Vitamin D status and body fat measured by dual-energy X-ray absorptiometry in a general population of Japanese children.

OBJECTIVE For a general population of children, data on the relationship between vitamin D status and adiposity are limited. The aim of this study was to assess the relationships between the serum concentration of 25-hydroxyvitamin D (25-OH-D) and body fat variables measured by dual-energy X-ray absorptiometry (DXA) in a general population of Japanese children, including underweight, normal, and overweight children. METHODS The source population comprised 521 fifth-grade children who attended either of the two public schools in Hamamatsu, Japan. Total and regional body fat mass (FM) measured by DXA were evaluated along with the serum concentration of 25-OH-D. RESULTS We were able to analyze the FM and 25-OH-D data of 400 of the 521 children. Among boys, significant inverse relationships were observed between serum vitamin D levels and body fat variables (total FM, r = -0.201; trunk FM, r = -0.216; appendicular FM, r = -0.187; P < 0.05 for all values). Mean values of total FM and trunk FM in the vitamin D-deficient group (25-OH-D <50 nmol/L) were larger than those in the vitamin D-sufficient group (25-OH-D ≥75 nmol/L) after adjusting for confounding factors, such as sedentary behavior (P < 0.05). No relationship was observed between vitamin D status and FM among girls. CONCLUSIONS Vitamin D deficiency was associated with higher total and trunk adiposities in a general population of Japanese children, particularly boys.