The 10-year mortality risk of elderly subjects carrying both the ACE D/D and PAI-1 4G/4G genotype was 0.8 (95% CI 0.6 to 1.2) from any cause and 0.9 (95% CI 0.5 to

Table 4. Ten-Year All-Cause and Cardiovascular Disease Mortality Risks According to Plasminogen Activator Inhibitor-1 Genotype $ in Subjects 85 Years Old

Cardiovascular Ischemic Heart Cerebrovascular All-Cause Disease Disease Disease PAI-1 Genotype n RR* 95% CI RR 95% CI RR 95% CI RR 95% CI 5 5 5 5 All subjects 644 n 575 n 242 n 61 n 78 5G/5G 124 1 1 1 1 4G/5G 340 0.8 (0.7–1.0) 0.9 (0.6–1.2) 0.9 (0.5–2.0) 0.9 (0.5–1.6) 4G/4G 180 0.9 (0.7–1.1) 0.9 (0.6–1.3) 1.6 (0.8–3.3) 0.7 (0.4–1.4) 5 5 5 5 Men only 181 n 159 n 61 n 19 n 19 5G/5G 32 1 1 1 1 4G/5G 95 1.9 (0.8–1.8) 1.3 (0.6–2.6) 3.3 (0.4–27) 2.5 (0.6–11) 4G/4G 54 1.2 (0.8–2.0) 1.6 (0.7–3.4) 8.2 (1.0–64) 1.9 (0.4–10) 5 5 5 5 Women only 463 n 416 n 181 n 42 n 59 5G/5G 92 1 1 1 1 4G/5G 245 0.7 (0.6–0.9) 0.8 (0.5–1.1) 0.7 (0.3–1.5) 0.7 (0.4–1.3) 4G/4G 126 0.8 (0.6–1.0) 0.7 (0.5–1.1) 0.9 (0.4–2.2) 0.6 (0.3–1.2)

*Relative risk (RR) indicates the mortality risk as estimated by a Cox proportional hazard model adjusted for age at baseline. 5 5 CI confidence interval; PAI-1 plasminogen activator inhibitor-1.

ACE and PAI-1 Gene Variants and Mortality

tion suggested a publication bias toward positive results for the smaller studies (36).

coronary heart disease (25), the PAI-1 polymorphism was not associated with myocardial infarction in the Etude Cas-Temoins sur l’Infarctus du Myocarde (ECTIM) study (men 25 to 64 years old) (19) and the Physicians’ Health Study (men 40 to 84 years old, mean follow-up eight years) (23). The variable outcomes of these studies may have resulted from chance, but may also point to population differences with respect to the pathogenesis of myocardial infarction or the prevalence of environmental factors mod- ifying the effect of the PAI-1 polymorphism.

A number of relatively large studies reported an associa- tion of the ACE D/D genotype with a history of myocardial infarction (4–7). In some studies the association was found to be stronger (4,39) or present only (9,15) in subgroups otherwise at a low risk using different criteria. Furthermore, the prevalence of the ACE D/D genotype was increased among patients who had a fatal myocardial infarction (40). However, most larger studies, eight in total including the only prospective study, found no evidence for an association with myocardial infarction (8–14) or ischemic heart disease (15). Also, in most studies, no association was observed in low risk subjects (5,8,10,12,13). Our observation—that the ACE D/D genotype was not associated with mortality or fatal cardiovascular disease in old age—indicates that the overall effect of the ACE polymorphisms on fatal disease is probably limited.

The current study could not provide an explanation for the gender-specificity of the association with fatal ischemic heart disease. One previous study also reported data on both genders separately, and these showed that the PAI-1 4G/4G genotype was a risk factor for myocardial infarction in men only (26). Hormonal differences with respect to estrogen are not likely to play a role because the elderly women were well beyond their menopause. Smoking has been suggested to modify the effect of the polymorphism (43). Different smoking habits between men and women might have explained our observation, but the numbers were too small to test for this possibility. Another explanation could have been a different prevalence of diabetes in men and women, because the effect of the PAI-1 4G/4G genotype is known to be more pronounced in individuals with features of insulin resistance (elevated levels of triglyc- erides, insulin and glucose) (20,21). However, none of the men who carried the apparently deleterious PAI-1 genotype and died of ischemic heart disease had been diagnosed as having diabetes. Overall, the (cardiovascular) mortality was not increased in elderly subjects carrying the 4G/4G geno- type with diabetes. In contrast, the mortality risk in these patients was even significantly reduced. We do not have an explanation for this finding.

Scha¨chter et al. (16) reported an increased prevalence of the ACE D/D genotype in French centenarians as com- pared with subjects 20 to 70 years old. They suggested that the ACE D/D genotype might be deleterious in middle age, but beneficial to survival in very old age. Recently, the same group developed a mathematic model predicting trajectories of genotype frequencies in aging cohorts as a consequence of differential population mortality rates for the genotypes (41). This model indicated that any genotype with an effect on survival before 95 years of any exhibits an opposite effect after this age. The increased frequency of the ACE D/D genotype in French centenarians was thus explained by assuming an increased mortality of ACE D/D carriers before 95 years old. Neither in our cross-sectional analysis nor in the prospective follow-up study among subjects $ 85-years-old could we find support for this assumption. In addition, no increased ACE D/D frequency was found in 187 Danish centenarians (42).

Interaction. Recent studies showed that the PAI-1 4G/4G as well as the ACE D/D genotype is associated with increased PAI-1 levels (28,29). Although the possible del- eterious effect on mortality of a decreased fibrinolytic capacity might have been more readily observed in subjects carrying both risk genotypes, none of our analyses indicated an increased mortality in this subgroup.