People who use cholesterol-lowering statins may have a slightly lower risk of developing pneumonia than non-users do, a study out Monday concludes.

Israeli researchers found that of nearly 18,000 adults in a clinical trial of rosuvastatin (Crestor), those given the drug were 17 percent less likely to develop pneumonia over several years, versus people given a placebo.

That's a small effect, and no one is suggesting people start on statins in the hope of warding off pneumonia.

Instead, the researchers say their findings give indirect support to clinical trials looking at whether statins help prevent certain complications in patients with serious infections.

We would not recommend using statins for the prevention of the infectious disease," said lead researcher Dr. Victor Novack, of Soroka University Medical Center in Israel.

We have to look at these results with a (large) grain of salt," he told Reuters Health in an email.

The study, reported in the Canadian Medical Association Journal, is in line with previous research that found statin-takers less likely to get, or die from, severe respiratory illnesses like flu and pneumonia.

That apparent protection is just one of several potential benefits that have been linked to statins. Users of the drugs have been found to have lower risks of everything from depression to Parkinson's disease, and fatal prostate cancer.

The catch, though, is that none of those studies proves the cholesterol medications are the reason. They were so-called observational studies, in which researchers compared statin users with non-users, through sources like medical records.

Those studies can't prove cause-and-effect because people on statins may simply be healthier than non-users, or have better access to preventive healthcare, for instance.

What's different about the current study is that it's based on a clinical trial, said Dr. Sascha Dublin, a researcher at Group Health Center for Health Studies in Seattle, who was not involved in the new work.

Novack's team used data from a trial in which people were randomly assigned to take Crestor or a placebo, to see whether the statin cut the risk of heart attack and stroke in people with normal levels of bad" LDL cholesterol.

That allowed the researchers to analyze factors that might affect pneumonia risk: The statin and placebo groups were similar as far as age, weight and smoking habits, for example.

I think it's an important paper," Dublin told Reuters Health. “It's among the strongest evidence we have that there really may be something there."

Past observational studies had come to conflicting findings. In her own medical-records study, Dublin found no evidence that statins themselves seemed to ward off pneumonia.

I haven't been impressed by the evidence so far," she said.

If statins can curb the risk of pneumonia, any benefit may be modest, according to Novack's team.

Of 8,900 Crestor users followed for up to five years, 1.1 percent developed pneumonia. That compared with 1.35 percent of placebo users.

When Novack's team weighed other factors, statin use was linked to a 17-percent lower risk of developing pneumonia. And that isn't huge," Dublin said.

Still, she noted, if that relative risk reduction could be translated to groups of people with fairly high rates of pneumonia -- people older than 65, for example -- the absolute benefit would be bigger.

Pneumonia is an inflammation of the lungs that usually arises after a bacterial infection or a viral infection, like the flu. The elderly and people with chronic health conditions, like heart or lung disease, are at increased risk of developing pneumonia -- and of having a severe, or even fatal, case.

If statins gave some of those people a little protection from pneumonia, that could be a welcome new tool," Dublin said.

For now, it's not clear why statins would affect pneumonia risk. Novack said statins have mild effects on inflammation, immune system activity and cell death. Since infections do their damage in part by triggering immune system overreactions, statins might help by limiting that damage.

Researchers are just beginning to study whether statins can help treat or prevent sepsis -- a life-threatening, overwhelming immune response to an infection.

About 750,000 Americans develop severe sepsis each year, according to the National Institutes of Health. And anywhere from about one-quarter to one-half of them die.

The current study provides some support for that sepsis research, Novack said.

But as far as preventing pneumonia or other infections in the first place, Novack thinks statin therapy would not be a cost-effective" way to go.

In the U.S., statins run anywhere from $11 to over $200 per month, depending on whether it's a generic or brand-name.

The drugs are generally considered safe, but they can have side effects like muscle and joint aches, nausea and constipation. Serious problems are uncommon, but include a breakdown of muscle called rhabdomyolysis. There have also been reports of memory loss in some users, and a small increase in diabetes risk.

The original clinical trial Novack's team studied was funded by Crestor maker AstraZeneca. Some of his co-researchers have financial ties to the company.