0.6 for homozygote atypical (GG; n = 2). In order to compare MT2A polymorphism with the mean ages and age groups statistically, AG and GG genotypes were gathered since distributionof GG genotype was observed at very low frequency. When the MT2A polymor- phism genotypes were compared with the mean ages, statistically significant association was found (p < 0.05). The mean ages of AA genotype carriers (G(cid:2)) were 56.18 B+ | 19.50 years, whereas AG + GG genotypes carriers (G+) were determined as 47.59 ) + 1 13.45 years (Table 1). Also, MT2A polymorphism was statistically analyzed in according to age groups and significant association was detected (p < 0.05). While the frequency of the G+ carriers in the age groups of 20–40 years and 41–60 years were 2.3% and 6.2%, this ratio in the age groups of 61–80 years and >80 years were only 0.8% and 0.3%, respectively (Table 2).

frequencies of MT2A and IL-6 alleles and genotypes were obtained by direct count, and the departure from the Hardy–Weinberg equilibrium was evaluated using the Haldane exact test. In order to compare two independent groups, Student’s t-test, more than two groups one-way ANOVA analysis were used in terms of metric variables. Categorical variables were compared by the x2 test. p < 0.05 was considered as statistically significant.

3. Results

In this study, IL-6 and MT2A polymorphisms in a sample of 354 healthy Turkish subjects were compared according to their ages, age groups and genders. The genotype frequencies of IL-6 (cid:2)174 G/ C and MT2A (cid:2)5 A/G polymorphisms in all samples were consistent with Hardy–Weinberg equilibrium (p = 0.178 and p = 0.221, respectively). Volunteers were subdivided into four groups according to their ages as 20–40 years (78: 39 females, 39 males), 41–60 years (150: 74 females, 76 males), 61–80 years (64: 32 females, 32 males) and >80 years (62: 32 females, 30 males).

Genotype frequencies of IL-6 and MT2A polymorphisms in male and female subjects were compared with x2-test, and no significant difference was found between the two genders (p > 0.05) (Table 3).

4. Discussion

The genotype frequencies of the IL-6 (cid:2)174 G/C promoter region SNP were determined as follows: 44.6% homozygote typical (GG), 46.9% heterozygote (GC) and 8.5% homozygote atypical genotype (CC). Mean ages of individuals with homozygote typical (n = 158), heterozygote (n = 166) and homozygote atypical genotype (n = 30) were 49.82   20.45 years, 58.57 T+ | 17.02 years and 66.73   14.00 years respectively. The mean ages were also calculated as 49.82  20.45 years for GG genotypes carriers (C(cid:2)) and 59.82 )+1   16.82 years for GC + CC genotypes carriers (C+). A highly statistically significant association was detected IL-6 genotype and allele frequencies in aging (p < 0.001) (Table 1). In addition, the frequency of the IL-6 (cid:2)174 C+ carriers in the age groups of 41–60 years, 61–80yearsand>80yearswere higherthanin theage groupof 20–40 years (Table 2).

At the present day, aging is a universal phenomenon and an inevitable consequence of being an organism. Aging process is considered to be strongly dependent on the interaction of the genetic, epigenetic, and environmental factors; and genetic factors appear to have an impact to reach longevity and avoid pathologies

Table 3

of the IL-6 and MT2A polymorphisms in males and females, n (%).

Polymorphisms Males Females p< MT2A G(cid:2) (AA) 163 (46.0) 157 (44.4) 0.667 G+ (GC+GG) 16 (4.5) 18 (5.1) IL-6 C(cid:2) (GG) 84 (23.7) 74 (20.9) 0.380 C+ (GC+CC) 95 (26.9) 101 (28.5)

For MT2A (cid:2)5 A/G single nucleotide polymorphism, the genotype frequencies were determined to be 90.4% for homozy- gote typical (AA; n = 320), 9.0% for heterozygote (AG; n = 32) and

relationship between (cid:2)5 A/G SNP and sporadic amyotrophic lateral sclerosis have been found (Hayashi et al., 2006).

in particular (Salvioli et al., 2006). Genes related to inflammation and oxidative stress response, especially the proinflammatory cytokines and MTs are included in the susceptibility to aging, age related diseases and infections (Mocchegiani et al., 2004).

In this study, there was significant association between (cid:2)174 G/C promoter region polymorphism and MT2A (cid:2)5 A/G promoter region polymorphism with longevity in Turkish tion, and IL-6 (cid:2)174 C+ carriers and MT2A (cid:2)5 G(cid:2) carriers determined to be more advantageous for longevity. However, it is affected not only by several genes but also by longevity might be population-specific and dependent on environment interactions. In this context, the authors suggest the future studies may be performed in larger samples from environmental conditions may also be taken into account.

IL-6 is a key proinflammatory cytokine and (cid:2)174 G/C SNP polymorphism located within the promoter regions of IL-6 gene, determining increased or decreased production of inflammatory cytokines has been reported. The IL-6 (cid:2)174 G/C polymorphism was first described by Fishman et al. (1998). In the Fishman’s study and almost all subsequent studies, while the C+ allele carriers had the lowest IL-6 levels, a clear trend associating the C(cid:2) allele carriers to a higher level of IL-6 was observed (Fishman et al., 1998; Giacconi et al., 2004; Albani et al., 2009). In contrast to these results, a few authors reported increased IL-6 values in C+ carriers (Jerrard-Dunne et al., 2003; Haddy et al., 2005). However, these opposite results may be considered as IL-6 has a short half-life and

Conflict of interest statement