Evaluation of vitamin D concentration in a population of young, healthy women - the effects of vitamin D supplementation.

Abstract

The goal of the study was an evaluation of serum vitamin D concentrations in healthy young women. A total of 106 healthy women, aged 20-30 years, were included in the study. Monthly evaluation - for three months - of the effects of calcium (500 mg) and vitamin D (1500 IU) administration in women with baseline values of vitamin D < 20 ng/mL (Group 1) plus the effects of an 800 IU/d dose in women with the baseline value of D > 20 ng/mL (Group 2). Additionally, calcium and PTH concentrations were assessed at the study onset and after a three-month supplementation. Only 67 women adhered to the prescribed therapeutic regime during the three months of observation. The mean vitamin D concentration in the entire study group was 16.56 ng/mL, being 12.6 ng/mL in Group 1 and 25.22 ng/mL in Group 2. In the course of vitamin D administration, its concentration increased statistically significantly, both in the entire group and in the subgroups, at all time points compared with the study onset. Moreover, its concentration in the whole population and in Group 1 was significantly higher in each of the time points not only in relation to the baseline, but also in comparison with the results of the previous measurements (after 1 and 2 months of supplementation). In Group 2, vitamin D levels also increased systematically throughout the whole study period, and after 3 months its concentration was significantly higher than after 1 and 2 months. Although there were no differences in calcium concentration after those three months, a statistically significant drop of PTH (p < 0.05) was recorded in the entire population and in Group 1. A moderate deficiency of vitamin D was observed in the studied population of young women. A supplementation with calcium plus vitamin D brought about an increase of vitamin D concentration as early as in the first month of administration. The optimal concentration of > 30 ng/mL was achieved in Group 1 after three months of vitamin D administration in 1500 IU/d dose.