ACE and PAI-1 Gene Variants and Mortality

Table 1. Angiotensin-Converting Enzyme Inhibitor Genotype $ Distributions in Subjects 85 Years Old and Young Subjects Whose Families Originated From the Same Geographic Region

Leiden between 1887 and 1901. Therefore, an investigation was made of whether the young control population was likely to represent the Leiden genotype distribution of two generations before. The frequencies of the ACE D/D genotype were 27.1%, 27.0%, 27.5% and 22.4% among 5 young subjects with either one or more (n 203), two or 5 5 5 more (n 178), three or more (n 120) and four (n 76) Leiden-born grandparents, respectively. For the PAI-1 4G/4G genotype these frequencies were 29.6%, 30.9%, 30.8% and 27.6%, respectively. Thus, the ACE and PAI-1 genotype frequencies in control subjects were independent of the number of grandparents born in Leiden, except for the relatively low frequency of the ACE D/D genotype in the young subjects with four Leiden-born grandparents. Among elderly subjects born in Leiden, however, the prevalence of the ACE D/D genotype was somewhat higher (29.2%) as compared with elderly subjects born elsewhere in The Netherlands (28.6%). These data indicate that no specific Leiden ACE or PAI-1 genotype distribution ex- isted around the year 1900.

Subjects ACE Genotype Elderly* Young† 5 5 All subjects n 353 n 250 I/I 73 (20.7%) 62 (24.8%) I/D 177 (50.1%) 122 (48.8%) D/D 103 (29.2%) 66 (26.4%) 5 5 Men only n 112 n 139 I/I 26 (23.2%) 37 (26.6%) I/D 57 (50.9%) 69 (49.6%) D/D 29 (25.9%) 33 (23.7%) 5 5 Women only n 241 n 111 I/I 47 (19.5%) 25 (22.5%) I/D 120 (49.8%) 53 (47.7%) D/D 74 (30.7%) 33 (29.7%)

*Median age 89 years (range 85 to 100). †Median age 31 years (range 18 to 40). Data are presented as number (%) of subjects. 5 5 5 ACE angiotensin-converting enzyme; D/D deletion/deletion; I/D 5 insertion/deletion; I/I insertion/insertion.

Prospective follow-up study. All participants in the Lei- den 85-plus study were followed up for mortality until October 1, 1996. Among 640 subjects genotyped for the ACE polymorphism and 646 for the PAI-1 polymorphism, two were lost to follow-up, leaving 638 and 644 subjects, respectively, for the prospective follow-up study. Primary causes of death were obtained from the Dutch Central Bureau of Statistics and categorized according to the 9th International Classification of Diseases (ICD-9) (35) for cardiovascular disease (ICD-9 codes 390–459), ischemic heart disease (codes 410–414) and cerebrovascular disease (codes 430–438).

subjects born in Leiden (n 353, 55% of the complete cohort) were compared with those in young subjects 18 to 40 years old whose families originated from the Leiden area 5 (n 250) (Table 1). Genotype frequencies in both groups were in agreement with the distribution predicted by the Hardy-Weinberg equilibrium and similar to that in other white groups (36). The distribution of ACE genotypes was 5 similar in elderly and young subjects (p 0.46) and also not 5 5 significantly different for men (p 0.81) and women (p 0.81) when analyzed separately. On the basis of genotype frequencies, the mortality risk up to the age of 85 years associated with the ACE D/D genotype was estimated at 0.8 (95% CI 0.5 to 1.2) as compared with that associated with the ACE I/I genotype.

Statistical analysis. In the cross-sectional analysis, distri- butions of alleles and genotypes were compared by using the chi-square test. Mortality risks up to the age of 85 years were estimated with the exposure odds ratio. In the pro- spective follow-up study, survival times for subjects were computed from the date of the home visit to the date of one of the following events: death from a specific cause, death from any cause or October 1, 1996. Survival was estimated using the Kaplan-Meier product-limit method. Age- and gender-adjusted (when applicable) mortality risks and 95% confidence intervals (CIs) were estimated with Cox propor- tional hazards models. Causes of death were assumed to be , independent. P values 0.05 were considered to indicate statistical significance, and all p values were based on two-sided tests. The analyses were performed using the SPSS statistical software, version 6.1 (Chicago, Illinois).

Ten-year survival of the complete cohort of elderly subjects according to ACE genotype is shown in Figure 1. During follow-up, the all-cause mortality rate was 89% and the cardiovascular mortality rate was 38%. The all-cause mortality risk of elderly ACE D/D carriers was 0.9 (95% CI 0.7 to 1.1) as compared with that of ACE I/I carriers (Table 2). The ACE D/D genotype was not associated with the risk of death due to cardiovascular disease (relative risk [RR] 0.8, 95% CI 0.6 to 1.2) (Table 2). Similar estimates were obtained for men and women, except for the ACE I/D genotype. In men, the heterozygous genotype was associ- ated with an increased mortality risk. This is not compatible with a recessive or (co-)dominant effect.

RESULTS

PAI-1 4G/5G polymorphism. The PAI-1 genotype fre- quencies were 19.2% (5G/5G), 52.9% (4G/5G) and 27.9% $ (4G/4G) in the cohort of elderly subjects 85 years old 5 (n 646). The PAI-1 genotype distributions in the elderly 5 subjects born in Leiden (n 354) and in young subjects

ACE I/D polymorphism. The ACE genotype distribution was 22.5% (I/I), 49.7% (I/D) and 27.8% (D/D) in the $ 5 cohort of subjects 85 years old (n 640). For the cross- sectional analysis, ACE genotype frequencies in the elderly

ACE and PAI-1 Gene Variants and Mortality

Table 3. Plasminogen Activator Inhibitor-1 Genotype $ Distributions in Subjects 85 Years Old and Young Subjects Whose Families Originated From the Same Geographic

Survival Probability0.8oa°BR°io 4 6Years Follow-up