n American Cancer Society-funded study suggests estimates from the Surgeon General that show smoking kills about 480,000 people in the United States every year, exclude tens of thousands of Americans who die from diseases not counted as caused by smoking, Notícias médicas hoje reported.

For their analysis, Dr. Eric J. Jacobs, strategic director of Pharmacoepidemiology at the American Cancer Society, and colleagues reviewed data from five large studies, including their Cancer Prevention Study-II, the Health Professionals Follow-up Study, the Nurses’ Health Study, and the National Institutes of Health American Association of Retired Persons Diet and Health Study.

The data covers nearly a million Americans 55 and older who were followed for about 10 years, during which time there were more than 180,000 deaths, including nearly 16,500 among current smokers.

As expected, the analysis showed current smokers were nearly three times more likely to die in that time than people who never smoked.

Most of the excess deaths in smokers were due to diseases that are known to be caused by smoking. These include 12 types of cancer, stroke, coronary heart disease and chronic obstructive pulmonary disease (COPD – which includes chronic bronchitis, emphysema and chronic obstructive airways disease).

Smokers had double risk of death from diseases not classed as caused by smoking. Their analysis also showed that excess risk of death from each of these conditions fell when participants gave up smoking.

The team found smoking was also tied to smaller increases in risk of death from breast cancer, prostate cancer and cancers of unknown sites. These diseases are not formally classified as being caused by smoking.

Smoking-related deaths caused by diseases on the Surgeon General’s list cause an estimated 437,000 deaths per year. Adding the additional deaths pushes smoking-related mortality up to about a half-million people a year. That’s 1 in 5 deaths overall in the United States.