Second-hand smoke globally kills more than 600,000 people each year, accounting for 1% of all deaths worldwide, according to a new study.
The alarming findings - published on Thursday in the British medical journal Lancet - are based on a survey of 192 countries in 2004.
Researchers estimated that annually second-hand smoke causes about 379,000 deaths from heart disease, 165,000 deaths from lower respiratory disease, 36,900 deaths from asthma and 21,400 deaths from lung cancer.
Children account for about 165,000 of the deaths, according to the researchers.
"This helps us understand the real toll of tobacco," said Armando Peruga, of the World Health Organization, who led the study. He said the estimated 603,000 deaths from passive smoking should be added to the 5.1 million that smoking claims annually.
The study found that 40% of children and 30% adults regularly breathe in second-hand smoke.
Nationally, second-hand smoke causes 46,000 deaths from heart disease each year.
via Second-hand smoke kills 600,000 people a year: Study.