longevity suggests involvement of other pathways, which may be important for survival. As our data suggest, the time when the C allele exhibits its protective properties lies in the age range of group 2 subjects (80–89 years old). In subse- quent years, it continues to work, as the C-allele proportion increases considerably in group 3 subjects (90–106 years old). Cardiovascular diseases are the main cause of death in elderly individuals, but IHD and AH are not associated with increased incidence of the variant allele of the T-455C poly- morphism. Cancer, the second leading cause of death in de- veloped countries with long life spans, has a controversial relationship with the levels of serum cholesterol and triglyc- erides. At least for two tumor localizations, breast and col- orectal cancer, the level of cholesterol has an inverted corre- lation with the rate of malignancy. At the same time, the level of triglycerides is a positive risk factor for other tumor localizations (28,29). Thus, the possible influence of the C allele on the development of certain localizations of cancer and subsequent changes in the rate of survival cannot be ex- cluded. Other potential pathways involved are insulin resis- tance and AH counteractions. Insulin, together with phorbol esters, can inhibit the transcription of the PEPCK gene, thus decrease gluconeogenesis (9,30), and simultaneously directly repress the apoC-III promoter through its own PEPCK-like insulin/phorbol ester-response element (10). Complications of insulin-resistance and developing diabetes mellitus are known to considerably contribute to total mortality. Possible involvement of linkage disequilibrium with the polymorphic sites of the apoA-I/C-III/A-IV complex in the cumulation of the variant (-455C) allele must be also acknowledged, de-

The -455C allele of the apoC-III polymorphism does not seem to affect the predisposition to IHD in this population.

C-Allele Frequency0.6500.6000.5500.5000.4500.4002040 60Age (y)80 100

Figure 2. Relative accumulation of the C allele of the apoC-III T-455C polymorphism with aging. The allele frequency in the control group of schoolchildren (6–17 years old; mean age, 11.0 years) are in- dicative of the initial allele distribution in the general population. The ratio of alleles is not changed significantly until 80 years of age or older, when the accumulation of the C allele becomes statistically sig- nificant and predominates. *Statistically significant difference in the distribution of alleles for group 2 (80–89 years old; mean age, 84.4 years) versus group 4 (control; p , .05); †statistically significant dif- ference in the distribution of alleles for group 3 (90–106 years old; mean age, 94.5 years) versus group 4 (control; p , .02).

Table 3. Allele Distribution as a Function of Age and Arterial Hypertension

Genotype (n) Total C-Allele (n) TT TC CC Frequency x2 Fisher Exact Test p Values Group 1 (70–79 y) AH1 20 4 14 2 0.450 0.57 0.82 NS AH2 23 5 14 4 0.478 — — — Group 2 (80–89 y) AH1 27 2 18 7 0.593 1.04 0.71 NS AH2 25 4 16 5 0.520 — — — Group 3 (90–106 y) AH1 23 2 16 5 0.565 1.44 0.38 NS AH2 19 1 10 8 0.684 — — — Total groups 11213 AH1 70 8 48 14 0.543 1.17 0.57 NS AH2 67 10 40 17 0.552 — — —

Notes: AH arterial hypertension; NS not significant; presence of AH; absence of AH. p values were tested using test (value shown) and two- tailed Fisher exact test (probability shown) in groups 1–3 for AH1 vs AH2 subgroups.

spite the controversial findings on the effect of haplotypes, including -455 apoC-III polymorphism (7,18–21). World trends in older population mortality reductions may further contribute to the age-specific differences in studied gene al- lele proportions and genotypes observed, as mortality pat- terns could differ for the carriers of different alleles, but this factor equally inclines genetic aspects of all cross-sectional gerontological studies (31,32).

the close distribution of allele frequencies in the group and those of subjects aged 70 to 79 years old youngest group of elderly subjects studied) make the tution of cross-sectionally–studied groups reliable.

Geriatric populations allow assessment of polymorphic sites for longevity and survival. Control groups consisting of children provide valuable information regarding the orig- inal distribution of alleles of interest in a particular popula- tion. The use of young and older age groups in our study gave us the ability to detect the effect of relative accumula- tion with age of the apoC-III gene T-455C polymorphism C allele. Although we show that in this population none of the polymorphism alleles is associated with IHD or AH, the question of the possible mechanisms involved is still open and should stimulate further investigations.

St. Petersburg has one of the most advanced systems of geriatric help in Russia, which, together with the size of its population, made our study possible. However, the longitu- dinal cohort studies covering these wide age ranges are quite hard to perform. We have to admit that the initial fre- quencies of respective alleles and genotypes could differ slightly in the elderly and children’s groups, as there is no way to ensure genetic solidarity of these groups when tak- ing into account the losses the St. Petersburg population suf- fered during the Siege of 1941 to 1944 and the resulting changes in population structure. However, the fact that St. Petersburg was repopulated almost exclusively by the evac- uated dwellers and members of their families, the ethnic likeness of both the control and subject groups studied, and

The proposed method of -455 apoC-III polymorphism identification based on the mismatch PCR-mediated site- directed mutagenesis and restriction fragment length poly- morphism seems to be time- and cost-reducing compared with other nonradioactive methods, such as allele-specific amplification and allele-specific oligonucleotide hybridiza- tion, described previously (33).