Switching to low-tar cigarettes does not reduce CVD risk
Smokers who have failed to quit can be tempted to think that switching to a low-tar, low-nicotine cigarette will reduce the risk to their health. Cancer Research UK recently warned of the danger of these so-called light cigarettes, pointing out that research does not support the popular view that they are less likely to cause cancer. But what of the other major risks from smoking, such as cardiovascular disease?
A new study, published in Heart, has investigated the effect smoking light cigarettes has on the coronary arteries.
The study included 62 people, aged 18 to 40, who were apparently healthy and had no evidence of heart disease. Twenty smoked low-tar, low-nicotine cigarettes, another 20 smoked regular cigarettes and the remainder were non-smokers.
Each participant underwent echocardiography. This included measurement of coronary flow velocity reserve (CFVR) which, if reduced, serves as an indicator of endothelial dysfunction of the coronary arteries. Measurements of CFVR were taken in smokers after a 12-hour period of fasting and smoking abstinence to see the chronic effect of their smoking. The measurements were then repeated two days later within 30 minutes of the participant smoking two of their usual cigarettes.
The results showed that smokers of both light and regular cigarettes had chronically impaired CFVR compared with non-smokers, and that CFVR was further depressed immediately after smoking. There was no difference between light and regular cigarettes in the extent of the damage caused.
Smoking, even at low levels, has a marked effect on the vascular endothelium. This study shows that switching to low-tar cigarettes does nothing to reduce the risk of cardiovascular disease. Smoking doubles the risk of coronary artery disease and is responsible for one-fifth of all cardiovascular deaths. The message to patients surely must be that all forms of smoking are dangerous and that only quitting offers true protection.
Gullu H, Caliskan M, Ciftci O et al. Light cigarette smoking impairs coronary microvascular functions as severely as smoking regular cigarettes. Heart 2007; doi:10.1136/hrt.2006.100255Reviewer
Dr Kevin Lewis
Former GP, Clinical Director of Smoking Cessation, Shropshire County Primary Care Trust