Abstract
The purpose of this study was to investigate the role of lifestyle (farming vs nonfarming), age, season, and percent body fat on serum 25-hydroxyvitamin D (25-OHD) and parathyroid hormone (PTH). Serum 25-OHD concentrations were lower in winter than in summer and in older than in younger individuals. Dietary intake of vitamin D was associated with greater serum 25-OHD concentrations. A significant inverse relationship between PTH and 25-OHD was observed in older but not younger individuals. Trabecular volumetric bone mineral density was inversely associated with serum PTH, but not 25-OHD concentrations. Modern farm practices do not necessitate excessive sunlight exposure and that may help explain the lack of differences between farming and nonfarming populations.