A positive outlook may help guard against heart disease and increase the chances of a long life, a new study suggests, bolstering previous findings.

Researchers from Duke University Medical Center followed 2,800 patients who'd been hospitalized with heart disease. Those with the most optimistic attitudes about making a full recovery were more likely to live longer than their pessimistic counterparts, according to lead author John Barefoot.

Specifically, the upbeat heart patients had a 30 percent greater chance of survival after 15 years than the negative ones.

"Our research shows better physical recovery and a higher likelihood of survival is linked to attitude -- personal beliefs about their illness," Barefoot, a professor emeritus at Duke, told USA Today.

The team of scientists asked the cardiac patients being treated for coronary artery disease to fill out a questionnaire while they were in the hospital being diagnosed. The survey asked them how they felt about their recovery and their outlook on resuming their normal way of life.

They were told to "agree" or "disagree" with statements including "I expect my lifestyle will suffer;" "I can still live a long, healthy life;" and "I doubt that I'll ever fully recover," according to Barefoot.

The researchers tracked the patients for about 15 years after their treatment and accounted for a wide range of factors, including age, gender, RIFT Platinum seriousness of condition, depression and income level, the paper said. They still found that optimism was linked with longevity and better health.

Though it isn't known exactly why a positive attitude seems to be correlated with good health, Barefoot theorizes it may be because optimistic people handle illness better, rift gold are less likely to give up hope, are more adept at problem solving, have less of a physiological reaction to stress and exercise more regularly.

"I think those kinds of things need to be investigated in much more detail," he said.

There could be other explanations for the results, however.

Dr. Steven E. Nissen, department chair of cardiovascular medicine at the Cleveland Clinic, RIFT Platinum told ABC News that patients "with a 'positive' attitude may simply be healthier than patients with a negative attitude. In fact, their 'attitude' may reflect their health status."

The optimistic participants may also have been getting higher-quality medical treatment than the pessimistic ones. Rift Gold

"Cardiovascular providers [might] give better care to patients with a positive outlook -- perhaps spending more time with them or being more conscientious," Dr. James Kirkpatrick, assistant professor of medicine at the University of Pennsylvania, told ABC.