MILWAUKEE (AP) –– One of life's simple pleasures just got a little sweeter. After years of waffling research on coffee and health, even some fear that java might raise the risk of heart disease, a big study finds the opposite: Coffee drinkers are a little more likely to live longer. Regular or decaf doesn't matter.

The study of 400,000 people is the largest ever done on the issue, and the results should reassure any coffee lovers who think it's a guilty pleasure that may do harm.

"Our study suggests that's really not the case," said lead researcher Neal Freedman of the National Cancer Institute. "There may actually be a modest benefit of coffee drinking."

No one knows why. Coffee contains a thousand things that can affect health, from helpful antioxidants to tiny amounts of substances linked to cancer. The most widely studied ingredient - caffeine - didn't play a role in the new study's results.

Careful, though - this doesn't prove that coffee makes people live longer, only that the two seem related. Like most studies on diet and health, this one was based strictly on observing people's habits and resulting health. So it can't prove cause and effect.