Our dear friend Blanaid has written a marvellous longer read to savour over the coming festive season. It’s got a bit of everything – movie stars, great yarns, history, genetics, geopolitics, myth-busting and some very interesting pain science. Enjoy!
Tough, feisty, fiery and red-headed
The wonderful screen icon Maureen O’Hara passed away recently at the great age of 95. Her Hollywood career spanning 50 years included memorable collaborations with actors John Wayne, Jimmy Stewart, Henry Fonda and directors Alfred Hitchcock and John Huston to name but a few. Starring in classics such as Rio Grande, The Quiet Man, The Hunchback of Notre Dame and Miracle on 34th St, O’Hara was known for her toughness and feisty nature. Hardly an obituary has been written that does not include a mention of her great beauty, fiery temper and red hair. The latter apparently led her to being cast in roles of more spirited nature
It struck me that a fiery temper was one of the most common characteristics associated with her. I wondered if there was any truth to the myths surrounding red hair and disposition. In O’Hara’s case, legend has it that she did indeed have a quick temper. During the filming of The Quiet Man, tiring of both her director and leading man, she struck Wayne with full force during a fight scene. Speedy reflexes saved the day and the only one hurt was O’Hara with a broken bone in her hand. Wayne later complained she nearly broke his jaw, while her reply was that this had been her intention! Nonetheless, they were firm friends and remained so for all of their lives, making many more films together.
Spartacus and the red-headed Thracians
O‘Hara isn’t the only feisty-natured redhead who demanded respect. Indeed, the ancient Greeks were wary of their Thracian neighbours (the gladiator Spartacus amongst them) and were reluctant to rile them because of their red hair, combative nature and willingness to embroil themselves in a good fight. Depictions on Athenian pottery of glorious battles show the Greeks fighting the mythological Thracian King Rhesus with wild red hair and a pointy beard. The earliest known description of the Thracians’ hair colour comes from the Greek poet Xenophanes in 500 BC who claimed:
“Men make their Gods in their own image… those of the Thracians have blue eyes and red hair”.
Indeed, surviving Thracian tombs in Ostrusha Mound, Bulgaria, have mosaic images of red-haired ancestors and are adorned with the word “Rufus”, the Latin word for red-haired.
Of course, red-head frequent the military history books from Boudicca, Napoleon and Cromwell to George Armstrong Custer and Winston Churchill. Boudicca was the Queen of the Iceni tribe, the Celts living in modern day East Anglia. Famous for “a great mass of red hair which fell to her knees”, she reportedly cut a terrifying figure. Enraged when the Romans confiscated her lands, whipping her like a slave and violating her daughters, she set about raising an army to defeat the unpopular Roman Empire. In AD 61, she reputedly led a vast army of over 100,000 men to fight the Romans inflicting defeats on the Roman 9th Legion and destroying Colchester, the then capital of Roman Britain. Onwards to Londinium where further victories ensued. Luck eventually ran out for Boudicca as the superior organisation of the Roman Empire was brought to bear, defeating her army and securing the Empire for a further 400 years. So what of this fearsome warrior and her flame red hair? If she was a brunette, would she have been any less fearsome or successful? Probably not, but it plays into the notions of strength of character, fieriness and hair colour.
It seems that a quick temper is often explained by a person’s red hair but perhaps something more elemental is at work? Speculation abounds that people with red hair can make adrenaline more quickly than the rest of us, or can metabolise it more readily. Could this possibly explain their tempestuous nature or is it all part of the well-constructed myth? Little is published but much is accepted as fact, with the quick temper of a few perhaps, confirming the myth of the fiery nature for all.
Superstitions and prejudice
Over the course of time, red heads have been subject to superstitions and prejudice often leading to a violent end. The Ancient Greeks believed they turned into vampires when they died, while the Romans bought red-haired slaves (often Thracian) at a higher price believing them to be a sign of good luck. Ancient Egyptians were thought to have sacrificed red-haired men by burning them and scattering their ashes at the grave of Osiris, the King of the Dead, something they believed would protect them and appease the Gods. Whatever the fate of our ancient red-haired ancestors, evidence exists in medieval times of beliefs that red-haired women were witches. Estimates of mass burnings at the stake in the 15th and 16th Centuries in central and southern Europe were a widespread occurrence.
Some say that the belief that red heads were untrustworthy emanated from artistic depictions of both Mary Magdalen and Judas Iscariot as being red-haired, thereby cementing the notion that they were either of ill repute or untrustworthy. This belief is most probably based on early artistic representations in the 12th Century which depicted Judas as a red-head, perhaps to single him out from the other dark-haired apostles. The myth, once created, was repeated over and over again through the ages.
“Let not the eye of a red-haired woman rest upon you”
Superstitions have continued unabated in many cultures where the red-haired lady brought with her great fortune or pending catastrophe, depending on where you lived. In Ireland, the negative association was in part due to the belief that raiding parties of Vikings brought the red hair to these shores. Considering the risks, perhaps it is not surprising that fishermen were amongst the most superstitious of all. In Ireland, fishermen were particularly wary of seeing a red-haired girl before leaving shore: it was a portent of bad luck. They said “Let not the eye of a red-haired woman rest upon you” for it bode ill and many fisherman refused to set sail as a result.
Prevalence of red hair worldwide
While good old-fashioned prejudice and superstitions are most probably the source of all the distrust our red haired friends have had to endure, the prevalence itself may have contributed to the problem. Red hair is by far the least common of the hair colours accounting for less than 2 percent worldwide. While there are well-recognized pockets of distribution in Russia, Turkey (our Thracian friends), Egypt (Pharaoh Ramesses II) , China, Pakistan (Pashtun Tribe) and even the Polynesian islands, the vast majority of people would associate red hair with the Celts of North Western Europe. The prevalence rises to 11 percent in Ireland with Scotland topping the polls at 13 percent of the population. It is estimated that up to 45 percent in Ireland carry the recessive melanocortin-1 receptor gene (MC1R).
Discovery of the recessive gene MC1R required for red hair
It is interesting to note that the gene was only identified in Scotland in 1997. Red hair occurs as a mutation of the gene MC1R located on Chromosome 16. For a child to have red hair both parents must be carriers of the gene. Due to the recessive nature of the gene, even if both parents have dark hair they can still be carriers for the gene and have red-haired children.
Why would the MC1R gene mutate?
It makes sense to question why the MC1R gene would mutate and whether it is of any benefit. It is known that 80 percent of those with the MC1R gene mutation also have less melanin, leading to fair skin and freckles in association with their red hair. Most of these live in Scotland and Ireland. Living so far north of the equator may reduce one’s exposure to sunshine and therefore the ability to produce Vitamin D. Living in Scotland and Ireland, where we have more cloud cover, reduces further the hours of sunshine available to make the vitamin. A lack of Vitamin D interferes with the absorption of calcium and can lead to rickets. Actually having less melanin means red heads with fair skin are able to absorb more Vitamin D at lower light levels. Perhaps the mutation is in a way a clever adaptation to reduced light levels when living this far northwest of the equator.
Half truths and confirmation bias
I am always interested in confirmation bias … particularly my own! It is the easiest thing to trot out half confirmed beliefs. They sound so reassuring and true they are often hard to resist. I caught myself doing such a thing recently. On treating a patient with a badly fractured leg we were remarking on the amount of swelling and bruising in the area. Glancing at his red hair I was just about to say, “you will probably bleed more than others”. Thinking the better of it I held my counsel and raced to the literature to see if there was any evidence to support the long held view that red heads are more prone to bleed. I am glad I did. For here is a perfect example of my beliefs and lack of evidence colliding.
In 2006, Liem and colleagues used a range of coagulation tests to compare the bleeding tendencies of 25 brown-haired and 25 red-haired women. Despite self-reported bruising being significantly higher in the red-haired group, there were no differences in terms of haemoglobin concentration, prothrombin time, INR (International Normalised Ratio) or APTT (Activated Partial Thromboplastin Time), all commonly used clotting tests. In addition, there were no significant differences between the groups in platelet function. The authors concluded that:
“If redheads have haemostasis abnormalities, they are subtle.”
But what about the difference in self-reported bruising? This raises the possibility of confirmation bias, red-heads being just as attuned to the stories of their increased bleeding risk as the rest of us. Alternatively, it is possible that the bruising was simply more visible on their paler skin.
A 2010 review in the British Medical Journal echoes Liem’s findings, and on the subject of bleeding, the authors did not hold back, concluding:
“It would seem that the reputation of people with red hair for having increased perioperative risk is without any basis in fact and should only be used as an excuse of last resort by surgeons defending problematic bleeding.”
General anaesthetic requirements
There is an anecdotal impression that red-heads have greater general anesthetic requirements than others. But is there any truth to this impression? In order to assess this theory, researchers Liem et al (2004) studied two groups of healthy female volunteers, ten of whom had red hair and ten of whom were brown-haired. Blood samples were taken to analyse melanocortin-1 receptor (MC1R) alleles. The researchers induced anaesthesia in the participants and then applied a noxious electrical stimulation via intradermal needles inserted in the participant’s thighs. Based on the unconscious movement response of the anaesthetised participants, the researchers adjusted the levels of anaesthesia to determine how much was required to stop ‘purposeful response’ to the electrical stimulation. Results reported that the volunteers with red hair required significantly more (a statistically significant 19% more) anaesthesia than those with dark hair. The authors concluded that their results confirmed anecdotal clinical impressions that inhaled anesthetic requirements are greater in red-heads.
While it is tempting to be impressed with such significance values, it is important to consider a number of aspects of the study. Firstly, drawing conclusions based on a sample of 20 subjects must surely be done with great caution. Secondly, the effect size was actually small, meaning that the study may have been statistically significant, but it is less clear whether it was clinically significant. Finally, it is worth noting the blinding conditions of the study. An independent investigator was brought in to assess the movement response, and while they were blinded to the level of anaesthesia, they were not blinded to the hair colour and skin complexion of the participants due to “practical and technical difficulties involved”.
To answer questions raised by the Liem study, a much larger study was recently conducted. Gradwohl (2015) examined overall anaesthetic management in 319 red-heads and 1595 matched controls. They compared a number of measures including inhaled anaesthetic requirements; postoperative pain; time to recovery; and intraoperative awareness risk (the unexpected and explicit recall by patients of events that occurred during anesthesia, occasionally even perceiving pain during the procedure), but found no significant differences. The authors concluded that:
“perioperative anesthetic and analgesic management should not be altered based on self-reported red-hair phenotype.”
Local anaesthesia requirements
What then, about local anaesthetic efficacy, such as the inferior alveolar nerve block (IAN) commonly used by dentists? A 2012 study examined dental anaesthetic levels in 62 red-haired and 62 dark-haired subjects when they were administered equal amounts of lidocaine with epinephrine via the IAN block. No significant differences in anaesthetic success were seen between the groups. However, red-haired women were significantly more likely to report higher levels of dental anxiety than the control group making them twice as likely to avoid visiting the dentist at all.
What about pain?
So much for bleeding and anaesthetic requirements. What about pain in red heads -do they differ from the norm? Here is where the picture becomes somewhat conflicting. In a follow up to their 2004 study on anaesthetic requirements in red-heads Liem et al (2005) investigated whether women with natural red hair were more sensitive to thermal stimuli and more resistant to topical and subcutaneous anaesthetic (lidocaine). They evaluated responses in 30 red-haired women and 30 brunettes to electrical current, and hot and cold temperature after 1-hour exposure to both liposomal and subcutaneous lidocaine. None of the baseline responses to electrical stimulation including current perception or pain report differed significantly between the two groups.
However, there was a difference seen in the response to thermal stimuli and anaesthetic efficacy. What was clear was that red-heads were more sensitive to cold – both in terms of when red-headed participants first reported pain when exposed to cold stimuli, and how much cold they could tolerate. The authors also reported that red-heads were resistant to anaesthesia produced by subcutaneous lidocaine. Surely being more resistant to the pain numbing effects of a widely used anaesthetic is of clinical significance? No dose response relationship could be established and so it may be that red heads simply required more local anaesthetic to achieve the same response as others. The authors concluded that:
“… mutations of the melanocortin 1 receptor, or a consequence thereof, thus modulate pain sensitivity.”
Andresen et al (2011) followed up previous studies and examined outcomes that included response to pressure, cutaneous heat, and areas of pinprick hyperalgesia and brush allodynia after using heat and topical capsaicin in the area. Interestingly, redheads were shown to develop smaller areas of pinprick hyperalgesia compared to controls, but showed no difference in the other metrics.
Time to challenge the half truths
It appears time to challenge some of the well-worn myths, including those suggesting red heads are more prone to bleeding, or require more general anaesthetic than others. When it comes to pain, a more conflicting view emerges. While some evidence exists to support the view that red-heads are more sensitive to noxious cold and may be less responsive to local anaesthetic, they are less likely to develop pinprick hyperalgesia induced by capsaicin. Although there is some evidence suggesting that they have a greater response to analgesic opiates, the conclusions are by no means definitive.
Perhaps the best way to debunk redheaded myths is to look past the hair colour and complexion, and look at the person, listen to the person, and appreciate that all pain (and of course not just pain) experiences are unique and highly individual.
Thankfully one myth – the predictions of the demise of the red-haired gene due to climate change – seems completely unfounded. So the gene that contributed to the likes of Van Gogh and Galileo, George Washington and Emily Dickinson, Lucille Ball and J.K Rowling is here to stay, a fact that I, for one, applaud.
Blanaid Coveney is a practicing physiotherapist in Dublin, Ireland. Her professional interests include epidemiology, pain and all things brain related.