Stroke risk per cigarette quantified
Any amount of cigarette smoking at all more than doubles a woman's risk of ischemic stroke. Moreover, stroke risk can increase up to ninefold based on the number of cigarettes smoked per day.
One of the largest studies of early-onset ischemic stroke in young women analyzed data from the population-based Stroke Prevention in Young Women Study. Investigators evaluated the cases of 466 women, aged 15-49 years, in the Baltimore-Washington, D.C., area who had suffered a stroke, comparing them with 604 women with no such history.
The findings revealed that ischemic stroke was 2.6 times more common among current smokers than among never-smokers (Stroke. 2008;39:2439-2443). When stroke risk was calculated based on smoking frequency, the risk for women who smoked two packs (40 cigarettes) or more per day was a full nine times higher than for nonsmokers. For other smokers compared with nonsmokers:
• The risk was 4.3 times higher for smokers of 21-39 cigarettes per day.
• The risk was 2.5 times higher for smokers of 11-20 cigarettes per day.
• The risk was 2.2 times higher for smokers of 1-10 cigarettes per day.
No difference in stroke risk was seen between former smokers and never-smokers.