Secondhand smoke is known to increase the risk of heart disease and lung cancer.
Now, a new report suggests that exposure to cigarette smoke from a family member or co-worker also increases the risk of stroke. Dr. Ruth Bonita, of the University of Auckland, New Zealand, and colleagues, found that people who never smoked or had quit smoking for at least 10 years had almost twice the risk of stroke if they were exposed to secondhand smoke compared with people not exposed to cigarette smoke. Active smokers had more than four times the stroke risk of nonsmokers in general and more than six times the risk compared with nonsmokers not exposed to secondhand smoke, according to the report in the journal Tobacco Control. The survey results were compared with those of 1,851 people aged 35 to 74 who had not had a stroke. An individual was considered to be exposed to passive smoke if a household member or co-worker smoked in their presence for at least one year in the previous 10 years.