(January 23, 2009 - Insidermedicine) Tobacco smoke may be a much heavier contributor to the risk of developing cancer than was once believed, according to research published in BMC Cancer.

Here is some information about worldwide tobacco use from the WHO:

•    Over 1 billion of the world's population currently smokes.

•    Almost half of the children of the world breathe air polluted with tobacco smoke.

•    While rates of tobacco use are dropping in the developed world, they are increasing in the developing world.

Researchers from the University of California Davis looked at the association between death rates from lung cancer and death rates from other forms of cancer among men living in Massachusetts between 1979 and 2003.

Based on the association between deaths from lung cancer and other cancers, the researchers estimate that about 73% of all cancer deaths could be attributed to tobacco smoke exposure. That is more than double most previous estimates and translates to 196 deaths per 100,000 men.

We had a chance to speak with Dr. Bruce Leistikow, the principal investigator of this study, who offered some further insight.

Today's research indicates that previous estimates of the impact of tobacco smoke on cancer rates were much too low. These findings have important implications for public policy regarding tobacco products.

For Insidermedicine in Depth, I'm Dr. Susan Sharma.