Abstract
Introduction
Vitamin D is a potent secosteroid hormone that provides many health benefits. The ubiquitous nature of vitamin D receptor (VDR) suggests widespread effect.
Purpose
The purpose of this study was to investigate the relationship between 25-hydroxyvitamin D (25OHD) levels and muscle strength, maximal oxygen consumption (VO2max), and body mass index (BMI) in Iranian young and middle adulthood women.
Participants and methods
A cross-sectional descriptive study was conducted in 182 healthy Iranian women within the age range of 26–60 years. Body weight and height were measured, and BMI was calculated. VO2max was determined by the Rockport test. Muscle strength was determined by the chest press, leg press, and hand grip test. Also, circulating levels of 25OHD were evaluated.
Results
Results showed a significant relationship between 25OHD levels and BMI, VO2max, and muscle strength (chest press, leg press, hand grip dominant hand [HGDH], and hand grip nondominant hand [HGNDH]) in young and middle adulthood women (BMI in young and middle adulthood: r=−0.48, P<0.001 and r=−0.27, P=0.01, respectively; VO2max in young and middle adulthood women: r=0.69, P<0.001 and r=0.57, P<0.001, respectively; chest press, leg press, HGDH, and HGNDH in young adulthood: r=0.58, r=0.59, r=0.65, and r=0.42, respectively, P<0.001; and in middle adulthood: r=0.73, r=0.34, r=0.66, and r=0.55, respectively, P≤0.001). Multiple linear regression analysis showed that higher levels of VO2max, HGDH, and chest press predicted higher 25OHD levels in the young adulthood women (R2=0.75; β=0.39, β=0.35, and β=0.30, respectively; P<0.001). Moreover, VO2max and HGDH were the strongest predictor of 25OHD levels in the middle adulthood women (R2=0.71; β=0.35, β=0.40, respectively; P<0.001).
Conclusion
Based on the results, it could be concluded that VO2max and strength are useful indirect marker for 25OHD levels in the young and middle adulthood women. It also seems that VO2max and HGDH strength had stronger associations with 25OHD levels in the young adulthood women, and chest press and HGDH had stronger associations with 25OHD levels in the middle adulthood women.
Acknowledgments
The authors hereby declare their gratitude to all those who participated as subjects in this study.
Author contributions
HA designed the research. EE conducted the research including sample analysis. HA and EE analyzed the data and wrote the paper. Both authors contributed toward data analysis, drafting and revising the paper, gave final approval of the version to be published and agree to be accountable for all aspects of the work.
Disclosure
The authors report no conflicts of interest in this work.