Association between electrocardiographic ischemic abnormalities and ischemic heart disease risk factors in a Japanese population.
This cross-sectional study was undertaken to investigate the association of electrocardiographic (ECG) ischemic abnormalities with ischemic heart disease (IHD) risk factors in a Japanese population. Resting ECGs of 1201 subjects (572 men and 629 women, aged 30 to 89 years), were coded independently by two coders according to the Minnesota Code. Blood pressure (BP) was recorded using a standard sphygmomanometer, and non-fasting serum total cholesterol and high-density lipoprotein cholesterol were measured. Codes 1.1 and 1.2 were classified as myocardial infarction and codes 1.3, 4.1-4.4, 5.1-5.3 and 7.1 were classified as ischemia. Prevalence of ECG with evidence of IHD (IHD ECG) was defined as myocardial infarction and ischemia together. Levels of risk factors were compared between subjects with IHD ECGs and those without IHD ECGs. Multiple logistic regression analysis was used to ascertain the associations between IHD ECG and risk factors. The prevalence of myocardial infarction in the total population was 1.5% and 0.7% in men and women, respectively and the prevalence of IHD ECGs was 10% and 11.3% in men and women, respectively. Systolic blood pressure (SBP) was consistently higher in subjects with IHD ECGs in the total population of both sexes (P < 0.001, P = 0.001 for men and women respectively). Diastolic blood pressure (DBP) was higher only in men with IHD ECGs (P = 0.002). In middle-aged men (aged 30-59 years), total cholesterol was considerably higher in subjects with IHD ECGs, although this relationship was statistically not significant. In multiple logistic regression analysis, SBP was independently associated with IHD ECGs in both sexes (P = 0.001). Associations between IHD ECGs with total cholesterol, alcohol intake and smoking were not statistically significant. This study showed that electro-cardiographic IHD evidences in Japanese are predominantly associated with blood pressure level in both sexes.