Factors affecting peak bone density in Japanese women.

Both genetic and environmental factors have been shown to contribute to the determination of bone density. To clarify the interaction between genetic and environmental factors affecting peak bone mass, we investigated the correlation between bone mineral density (BMD) and physical constitution, vitamin D receptor (VDR) genotype, age, age of menarche, history of menstrual dysfunction, and exercise in 157 healthy young Japanese women. History of exercise and menstrual dysfunction were significant independent predictors of BMD. The VDR genotype also affects peak bone density. Exercise has been shown to increase BMD in a similar way for each VDR genotype including those women who have the particular genotype associated with low bone density. This data indicate that there are complex gene-environmental interactions particularly in relation to menstrual history, exercise, and genetic factors during childhood/adolescence that may have implications for the development of adult BMD in women.