Background and Aim: Coronary artery disease (CAD) and its complications at a low age are more serious and more progressive than at higher age. Because of this difference in the natural history of the disease as a function of age, this study was conducted to compare CAD risk factors between two age groups, namely people below and above 45 years old.

Materials and Methods: Two groups of 200 hospitalized CAD patients each, one below, and one above, 45 years old were selected by simple random sampling between 2005 and 2007. Two groups were similar with regard to dates and duration of hospitalization. The following data were collected from the patients' hospital files and analyzed using SPSS/Win: age, sex and marital status; area of residence; a history of smoking, diabetes, and hypertension; a family history of early-onset cardiovascular disease (CVD); weight and height; and lipid profile. The logistic regression test was used to compare the variables between the two groups.

Results: The following variables were found to be positively associated with CAD in the under-45 year group: smoking history (OR=2.54 p=0.009), a history of early-onset CVD (OR=3.15 p=0.009), low high- density lipoprotein cholesterol (HDLc) (OR=5.53 p<0.001), and high blood cholesterol (OR=3.96 p<0.006).

Conclusion: The most important coronary heart disease risk factors at a lower age are smoking, a history of early-onset CVD, low blood HDLc, and high total blood cholesterol.