['We studied the association between CYP2R1 genetic polymorphisms and circulating 25-hydroxyvitamin D [25(OH)D] before and after supplementation with vitamin D3 in 218 elderly. We found differences between 3 and 8\xa0ng/ml in circulating levels at baseline in women but not in the response after 1\xa0year of supplementation.', 'This study evaluated the association between polymorphisms in four single nucleotide polymorphisms (SNPs) of the CYP2R1 gene and 25(OH)D levels before and 1\xa0year after supplementation with two different doses of vitamin D3 (600\xa0IU daily or a dose equivalent to 3750\xa0IU daily), in a cohort of 218 (96 men and 122 women) Lebanese elderly overweight subjects.', 'Genotyping was performed for rs12794714, rs10741657, rs1562902, and rs10766197 SNPs using real-time PCR. The 25(OH)D levels were measured by liquid chromatography tandem mass spectrometry.', 'At baseline, the mean\xa0±\xa0SD age was 71.0\xa0±\xa04.7\xa0years, BMI 30.3\xa0±\xa04.6\xa0kg/m'] Are cYP2R1 polymorphisms important modulators of circulating 25-hydroxyvitamin D levels in elderly females with vitamin insufficiency , but not of the response to vitamin D supplementation?