Vitamin D receptor gene polymorphism and bone metabolism during low-dose oral contraceptive use in young women

With the aim to determine whether bone metabolism in young women using low-dose oral contraception is influenced by vitamin D receptor (VDR) genotype, we designed the prospective clinical study of 41 healthy women aged 20–27 years. Twenty-one women of the study group were prescribed an oral contraceptive (30 μg ethynyl estradiol and 150 μg levonorgestrel) and 20 women of the control group a nonhormonal contraceptive or none. Biochemical markers of bone metabolism (bone-specific alkaline phosphatase, osteocalcin, deoxypyridinoline) and VDR genotype, using BsmI endonuclease, were determined. After 3 months in the study group, the BB genotype subgroup showed significantly decreased osteocalcin (p = 0.010), in the Bb genotype subgroup bone-specific alkaline phosphatase (p = 0.043) and osteocalcin (p = 0.006) decreased, and in the bb genotype subgroup no changes were observed. In the control group, there were no significant changes in markers of bone metabolism regarding VDR genotype. In conclusion, our study shows that in young women VDR gene polymorphism could influence bone metabolism during low-dose oral contraceptive use.