All types of tobacco can cause heart disease, not just smoking, according to a large international study led by researchers at the University of Hamilton in Ontario, Canada.

WebMD reported Aug. 17 that researchers looked at health data on 27,000 people from 52 countries and concluded that "tobacco use is one of the most important causes of [heart attack] globally, especially in men. All forms of tobacco use, including different types of smoking and chewing tobacco and inhalation of secondhand smoke, should be discouraged."

The study found that smokers triple their risk of having a heart attack, but chewing tobacco also doubles the risk of heart attack. People exposed to one to seven hours of secondhand smoke weekly have a 24-percent higher risk of heart attack, while those who are exposed to 21 hours or more of secondhand smoker per week are 62 percent more likely to have a heart attack, the study said.

The research appears in the Aug. 19, 2006 issue of The Lancet.