Mean (±SEM) changes in serum 25(OH)D, PTH, total T, and estradiol during the intervention in men adhering to WL and WM (n = 38). A repeated-measures ANCOVA analysis that used mixed models was performed with time (0, 1, 3, and 6 mo) and group (WL or WM) as independent variables. The following covariates were included in the analysis: age, season, physical activity level, and body weight. aTime effect in WL and WM groups with no difference between groups, P < 0.05; b WM group differed from WL group (interaction effect over time and at the 6-mo post hoc test), P < 0.05. Diamond dotted lines represent WL, and square solid lines represent WM. PTH, parathyroid hormone; T, testosterone; WL, weight loss; WM, weight maintenance; 25(OH)D, 25-hydroxyvitamin D.