Bald men have a higher risk of developing heart disease than men with a full head of hair, a new study suggests.
Researchers from Japan found that men who had lost most of their hair were a third more likely (32%) to develop coronary heart disease (CHD) than those who retained a full head of hair.
Bald or extensively balding men aged between 55 and 60 were 44% more likely to develop coronary artery disease, according to the study published in the online journal BMJ Open.
The researchers from Japan examined six studies, including three studies that tracked the health of balding men for at least 11 years, involving 37,000 men.
They found that the link between CHD and baldness depends on the severity of the baldness.
Severe baldness on the top or crown of the head, also known as the vertex, was associated with a 48% increased risk while moderate vertex baldness and mild vertex baldness were linked to a 36% and 18% risk respectively.
The authors also looked at differing grades of baldness - frontal, crown-top and combined.
Men with both frontal and crown-top baldness were 69% more likely to have CHD than those with a full head of hair, while those with just crown-top baldness were 52% more likely to do so.
Those with a receding hairline were 22% more likely to develop the disease.
The authors note that the explanation of the link is "unclear" but say that it has been previously suggested that classical coronary risk factors such as age, hypertension and smoking might influence both conditions.
They also say that baldness has previously been linked to insulin resistance, metabolic syndrome and hypertension. And it has been suggested that male pattern baldness has been linked to coronary heart disease through chronic inflammation or increased sensitivity to testosterone.
CHD is the UK's biggest killer, causing around 82,000 deaths every year. About one in five men and one in eight women die from the disease.