The frequency of vitamin D insufficiency in healthy female adolescents

Aim: To establish the frequency and causes of vitamin D insufficiency in healthy female adolescents in Izmir, Turkey. Methods: 64 adolescents from a low- (Ikinci Inonu) and a high- (Ilica) socio-economic settlement were included. Parents' monthly income was classified as low, middle and high. The blood samples were drawn at the end of the summer and winter periods. Results: Vitamin D insufficiency percentages for the end-of-winter period were 59.4% in Ikinci Inonu and 15.6% in Ilica, and for the end of summer 25% and 15.6%, respectively. Calcidiol levels of cases from Ikinci Inonu were found to be lower compared with the levels of cases from Ilica (34 ± 15 vs 59 ± 24 nmol/l for end of winter, p =0.000; 51 ± 22 vs 65 ± nmol/l for end of summer, p =0.03). Calcidiol levels of cases whose parental monthly income was low and whose mothers were illiterate were significantly lower than the others (48 ± 18 vs 65 ± 29 nmol/l for end of summer, p=0.01; 33 ± 16 vs 56 ± 23 nmol/l for end of winter, p = 0.000; 45 ± 13 vs 64 ± 29 nmol/l for end of summer, p=0.007; 36 ± 17 vs 51 ± 25 1 for end of winter, p =0.02; respectively). Conclusion: Vitamin D insufficiency was frequent, especially in the end-of-winter period. Basic risk factors were low socio-economic status, illiteracy of mothers and low calcium intake.