Association Of Smoking Status With Incident Cardiovascular Disease In The Middle-aged And Older Male Populations

Objective:Previous studies have demonstrated that smoking is an independent risk factor for cardiovascular disease（CVD）,while most of the studies were based on Western populations or regarded cardiovascular mortality as outcome.Besides,few prospective studies have investigated the associations between smoking cessation and incident CVD based on Chinese populations.This study aimed to investigate the associations of smoking status with incident CVD and its subtypes in the middle-aged and older males of Dongfeng-Tongji（DFTJ）cohort,and to further explore the combined effects of smoking and other influencing factors on the risk of CVD.Methods:This study selected male populations from DFTJ cohort,and excluded participants with coronary heart disease（CHD）,stroke,or severely abnormal electrocardiogram（ECG）at baseline and those without smoking information or lost to follow-up,finally a total of 13940 participants were included.All participants completed baseline questionnaires,physical examinations,clinical biochemical tests and blood sample collection.Cox proportional hazard models were used to explore the association of smoking status with incident CVD and its subtypes,and to estimate the hazard ratios（HRs）and 95%confident intervals（CIs）.Results:During a mean follow-up of 5.6 years,2971 incident CVD events were identified.Compared with never smokers,current smokers had significant higher risks of CVD,CHD and stroke,the adjusted HRs of current smokers who smoked for more than 40 pack-years were 1.49(95%CI,1.32-1.68;P_trend=0.001),1.40(95%CI, 1.22-1.62;P_trend=0.026)and 1.59(95%CI,1.26-2.00;P_trend=0.029)for CVD,CHD and stroke,respectively;and the adjusted HRs of current smokers who started smoking before 20 years old were 1.29(95%CI,1.06-1.58;P_trend=0.007)and 1.30(95%CI,1.03-1.64;P_trend=0.010)for CVD and CHD,respectively.Former smokers who had quitted smoking for 10 or more years had significant lower risks of CVD(HR,0.80; 95%CI,0.71-0.91;P_trend=0.017)and stroke(HR,0.65;95%CI,0.50-0.84;P_trend=0.207)when comparing to current smokers.There were statistically significant additive interactions between smoking and hypertension（RERI,0.104;95%CI,0.055-0.153;P<0.001）,hyperlipidemia（RERI,0.050;95%CI,0.005-0.096;P=0.029）or diabetes（RERI,0.060;95%CI,0.002-0.118;P=0.044）on incident CVD.Conclusions:This study found that smoking was significantly associated with higher risks of CVD,CHD and stroke,greater amount of smoking was associated with increased risks of CVD,CHD and stroke,and earlier age at smoking initiation was significantly associated with higher risks of CVD and CHD.Smoking cessation was associated with reduced risks of CVD and stroke,and longer duration of smoking cessation was significantly associated with lower risk of CVD.The effect of smoking on the risk of CVD was strengthened by hypertension,hyperlipidemia and diabetes.