Our strategy of selecting SNPs in candidate genes and regions previously reported to be associated with longev- ity yielded interesting findings. For age at death, we iden- tified SNPs in or near several genes including KL, LEPR, PON1, SOD2, and WRN. Defects in the WRN gene are the cause of Werner Syndrome, an autosomal recessive disor- der characterized by premature aging. A longitudinal study of ageing Danish twins recently reported a possible association between a successful aging trait and 3 SNPs in the WRN gene [44]. We were unable to determine if our SNP (rs2725369) was in LD with the SNPs in the prior report because the SNPs were not included in HapMap. Mutations in the KL (Klotho) gene in the mouse lead to a syndrome resembling human aging [45-47]. There has been one report linking a functional variant of the KL gene to human longevity [15]. Thus, results from this GWAS may direct resources to the most relevant candidate genes and pathways for further investigation in humans.

Abbreviations

CVD = cardiovascular disease; FBAT = family-based asso- ciation test; FHS = Framingham Heart Study; GEE = gener- alized estimating equations; GWAS = genome-wide association study; LD = linkage disequilibrium; LOD = logarithm of the odds; NCBI = National Center Biotech- nology Information; OSS = osseographic scoring system;

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SNP = single nucleotide polymorphism; TIA = transient ischemic attack.

Competing interests

The authors declare that they have no competing

Authors' contributions