The WHO researchers looked at data from 192 countries for their study. To get comprehensive data from all 192, they had to go back to 2004. They used mathematical modeling to estimate deaths and the number of years lost of life in good health.
Worldwide, 40 percent of children, 33 percent of non-smoking men and 35 percent non-smoking women were exposed to second-hand smoke in 2004, they found.
This exposure was estimated to have caused 379,000 deaths from heart disease, 165,000 from lower respiratory infections, 36,900 from asthma and 21,400 from lung cancer.
For the full impact of smoking, these deaths should be added to the estimated 5.1 million deaths a year attributable to active tobacco use, the researchers said.
