Relationship between Smoking and Cardiometabolic Index in Middle-Aged Men

Background: Cardiometabolic index (CMI) is a new index for discriminating diabetes mellitus and has been demonstrated to be associated with the degree of atherosclerosis in patients with peripheral arterial disease. The purpose of this study was to clarify the relationship of CMI with smoking, a major risk factor for atherosclerotic disease. Methods: The subjects included 31,742 Japanese men (35- 60 years old) receiving health-checkup examinations at their workplaces. CMI was calculated as a product of waist-to-height ratio and triglycerides-to-IIDL cholesterol ratio. Relationships between CMI and smoking were investigated by using analysis of covariance and logistic regression analysis after adjusting for age and histories of alcohol drinking and regular exercise. Results: Odds ratios (with their confidence intervals) vs. nonsmokers for high CMI (>= 1.748) were 1.16 (1.10 - 1.23, p < 0.01) in light smokers (<= 20 cigarettes/day), 1.60 (1.49 - 1.70, p < 0.01) in heavy smokers (> 20 and <= 40 cigarettes/day), and 2.34 (1.77 - 3.09, p < 0.01) in very heavy smokers (> 40 cigarettes/day). CMI was significantly higher in each smoker group than in the nonsmoker group and tended to be higher with an increase in amount of smoking. The odds ratio (with its confidence interval) for diabetes of subjects with vs. those without high CMI was 2.27 (2.06 - 2.50, p < 0.01) in overall subjects and was not significantly different in each smoker group compared with the odds ratio in the nonsmoker group. Conclusions: There was a dose-dependent relationship between CMI and amount of smoking, while the association between CMI and diabetes was not different in smokers and nonsmokers. Thus, CMI was suggested to be useful for discriminating diabetes both in smokers and nonsmokers.