The Pharmaceutical Journal
Vol 269 No 7211 p207
17 August 2002

This article
Reprint
Photocopy

News summary

Related websites
Journal of Epidemiology and Community Health (jech.bmjjournals.com)

Even light smoking increases risk of MI

Smoking as few as three cigarettes a day increases the risk of myocardial infarction (MI), Danish researchers have found. Furthermore, women are more susceptible than men to the effects of tobacco on vascular morbidity, even if they do not inhale.

The researchers, from the Institute of Preventive Medicine, Copenhagen, used data from the Copenhagen city heart study — a 22-year follow-up of 12,149 men and women — to determine the risk of MI and all cause mortality associated with light smoking and inhalation habits.

From the start of the study in 1976 until 1998, 872 men and 476 women suffered an MI, of which 40 per cent of cases were fatal. During the same period, a total of 2,883 men and 2,305 women died from all causes.

The researchers found that, compared with non-smokers, men who inhaled the smoke of 6–9g of tobacco (equivalent to six to nine cigarettes) a day doubled their risk of MI (relative risk 2.10, 95 per cent confidence interval 1.40–3.14).

Among women, inhaling the smoke of just 3–5g of tobacco a day doubled the risk for MI or death from all causes (relative risk 2.14, 1.11–4.13 and 1.86, 1.37–2.51, respectively). Smoking 6–9g a day, but not inhaling, increased a woman's risk of MI by almost 60 per cent (relative risk 1.58, 1.03–2.43).

The differences in smoking-related vascular morbidity seen between men and women may be explained biologically by the anti-oestrogenic effect of smoking, the researchers say.

They add that in current inhaling smokers they saw a clear dose-response relationship between amount smoked and risk of MI and all-cause mortality.

"Although, from a toxicology point of view, it is not surprising that the dose-response relation between smoking and morbidity does not have a lower threshold limit, from a public health point of view it is important to recognise the increased risk associated with even a low consumption of tobacco," they conclude (Journal of Epidemiology and Community Health 2002;56:702).