Asymptomatic rickets in adolescent girls

Objective. Inadequate sunlight exposure and calcium intake during rapid growth at puberty lead to hypocalcemia, hypovitaminosis D and eventually to overt rickets. To determine serum biochemical findings of rickets in healthy 11-15 yr old girls, the effect of sunlight exposure and oral vitamin D supplementation on serum 25- hydroxy vitamin D and calcium administration in girls with abnormal findings during December 2002 through March 2003 in Tehran, Iran. Methods. Healthy middle school girls were selected for estimation of vitamin D, calcium and phosphorus intake by a three-day food recall. And measurment of serum calcium, phosphorus, parathyroid hormone, alkaline-phosphatase and 25- hydroxyvitamin D concentration. The girls with abnormal findings divided in two groups. Hypovitaminosis D girls subdivided into two groups, supplementary sunlight exposure and vitamin-D administrated for them and calcium administration for the second group for 20 days. Results. Of 414 girls, the mean daily vitamin D acquirment and calcium intake were 119 +/- 52 IU and 360 +/- 350 mg among all girls respectively. Mean serum 25-hydroxyvitamin D with two or more abnormal biochemical findings in 15 (3.6%) girls (group I) were 7.8 ng/ml and alkaline phosphatse with normal or low calcium in 29 (7%) girls ( group II) was 1187 IU/L. Mean serum calcium was 8.2 mg % in 8 of 29 girls. Serum 25- hydroxyvitamin D before and after sunlight exposure was 7.1 +/- 1.9 ng/ml and 13.9 +/- 2.4 ng/ml and vitamin D administration was 7.4 +/- 1.8 ng/ml (group Ia) and 27.9 +/- 4.2ng/ml (group Ib) respectively. Serum alkaline phosphatase before and after calcium administration were 1187 IU/L and 666 IU/L respectively. Conclusion. We conclude that low daily calcium intake, and vitamin D acquirment are two important problems in Iranian girls during rapid growth at puberty; therefore, for prevention of overt rickets calcium and vitamin D Supplementation appear to be necessary.