Nearly a half million Americans die every year from diseases directly attributable to cigarette smoking, such as lung cancer and heart disease, but a new study indicates thousands more deaths should be included in the annual tally.
"We think, if our results stand up, that we should add about 60,000 extra deaths to [cigarette smoking] a year," said Brian Carter, an American Cancer Society epidemiologist and lead author of the study. "For perspective, that's more than deaths that come from other common causes of death, like influenza or motor vehicle accidents."
The findings, published in the New England Journal of Medicine, were based on a new, 10-year study that followed nearly 1 million people. An analysis of data collected between 2000 and 2011 found that smokers, compared with people who had never smoked, were two times more likely to die of a number of diseases not usually thought to be related to cigarettes.
Carter said the diseases included infections, kidney disease, and prostate and breast cancer.
"There's one good hypothesis that women that start smoking when they are young, before their first birth, that might affect the breast more adversely than people that smoke after their first birth, because the breast doesn't fully mature until pregnancy," he said. "With prostate cancer, there's also a lot of good evidence that [smoking] might increase the proliferation of cancer in the prostate."
The study also found that smokers were six times more likely to die of blood insufficiency to the intestines, a rare cause of mortality.
Researchers were careful to caution that the findings were based on observations and did not prove a cause-and-effect relationship between cigarette smoking and previously unreported diseases.