These data suggest that haplotype analysis that encompasses different domains of the VDR gene might further our understanding of associations between the VDR gene and colon and rectal cancer.
The FF genotype of the Fok1 VDR gene was associated with reduced risk of colon cancer among women with any allele of 23+ CAG repeats (OR 0.62 95% CI 0.44, 0.88), whereas men with the LL/bb VDR genotypes were at reduced risk of rectal cancer if they also had 23+ CAG repeats (OR 0.71 95% CI 0.48, 1.05) relative to men with fewer than 23 CAG repeats of the AR gene.
Modifiable dietary risk factors may be differentially important among individuals by VDR genotype and may act through the insulin pathway to affect colon cancer risk and through fat, calcium, or other means to influence rectal cancer risk.
The association between energy intake and colon cancer appears to be driven more by energy intake than Bsm1 or polyA VDR genotypes, although there was a significant interaction between the Fok1 VDR polymorphism and energy intake and risk of both colon and rectal cancer (p interaction 0.01 for colon and 0.04 for rectal).
We evaluate the association between calcium, vitamin D, dairy products, and VDR polymorphisms in 2 case-control studies of colon and rectal cancer (n = 2,306 cases and 2,749 controls).
In our study, XbaI and PvuII polymorphisms of the ER gene and the BsmI polymorphism of the VDR gene were studied in 56 Caucasian patients with rectal cancer.