How's your attitude? Are you the optimistic glass-half-full person or the pessimistic glass-half-empty type? If you're the former, I have some good news for you: All of that optimism is good for your health. It might even make you live longer.

Using data from the long-running Nurses' Health Study which started in 1976, researchers looked at how more than 70,000 women answered questions about how optimistic they were. They tracked the deaths of those women (who were an average age of 70) several years later. The results were published in the American Journal of Epidemiology.

They found that the women who reported the highest level of optimism were 29% less likely to die in that period than those who were the lease optimistic. That reduced risk was for various causes of death including cancer, heart disease, stroke, respiratory disease and infection.

Optimism could be linked to better health and mortality for several reasons, Eric Kim, an author of the study and research fellow at the Harvard T.H. Chan School of Public Health, told NPR. People who are more optimistic often tend to have healthier eating, exercise and smoking habits. Optimism may somehow impact biological function, potentially through lower levels of inflammation or better immune function. Optimistic people may also have better coping skills.

"When they face life challenges, they create contingency plans, plan for future challenges and accept what can't be changed," Kim told NPR.

Optimism and your heart

Other studies have shown a link between optimism and health.

A meta-analysis, published in JAMA Network Open, looked at 15 studies that measured optimism and pessimism. Ten of the studies, which included data on more than 209,000 people, involved heart disease. Researchers found that compared with pessimists, optimists had a 35% lower risk for heart-related events.

That's similar to what researchers from the University of Illinois found: People who are more optimistic are also more likely to have good heart health. For their study, researchers evaluated the heart health, mental health and optimism levels of 5,100 adults ranging in age from 45 to 84 years old. They tracked each participant over an 11-year period and found that heart health scores, which are based on body mass index and blood pressure, improved in direct relationship with levels of optimism.

"Individuals with the highest levels of optimism have twice the odds of being in ideal cardiovascular health compared to their more pessimistic counterparts," said lead author Rosalba Hernandez, social work professor at the University of Illinois, in a statement. "This association remains significant, even after adjusting for socio-demographic characteristics and poor mental health."

The results were published in Health Behavior and Policy Review.

According to the Centers for Disease Control and Prevention, heart disease is the leading cause of death in the United States, killing about 610,000 Americans every year. And it affects people of all ages and backgrounds.

Hernandez and her team believe that health experts should use these results when considering programs to improve Americans' cardiovascular health. She said even a moderate difference in cardiovascular health can dramatically reduce death rates and help people live longer, happier lives. And finding a better outlook on life is a preventative treatment option available to anyone and everyone regardless of age, race or financial status.

And who couldn't use another good reason to smile?

Editor's note: This story was originally published in January 2015 and has been updated with new information.

Smile! Optimism is good for your health
Turn that frown upside-down if you want to improve your health and live longer.