Coronary risk variables in young asymptomatic smokers

Smoking plays a dominant role in premature atherosclerosis particularly among males in South Asian countries. It initiates and promotes atherosclerosis by altering cardiac haemodynamics, causing dyslipidaemia and producing oxidative damage. Not much information is available from our country. We therefore undertook this study to see the effect of smoking on electrocardiogram (ECG), blood pressure, lipids, apolipoprotein B level and free radical activity in young asymptomatic male smokers.

The study included 100 consecutive male subjects (50 smokers and 50 non smokers) aged 30-40 yr. Smoking profile, detailed cardiovascular assessment including ECG and lipid profile were evaluated in each subject.

Of the 50 smokers, 22 (44%) had grade I hypertension as against 5 of 50 non smokers. Sinus tachycardia (10%) and P-pulmonale (8%) were the only notable ECG abnormalities. Dyslipidaemia was detected in 92 per cent smokers and 48 per cent non smokers (P<0.001). Total serum cholesterol, low density lipoprotein (LDL)-cholesterol, triglycerides and apolipoprotein B levels were significantly higher (P<0.001) in smokers compared to non smokers. LDL-cholesterol was > or =135 mg/dl in 94 per cent dyslipidaemic smokers. However, no significant difference was found in high density lipoprotein (HDL)-cholesterol. Smokers had significantly higher serum malondialdehyde levels (P<0.001) and low superoxide dismutase (P<0.001) compared to non smokers.

Our data indicate that young asymptomatic male smokers tend to have hypertension, dyslipidaemia and increased production of free oxygen radicals, perhaps by attenuation of oxidative stress by cigarette smoking. This makes them prone for premature coronary artery disease. However, the findings need to be confirmed on a larger sample.