Secondhand smoke has been linked to a 30 percent increase in stroke risk for nonsmokers exposed to others’ tobacco fumes.

The study, study published in the American Journal of Preventive Medicine, suggests a sizable number of the nearly 800,000 strokes Americans suffer a stroke each year are attributable to secondhand smoke.

Stroke is responsible for one out of every 19 deaths in the U.S. and a leading cause of disability.

The findings are based on an analysis of medical records from 22,000 patients enrolled in the Reasons for Geographic and Racial Differences in Stroke (REGARDS) study, a long-running national study.

Investigators found that even after taking into account other stroke factors such as hypertension, diabetes, and heart disease, the 30 percent risk for nonsmokers remained for those exposed to tobacco smoke.

"Our findings suggest the possibility for adverse health outcomes such as stroke among nonsmokers exposed to [secondhand smoke] and add to the body of evidence supporting stricter smoking regulations,” said lead researcher Angela M. Malek, of the Department of Public Health Sciences, Medical University of South Carolina, Charleston.

“Future research will need to investigate the role of cardiovascular disease risk factors in the association and explore potential exposure to additional environmental variables, such as ambient air pollutants, in relation to stroke."