Smile: People with diabetes who are more emotionally upbeat have a greater chance of living longer, according to a recent study.

In the study, published in Jan. 2008 in the journal Health Psychology, roughly 3,500 participants—about a fifth of whom had diabetes—supplied information about their health and emotional state at two points 10 years apart. Results revealed a strong association between positive emotion and longevity among people with diabetes. For every one point increase in positive emotion, their risk of dying sooner decreased 13 percent, with those who reported enjoying life showing the biggest longevity boost.

The researchers found no such relationship in those without diabetes—until they looked at results for people over 65. In that subsample, being hopeful and enjoying life appeared to help prolong life.

Speculating on why happiness might boost longevity in diabetes, lead researcher Judith Tedlie Moskowitz, PhD, MPH, says it could positively affect the body’s neuroendocrine response, buffering the effects of diabetes-related stress. Or it could make people more apt to take their meds and stick to their diet.

But Moskowitz emphasizes that people with diabetes should not interpret the results to mean “they should just buck up and be happy.”

“When you have a chronic disease like diabetes, it’s normal to feel depressed or down sometimes,” explains Moskowitz, of the University of California, San Francisco. “These results suggest it’s worth focusing on bringing more positive experiences into your everyday life. Notice a beautiful sunrise. Set aside moments of gratitude for what you have. Set small, attainable goals, like testing your blood sugar more often. Then get a hit of positive emotion from accomplishing them.”