Plasma vitamin D biomarkers and leukocyte telomere length in men.

PURPOSE

Vitamin D may reduce telomere shortening through anti-inflammatory and anti-cell proliferation mechanisms. In women, higher plasma 25-hydroxyvitamin D (25(OH)D) has been shown to be associated with longer telomere length, but the relationship has not been assessed in men.

METHODS

We conducted a cross-sectional analysis of 25(OH)D, 1,25-dihydroxyvitamin D (1,25(OH)D) and relative leukocyte telomere length (LTL) among 2483 men [1832 men for 1,25(OH)D] who were selected as cases and controls in three studies of telomeres and cancer nested within the Health Professionals Follow-up Study. We also genotyped 95 SNPs representing common genetic variation in vitamin D pathway genes. LTL was measured by quantitative PCR, and z-scores within each study were calculated. Associations were assessed by linear as well as logistic regression adjusting for age and other potential confounders.

RESULTS

Age (P-trend < 0.0001), pack-years of smoking (P-trend = 0.04) and body mass index (P-trend = 0.05) were inversely associated with LTL. Neither 25(OH)D nor 1,25(OH)D was associated with LTL (multivariable-adjusted P-trend 0.69 and 0.41, respectively, for the linear regression model). One SNP in the retinoid X receptor alpha gene was associated with long LTL (P = 0.0003).

CONCLUSIONS

In this cross-sectional study of men, 25(OH)D and 1,25(OH)D were not associated with relative LTL.