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 Inönü) 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 Inönü and 15.6% in Ilica, and for the end of summer 25% and 15.6%, respectively. Calcidiol levels of cases from Ikinci Inönü 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+/-28 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 nmol/l 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.