Tobacco use is the leading preventable cause of disease and premature death


Despite decades-long efforts to curtail its use, tobacco remains a serious health issue. A new study by the Centers for Disease Control and Prevention (CDC) reports some 2.4 million cases of tobacco-related cancers were diagnosed in the United States from 1999 to 2004, with lung and bronchial cancer accounting for almost half of these diagnoses.

The study marks the first time CDC has reported on all tobacco-related cancers for more than 90 percent of the population.

"The data in this report provides additional, strong evidence of the serious harm related to tobacco," said Sherri Stewart, Ph.D., in CDC's Division of Cancer Prevention and Control, who is the lead author of the study. "We've long known tobacco was associated with lung and laryngeal cancer, but this study gives us even greater clarity. The rates for these two cancers were highest in areas with the highest prevalence of tobacco use."

Since 1964, the U.S. Surgeon General has found tobacco use causes cancers of lung and bronchial, laryngeal, oral cavity and pharyngeal, esophageal, stomach, pancreatic, kidney and renal pelvis, urinary bladder, cervical and acute myelogenous leukemia.

Though tobacco is a major cause for all the cancers presented in this report, not all cases of cancer studied could be linked directly to tobacco use, the authors said. Some of these cancers have several important risk factors such as infections or genetic factors that can operate in concert with, or independently, of tobacco. In addition, information on tobacco use was not available in these databases. Therefore, some cases of cancer included in this report may not be attributable to tobacco use.

Key Findings:

Age-adjusted rates are presented in parentheses where appropriate and are per 100,000 persons.

• The incidence of tobacco-related cancers was higher among black and non-Hispanic populations, and among men, which reflect patterns of tobacco use.

• Lung, laryngeal, and cervical cancer incidence rates were highest in the South, where the highest prevalence of smoking exists. Kentucky had the highest rates of lung cancer among men and women (133.2 and 75.5, respectively), the third highest rate of laryngeal cancers among men (9.7) and the highest rate of laryngeal cancer among women (2.6). Kentucky had the highest prevalence of current smoking (28.6 percent).

• States with the lowest smoking rates are in the West: Utah (10.4 percent), California (18.5 percent), and Montana (18.5 percent). Cancer incidence rates were consistently lowest in the West for all the cancers, with the exception of stomach cancer.

• In 2004, lung and bronchial cancer incidence rates were highest among men in the South (97.9) and lowest in the West (66.0); Among women, rates were similar in the South, Midwest, and Northeast regions (55.3-56.4) and were lowest in the West (48.1)

• In 2004, laryngeal cancer incidence rates were highest among men in the South (8.4) region of the United States and lowest in the West (4.8). Among women, rates were similar in the South, Midwest, and Northeast (1.6-1.7) and were lowest in the West (1.1).

• The high incidence rates of both lung and laryngeal cancer in the South are consistent with smoking patterns and reflect the strong association of these cancers with tobacco use.

The report also noted other cancers associated with tobacco use (pancreas, urinary bladder, esophagus, kidney, stomach, cervix, and AML) accounted for more than 1 million cases diagnosed.

"Tobacco use is the leading preventable cause of disease and premature death in the United States and the most prominent cause of cancer," said Matthew McKenna, M.D., M.P.H., director, CDC's Office on Smoking and Health. "The tobacco-use epidemic causes a third of the cancers in America. If proven strategies were fully implemented to decrease tobacco use, much of the suffering and death that cancer inflicts on families and communities could be prevented."

Study: Cutting down on cigarettes cuts lung cancer risk

Not ready to quit smoking cold turkey? A new study shows that just cutting down on the number of cigarettes you smoke can reduce your risk of lung cancer.

Noting that "many smokers are unable or unwilling to completely quit smoking," a team of researchers from Denmark set out to determine the impact reducing the amount people smoke could have on their lung health. Their findings appear in the Journal of the American Medical Association.

The researchers looked at data from nearly 20,000 men and women who had undergone two physical examinations with five to 10 years between checkups as part of a larger study. At both exams, participants filled out questionnaires on their lifestyle habits, including questions about how much and how often they smoked. Former smokers were asked about past habits and the amount of time since they had quit.

At the first checkup, participants were categorized as heavy smokers (15 or more cigarettes per day), light smokers (one to 14 cigarettes per day), ex-smokers and never smokers. At the second visit, the researchers divided the participants into further categories: continued heavy smokers, reducers (reduced smoking from 15 or more cigarettes per day by a minimum of 50% without quitting), continued light smokers, quitters (quit since the first examination), continued ex-smokers and never smokers.

Between exams, 832 people reduced their smoking by at least 50%, with the average reducer going from 22.2 cigarettes per day to 8.5 cigarettes per day. More than 7,300 participants remained categorized as heavy smokers, smoking an average of 20 cigarettes per day at both exams. Compared to those who continued to smoke heavily, reducers were older, more likely to be male and had smoked slightly more and for a longer period.

Participants were followed from their second examination for an average of 18 years, during which time 864 people developed lung cancer.

After analyzing the data, the researchers found that while consistent light smoking or quitting smoking after being a light smoker carried a bigger reduction in lung cancer risk, heavy smokers who managed to reduce their daily number of cigarettes from about 20 to fewer than 10 cut their risk by 27%.

But this finding doesn't mean that if you are a smoker your goal shouldn't still be to butt out altogether. The researchers note that other studies haven't found that reducing the number of cigarettes smoked per day cuts the risk of heart attack or chronic obstructive pulmonary disease (COPD), and they conclude that the focus should be on quitting, not cutting down.

"More data from long-term studies of smoking reduction are warranted, but for the present, smoking cessation and not smoking reduction should still be advocated as the ultimate method of reducing harm from smoking," they write.

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