The Sp1 binding site polymorphism in the collagen type Iα1 (COLIA1) gene is not associated with bone mineral density in healthy children, adolescents, and young adults

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 Spl 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 BRID 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 COLI41 genotypes. In conclusion, the data indicate that the polymorphism at the Spl site in the COLIA1 gene is not associated with BMD or gain of forearm BMD ir healthy boys and girls.