Table 5

Estimation of haplotype frequencies in the UCP3 SNPs and association with hand grip performance in 1905 Cohort.

Haplotype rs647126 rs1685354 rs3781907 rs11235972 Freq.a Score pb GAGA G A G A 0.225 (cid:4)2.385 0.008 GAAA G A A A 0.024 (cid:4)1.893 0.068 AAAA A A A A 0.006 (cid:4)0.780 0.455 GAAG G A A G 0.032 (cid:4)0.644 0.515 AAGA A A G A 0.016 (cid:4)0.255 0.794 GGGA G G G A 0.003 0.032 0.972 GAGG G A G G 0.012 0.252 0.803 AAGG A A G G 0.042 0.459 0.640 AAAG A A A G 0.377 0.567 0.575 AGAG A G A G 0.003 1.358 0.156 GGAG G G A G 0.246 1.974 0.051 GGGG G G G G 0.012 2.396 0.029

a Estimated haplotype frequency. b Monte-Carlo p-value from 106 replications.

Table 6

Estimated coefficients of the fitted Accelerated Failure Time (AFT) model in 1905-Cohort including sex and one SNP (among rs11235972, rs1685354, rs3781907 rs647126) as covariates. Standard errors (SE), Wald test statistics (z) and significance (p-value) are also reported.

Coefficient SE z p-value rs11235972 Intercept 3.994 0.038 104.500 <0.001 Sex=Male (cid:4)0.171 0.057 (cid:4)3.020 0.002 SNP (cid:4)0.090 0.041 2.190 0.029 Log(scale) (cid:4)0.269 0.028 (cid:4)9.750 <0.001 rs1685354 Intercept 3.954 0.039 102.640 <0.001 Sex=Male (cid:4)0.176 0.057 (cid:4)3.105 0.002 SNP (cid:4)0.013 0.041 (cid:4)0.300 0.762 Log(scale) (cid:4)0.267 0.028 (cid:4)9.680 <0.001 rs3781907 Intercept 3.994 0.040 100.480 <0.001 Sex=Male (cid:4)0.169 0.057 (cid:4)2.980 0.003 SNP (cid:4)0.080 0.041 (cid:4)1.960 0.050 Log(scale) (cid:4)0.269 0.028 (cid:4)9.750 <0.001 rs647126 Intercept 3.921 0.047 83.870 <0.001 Sex=Male (cid:4)0.173 0.057 (cid:4)3.040 0.002 SNP 0.028 0.037 0.760 0.447 Log(scale) (cid:4)0.268 0.028 (cid:4)9.680 <0.001

variability and HG strength in a southern Italian population (Crocco et al., 2011), and taking into account the different quality of aging demonstrated between southern and northern Europeans (Jeune et al., 2006; Andersen-Ranberg et al., 2009), in this paper we wanted to further test this association in a larger sample of 1616 individuals (908 nonagenarians and 708 younger subjects), belonging to a northern European population, the Danes. To this aim, we carried out an association analysis between four common variants in the UCP3 gene and HG performance, both at single and haplotypic levels. We found that UCP3 markers previously associated with age-related phenotypes (diabetes, obesity, serum lipid levels and BMI) (van Abeelen et al., 2008; Salopuro et al., 2009) significantly influenced also the HG performance in the analyzed cohorts. In particular, the minor allele of rs1685354 had significant effects on the HG performance both in the younger and in the older sample, although in opposite sense. In nonagenarians, the less frequent allele of rs11235972 was negatively associated with HG, while a marginal positive effect was observed for rs647126 in the younger sample.

carriers of the A allele at rs11235972 variation and carriers of the G allele at rs3781907 (that are the less frequent alleles for these SNPs) showed a reduced survival chance (coefficient = (cid:4)0.090 and (cid:4)0.080, respectively). In addition, male sex was associated with a reduced survival probability in all four models (p < 0.01). Interestingly, the rs11235972-A variation was also associated with a decreased HG performance in the previous analysis in this cohort. As for the rs3781907, despite the borderline association with HG performance (p = 0.062, see Table 4), it significantly influenced survival in this cohort.

For each polymorphism, the survival functions obtained the fitted AFT models are shown in Fig. 2.

Considering the previously demonstrated LD between SNPs and the haplotypic effect on the HG performances, we then carried out a haplotype-based survival analysis, as previously described in Section 2. No significant association was found between any UCP3 haplotype and survival in the Danish 1905 sample (data not shown).

4. Discussion

With the exception of rs11235972 in the 1905 Cohort, no other association hold a Bonferroni’s correction (p < 0.0125). However, this correction seems more suitable when searching for associa- tions without a priori hypotheses but too conservative when assessing a specific research question, as in our case, with a candidate gene chosen for its relevance with respect to the

Several studies have hypothesized a correlation between uncoupling process and the regulation of muscle metabolism in elderly (Cortright et al., 1999; Nabben and Hoeks, Considering the association demonstrated between UCP3

TST060504TST1Z309 12     60 90 120Months30ors647126      org0 90 Oo 20 00Auigeqorg [eAlaing     60 90 120Months30oO183781907or#0 90 0 20 00Auigeqorg leaning      oL#0 90 0 z0 00Auigeqosg |eaiaingor#0 90 0 20 00Auigeqoig leAinung60 90 120Months30Oo60 90 120Months30oO

Fig. 2. Panel showing the survival functions of the different genotypes at the four analyzed UCP3 SNPS in the 1905 Cohort sample, as obtained from the fitted AFT models.

analyzed phenotype (Perneger, 1998). Furthermore, because this work confirmed a previous association between UCP3 variability and hand grip levels at old age, we believe that also borderline and trend results should be taken into account.

production, thus preventing or reducing the age related decay of the aging muscle (Nabben et al., 2008; Mookerjee et al., 2010).