Low potentiality of angiotensin-converting enzyme gene insertion/deletion polymorphism as a useful predictive marker for carotid atherogenesis in a large general population of a Japanese city - The Suita study

Background and Purpose - Some previous studies, almost all western, have in vestigated whether there is a relationship between the insertion/deletion ( I/D) polymorphism of the angiotensin-converting enzyme (ACE) and carotid at herosclerosis. The results, however, have not been consistently positive. F urther, there have been few investigations based on a large, general popula tion. Therefore, the present study aimed to clarify whether ACE gene deleti on polymorphism was associated with carotid atherosclerosis in a large Japa nese general population with a more homogeneous genetic background than Cau casian populations. Methods - Subjects aged 30 to 86 years were randomly selected from Suita Ci ty, located in Osaka, the second largest urban area of Japan, and included 1894 men and 2137 women. With the aid of high-resolution ultrasonography, c arotid atherosclerosis was evaluated using our atherosclerotic indexes of i ntimal-medial thickness (IMT), plaque number (PN), plaque score (PS), and p ercentage of stenosis of the carotid artery assessed using high-resolution B-mode ultrasonography. ACE gene I/D polymorphism was detected by polymeras e chain reaction. Results - There were no significant differences among the ACE genotypes for age and conventional cardiovascular risk factors, except for systolic bloo d pressure (SBP) and the percentage of hypertension in men. The values of I MT, PN, and PS as carotid atherosclerotic indexes were not significantly di fferent among genotypes for either sex. After adjusting for age, body mass index, smoking habit, high-density lipoprotein cholesterol, triglycerides, presence of hypertension, presence of diabetes mellitus, and presence of hy perlipidemia, the estimated ORs for the presence of IMT greater than or equ al to1.10 mm (defined as thickened IMT), according to ACE genotype (DD vers us II, DD+ID versus II, and DD versus ID+II), for men were 0.80 (95% CI 0.6 0 to 1.23), 0.89 (0.62 to 1.29), and 0.89 (0.70 to 1.28), respectively. On the other hand, the ORs for women after the same adjustment were 0.92 (95% CI 0.58 to 1.35), 0.93 (0.59 to 1.45), and 0.91 (0.59 to 1.27), respectivel y. Conclusions - Our present data suggest that ACE I/D polymorphism is not pot entially a useful predictive marker for carotid atherogenesis when investig ated in a large and homogeneous general Japanese population of 4031 subject s, a finding similar to that in a Caucasian population study, the Perth Car otid Ultrasound Disease Assessment Study, an Australian study based on a ge neral population using 1111 subjects.