Even very light smokers run serious heart attack risk

Very light smokers significantly increase their risk of a heart attack, shows research in the Journal of Epidemiology and Community Health. Furthermore, women are much more susceptible than men to the detrimental effects of tobacco, even if they don’t inhale.

The findings are based on a population sample of over 12,000 men and women taking part in the Copenhagen City Heart Study, which began in 1976.

The participants, all aged 20 or older at the start of the study, were monitored up to 1998. During this period, 872 men and 476 women had a heart attack, and 2883 men and 2305 women died from other causes

After adjusting for major cardiovascular disease risk factors, including total cholesterol, lifestyle, family history, weight and diabetes, there was a strong and increasing link between the amount smoked and the risks of heart attack and death from other causes.

For the purposes of the study, a cigarette was equated to 1 gram of tobacco, a cheroot to 3 grams, and a cigar to 5 grams. Over 80 per cent of women smokers smoked cigarettes compared with just under 57 per cent of male smokers.

Compared with non-smokers, men doubled their risk of a heart attack inhaling the smoke of 6 to 9 grams of tobacco a day; not inhaling the same amount increased the risk by 13 per cent.

But among women, the detrimental effects were evident at lower levels of consumption. Inhaling the smoke of just 3 to 5 grams of tobacco a day doubled a woman’s chance of a heart attack or death from all causes. Smoking 6 to 9 grams a day, but not inhaling, increased her risk of a heart attack by almost 60 per cent.

And compared with non-smokers, women who smoked had significantly higher overall risk for heart attack and death from all causes than men. Health risks were highest for cigarette smokers of both sexes, although the impact was greater in women.

Women’s greater susceptibility to the detrimental effects of tobacco is thought to be because they are more prone to respiratory disease than men, say the authors, and smoking affects the oestrogen balance, the hormone which protects against cardiovascular disease.

The authors conclude that many smokers think that they will reduce the health risks associated with smoking tobacco by cutting down what they smoke or by not inhaling, but the authors says that this research proves them wrong.