New Japanese research shows a potential link between male pattern baldness and an increased risk of coronary heart disease. But it only affects men who are balding at the top of their heads. Those who have initial baldness in the hairline are not at risk, the researchers reported.
The findings come from an analysis of six published studies on hair loss and cardiac health involving approximately 37,000 men.
Although the researchers admitted that the small size of the studies was a limitation, they reported that men whose baldness affected the crown faced an increase of between 32 and 84% in the risk of developing heart disease, compared to men without baldness or with a recessive hairline.
The lead author of the study, Tomohide Yamada , of the department of diabetes and metabolic diseases of the Faculty of Medicine Graduate of the University of Tokyo, in Japan, reported his findings in the current edition of the magazine BMJ Open.
Although the review of the research found an association between baldness and the risk of heart disease, it did not prove a causal link.
Male pattern baldness (technically known as "androgenetic alopecia") affects up to 40% of adult men and is the most common type of hair loss, the researchers reported.
To explore the link with heart disease, the researchers analyzed databases covering the period between 1950 and 2012. Of the 850 related investigations, they chose six studies, all published in the United States, Denmark or Croatia between 1993 and 2008.
In the three studies that tracked patients for a minimum of eleven years, the research showed that, in general, men who were balding were facing a 33% increase in heart disease risk than other men and those between 55 and 60 years of age faced an even higher risk of 44%.
The other three studies, comparing the heart health of men who were getting bald with those who did not, showed a 70% increase in the risk of disease in the group with baldness and a risk of 84% among men younger people who were getting bald.
In addition, the risk of a man's heart disease seemed to depend on the severity of the hair loss and increased baldness translated into increased risk, the studies showed.
Yamada's team said the responsible mechanism underlying the connection is not known, but they theorized that baldness could be a marker of insulin resistance, chronic inflammation or increased sensitivity to testosterone, factors that have to do with the onset of heart disease.
Yamada said that, independently, men who are going bald should do what all men should do to control the risk of heart disease.
"I recommend adopting a healthy lifestyle for the heart, including a low-fat diet, exercise and less stress to mitigate the classic coronary risk factors" such as age, hypertension, problems with blood lipids and smoking history, he advised.