OBJECTIVETo investigate the relevant factors of coronary artery disease (CAD) in young people under 40 years of age.

METHODSThe study population was 292 young patients accepting coronary angiography in Fuwai Hospital from July to December 2006, including 272 men and 20 women, with the mean age being 36.7 ± 3.7 years. The diagnosis of CAD was made in the cases presenting ≥ 50% stenosis in coronary lumen in coronary angiography. Based on the diagnosis, 217 patients (204 men, 13 women) were assigned to CAD group, and 75 (68 men, 7 women) to non-CAD group. Clinical data and metabolic characteristics of the patients were collected and analyzed using t-test, χ² test, and multinomial logistic regression with SPSS 8.0 software.

RESULTSMost study subjects were current smokers (209/292, 71.6%), and more than half had body mass index (BMI)>24 kg/m² (230/292, 78.8%) and usually took high-fat diet (162/292, 55.5%). The proportion of heavy smokers (smoking history ≥ 10 years and ≥ 20 cigarettes per day) were significantly higher in the CAD group than in the non-CAD group [20.7% (45/217) vs. 9.3% (7/75), P=0.015)]. Heavy smoking [odds ratio (OR), 1.89; 95% confidence interval (CI), 1.74-2.05], hypertension (OR, 1.56; 95% CI, 1.48-1.65), alcohol (OR, 1.37; 95% CI, 1.30-1.46), type 2 diabetes mellitus (OR, 1.37; 95% CI, 1.25-1.50), high-fat diet (OR, 1.35; 95% CI, 1.28-1.43), and BMI>24 kg/m² (OR, 1.09; 95% CI, 1.03-1.17) were factors related to CAD in the young patients (all P<0.05). Total cholesterol (4.56 ± 1.46 mmol/L vs. 4.09 ± 1.00 mmol/L), low-density lipoprotein cholesterol (2.38 ± 1.11 mmol/L vs. 2.14 ± 0.63 mmol/L), lipoprotein a (134.97 ± 109.70 mg/L vs. 101.58 ± 58.39 mg/L), uric acid (359.89 ± 100.09 μmol/L vs. 336.75 ± 94.36 μmol/L), erythrocyte sedimentation rate (9.98 ± 12.19 mm/hour vs. 4.89 ± 4.92 mm/hour), high-sensitivity C-reactive protein (3.42 ± 4.39 mg/L vs. 2.80 ± 3.77 mg/L) and Big endothelin-1 (1.41 ± 1.50 fmol/mL vs. 0.77 ± 1.13 fmol/mL) in plasma were significantly increased in the CAD group compared with the non-CAD group (all P<0.05).

CONCLUSIONSHeavy smoking, hypertension, alcohol consumption, type 2 diabetes mellitus, high-fat diet and BMI>24 kg/m² were significantly related to CAD in patients aged ≤ 40, with heavy smoking presenting the highest OR. Metabolic syndrome and inflammation were also more common in young CAD patients than in non-CAD patients.