Advanced onset of menarche and higher bone mineral density depending on vitamin D receptor gene polymorphism.

Bone mineral density (BMD) at distal forearm, and weight and height of healthy Japanese girls aged 18-19 years were measured and their age at menarche was obtained through a questionnaire. A statistically significant association was found between BMD at distal radius and vitamin D receptor (VDR) gene polymorphism at the ApaI site. The age at menarche in the population with Aa genotype was significantly earlier than that in the aa population. In addition, BMD was significantly dependent on the earlier onset of menarche in the population with genotype Aa but not in the population with genotype aa. BMD was also positively associated with the body mass index (BMI) in the population with genotype Aa. Statistical analysis suggested a stronger effect of VDR genotype on age at menarche than on BMI. Thus, we show that VDR gene polymorphism advances the age at menarche and increases BMD in cooperation with age at menarche.