Strong family history and cigarette smoking as risk factors of coronary artery disease in young adults.

This study is based on 435 consecutive patients age 50 or less who had coronary arteriography. There were 335 patients with coronary artery disease and 100 with normal coronary arteries. Risk factors reviewed were "packet-years" of cigarette smoking, family history of coronary disease in first-degree relatives 50 years of age or less, age- and sex-corrected serum cholesterol and triglycerides, hypertension, and diabetes. By univariate analysis, each risk factor except hypertension and diabetes was significantly more frequent in patients with coronary disease than in those without. By multivariate analysis of all risk factors in patients with and without coronary disease, the male or female patient with coronary disease could best be identified by the strong family history, cigarette smoking history, and age- and sex-corrected serum cholesterol. The percentage of patients with coronary disease when the three risk factors were present was 95%, two factors present 88%, one factor present 67%, none of the three 25%, strong family history alone 90%, smoking alone 66%, and serum cholesterol greater than 80th centile alone 52%.