A British study says that people who are exposed to second-hand smoke have a far higher risk of heart disease than previously thought.

The authors of the study, which was announced recently in the British Medical Journal, said that previously, scientists thought non-smokers exposed to smoke produced by others faced a 25 percent to 30 percent increase in risk of heart disease.

However, the new study measured a chemical called Hocotinine, which is a byproduct of smoking, in those non-smokers. Based on those measurements, the authors concluded that non-smokers exposed to second-hand smoke faced a 50 percent to 60 percent higher risk of coronary problems.

The results of the study, the authors wrote in the medical journal, suggest “that the effects of passivesmoking may have been underestimated in earlier studies. … our results add to the weight ofevidence suggesting that exposure to passive smoking is a publichealth hazard and should be minimized.^”