3. Do left-handed women die younger?
Members have been contacting us regarding a study that has just been published in the journal Epidemiology, suggesting that women who are left-handed have a higher risk of dying from cancer or circulatory diseases. The findings of what is very much an initial study by a team from University Medical Centre Utrecht have been picked up and widely reported in the press, despite a great deal of scepticism among academics.
Though this study was of only 252 deaths in total (right and left-handed) over a 13 year period and would seem far too small to elicit any sound evidence, the team have reported that when left-handed women were compared with the other women and the data were “adjusted for a number of potentially confounding factors” which are neither detailed nor explained in the reporting, lefties had a 40% higher risk of dying from any cause, a 70% higher risk of dying from cancer and a 30% higher risk of dying from diseases of the circulatory system.
Left-handed women, it is claimed in the study, also had a 2-fold increased risk of dying from br east cancer, close to a 5-fold risk of dying from colorectal cancer and more than a 3-fold higher risk of cerebrovascular mortality.
Working on a such a small sample, it would surely seem difficult to conclude anything more than chance findings of a trend relating to these various causes of death, and the evidence is far from conclusive. The one hypothesis for a possible connection between handedness and the cause of these illnesses that has been put forward by the researchers is “intrauterine influences, such as exposure to sex hormones” referring to one theory that left-handed babies are exposed to higher levels of testosterone in the womb. It fails to take into account other possible reasons for left-handedness such as genetics and birth stress.
However, widespread media reporting and sensational headlines are in danger of creating, not for the first time, the sort of hype and hysteria that can turn conjecture into fact, and create urban myths quoted and revisited for years to come. Academics who have studied the research are, not surprisingly, highly dubious. One such, Dr Olga Basso who is left-handed, has written a commentary on this study, in which she voices her frustration with this and other recent studies that have related disease and death with handedness. She states “I am not alone in thinking that the literature on handedness suffers from a number of ills, regardless of the putative illnesses seen in those who are left-handed. Having successfully dodged a number of disorders” adds Basso, “I doubt that my left hand is prematurely pulling me towards my grave.”
There is also a response to the study from haematology specialist Adrian J Bloor who suggests the authors should consider whether their results "...indicate that the apparent association is nothing more than a spurious correlation".
Having seen many such studies receive widespread media attention, only to be disproved by later studies, the LHC would be inclined to agree with Dr Basso, and remain more concerned about the content and quality of the research than its results.
Use this link to view details of the study
Follow this link to read Dr Basso’s commentary on the research
(this is quite a major piece with lots of references to other left-handed research papers)
That's it for this month - we will be in touch again soon
Keith & Lauren Milsom
and all at the Left Handers Club
Tel: +44 (0)20 8770 3722
Fax: +44 (0)20 8715 1220
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Handers Club, please tell your family and
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