[Case control study on the association of coronary artery disease and cigarette smoking]

To determine the association of cigarette smoking and coronary artery diseases (CAD).

A case-control study involving 355 people classified as CAD or without CAD was performed. But people treated with diuretic, aspirin, lipid-lowering agents, heparin or those with renal, hepatic diseases were excluded. Gender, age, body mass index, plasma glucose under fasting, total cholesterol, triglyceride, high-density lipoprotein cholesterol, low-density lipoprotein cholesterol, fibrinogen, cigarette smoking consumption grade (0: no smoking, 1: less or equal 100 cigarette year, 2: one hundred cigarette year < cigarette index

In multiple logistic regression, age, gender, fasting plasma glucose, fibrinogen and cigarette smoking showed significant independent association with CAD. Compared with non-smoker, the odds ratio (OR) of CAD of grade 3-cigarette smoking was 3.519 (95% CI: 1.538 - 8.053, P = 0.003). However with grade 1 cigarette smoking group, no significant independent association was found with CAD (OR = 0.948, P = 0.959). With more than grade 2 [grade 2 + 3, compared with less than grade 2 (0 + 1)] and grade 3 [compared with less than grade 3 (0 + 1 + 2)] cigarette smoking, ORs of CAD were 2.094 (P = 0.027), 3.463 (P = 0.002) respectively. Three hundred fifty-five people were divided into 3 groups: control, stable angina (SA) and unstable angina (UA) groups. In multinomial logistic regression, when comparing with UA, parameter estimate of cigarette smoking degree in the SA group were beta = -0.220, s(x) = 0.138, P = 0.112, OR = 0.803 respectively.

Cigarette smoking was a significant independent risk factor for CAD. With more cigarettes smoked, a higher odds ratio of CAD was seen. Gender, age, fibrinogen and plasma glucose during fasting were also independent factors significantly associated with CAD. No significant independent association between cigarette smoking and unstable angina was found.