Results of many studies indicate that the BsmI polymorphism in the vitamin D receptor (VDR) gene may influence bone tissue metabolism and may be useful in identifying patients at greater risk of osteoporosis. As far as long-term glucocorticoid treatment is a major risk factor for osteoporosis development, we looked for the BsmI VDR gene polymorphism and its relation to phenotypic features characterizing bone status (BMD and metabolic bone turnover) in 74 premenopausal women: 51 asthmatic patients treated for a long-term with GCs and 23 healthy controls. BMD was measured using DXA method. Serum levels of osteocalcin and ICTP (as markers of bone turnover) were measured using IRMA and RIA methods respectively. VDR gene genotypes were determined using PCR-RFLP method. Results: Genotype bb was found in 32.4%, BB in 10.8%, and bB in 56.8%. There were no significant differences regarding BMD, biochemical and hormonal parameters between any of genotypes.
Conclusions: Genotype distribution was similar to those observed in other Caucasian populations. The data suggest that the VDR BsmI polymorphism does not seem to be useful for identifying patients at greater risk of glucocorticoid-induced osteoporosis, however it needs to be confirmed by a population-based study.