New research out of Japan shows a potential link between male baldness and an increased risk for coronary heart disease.
But it only affects men who are balding on top. Those with a receding hairline are not at risk, the researchers reported.
And although the researchers admitted the small study size was a limitation, they reported that men whose baldness affected the crown on their head faced a 32 percent to 84 percent increase in the risk of developing heart disease compared to men with a full head of hair or a receding hairline.
Study lead author Dr. Tomohide Yamada, of the department of diabetes and metabolic diseases at the University of Tokyo's Graduate School of Medicine, in Japan, reported his findings in the current issue of the journal BMJ Open and called for more research on the topic. Although the research review found an association between baldness and heart disease risk, it did not prove a cause-and-effect link.
Male pattern baldness (technically referred to as "androgenetic alopecia") affects up to 40 percent of adult men and is the most common type of hair loss, the researchers reported. By age 80, about four in five men will experience this form of baldness.
To explore the link to heart disease, the researchers analyzed databases covering the period 1950 through 2012. Out of 850 related investigations, they selected six studies, all published between 1993 and 2008 in the United States, Denmark or Croatia.
In the three studies that tracked patients for a minimum of 11 years, the research showed that, overall, balding men face a 33 percent greater risk for heart disease than other men, and those between 55 and 60 years old faced an even higher risk (44 percent).
The other three studies, comparing the cardiac health of balding men to non-balding men, showed a 70 percent bump in heart disease risk among the balding group, and an 84 percent risk for younger balding men.
What's more, a balding man's heart disease risk appeared to be dependent on the severity of his hair loss, with more severe loss translating into greater risk, the studies showed.
Yamada's team said the driving mechanism behind the connection is unknown, but they theorized that baldness could be a marker for insulin resistance, chronic inflammation or an increased sensitivity to testosterone, all of which are factors in the onset of heart disease.
Regardless, Yamada said, balding men should do what all men should do when it comes to controlling heart disease risk. "I recommend adapting a heart-healthy lifestyle that includes a low-fat diet, exercise and less stress [in order to mitigate against] classical coronary risk factors," such as age, high blood pressure, blood lipid disruption and a history of smoking, he said.
Cardiologist Dr. Gregg Fonarow, of the University of California, Los Angeles, agreed that the tried-and-true approach to heart health stands -- regardless of your hairline.
"Clearly, wearing a toupee or a hat is not going to lower the risk," he said with a chuckle. "But what is true is that well-established means of maintaining a healthy diet and weight, exercising, and watching blood pressure and cholesterol levels can all lower your risk for heart disease."
Dr. Christopher Cannon, a cardiologist at Brigham and Women's Hospital in Boston, agreed.
"Unfortunately, this is bad news for me personally," he said. "But if you are at a higher risk for heart disease, as I myself would appear to be, then you have to try and reduce that risk by doing the things that have long been shown to help. And stay tuned for future research that may help us understand what is underlying this."
SPECIAL: These 4 Things Happen Right Before a Heart Attack — Read More.