Drinking several cups of joe a day may cut your risk of suicide, but it might just kill you anyway. A new study has linked heavy coffee drinking—that's 28 cups a week, or four per day—with a higher death risk in those under 55. Women who guzzled the brew were twice as likely to die, while the male risk jumped 56%, USA Today reports. Over 55? Drink three or less cups a day? You're safe to sip away, researchers say. The study also found heavy coffee drinkers were more likely to smoke and had less healthy hearts and lungs.
The study analyzed nearly 45,000 people, aged 20 to 87, and found 2,500 had died after 17 years, though coffee's precise role isn't clear. "The exact mechanism between coffee and mortality still needs clarification," a co-author told the Guardian, though the habit may be associated with a poor diet or sleeping late. But "dietary factors, marital status and other socioeconomic factors that were not adjusted for in this study may account for some or all of these observations," a doctor said. Until more research can be done, "avoid excessive coffee drinking," says the study's lead author. (Read more coffee stories.)