Want to avoid prostate cancer? Evidence suggests that one thing you could do, if you’re a smoker, is to stop smoking

As fewer men are smoking, fewer are dying from prostate cancer, and the trends appear to be related, especially in Kentucky.

“From 1999 through 2010, decreasing prostate cancer mortality rates were consistent with a reduction in cigarette smoking at the population level,” says the report, published in the journal Preventing Chronic Disease.

The study looked at four states: Kentucky, with the highest smoking rate (24.8 percent), Utah, with the lowest rate (9.1 percent), and Maryland (15.2 percent) and California (12.1 percent), with average rates.

Researchers found that in Kentucky and Maryland, smoking rates declined by 3 percent and prostate cancer deaths declined by 3.5 percent annually. Among black men in Kentucky, there was little change in the smoking rate or the prostate-cancer death rate.

In California and Utah, smoking declined by 3.5 percent annually, and prostate cancer deaths declined by 2.5 percent and 2.1 percent respectively each year.

The report says current cigarette smoking, rather than past or cumulative smoking, is a risk factor for prostate cancer development, progression, recurrence and death. The U.S. surgeon general named smoking as a cause of prostate cancer in 2014.

Men were classified as current smokers if they reported smoking at least 100 cigarettes in their lifetime and continued to smoke at least occasionally.

The researchers note that these findings do not prove causation, only that the two time trends were similar. They also noted that further studies should be done to include more states.