Vitamin D receptor gene polymorphism is associated with reduced disability in multiple sclerosis

Ultraviolet radiation (UVR) may contribute to multiple sclerosis (MS) outcome by a mechanism involving vitamin D and the vitamin D receptor (VDR). In 512 patients with MS duration of 10 or more years, we studied the association of VDR single nucleotide polymorphisms (A/G(1229), C/G(3444), G/A(3944), CC(20965), CC(30056), F/f(30875), C/T(48200), T/t(65013)) with outcome or disability. ff(30875) frequency was lower in cases with EDSS > or = 6.0 than with scores < 6.0 (odds ratio = 0.38, 95% CI = 0.20-0.70). The association of ff(30875) with outcome was not mediated by cumulative exposure to UVR as assessed by questionnaire; low exposure (odds ratio = 0.42, 95% CI = 0.14-1.34) and high exposure (odds ratio = 0.34, 95% CI = 0.16-0.73).