Vitamin D intake is low and hypovitaminosis D common in healthy 9- to 15-year-old Finnish girls

Objectives: To study the prevalence of hypovitaminosis DI the effect of vitamin D supplementation an serum 25-hydroxyvitamin D [S-25(OH)D], and the intakes of vitamin D and calcium in Finnish 9- to 15-year-old athletic and nonathletic girls. Design: 1-year follow-up study (February 1997-March 1998 with three months of vitamin D supplementation (10 mu g/d) from October to January. Setting: Turku University Central Hospital. Finland. Subjects: 191 female volunteers aged 9- 15 y (131 athletes and 60 controls. Methods: Vitamin D and calcium intakes were estimated by a four-day food recording and a semi-quantitative food frequency questionnaire (FFQ). S-25(OH)D was followed by radioimmunoassay (RIA). Results: At baseline the mean S-25(OH)D concentration was 33.9 nmol/l among all girls. In winter severe hypovitaminosis D (S-25(OH)D < 20 nmol/l) occurred in 13.4% of the participants and in 67.7% S-25(OH)D was below 37.5 nmol/l. By the next summer the mean S-25(OH)D concentration was 62.9 nmol/l and in 1.6% of the subjects it was below 37.5 nmol/l. The prevalence of severe hypovitaminosis D was not significantly reduced by three months of vitamin D (10 mu g/d) supplementation At baseline, the mean intake of vitamin D was 2.9 mu g/d by food recording and 4.3 mu g/d by FFQ. The mean calcium intake was 1256 mg/d and 1580 mg/d, respectively. The intakes of vitamin D and calcium remained unchanged during the follow-up period. The athletes consumed more calcium than nonathletic controls, whereas the intake of vitamin D was quite similar among both groups. The vitamin D intake by FFQ correlated with the S-25(OH)D concentration in wintertime (r = 0.28, P < 0.01). Conclusion: Kqpovitaminosis D is fairly common in growing Finnish girls in the wintertime, and three months of vitamin D supplementation with 10 mu g/d was insufficient in preventing hypovitaminosis D. The dairy dietary vitamin D intake was insufficient (< 5 mu g/d) in the majority of participants, while the calcium intake was usually sufficient.