Cigarette smoking caused at least 14 million cases of major medical conditions among U.S. adults in 2009, investigators reported online Oct. 13 in JAMA Internal Medicine.
The statistic substantially exceeds a 2000 estimate by the Centers for Disease Control and Prevention of 12.7 million smoking-related conditions among 8.6 million individuals, said Brian L. Rostron, Ph.D., at the U.S. Food and Drug Administration, Silver Spring, Md., and his associates.
The discrepancy most likely stems from the fact that respondents in national health surveys tend to underreport chronic obstructive pulmonary disease (COPD), the leading medical consequence of smoking, the researchers said. Using spirometry data, they estimated more than 7.4 million cases of COPD attributable to smoking in 2009, which was 70% higher than past statistics based on self-reported data, they said (JAMA Intern. Med. 2014 Oct. 13 [doi:10.1001/ jamainternmed.2014.5219]). For the study, the researchers used data from the 2009 U.S. Census Bureau, the 2006-2012 National Health Interview Survey, and the National Health and Nutrition Examination Survey to calculate the population-attributable risk of major smoking-related conditions among U.S. adults aged 35 years and older. Besides COPD, these conditions included diabetes mellitus, heart attacks, cancer, and stroke.
This approach yielded an estimate of 6.9 million adults in the United States with at least one major medical condition secondary to smoking (95% confidence interval, 6.5-7.4 million), with a total of 10.9 million conditions identified (95% CI, 10.3-11.5 million), the researchers said.
To better estimate the burden of COPD secondary to smoking, the investigators then used self-reported and spirometry data from the National Health and Nutrition Examination Survey. This analysis identified 14 million smoking-attributable conditions overall (95% CI, 12.9 to 15.1 million), including more than 7.4 million cases of COPD, they said. Notably, COPD was 3.78 times more common among current female smokers than never smokers (95% CI, 3.46-4.12), and four times more common among male smokers than never smokers (95% CI, 3.54-4.52), they said.
The results are “generally conservative, owing to the existence of other diseases and medical events that were not included in these estimates,” the researchers wrote, adding that “the International Agency for Research on Cancer has concluded, for example, that ovarian cancer, specifically mucinous tumors, is caused by smoking.” Current estimates also do not capture the prevalence of cardiovascular surgeries, congestive heart failure, peripheral arterial disease, rheumatoid arthritis, and macular degeneration attributable to smoking, said the investigators.
Descriptions of medical diagnoses were self-reported and therefore might not always be accurate, Dr. Rostron and associates noted. They reported no funding sources or conflicts of interest.