Studies of bone density, quantitative ultrasound, and vertebral fractures in relation to collagen type I alpha 1 alleles in elderly women

Previous studies have demonstrated that an Spl binding site polymorphism in the collagen type I gene (COLIA1) is related to reduced bone mineral densi ty (BMD) and osteoporotic fractures in certain populations, particularly in the elderly. We have examined the relationship among these COLIA1 Sp1 alle les, BMD, quantitative ultrasound properties of bone, and fractures in a po pulation-based cohort of elderly women from the UK. The study group compris ed 314 women aged 75 years and over who agreed to participate in a clinical study of bisphosphonate therapy in preventing bone loss at the hip. Women were enrolled regardless of the presence or absence of osteoporosis, but th ose with other diseases that might affect skeletal metabolism were excluded . The genotype distribution for the Spf polymorphism was in Hardy-Weinberg equilibrium (SS - 78%; Ss - 20%; ss 2%) but the proportion of individuals w ho carried the "s" allele (22%) was significantly lower than previously obs erved in another study of the UK population (37.1%) (P < 0.001). There were no significant associations between COLIA1 genotypes and metacarpal cortic al index, BMD of the forearm, tibial SOS, calcaneal SOS, or calcaneal BUA. While there was a trend towards lower BMD values at the hip in patients wit h Ss and ss genotypes, this was not statistically significant (SS = 0.721 /- 0.14; Ss = 0.704 +/- 0.13; ss = 0.683 +/- 0.20 P = 0.6). Prevalent verte bral fractures occurred in 22% of subjects and prior fractures of the wrist , ankle, and hip were reported by 20%, but there was no significant differe nce in COLIA1 genotype distribution between fracture patients and controls. We conclude that COLIA1 Spl alleles are not significantly associated with BMD, ultrasound properties of bone, or fractures in this population-based s ample of elderly women.