Women who have an optimistic view on life are more likely to live longer, a US study said on Wednesday. The study, published in the American Journal of Epidemiology, analyzed data from 2004 to 2012 from 70,000 women enrolled in the Nurses' Health Study, a long-running US study tracking women's health via surveys every two years.

The researchers looked at participants' levels of optimism and other factors that might play a role in how optimism may affect mortality risk, such as race, high blood pressure, diet and physical activity.

It found the most optimistic women, or the top quartile, had a nearly 30 percent lower risk of dying from any of the diseases analyzed in the study compared with the least optimistic women, or the bottom quartile.

The most optimistic women had a 16 percent lower risk of dying from cancer; 38 percent lower risk of dying from heart disease; 39 percent lower risk of dying from stroke; 38 percent lower risk of dying from respiratory disease; and 52 percent lower risk of dying from infection.

Previous studies have linked optimism with reduced risk of early death from cardiovascular problems, but this was the first to find a link between optimism and reduced risk from other major causes.

"While most medical and public health efforts today focus on reducing risk factors for diseases, evidence has been mounting that enhancing psychological resilience may also make a difference," says Eric Kim, research fellow at the Harvard T.H. Chan School of Public Health and co-lead author of the study.

"Our new findings suggest that we should make efforts to boost optimism, which has been shown to be associated with healthier behaviors and healthier ways of coping with life challenges."

The study also found that healthy behaviors only partially explain the link between optimism and reduced mortality risk.

One other possibility is that higher optimism directly impacts our biological systems, Kim says.