The Sp1 binding site polymorphism in the collagen type I α 1 (COLIA1) gene is not associated with bone mineral density in healthy children, adolescents, and young adults

Abstract

Up to 85% of the variance in bone mineral density (BMD) is genetically determined. A putative candidate gene involved in the regulation of bone mass is the COLIA1 gene encoding type I collagen, which is the major protein of bone. We examined possible allelic influences of a G to T COLIA 1 gene polymorphism in a recognition site for the transcription factor Sp1 on: (i) gain of forearm BMD using single photon absorptiometry (SPA); and (ii), BMD of the forearm, spine, hip, and whole body with dual X-ray absorptiometry (DXA). At baseline, 269 healthy boys and girls aged 8.2-16.5 years were eligible for the study. Forearm BMD measurements obtained at baseline and after 3.8±0.1 years (± S.D.) were used to calculate the annual percentage change in BMD. Calcium intake and physical activity were determined by a detailed questionnaire at baseline and after 1 year. Essentially no significant differences in forearm BMD gain or in BMD assessed at the forearm, spine, and whole body were observed among the three COLIA 1 genotypes. In conclusion, the data indicate that the polymorphism at the Sp1 site in the COLIA1 gene is not associated with BMD or gain of forearm BMD in healthy boys and girls.