Study Estimates More than 600,000 Deaths Worldwide Caused by Secondhand Smoke

Secondhand tobacco smoke is estimated to have caused more than 600,000 deaths and the loss of more than 10 million disability-adjusted life years (DALYs) worldwide in 2004, according to the first analysis of its kind. Women and children were more likely than men to be exposed to secondhand smoke and to suffer morbidity and mortality from this exposure. The findings were published online November 25 in The Lancet.

Researchers led by Dr. Mattias Öberg of the Karolinska Institute in Stockholm, Sweden, used data for their analysis from the Global Youth Tobacco Survey and 19 additional surveys published between 1980 and 2007. They used models to estimate the burden of disease from secondhand smoke exposure for countries without direct survey data. The research team used the comparative risk assessment method, which is based on the proportion of people exposed to a pollutant and the known relative risk of disease related to that exposure.

The authors estimate that, worldwide, 40 percent of children, 35 percent of female nonsmokers, and 33 percent of male nonsmokers are exposed to secondhand smoke. In 2004, secondhand smoke caused 379,000 deaths from ischemic heart disease, 165,000 deaths from lower-respiratory infections, 36,900 deaths from asthma, and 21,400 deaths from lung cancer. Forty-seven percent of these deaths occurred among women and 28 percent occurred among children.

“Two-thirds of these deaths [among children] occur in Africa and south Asia…. The combination of infectious diseases and tobacco seems to be [deadly] for children in these regions,” wrote the authors. “Prompt attention is needed to dispel the myth that developing countries can wait to deal with tobacco-related disease until they have dealt with infectious diseases.

“The provisions of the WHO Framework Convention on Tobacco Control should be enforced immediately to create complete smoke-free environments in all indoor workplaces, public places, and on public transport,” the authors recommended.

“This landmark study documents the global magnitude of the problem of secondhand smoke exposure and its devastating consequences,” said Dr. Cathy Backinger, chief of NCI’s Tobacco Control Research Branch. “These findings should encourage a sense of urgency for ensuring that nonsmokers are protected from secondhand smoke exposure—a completely preventable health hazard.”