Count your blessings, be grateful for what you have, and always look on the bright side: A new study of just under 50,000 geriatric nurses in the U.S. suggests that gratitude is linked to extra years in life. The study, conducted by a team led by researchers from the Harvard T. Chan School of Public Health, suggests that mental outlooks can affect physical health, though it doesn’t show a direct cause-and-effect relationship.

“Previous research has shown a link between gratitude and a lower risk of mental disorders and greater emotional and social well-being,” says epidemiologist Ying Chen of the Harvard T.H. Chan School of Public Health. “But the link to physical health is less clear. Our study provides the first empirical evidence on this issue.”

The average age of study participants was 79 when they were asked to fill out a survey in 2016 to rate how grateful they were for everything in their lives. The researchers then checked records collected as part of a larger project to see how many deaths had occurred through 2019.

A total of 4,608 people died over three years, but about 9 percent of them were those who scored highest on the gratitude scale. Those who expressed more gratitude were found to have better attitudes toward all causes of death, especially cardiovascular disease.

Although the data controlled for factors such as sociodemographics, health history and lifestyle, this is not enough to say that gratitude is the cause of increased life expectancy; many variables are involved, including congruent views such as optimism (also previously linked to improved heart health).

It’s also possible that people who are healthier for other reasons are more likely to be grateful.

Other researchers believe there is weak evidence that gratitude improves well-being, and a 2020 meta-analysis found that gratitude interventions are of limited benefit at best for people with anxiety and depression.

But deliberate acts of gratitude, such as writing letters detailing what we’re grateful for, have proven helpful for some people in the past, suggesting that a little gratitude can go a long way for at least some of us.

“Preliminary research suggests that there are ways to intentionally cultivate gratitude, such as writing or talking about things you are grateful for several times a week,” Chen says.

The research team next wants to examine the relationship between gratitude and mortality in a larger, more diverse group of people. Of course, there are reasons to be grateful other than living longer; it’s generally a positive attitude.

Previous studies have shown that people who are grateful are more likely to follow healthy habits, which may be one reason for the results of this study. Gratitude may also help us strengthen social bonds, which are associated with longer life.

“Promoting healthy aging is a public health priority, and we hope that further research will advance our understanding of gratitude as a psychological resource for extending life,” Chen says. The study was published in: JAMA Psychiatry.