Many stomach cancer cases caused by tobacco use

Cigarette smoking and use of other tobacco products significantly increases the risk of death from stomach cancer in men and women, a large study of US adults indicates.

Stomach cancer is the second most common cancer worldwide and is known to be linked to chronic infection with the ulcer-causing bacteria Helicobacter pylori.

In its Review of Tobacco conducted in June of this year, the International Agency for Research on Cancer concluded that there is "sufficient evidence in humans" to infer a causal relationship between stomach cancer and tobacco use, says Dr. Ann Chao of the American Cancer Society in Atlanta, Georgia.

Chao's group examined stomach cancer mortality in relation to cigarette smoking in women and cigarette, cigar, pipe and smokeless tobacco use in men enrolled in the Cancer Prevention II Study. They identified 996 and 509 stomach cancer deaths among 467,788 men and 588,053 women, respectively.

The researchers found that compared to non-smokers, male cigarette smokers had slightly more than double the risk of dying from stomach cancer, while the risk for female smokers was 49% higher than for non-smokers. Among men, current cigar smoking increased the risk of death from stomach cancer 2.3 times compared to non-smokers.

Men with chronic indigestion or stomach ulcers who smoked cigarettes were more than 3 times more likely to die from stomach cancer, and nearly 9 times more likely to die from the disease if they smoked cigars, compared with non-smokers, the authors report.

If causal, the authors estimate that the proportion of stomach cancer deaths attributable to tobacco use would be 28% in US men and 14% in women.

"These results were very consistent in our study population that has overall lower rates of stomach cancer compared to other countries, and have major implications for countries with much higher stomach cancer rates and increasing smoking prevalence," says Chao.