NEW YORK - Failing erections may be a harbinger of heart disease in some men, according to a review of a number of studies -- but heart-healthy lifestyle changes or cholesterol-lowering drugs could have a positive impact on men's sexual health.

Scientists have long known about the link between impotence, or erectile dysfunction, and heart health. Although there is no proof so far, a common theory is that arteries supplying the penis with blood during erections may clog up earlier than those in the heart, which are larger, thus providing an early warning of possible later coronary artery disease.

To address the connection between the two, Jia-Yi Dong of Soochow University in Suzhou, China, and colleagues combined twelve earlier studies of impotence and heart disease, covering nearly 37,000 men.

"This meta-analysis ... suggests that erectile dysfunction significantly increases the risk of cardiovascular disease, coronary heart disease, stroke and all-cause mortality, and the increase is probably independent of conventional cardiovascular risk factors," they wrote in the Journal of the American College of Cardiology.

They found that men with erectile problems had a 48 percent increase in their risk of developing heart disease, and also had higher death rates than men who didn't have sexual problems.

Traditional risk factors such as smoking, obesity, diabetes and high blood pressure didn't explain the link, strengthening the case that impotence, when it isn't due to partnership problems or other psychological issues, is a risk factor for heart disease in its own right.

But another study, published in the Archives of Internal Medicine, found that both lifestyle changes and cholesterol-lowering drugs such as statins appeared to improve men's erectile problems -- but only a little.

Men who exercises more or were put on a Mediterranean diet rich in whole grain, fruits, vegetables nuts and olive oil, for instance, reported a 2.4 point improvement on a 25-point scale of erectile problems.

Those put on statins saw a similar improvement of 3.1 points, said Bhanu Gupta and colleagues at the Mayo Clinic in Rochester, Minnesota. The results were based on six trials with 740 participants.

"The results of our study further strengthen the evidence that lifestyle modification and pharmacotherapy for cardiovascular risk factors are effective in improving sexual function in men with erectile dysfunction," they wrote.

They added that lifestyle changes appeared to work regardless of whether the men were taking Viagra, the most common drug to treat impotence, or not.