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.
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 Centers 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.
The researchers say 9 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.