ABSTRACT
Objective To investigate the synergistic effect of hyperhomocystinemia (HHcy) and smoking on the incidence of Coronary heart disease. Methods A total of 22 043 subjects were enrolled from health care center. Participants were classified into two groups: Non-coronary heart disease group (control group, n = 19 410) and coronary heart disease group(n=2 633).A questionnaire survey,physical examination and blood homocysteine (Hcy)test were carried out among the participants.Results After controlling the confounding factors,multivariable Logistic regression analysis showed that the risk of coronary heart disease in patients with smoking was 4.832 times higher than that of patients with normal waistline. The risk of coronary heart disease in patients with HHcy was 1.019 times higher than that of patients with normal Hcy (OR = 4.832,1.019,P < 0.05).Interaction analysis showed that the risk of patients with HHcy and smoking was 2.473 times higher than that of patients without HHcy and no-smoking.The synergy index between HHcy and smoking on the incidence of Coronary heart disease was 1.739. The pure attributable proportion due to the interaction was 42.9%. Conclusions HHcy and smoking are risk factors for coronary heart disease and there is a positive synergistic effect between HHcy and smoking on the incidence of coronary heart disease.