Variation in the klotho gene is not associated with mortality risk among elderly men in MR OS Sweden

Polymorphisms in the Klotho (Kl) gene, which is central for vitamin D regulation by fibroblast growth factor 23 (FGF23), have been associated with longevity, coronary disease and stroke. The CC genotype of the single nucleotide polymorphism (SNP) rs577912 in the Kl-gene is associated with decreased Kl expression, as well as increased mortality in end stage renal disease. We examined if SNP in the Kl-gene was associated with mortality in the community derived cohort of 70 to 80 year old males of MrOS Sweden (N = 3014). High throughput genotyping of the KLOTHO SNPs was achieved by use of SequenomR MassEXTEND/Mass/ARRAY technology. 2738 subjects had a valid result for rs577912: CC 73.1% and CA + AA 26.9%. There were no differences in the serum levels of FGF23, phosphate, parathyroid hormone or renal function between genotypes CC and CA + AA. During a follow-up of a median of 4.5 years there were 337 deaths, 253 (12.6%) in the CC group and 84 (11.4%) in the CA + AA group. With log rank analysis there were no differences in mortality between the genotypes for all cause mortality (P = 0.39) or cardiovascular mortality (P = 0.60). None of the other SNPs in the Kl gene was associated with mortality in this cohort either. Conclusion: There is no association between the SNP rs577912 in the Kl-gene and mortality among elderly men.