April 3, 2013

expert reaction to new study into baldness and coronary heart disease

An analysis in the BMJ Open suggested a link between male pattern baldness and an increased risk of coronary heart disease, but only on the top/crown of the head, rather than at the front.

Professor Kevin McConway, Professor of Applied Statistics, Faculty of Mathematics, Computing and Technology, The Open University, said:

“I’m lucky enough not to have gone bald (says he smugly), but I have several balding male relatives and friends.  Should I be worrying more about their heart health, given this study?  I’d say not.

“The study reports rather large numbers of increases in the risk of heart disease, comparing severely bald men with men who aren’t bald. But we could do with more information before deciding how big an issue this is.

“The study reports (in one place) that severely bald men in younger age groups have a 44% greater risk of coronary artery disease than their hairier counterparts, but it doesn’t answer the question “44% greater than what?”  To make sense of this we need to know the absolute risks – how likely is a 50 year old man with a full head of hair to have a heart attack in the next 10 years?  How likely is it for a 50 year old bald man?

“In addition, these figures on increased risk aren’t actually known very precisely.  The press release doesn’t mention that, but from the paper we can see that, for instance, the 44% increase might plausibly be an 11% increase, or any 86% increase, or anywhere in between. There just isn’t enough information to be more precise.

“The researchers describe what they found as a ‘potential relationship’ between baldness and heart disease, and suggest it should be investigated in further major studies to see if it can be confirmed. They do suggest that bald younger men should be encouraged to improve their heart risk profile, presumably by healthier eating, giving up smoking and so on, but that probably applies to all of us. And they specifically warn against screening men for signs of heart disease just because they are bald.

“So yes, this is interesting, but I won’t be advising my bald friends to do anything different.”

Professor Patrick Wolfe, Royal Society Research Fellow and Professor of Statistics at University College London, said:

“This article follows several studies from the 1990s and onwards that have suggested evidence of a link between baldness and heart disease in adult men.  It reports a meta-analysis of 6 such studies in the English language, 5 of which reported evidence of a link, and concludes results that overall are qualitatively consistent with many previous studies.

“The idea of a link between baldness and heart disease can seem alarming, because many adult men are affected by male pattern baldness.  Most of us don’t look forward to going bald, and so it would be nice if there were a silver lining!  

“But it is important to remember that the study reports an increase in relative risk, after factors such as body mass index and smoking have been taken into account.  So, if we consider the case of two male, non-smoking marathon runners in top physical condition, one of whom is bald and the other not, then their absolute risks for heart disease are likely to be quite small – despite the fact that their relative risks may be different – both because of baldness and because of other factors, including family history.

“Right now the link that is seemingly responsible for this relative risk increase is not well understood, and so in future we might look forward to a day when understanding more about the various mechanisms underlying heart disease will tell us more about those underlying male pattern baldness, and vice-versa.  In the meantime it’s a case of focusing on the things that we can control – our diet, exercise regimens, and other risk factors – to lower our overall risk for heart disease.”

Professor David Spiegelhalter, Winton Professor of the Public Understanding of Risk, University of Cambridge, said:

“This study estimates that keeping hair on your crown is associated with a similar reduced risk of heart disease as taking a statin.  But sensibly no causal link is made: it’s a nice example of where a common factor may contribute to both baldness and heart disease.

“I am sceptical about the claim that different types of baldness have varying associations with heart disease, although it would be a relief to older men like me with bare temples but still a bit of fuzz on top.”

Dr Anita Thomas, Research Associate, School of Clinical Sciences, University of Bristol, said:

“Male gender has been linked with cardiovascular disease (CVD) incidence for a considerable period of time. Men tend to develop CVD and other vascular diseases earlier than pre-menopausal women (although there is catch-up after menopause).

“There is an interesting (and similar) report to this BMJ Open press release that was published in 2000. The previous study found that, compared with men with no hair loss, men with frontal baldness had a 9% increased risk for heart conditions and those with vertex baldness had a 23% increased risk.  Those with near-complete baldness had a 36% increase in risk for heart conditions (nonfatal heart attack or angina, procedures to open blocked coronary arteries (e.g. angioplasty, stenting and bypass surgery)).  Reference:  Lotufo PA, Chae CU, Ajani UA, Hennekens CH, Manson JE. Male pattern baldness and coronary heart disease: the Physicians’ Health Study. Arch Intern Med. 2000 Jan 24; 160(2):165-71.”

‘Male pattern baldness and its association with coronary heart disease: a meta-analysis’ by Tomohide Yamada et al. published in BMJ Open on Wednesday 3 April 2013.