Women with an optimistic outlook may live longer and be less likely to develop heart disease than women who take a dimmer view of life, according to a study published Monday.

Researchers found that among more than 97,000 U.S. women between the ages of 50 and 79, those with generally optimistic dispositions were 14 percent less likely to die over eight years than their pessimistic counterparts.

They were also 9 percent less likely to develop coronary heart disease, and 30 percent less likely to die of heart complications.

That meant that the one-quarter of women who scored highest in optimism had lower rates of developing heart disease than the one-quarter with the lowest scores (deemed “pessimists”): 43 cases per 10,000 women, versus 60 cases. They also had fewer deaths over the eight years: 46 per 10,000 women, versus 63 among pessimists.

The findings, published in the journal Circulation, add to evidence that personality traits may affect people’s long-term health.

A number of studies have suggested that people with hostile, angry dispositions face higher risks of heart disease and other health problems. And in this study, women who scored high on a measure of “cynical hostility” had higher risks of dying from any cause over eight years.

But the apparent effects of optimism and hostility were independent of each other.

It’s possible that optimism has direct effects that help ward off disease, explained Dr. Hilary A. Tindle, the lead researcher on the study and an assistant professor of medicine at the University of Pittsburgh.

Personality traits may, for instance, influence the nervous, immune or hormonal systems in ways that affect the risks of a range of health problems.

On the other hand, optimists may also lead healthier lifestyles. Tindle and her colleagues found that the most optimistic women were in fact less likely to smoke or to be obese or sedentary; they also had lower rates of high blood pressure, diabetes and High cholesterol.

When the researchers accounted for those factors, optimism itself was still linked to a lower risk of heart disease or death. However, making such statistical adjustments may underestimate the importance of optimism, Tindle said.

“The optimistic attitude itself may be what’s driving some of those lower rates of risk factors,” she explained.

The findings are based on questionnaires given to 97,253 U.S. women taking part in a large government study called the Women’s Health Initiative. Optimism was gauged by asking participants whether they agreed with statements such as, “In unclear times, I usually expect the best,” and “If something can go wrong for me, it will.”

The measure of cynical hostility included statements such as “It is safer to trust nobody,” and “I have often had to take orders from someone who did not know as much as I did.”

So will adopting a sunnier outlook help people live longer?

“This study does not address that,” Tindle said, noting that they simply observed people, rather than trying to change them from pessimists to optimists to see what would happen.

“But,” she added, “logically, we know people can change.”

The question then becomes whether this leads to lower disease risks, Tindle said. Studies into that question, she noted, “are coming down the pike.”

SOURCE: Circulation: Journal of the American Heart Association, August 25, 2009.