MILWAUKEE -- One of life's simple pleasures just got a little sweeter.
After years of waffling research on coffee and health, including 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 on the issue, and the results should reassure coffee lovers who think it's a guilty pleasure that may be harmful.
"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 study's results.
It's not that earlier studies were wrong. There is evidence that coffee can increase LDL, or bad cholesterol, and blood pressure, at least in the short term. Those in turn can raise the risk of heart disease.
Even in the new study, it first seemed that coffee drinkers were more likely to die at any given time. But they also tended to smoke, drink more alcohol, eat more red meat and exercise less than non-coffee-drinkers. Once researchers accounted for those things, a pattern emerged: Each cup of coffee per day nudged up the chances of living longer.
The study was done by the National Institutes of Health and AARP. The results are published in today's New England Journal of Medicine.
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.
But with so many people, more than a decade of follow-up and enough deaths to compare, "this is probably the best evidence we have" and are likely to get, said Dr. Frank Hu of the Harvard School of Public Health. He had no role in this study but helped lead a previous one with similar findings.
The new one began in 1995 and involved AARP members ages 50 to 71 in California, Florida, Louisiana, New Jersey, North Carolina, Pennsylvania, Atlanta and Detroit. People who had had heart disease, a stroke or cancer weren't included. Neither were folks who ate too many or too few calories per day.
The rest gave information on coffee drinking at the start of the study.
Of the 402,260 participants, about 42,000 drank no coffee. About 15,000 drank six cups or more a day. Most had two or three.
By 2008, about 52,000 of them had died. Compared with those who drank no coffee, men who had two or three cups a day were 10 percent less likely to die at any age. For women, it was 13 percent.
Even a single cup a day seemed to lower the risk a little: 6 percent in men and 5 percent in women. The strongest effect was in women who had four or five cups a day -- a 16 percent lower risk of death.
None of these are big numbers, though, and Freedman can't say how much extra life coffee might buy.
"I really can't calculate that," especially because smoking is a key factor that affects longevity at every age, he said.
Coffee drinkers were less likely to die from heart or respiratory disease, stroke, diabetes, injuries, accidents or infections. No effect was seen on the risk of cancer death, though.
About two-thirds of study participants drank regular coffee; the rest drank decaf. The type of coffee made no difference.