Men who are bald have a much higher chance of developing coronary heart disease compared to their full headed peers, according to a new study.
Researchers said male pattern baldness is linked to an increased risk of coronary heart disease, but only if it's on the top or crown of the head, rather than at the front.
However, a receding hairline is not linked to an increased risk, finds an analysis of published in the British Medical Journal (BMJ).
The researchers trawled the Medline and the Cochrane Library databases and came up with 850 possible studies, published between 1950 and 2012.
Three of the studies were cohort studies - meaning that the health of balding men was tracked for at least 11 years.
Analysis of the findings from these showed that men who had lost most of their hair were a third more likely (32 per cent) to develop coronary artery disease than their peers who retained a full head of hair.
When the analysis was confined to men under the age of 55-60, a similar pattern emerged. Bald or extensively balding men were 44 per cent more likely to develop coronary artery disease.
Analysis of the other three studies, which compared the heart health of those who were bald/balding with those who were not, painted a similar picture.
It showed that balding men were 70 per cent more likely to have heart disease, and those in younger age groups were 84 per cent more likely to do so.
Three studies assessed the degree of baldness using a validated scale. Analysis of these results indicated that the risk of coronary artery disease depended on baldness severity, but only if this was on the top or crown of the head.
Extensive vertex baldness boosted the risk by 48 per cent, moderate vertex baldness by 36 per cent, and mild vertex baldness by 18 per cent. By contrast, a receding hairline made very little difference to risk, the analysis showed.
Men with both frontal and crown-top baldness were 69 per cent more likely to have coronary artery disease than those with a full head of hair, while those with just crown-top baldness were 52 per cent more likely to do so. Those with just frontal baldness were 22 per cent more likely to do so.
Explanations for the reasons behind the association vary, but include the possibility that baldness may indicate insulin resistance, a precursor to diabetes, a state of chronic inflammation or increased sensitivity to testosterone, all of which are involved directly or indirectly in promoting cardiovascular disease, said the researchers.
"(Our) findings suggest that vertex baldness is more closely associated with systemic atherosclerosis than with frontal baldness," researchers conclude.
"Thus, cardiovascular risk factors should be reviewed carefully in men with vertex baldness, especially younger men" who should "probably be encouraged to improve their cardiovascular risk profile," they said.
