Association of 25-hydroxyvitamin D levels and vitamin D receptor gene polymorphisms with breast cancer risk in Bangladeshi women.

Breast cancer (BrCa) is a leading cause of mortality among Bangladeshi women. Deficiency of 25-hydroxyvitamin D [25(OH)D] and vitamin D receptor (VDR) polymorphisms have been linked to cancer susceptibility, but evidence from South Asia is scarce. We conducted a case-control study of 400 BrCa patients and 400 age-matched controls to assess serum 25(OH)D levels and four VDR variants (rs731236, rs2228570, rs1544410, rs7975232) in relation to BrCa risk. Logistic regression showed significant associations for rs2228570 (FokI; odds ratio [OR] 1.52, 95% confidence interval [CI] 1.14-2.02, p = 0.004) and rs1544410 (BsmI; OR 1.52, 95% CI 1.14-2.02, p = 0.0044) under dominant models, while rs731236 (TaqI) and rs7975232 (ApaI) showed no effect. Serum 25(OH)D levels were lower in cases than controls, with 80.7% of cases deficient; low 25(OH)D was associated with increased risk (OR 2.15, 95% CI 1.06-4.38, p = 0.035). No variant correlated with 25(OH)D levels. These findings suggest that FokI, BsmI, and low 25(OH)D independently contribute to BrCa risk in Bangladeshi women.