Cigarettes contribute to more than 1 in 4 cancer deaths in the US. The rate is highest among men in southern states where smoking is more common and tobacco control policies are less strict.
High human cost
The American Cancer Society study found the highest rate among men in Arkansas, where 40 percent of cancer deaths were linked to cigarette smoking. Kentucky had the highest rate among women – 29 percent.
The lowest rates were in Utah, where 22 percent of cancer deaths in men and 11 percent in women were linked with smoking.
"The human costs of cigarette smoking are high in all states, regardless of ranking," the authors said.
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They analysed 2014 health surveys and government data on smoking rates and deaths from about a dozen smoking-linked cancers. Lung, throat, stomach, liver, colon, pancreas and kidney cancers were among those included, along with leukaemia. The researchers estimated how many cancer deaths were likely attributable to smoking, and compared that with deaths from all cancers.
Results were published in JAMA Internal Medicine.
While US smoking rates have been falling, 40 million US adults are cigarette smokers and smoking is the top cause of preventable deaths, according to the federal Centres for Disease Control and Prevention.
The study found that at least 167,000 cancer deaths in 2014 – about 29 percent of all US cancer deaths – were attributable to smoking.
Most of the 10 states with the highest rates of smoking-attributable cancer deaths were in the South, while most of the 10 states with the lowest rates were in the North or West.
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Among men, where smoking is generally more common, the cigarette-linked cancer death rate was highest in blacks at 35 percent, compared with 30 percent for whites and 27 percent for Hispanics. Among women, whites had the highest cigarette-linked cancer death rate – 21 percent, compared 19 percent for blacks and 12 percent for Hispanics.
The researchers say nine of 14 states with the least comprehensive smoke-free indoor air policies are in the South. The average cigarette excise tax in major tobacco states, mostly in the South, is 49 cents, compared with $1.80 elsewhere. The tobacco industry heavily influences these policies and most of the US tobacco crop is grown in the South, the researchers said. The region also has relatively high levels of poverty, which is also linked with smoking.
Dr Hilary Tindle of Vanderbilt University in Nashville, Tennessee, said the results reflect what she sees as a tobacco researcher and internal medicine specialist in the South. She was not involved in the study.
Smoking is more of a social norm there, and while her medical centre has an indoor smoking ban, she said it's not unusual to walk through cloud of cigarette smoke outside the entrance.
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Tindle said the study results highlight the need for stronger tobacco control measures and show why doctors should discuss smoking at every patient visit, encourage smokers to quit and inform them about effective ways to do so.
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