a) Males Gene Best SNP F statistic P-value ADL GPX4 rs4588110 4.174 0.045 SOD3 rs17878863 4.114 0.031 UQCRFS1 rs10420904 6.845 0.002 XDH rs1429372 3.185 0.020 HG GCLC rs2397147 3.413 0.024 WS UCP2 rs659366 6.125 0.009 MMSE NOS3 rs743506 101.535 0.050 CCS CP rs9853335 3.222 0.021 CYC1 rs11780874 5.141 0.022 b) Females Gene Best SNP F statistic P-value ADL TXNRD1 rs7310505 4.979 0.002 TXN2 rs12159295 3.990 0.016 ACOX1 rs3643 3.186 0.039 HG GLRX rs6556884 5.750 0.001 UCP3 rs11235972 6.619 0.002 UCP2 rs7109266 5.650 0.008 NOX1 rs5921669 3.752 0.024 WS SOD2 rs2842980 5.103 0.005 GCLC rs2100375 4.159 0.007 MMSE MT1A rs4784701 7.717 0.002 CCS ACOX1 rs8065144 3.176 0.046 NOS3 rs2853792 3.471 0.023 Survival NDUFS1 rs6435324 5.115 0.009 SOD2 rs911847 3.715 0.035 TXNRD1 rs10861169 3.587 0.024 UCP3 rs11235972 4.004 0.041

In this work, to the aim of investigating the possible of the pro–anti-oxidant pathway to functional status at old age, we tested the association of genes belonging to pro- and anti-oxidant pathways with predictors of physical (HG, ADL and WS) and cognitive decline (MMSE andCCS)atoldage,inacohortof Danishnonagenarians.Fewstudiesin- vestigated the genetic variations influencing physical abilities at old age and samples were mainly drawn from hospitalized and affected pa- tients. Positive association was reported between ADL levels and ACE gene by Seripa et al. (2011), while no correlation was found with APOE gene by Kulminski et al. (2008) and Bader et al. (1998), the last in a cohort of 253 healthy and disabled Italian octo- and nonagenarians. As for cognitivefunctioning, studies found an involvementof genes spe- cifically involved in neurological metabolism and dopaminergic neuromodulation, as APOE, COMT, BDNF and DTNBP1 genes, with cogni- tive ability in older adults less than 85 years (De Blasi et al., 2009; Lindenberger et al., 2008). In particular, studies demonstrated an in- volvement of genetic variability on specific cognitive areas; moreover, they suggest that aging magnifies the functional consequences of com- mon genetic polymorphisms on specific abilities, such as executive functioning and working memory, contributing to the marked hetero- geneity in late-life cognitive functioning.

We moved forward exploring the association with functional status of genes belonging to a specific metabolic pathway, demonstrated to be biologically involved in physical and cognitive impairment.

Overall, only 2 of the top 14 genes found associated with functional in this work have been previously reported in association studies physical status at old age, in Italian and Danish Cohorts (the latter the same used in the present paper), and they belong to UCPs family et al., 2011; Dato et al., 2012b). Both UCP2 and UCP3 confirmed have a major effect on physical tests such as HG and WS in the whole as well as in the two gender separately, with the rs11235972 survivalatold age too. Theassociation of UCP3 gene var- with physical exercise is particular relevant, considering its ex- in skeletal muscle, where it regulates fatty acid metabolism, status, and ROS production, suggesting a correlation between uncoupling process and the regulation of muscle metabolism/ in the elderly (Dato et al., 2012b and references therein).

All theotherassociationsare new and opentheinvestigationof their variability in future studies. Furthermore, associations holding the mul- tiple comparison correction were found in the female sub-sample, sug- gesting a sex-specific effect of the pro–anti-oxidant pathway on the analyzed functional parameters.

4. Discussions

tive performances) is a well-recognized marker of longevity (Schupf et al., 2004). Physicalactivityhasmanywell-establishedhealthbenefits, going from the maintenance of muscle mass to the delay of cognitive impairment, to the promotion of a psychological wellness; however, itisknownthatastrenuousexercisecanbedisadvantageousforlongev- ity, because it can increases muscle oxygen flux, stimulating intracellu- lar events leading to an enhanced oxidative stress (Dato et al., 2013 and references therein). A moderate exercise can instead induce anti- oxidant adaptation, thereby balancing oxidative stress and muscle dete- rioration, as demonstrated by an increase of two years in the average lifespan and a delayed in disabilities of physically active people in com- parisonwithlessactive(Ji,2002).Progressiveoxidativedamageisalsoa conserved central mechanism of age-related cognitive decline, because of the higher consumption of oxygen (more than 20% than other tis- sues) in the brain, with the consequent exposition to ROS from mito- chondrial respiration. As for the muscle mass, a regular physical activity seems to protect against brain damage, by preventing brain

Thegene having a major effectonADLphenotype is TXNRD1, bothin the whole sample (p = 0.010) and specifically in the female sub-group, where the association is very close to significance also after correction for multiple testing (p = 0.002). Although borderline, TXNRD1 was as- sociated with WS in the whole sample too, confirming the influence that this genecan have on functionalactivity.Thioredoxin(Trx)is acru- cialproteinfor antioxidant defense, is aredox regulator of theintra- and extra-cellularsignalingpathways andtranscriptionfactors,and contrib- utesintheproteinfoldingthroughthecatalysisofsulfur-exchangereac- tions among protein complexes. Mammalian Trx have been associated with neuro-protection against Alzheimer's and Parkinson's disease (Masutani et al., 2004) and their up-regulation has been suggested as a good strategy for prevention and treatment of these disabling age- related diseases. The genetic variability of TXNRD1 (rs10047589) has been found associated with late life survival in a previous work from our group (Soerensen et al., 2012b); the present work confirms the as- sociationofTXNRD1genewithsurvivalinthiscohort,inparticularinthe