RESULTS

The overall study population of 1344 participants was divided into four groups according to age, as follows: Group 1 (n = 292, 21.73%), participants aged ≤30 years (range from 22 to 30 years of age, mean age 27.29 ± 2.10 years); Group 2 (n = 629, 46.80%), participants aged from 31 to 44 years (mean age 36.76 ± 3.94 years); Group 3 (n = 270, 20.09%), participants aged from 45 to 59 years (mean age 50.44 ± 4.17 years); and Group 4 (n = 153, 11.38%), participants aged from 60 to 90 years (mean age 70.71 ± 7.51 years). This distribution reflected that of the healthy population living in the Apulia region as reported by the ISTAT (Istituto Italiano di Statistica) Report 2002 (25).

Centenarians (p = .792). However, after dividing the participants according to sex, a significant difference in e2 frequency was found in men aged ≥60 years compared to men less than 60 years of age, that is, Group 4 versus Groups 1–3 (22.89% vs. 9.63%, p < .001), Group 4 versus Group 3 (22.89(Table 1), a significantly higher frequency of the e2 allele was found in Group 4, which included participants aged from 60 to 90 years, compared to participants younger than 60 years in Groups 1, 2, and 3 (19.61% vs. 10.41%, p < .001). This finding was mainly due to a higher prevalence of the e2 allele in Group 4 than in Group 3 (19.61% vs. 9.26%, p < .002) and Group 2 (19.61% vs. 9.38%, p < .001). No significant difference in the frequency of the e2 allele was found between Group 4 and centenarians (19.61% vs. 29.69%, p = .105). None of the centenarians showed genotypes e2/e2, e2/e4, or e4/e4. In a linear model, no association was found between apoE genotypes and age. The ACE genotype frequencies of the total participant group of 1344 did not significantly differ from the expected Hardy-Weinberg frequencies (p = .299): estimated allele frequencies were I = 0.349 (95% CI, 0.331-0.367) and D = 0.651 (95% CI, 0.633-0.669). Similarly, ACE genotype frequencies in centenarians did not differ significantly from the expected Hardy-Weinberg frequencies (p = .999): expected allele frequencies were I = 0.313 and D = 0.688.

In Table 3, no significant differences were observed in the frequency of D participants in the oldest age group compared to participants less than 60 years of age, that is, Groups 1-3 (88.89% vs. 86.99%, p = .507), Group 3 (88.89% vs. 87.41%, p = .653), and Group 2 (88.89% vs. 86.96%, p = .521). Furthermore, no difference was found in the frequency of D participants in the oldest age group compared to centenarians (88.89% vs. 90.63%, p = .705). In a linear model, no association was found between ACE alleles and age.

DISCUSSION:

This study investigated the role of sex in apoE and ACE polymorphism and their association with healthy aging and longevity in two genetically homogeneous groups of Caucasians who lived in southern Italy, that is, a cohort of healthy participants and a group of centenarians. We found a significantly higher prevalence of the e2 allele in participants older than 60 years and in centenarians than in younger participants. These findings suggest a role of the e2 allele in healthy aging and longevity, and confirm previous studies reporting a significant increase in the e2 allele frequency with advancing age, including centenarians.

In a sex-genotype analysis, no significant differences were found in the total participant group or in centenarians. As expected, after dividing participants according to sex, no differences in the distribution of ACE alleles among the age groups were found. Logistic regression analysis (Table 4) confirmed the lack of a significant association between the D allele and age. After adjustment for sex, however, a significant association between the D allele and age was observed in the oldest age group (crude OR = 1.177; 95% CI, 0.693-2.001; sex-adjusted OR = 0.453; 95% CI, 0.453-0.897) and centenarians (crude OR = 1.419; 95% CI, 0.603-3.338; sex-adjusted OR = 2.135; 95% CI, 2.135-3.636).