Older men and women should confess any sexual problems to their doctor, or risk missing early cues for detecting heart disease and other illnesses.

"Sex is a legitimate part of medicine, but it has largely been kept separate from the rest of medicine," said Dr. Rosemary Basson, the lead author or a research paper published recently. She is based at the British Columbia Centre for Sexual Medicine in Vancouver.

Basson and her co-author, Dr. Willibrord Weijmar Schultz of the University Medical Centre in Groningen, the Netherlands, studied numerous medical databases looking for sexual dysfunctions in combination with diseases such as heart failure, diabetes, depression, multiple sclerosis and Parkinson's. Many sexual problems were identified as possible red flags of underlying or imminent medical conditions.

"If a man comes in with erectile dysfunction, it can be the tip of the iceberg," said Dr. Andrew McCullough, a sexual health expert at New York University Medical Center who was not connected to the paper.

Men with erectile dysfunction, the most common sexual disorder in older men, are often at increased risk of heart disease. In one study of 132 men who had heart surgery, nearly half had a history of erectile dysfunction. That diagnosis preceded the heart surgery in nearly 60 percent of the men.

Doctors are being urged to ask about patients’ sex lives, with questions about who they have sex with, how frequently and if they engage in potentially risky behavior.

"People aren't going to volunteer that kind of information unless they're specifically asked," said Dr. Jonathan Zenilman, chief of the infectious diseases division at Johns Hopkins Bayview Medical Center, who was not involved with the research.

What patients often fail to understand, physicians say, is that sexual dysfunctions can be symptomatic of a more serious condition.

Picking up on sex clues isn’t always easy.

"Women don't have as obvious a physical signal for sexual problems as men," said Basson. But a woman's lack of sexual desire reveals an underlying depression in up to 26 percent of cases. Taken together with other symptoms, sexual abnormalities in women could point to hormone conditions, kidney failure, diabetes, or other chronic diseases.

Using sexual problems as early indicators of medical complications, doctors can capitalize on valuable lead time to treat patients. "The first manifestation of early diabetes could be erectile dysfunction," Zenilman said. "It may not be what men want to hear, but if it's caught early enough, you can still do something about it."

In the case of depression, patients often go for years without being treated. If clinicians were able to make the connection between lack of sexual desire with psychiatric conditions such as depression or post-traumatic stress syndrome, patients could be offered treatment earlier, Zenilman said.

Moreover, the prospect of better sex may persuade people to lead healthier lives.

"Sex can be used as a great carrot for people," McCullough said. "People will be more willing to make lifestyle modifications to improve their health if they think they'll also get improved sex.”