Vitamin D receptor gene start codon polymorphism (Fokl) and bone mineral density in healthy male subjects

OBJECTIVE The genetic factors determining peak bone mineral density (BMD) in men are not well characterized, Recent studies have investigated the relationship between the start codon polymorphism (SCP) of the vitamin D receptor (VDR) gene and BMD in different populations, We have now examined the relationship between SCP of the VDR gene and BMD in a group of healthy Caucasian men from the northeast of England. SUBJECTS Ninety-six healthy men (median age 50, range 40.0-77.0 years). MEASUREMENTS Analysis of the Fokl genotypes of SCP of the VDR and measurements of BMD at the femoral neck and lumbar spine were performed. RESULTS FF, Ff and ff VDR Fokl genotypes were found to have the highest, intermediate and the lowest lumbar spine BMD, respectively (Mean +/- SD, for FF 1.07 +/- 0.14, Ff 1.05 +/- 0.16 and ff 0.95 +/- 0.10 g/cm(2)). There was a significant difference in spine BMD between FF and ff genotypes (P<0.05, analysis of Variance [ANOVA]), but no such difference was apparent between Ff and ff (P>0.05, ANOVA). Interestingly, there was no association between Fokl polymorphism and femoral neck BMD (Mean +/- SD, for FF 0.85 +/- 0.12, Ff 0.87 +/- 0.15 and ff 0.83 +/- 0.15 g/cm(2)). The distribution of Fokl VDR genotypes approached Hardy-Weinberg equilibrium and was similar to that reported for women from different ethnic groups, as the prevalence of FF and ff genotypes was 44% and 16%, respectively. CONCLUSION The study shows that in this population of healthy men there is a weak association between lumbar spine bone mineral density and Fokl restriction fragment length polymorphism at the translation initiation site of the vitamin D receptor gene.