If a chipper person in your life is annoying you, maybe you should brace yourself for that person outliving you in the long haul, according to findings of a new study.
A study of 100,000 women presented at the American Psychosomatic Society's annual meeting Thursday found a strong correlation between optimism and a person's risk for cancer-related death, heart disease and early death.
Researchers surveyed the personality traits of middle-age women in 1994 as part of the Women's Health Initiative study run by the National Institutes of Health.
Eight years later, researchers found that the self-reported optimistic women were less likely to have died for any reason and had a 30 percent lower death rate from heart disease.
Meanwhile, women scoring high on the hostile scales had a higher general death rate and a 23 percent greater risk of dying from a cancer-related condition by the end of the study.
The finding confirms previous studies that linked optimism to longer life, said Hilary Tindle, the lead author of the study and an assistant professor of medicine at the University of Pittsburgh.
However, the researchers could not tell if optimism was leading to healthier lifestyle choices, if optimism directly affected the physical manifestations of stress or both, Tindle said.
"What is the link? What is the mechanism? That's one thing my study can't answer," Tindle said.
Tindle suggested it could be that optimistic people physically react to mental stress better, or that they are more likely to follow a doctor's advice and, therefore, maintain their health. A third option may be a complex give-and-take between unhealthy and healthy behaviors and outlook on life.
For example, the optimistic women tended to have a healthier "risk profile," in general, Tindle said.
"They are less likely to smoke, they are more likely to be active and they are more likely to have a lower BMI [body mass index]," she said. "All of these are risk factors that certainly matter for length of life and health."
The opposite was true for women in the study who scored high on a cynical hostility scale, Tindle said.
The study found that women who scored high on cynicism in the first interview were also likely to smoke and not exercise over the years.
With all these correlations, Tindle said, it could be a happenstance that optimism tags along with healthy behavior rather than influencing someone's health. To find a more direct link, the research team tried to mathematically cancel out the statistical influence that behaviors like smoking or exercise had on death risk.
"Even after for controlling all of those factors, we found a link," said Tindle.
However cardiologists wonder whether someone could successfully weed out the effects of optimism on heart health with just one study.
"It's hard to adjust for everything; there is a possibility that they're missing things, and the people who are optimistic are maybe just eating better and sleeping well," said Dr. Christie Ballantyne, the director of the Center for Cardiovascular Disease Prevention at the Baylor College of Medicine and the Methodist DeBakey Heart and Vascular Center in Houston.
"Maybe they missed things in the cynical people ... elements in their lives that can affect heart disease," he said.