就学前児童における骨密度と栄養摂取状態

Abstract

The relationships between bone density and nutritional status were evaluated for two groups of urban and rural pre-school children aged 3 to 6 years. Bone density was measured at the phalanx 5-2 center by the X-ray densitometric method. The film exposure conditions using a soft X-ray instrument were 45KVP, 5mAS and 35cm focal distance. As a reference wedge, ivory was used. Bone density was calculated as a density index by the method of Williams and Mason. Bone density index is expressed as X-ray equivalent grams of ivory per cubic centimeter of bone.The bone density indexes of rural boys were significantly lower than those of urban boys, and the density values of rural girls were in a slight lower level as compared with urban girls, though the statistical significant differences were not seen between both groups. The nutrient intakes of rural children were much lower in animal protein, vitamin A and vitamin C than those of urban children. When 4-6 year-old boys and girls were divided into two groups respectively by the level of bone density index above “Mean+SD” and below “Mean-SD” and the nutrient intakes of these two groups were compared, vitamin A intake was found to be significantly different between them. And also, in two groups of boys who have taken a little amount of meat or milk and who have taken a little amount of vegetables in their dietary habits, their density values were significantly lower than the average density value of other boys group.These findings suggest that the bone density measurement at phalanx 5-2 center may be useful for evaluating bone formation with relation to nutritional status.