One of the first studies of the effect of passive smoking on strokes has shown that it increases the risk by more than three times that for coronary heart disease.
Because stroke has been mostly ignored in research on the effects of passive smoking, the overall risk of breathing other people's tobacco smoke may have been underestimated, the researchers say. In Britain there are 100,000 new cases of stroke each year.
The study of 521 patients with a first stroke, caused by a blood clot or ruptured blood vessel in the brain, who were compared with more than 1,800 people matched for age, sex and medical history, found smokers who had more than one cigarette a day had a six-fold increased risk compared with those who had never smoked.
Non-smokers who lived with a smoker, or had shared an office with one for at least a year in the past decade, had an 82 per cent increased risk.
The study, conducted in New Zealand, found that the greater the number of cigarettes smoked the greater the risk of stroke. The risk was higher for women than for men.
The researchers concluded: "The major finding of an independent, increased risk of stroke associated with exposure to environmental tobacco smoke provides support for current efforts to reduce the prevalence of passive smoking and strengthens public health arguments against smoking."
A spokesman for the Stroke Association said: "We would support the Government in introducing stricter controls on smoking in public and we hope the Department of Health will consider an awareness campaign to let people know of the connection between smoking and strokes."Reuse content