Serum vitamin D and body composition in adults undergoing fitness assessments: A correlation study

The purpose of this descriptive study was to assess serum levels of 25(OH) vitamin D3 (25(OH)D) in participants who voluntarily participated in a fitness assessment and correlate this with muscular strength, weekly exercise, overall body composition, and dietary intake of vitamin D and calcium. Thirty-six participants were recruited. Anthropometric measurements and handgrip strength were taken with blood analyses completed utilizing 25-hydroxyvitamin D assay. A dietary screening survey was used to assess calcium and vitamin D intake. All data collection was completed at time of assessment appointment. Statistical analyses completed utilized Pearson's and Kendall's Tau correlation, with level of significance set at p < 0.05. Twenty-two percent of our sample were 25(OH)D deficient and 33% 25(OH)D insufficient, with 16% consuming adequate vitamin D and 5% consuming adequate calcium. Eight of the females and one male had below average DXA assessments for bone health. Vitamin D intake was significantly correlated with serum 25(OH)D levels (τ = 0.29, p<0.01). In females there was an inverse relationship between 25(OH)D and weight (r = -0.45, p<0.05). Thirty-one percent of participants had higher than desirable waist circumference and were 25(OH)D insufficient or deficient. This sample had a high rate of 25(OH)D insufficiency and deficiency, with most not consuming adequate amounts of calcium and vitamin D. Normalizing serum 25(OH)D through food and supplements has the potential to positively impact several parameters of an individual's health including weight status, visceral adiposity and waist circumference, and bone health.