Association Between low Bone Mineral Density Risk Factors and Vitamin D Receptor Gene Polymorphism in Female Athletes

Abstract

This study aimed to investigate the relationship between risk factors for low bone mineral density (BMD) and vitamin D receptor (VDR) gene Apa I polymorphism in female athletes.

The subjects were 193 female athletes participating in 12 competitive sports (age 20.1±1.0 years). Data on sports participation, age of menarche, prior stress fracture and menstrual abnormalities were obtained by questionnaire survey. The competition types were classified into five types: endurance type, aesthetic type, aquatic type, ball type and high load type in consideration of exercise load characteristics. Whole body BMD was measured by the dual-energy X-ray absorptiometry method (DXA). Analysis of VDR gene Apa I polymorphism was done using the TaqMan® SNP Genotyping Assay.

There was no significant differences in BMD and VDR gene Apa I polymorphism for all competition types. The analysis of low BMD risk factors and BMD in all subjects, indicated that four items (BMI, competition type, age of menarche and prior stress fracture) were shown as significantly related to BMD. As for relationship between low BMD risk factors and BMD in each competition type, prior stress fracture in endurance type, age of menarche in aquatic type, and BMI in ball type and high load type showed a significant negative correlation. As a result of analysis of low BMD risk factor and BMD according to Apa I polymorphism of VDR gene, AA+Aa type significant association was recognized in two items (BMI, competition type). On the other hand, in the aa type, four items (BMI, competition type, age of menarche and prior stress fracture) were shown as significant related items.

It was suggested that risk factors for low BMD has different effects on BMD depending on competition type and female athletes with the expression of Apa I polymorphism aa type of VDR gene may be more susceptible to low BMD risk factor than AA+Aa type.