ± 4.8 kg/m2).
Results: At a bivariate level, serum 25-hydroxyvitamin D levels were inversely associated with regional and total body fat mass (P < 0.05), whereas positive associations were observed with regional and total body fat-free mass (P < 0.05). After controlling for age, serum intact parathyroid hormone, insulin-like growth factor I levels, ultraviolet B radiation exposure, and physical activity levels, most of the associations observed at a bivariate level between serum 25-hydroxyvitamin D levels and body composition indices (as obtained by dual-energy x-ray absorptiometry) remained significant. No significant associations were observed between anthropometric indices of body mass and serum 25-hydroxyvitamin D levels.
Conclusions: An independent inverse association between serum 25-hydroxyvitamin D levels and dual-energy x-ray absorptiometry measurements of total body and regional fat mass was observed in nonosteoporotic, overweight, postmenopausal women. Further clinical trials are required to come to safe conclusions on whether it is the fat mass that affects serum 25-hydroxyvitamin D levels or vice versa and whether there is a need to also take into account body composition when providing recommendations for vitamin D intake in postmenopausal women.
The present study found an independent inverse association between serum 25-hydroxyvitamin D levels and dual-energy x-ray absorptiometry measurements of adiposity in nonosteoporotic, postmenopausal women. Further clinical trials are needed to examine the role of body composition in providing recommendations for vitamin D use in postmenopausal women.
From the Department of Nutrition and Dietetics, Harokopio University of Athens, Athens, Greece.
Received October 9, 2008; revised and accepted December 22, 2008.
Funding/support: This study was supported by a research grant from Friesland Foods Hellas. The study sponsor had no role in the study design; the collection, analysis, or interpretation of the data; the writing of the manuscript; and the submission and revision of the paper.
Financial disclosure/conflicts of interest: Yannis Manios also works as a part-time scientific consultant for Friesland Foods Hellas. None of the other authors had any conflict of interest.
Address correspondence to: Yannis Manios, PhD, Department of Nutrition and Dietetics, Harokopio University, 70, El.Venizelou Ave, 176 71 Kallithea, Athens, Greece. E-mail: firstname.lastname@example.org