Objective

To describe the relation between spinal degenerative disease, allelic variation in the vitamin D receptor gene, and lifestyle factors in a population-based association study.

Methods-Random population-based sample of 110 men and 172 women over 60 years of age participating in the Dubbo Osteoporosis Epidemiology Study who had spinal radiographs (performed according to a standardised approach), assessment of lifestyle factors, bone densitometry as well as blood taken for genotyping.

Results

Spinal degenerative disease of varying severity was common in this sample.

Multivariate analysis of genetic and lifestyle factors simultaneously strengthened the statistical significance of each indicating the presence of additive gene environment interaction.

Allelic variation in the vitamin D receptor gene was associated with severity of osteophytosis (adjusted OR « TT » v « tt » 0.41,95% CI 0.17,0.97), presence of disc narrowing (adjusted OR « TT » v « tt » 0.45,95% CI 0.20,0.99) and weakly with presence of osteophytosis (adjusted OR « TT » v « tt » 0.47,95% CI 0.19,1.16) but not with severity of disc narrowing (OR « TT » v « tt » 1.05,95% CI 0.40,2.72) or apophyseal arthritis (OR « TT » v « tt » 0.63,95% CI 0.24,1.59).

Adjustment for femoral neck bone density did not change these findings suggesting that the association is not mediated through bone density.

Presence and severity of spinal degenerative disease increased with age at all sites. (...)