ors, the study found. (A person must have three of the five risk factors to be diagnosed with metabolic syndrome.) Sleep problems are "a big deal," says Jordan Josephson, M.D., an ear, nose and throat specialist at Lenox Hill Hospital, in New York City. "They're bad for the heart, bad for diabetes, and they lead to heart attacks and stroke.... It's going to shorten your life." (Dr. Josephson was not involved in the new research.) Overall, 14 percent of the study participants developed metabolic syndrome. African Americans were more susceptible than whites, as were sedentary people compared to those who were physically active. The findings, which appear in the journal Sleep, echo previous studies that have shown a link between sleep difficulties and health problems such as obesity and high blood pressure. But this is the first study to follow people with sleep problems over time to see if they develop metabolic syndrome, according to the authors. More from Health.com: Why is my snoring getting out of control? How much sleep do you really need? 7 tips for the best sleep ever Virend Somers, M.D., a professor of medicine at the Mayo Clinic, in Rochester, Minn., says that sleep deprivation is an epidemic that is almost in parallel with the obesity epidemic and the widespread rise of risk factors for heart disease and diabetes. The links between obesity and metabolic syndrome are well known, but the role that sleep plays has been less clear, Dr. Somers says. The new study can't prove that snoring or any other sleep problem actually causes metabolic syndrome, which affects roughly 25 percent of the adults in the U.S. And although the researchers did control for race, physical activity, alcohol consumption, and other factors, it's possible that obesity is partly responsible for the link between sleep problems and metabolic syndrome. However, sleep problems could directly contribute to risk factors for heart disease and diabetes. "Chronic sleep disturbances may produce high levels of stress hormones and have exaggerated ca