Case-control study of diet and sun exposure in adolescents with symptomatic rickets

Dietary intake and sun exposure were compared in a case-control study of 14 adolescent girls diagnosed to have symptomatic nutritional rickets with hypocalcaemia, hypophosphoraemia, elevated serum alkaline phosphatase and serum parathormone and reduced 25-hydroxy vitamin D levels and 20 controls without clinical rickets (ten girls) of the same age group and socio-economic background. In the control group, calorie intake was reduced in seven boys and eight girls, dietary calcium in seven boys and seven girls and vitamin D in six boys and eight girls. All 20 adolescents of both sexes were exposed to the sun for more than 60 min a day. In the group with rickets, calorie intake was reduced in 11 girls, calcium in 14 girls and vitamin D in nine girls). Sun exposure was significantly less in girls with rickets than in controls (p < 0.001). Adolescents in our population, especially females, are at high risk of developing nutritional rickets. Prevention by longer exposure to the sun is simple and cheap but when not practical for social or cultural reasons routine vitamin D supplementation might be indicated.