SNP prioritization

We used several strategies to prioritize SNPs associated with longevity and aging traits. First, we used an untar- geted approach whereby the top 50 SNP associations ranked according to the strength of the p-value for each trait were examined. Next, we explored the consistency of SNP associations across related sets of traits chosen a pri- ori (trait set one: age at death and morbidity-free survival at age 65 years; trait set two: biologic age and walking speed). Trait set one was chosen based upon linkage data in humans demonstrating that both longevity and a healthy aging trait were linked to the same region on chro- mosome 4 raising the hypothesis that the two phenotypes may share common genetic pathways [11,12]. The traits in set two reflect aging with good physical functioning and thus we postulated that biologic age and walking speed may have genetic variants in common. We also investigated SNP associations in candidate genes and regions reported to be associated with longevity identified from established databases including NCBI [14] using the search term "longevity" and the Science of Aging Knowl- edge Environment genes/intervention database http:// sageke.sciencemag.org/cgi/genesdb[30] choosing genes potentially related to lifespan in humans.

There were several additional associations not listed in Table 2a and 2b that were of interest. For age at death in the GEE analysis, SNP associations ranked numbers 9 and 13 were rs10507486 (p-value 0.000128) and rs4943794 (p-value 0.000277), both are intronic FOXO1A SNPs. For age at natural menopause, top ranked SNP associations in the GEE model included number 11, rs6910534 (p = 0.00003) near FOXO3a and number 18, rs3751591 (p = 0.00006) in CYP19A1.

Table 2c presents the LOD scores ≥2.0 and the corre- sponding 1.5-LOD support interval from genome-wide linkage for the three quantitative aging traits. None of the regions overlapped with SNPs associated with these aging traits in the FBAT and GEE analyses. Of note for biologic age by OSS the linkage peak on chromosome 21 con- firmed a prior Framingham Study report using a genome- wide scan with 401 microsatellite markers [10].

Table 3 provides all SNP associations with a GEE or FBAT p < 0.01 for both traits within the two pairs of related traits. For age at death and morbidity-free survival at age 65 years, FBAT models identified 7 SNPs and GEE models identified 9 SNPs associated with both traits including rs2374983 near PON1 (Tables 3a and 3b). For biologic age by OSS and walking speed, 13 SNPs in FBAT models and 6 SNPs in GEE models were associated with both traits (Tables 3c and 3d).

The SNPs were annotated using the UCSC genome browser tables using the May 2004 assembly http:// genome.ucsc.edu/[31,32]. All genes within 60 kb of the top ranked SNPs were identified.

Results

The longevity and aging traits available in the FHS 100K SNP resource are listed in Table 1. In this report, we con- sider only five of the traits listed in Table 1: multivariable- adjusted age at death, morbidity-free survival at age 65 years, age at natural menopause, walking speed, and bio- logic age by OSS. These traits include a pooled sample of Original Cohort and Offspring participants, with the exception of walking speed, which is reported in Off-

We identified from the literature 79 potential candidate genes and regions associated with longevity (see Addi- tional file 1 for listing). Of these, 12 genes had no SNPs and 67 genes had 1 to 45 SNPs within 60 kb of the gene

Table 1: Aging and Longevity Phenotypes for Framingham Heart Study 100K Project