1.000.50 0.75Cumulative mortality251.00 0.00 0.0.50 0.75Cumulative mortality25Cumulative mortality0.50 0.75 1.00 0.00 0.0.250.00All-cause mortality All-cause mortality All-cause mortality                 it-cc 3; — L1074L 8 1367— it-cT el lo7ar 27 |— C1367R3 FA074F  o|  R1367R£R £xgo go£28 $8=” aFR as6° oo8 885 90 95 100 105-985 90 95 100 105 © 85 90 95 100 105Age (years) Age (years) Age (years)Cardiovascular mortality @ Caldiovascular mortality Cardiovascular mortalityit-cc 8 L1074L > 8 1367CT zr L1074F 2 | — ci3e7R£o|—_ Fr074F Ew —— R1367RBS Bo —£8 ZegO BS; i i2zu a3Os ogg g85 90 95 100 105 85 90 95 100 105 ° 85 90 95 100 105Age (years) Age (years) Age (years)Cancer mortality Cancer mortality Cancer mortality1 i1-CC 8 L1074L 8 C1367C—it-CT 2 | — wor 2} — ci367R—_ S| — R1367R| # © F1074F z eES go£38 28ge B°3 3Ew Ew6g = 6s2z S85 90 95 100 105° 85 90 95 100 105 o 85 90 95 100 105Age (years) Age (years) Age (years)

Fig. 2. Kaplan–Meier curves of cumulative all-cause, cardiovascular and cancer mortality, dependent on i1-C/T, L1074F and C1367R genotypes in the combined cohort of 1245 individuals from age 85 years onwards.

person-years, 957 (77%) participants had died, of which 365 (38%) from cardiovascular disease and 143 (15%) due to cancer. The Kaplan–Meier estimates of cumulative mortality according to the genotypes of the different SNPs are presented in Fig. 2. According to the Kaplan–Meier mortality curves, it seems that carriers of the i1-CT genotype, and heterozygous and homozygous carriers of the 1367R allele have lower cancer mortality. Although not statistically significant, the mortality risk estimates of 0.56 (0.26–1.20) for i1-CT, 0.84 (0.59–1.20) for C1367R and 0.57 (0.27–1.17) for R1367R genotypes, show lower cancer mortality. The same trend was observed in cohort ’87 and ’97 (Supplemen- tary Table 1). The other all-cause and cause-specific mortality risks, calculated separately for all polymorphisms, were similar between the different genotype carriers of the i1-C/T, L1074F and C1367R polymorphisms, showing no evidence of altered survival.

and C1367R polymorphisms has been assessed previously only in one study (Bendixen et al., 2004). In that study, the Tallele of the i1-C/T SNP was associated with better cognitive function- ing in the elderly, and no associations with the C1367R SNP were found (Bendixen et al., 2004). The beneficial effect of the i1-T allele was only seen on the cognitive composite score and not on MMSE. In our study, carriers of the i1-Tallele seemed to perform better on all the analyzed cognitive domains, however the differences did not reach statistical significance. A significant association, on the other hand, was observed between the C1367R polymorphism and attention. Carriers of the 1367R allele had worse attention compared to the 1367C homozygotes. The other domains of cognition seemed to be unaffected. The positive association between the C1367R SNP and attention could be a chance finding. In this study, we did not correct for multiple testing, however if such correction had been applied then the borderline significance would have disap- peared. In order to exclude that the findings of this and the other study (Bendixen et al., 2004) between cognition and WRN gene polymorphisms are due to chance, corroboration in indepen- dent samples is needed. In WS patients’ cognitive decline and dementia have not been described. It has been reasoned that the central nervous system may be less prone for damage due to the absence of mitotic activity during adult life. However, subtle defects might emerge over time, if the WRN is important for

4. Discussion

The results of this study show that the i1-C/T, L1074F and C1367R polymorphisms in the WRN gene do not influence the occurrence of cardiovascular pathologies, cognitive perfor- mance and the risks of all-cause and cause-specific mortalities in a cohort of elderly aged 85 years and older.

From the three polymorphisms analyzed in this study, the C1367R SNP was found to be out of Hardy–Weinberg equilibrium in cohort ’97. Since all DNAs from cohort ’87, ’97 and from blood bank donors were genotyped simultaneously then a specific genotyping failure in cohort ’97 is unlikely. Furthermore, 10% of the samples were genotyped twice and for the C1367R SNP in cohort ’97 the genotyping error was less than 1%. Therefore, the marginal deviation from Hardy–Weinberg equilibrium could have been arisen by chance.

The influence of the WRN gene on mortality before the age of 85 years was examined in a cross-sectional design by comparing allele frequencies of the SNPs in elderly aged 85 years and older with those in young subjects. No differences were found in the allele frequencies between the elderly and young. With regard to the L1074F polymorphism, this finding is in contrast with a study showing an age-dependent enrichment of the 1074L allele in Finnish and Mexican populations (Castro et al., 2000). The latter indicates a beneficial effect on survival. To evaluate further the impact of the polymorphisms on lifespan, mortality risks after the age of 85 years, dependent on the SNPs, were assessed. The mortality risk estimates calculated for all-cause and cardiovascular mortality, did not differ between the different genotype carriers of the poly- morphisms. However, the observed trend for lower cancer mortality risks for the minor allele carriers of the i1-C/T and C1367R polymorphism needs to be studied in more detail, in order to make more profound conclusions. Taking together, the cross-sectional and prospective analyses provided no evidence for differential survival for any of these polymorphisms.