Prediction of myocardial infarction using coronary risk scores among Japanese male workers: 3M Study.

BACKGROUND: It remains unclear how much coronary risk factors contribute to the prediction of myocardial infarction among Japanese populations. METHODS AND RESULTS: A nested case-control study of Japanese male workers aged 35 to 65 years was conducted between 1997 and 2000 in the Morbidity of Myocardial Infarction Multicenter Study in Japan (3M Study). Two hundred four myocardial infarctions were identified and two controls per case were selected by matching for age. We calculated odds ratios using a conditional logistic regression model, and constructed risk predictive models for the risk of myocardial infarction using coronary risk factors. The multivariable odds ratios (95 percent confidence intervals) of myocardial infarction were 2.02 (1.29-3.16) for high blood pressure, 2.33 (1.51-3.59) for high LDL-cholesterol, 4.16 (2.36-7.33) for low HDL-cholesterol, 1.49 (0.94-2.35) for high triglycerides, 1.46 (0.89-2.39) for high glucose, and 2.95 (1.90-4.59) for current smoking. A large reduction of the predictive value for myocardial infarction was shown after exclusion of high LDL-cholesterol (reduction of predictive value was -3.4%), further exclusion of low HDL-cholesterol (-7.1%), and further exclusion of current smoking (-16.4%). CONCLUSIONS: High LDL-cholesterol and low HDL-cholesterol as well as current smoking had high predictive values for myocardial infarction among Japanese middle-aged male workers.

Associations between blood lipid profiles and risk of myocardial infarction among Japanese male workers: 3M Study.

AIM: To examine whether fasting blood lipid profiles are associated with the risk of myocardial infarction among Japanese men. METHODS: We conducted a nested case-control study in the Morbidity of Myocardial Infarction Multicenter Study in Japan (3M Study). For each case of myocardial infarction entered in the 3M Study between 1997 and 2000, we randomly selected two controls, matched for age (+/-3 years), from among the participants in risk factor surveys with no history of myocardial infarction. A total of 723 male employees (241 cases and 482 controls) aged 35 to 65 years were enrolled in the present study. RESULTS: The subjects had significantly higher mean fasting LDL-cholesterol and triglyceride, and lower mean HDL-cholesterol than controls. The multivariable conditional odds ratio (95% confidence interval) for myocardial infarction after adjustment for known cardiovascular risk factors was 3.87 (1.27-11.7, p for trend <0.001) for total cholesterol [-6.71 vs <4.65 mmol/L], 3.28 (1.12-9.60, p for trend=0.001) for LDL-cholesterol [-4.64 vs <2.59 mmol/L], 0.17 (0.07-0.43, p for trend=0.001) for HDL-cholesterol [-1.55 vs <1.03 mmol/L] and 3.03 (1.37-6.70, p for trend= 0.01) for triglycerides [-2.26 vs <1.13 mmol/L]. CONCLUSION: High total and LDL-cholesterol, low HDL-cholesterol and high triglycerides levels were independently associated with an increased risk of myocardial infarction among middle-aged Japanese male workers.

Morbidity of Myocardial Infarction Multicenter Study in Japan (3M Study): study design and event rates for myocardial infarction and coronary death by age category in Japanese workers.

BACKGROUND: Although there have been regional studies, there has not been a detailed nationwide investigation of the morbidity from acute myocardial infarction (MI) in Japanese workers. METHODS AND RESULTS: Registration of MI and sudden death was done by full-time occupational physicians in Japan. Among 133,099 workers (109,550 men, 23,549 women) from 41 workplaces (April 1994 to March 1997) and 257,440 workers (207,310 men, 50,130 women) from 76 workplaces (April 1997 to March 2000), 297 fatal and nonfatal cardiac events were registered. The definitions of MI and coronary death followed the criteria of the WHO MONICA Project. The event rate in men rose sharply around the age of 45 years. Using definition 1 (fatal definite + fatal possible + fatal unclassifiable + nonfatal definite), the age-standardized annual event rate and case fatality rate for men aged 35-64 years was 40.2 per 100,000 persons and 22.2%, respectively. These figures were significantly lower compared with those from Western reports and were also lower than previously reported for Japanese communities. CONCLUSION: The Morbidity of Myocardial Infarction Multicenter Study in Japan revealed a surprisingly low incidence of coronary events, which may be attributable to prevention and early treatment of coronary risk factors among company workers in Japan.