Science slowly unfolds what migraines are
Researchers are closer to understanding why women get more migraines than men, reports Wendy Zukerman
EVER had a headache — a really bad one that swept you right off your feet and into bed? Amy Lorimer, a 19-yearold nursing and paramedic student at Monash University started getting migraines when she was six.
‘‘ I lose the feeling in my hands; one side of my face tingles and on the other side I get a really bad headache,’’ she explains. ‘‘ My tongue goes numb, I am nauseous, I often throw up, and I become really sensitive to light.’’ It sounds bad, and it is — and new research shows that it’s more common that many people would realise.
A study published last month in the MedicalJournalofAustralia reported that 11.5 per cent (649 out of 5663) of Australian patients who went to the doctor in a twomonth period suffered from migraine (2007;187;142-146). The report also found that women in Australia are approximately three times more likely to get migraines than men, which is consistent with worldwide figures.
Associate Professor Richard Stark, a clinical neurologist at the Alfred Hospital in Melbourne and co-author of the report, says that because the subjects of his study were patients who were visiting a doctor, Australians who haven’t been diagnosed wouldn’t be accounted for.
‘‘ A lot of people who have migraine don’t recognise that it is migraine,’’ Stark says. ‘‘ On the other hand, there is a group of people who get really bad migraine, and feel cheated when people undervalue how debilitating they are.’’
In the study Stark speculated that, like many of us, GPs can underestimate the effect that frequent migraines have on patients.
Lorimer understands this feeling more than most. When she tells people she suffers from migraine — a patient sometimes referred to as a migraineur — the usual response is: ‘‘ I get migraines, too’’.
Nadia Matthiesson, a part-time office manager and fellow migraineur, says she never tells people she suffers from migraine. ‘‘ The response is either ‘ Oh, I get them’, or they think ‘ Oh, it’s one of those’,’’ she says.
Doctor Dale Nyholt, of Griffith University, has studied the causes and affects of migraine in Australia for a decade. He believes that migraine is ‘‘ definitely’’ misunderstood by the Australian community. Nyholt says migraine has a range of direct medical and indirect economic costs to individual sufferers as well as to the general community.
He calculates that the total cost of migraine to the Australian community could be over $1 billion per year, once medical consultations, drug treatment, lost productivity in the workplace and absenteeism are all factored in.
Clearly, this is more than can be cured with a paracetamol and a glass of water.
In Matthiesson’s case, on two occasions the throbbing from her headaches was so bad she had to be admitted to hospital: ‘‘ The pain was so intense, it frightened me’’.
When Lorimer’s migraine attacks are at their worst, she can’t read because focusing on small print intensifies her headaches. Working with computers or even working with lights, especially fluorescent lights, is impossible. ‘‘ I can’t do it — I just can’t,’’ she says.
Despite modern medicine, the best remedy for Lorimer’s migraines is turning off the lights and lying in bed in complete silence.
Matthiesson started getting migraines when she was eight years old. ‘‘ At that stage they didn’t call it migraine, they just thought you were sick — they didn’t realise what it was,’’ she says. Only in her late teens did doctors begin diagnosing her condition as migraine.
So, what is modern medicine saying about migraine now? And why are they more common in women?
This year, a review published in Pharmacology & Therapeutics (2007;113;321-340) reported that female sex hormones like estrogen could account for the prevalence of migraine in women. Migraines are thought to be caused by blood vessels in the brain expanding and activating nerves, which then stimulate pain receptors. Hormones, which are found in the blood, can increase and decrease the size of blood vessels. Plus, estrogen interacts with pain receptors around the arteries that surround the brain, and this could explain the throbbing felt during a migraine attack.
Whilst general grogginess during a woman’s period is one thing, a report in Neurology (2004;63:351) found 60 per cent of female migraneurs report attacks around their menstrual cycle, a time when there is a dramatic change in female hormone levels. In addition, hormone contraceptives, which contain estrogen-like chemicals, have been consistently shown to affect the frequency and intensity of migraines. Studies show male-tofemale transsexuals, who take hormone supplements, have an increased incidence of migraines since treatment.
Lorimer is the perfect poster child for these scientific theories. The week before her period she would get ‘‘ horrific headaches’’, and her mother experienced constant attacks when she was pregnant (when female sex hormone levels increase).
Stark supports the theory that hormones are a major cause of migraine. ‘‘ We know that the incidence of migraine in women is higher than men between teenage years and menopause,’’ he says. Before or after that time period, the amount of men and women suffering from migraine ‘‘ is fairly equal’’.
Unfortunately, studies on the effect of hormones on migraineurs are inconsistent. Some show oral contraceptives worsen symptoms, while others show women are less likely to suffer from migraine when on the pill.
Lorimer takes a progesterone-only form of contraceptive as preventative treatment for her migraines, which helps reduce the attacks. But Matthiesson can’t attach any hormonal explanation to her headaches. It seems that the effect of hormones on migraine is as individual as menstruation itself.
Evidence suggests that genetic factors play an important role in migraine. Nyholt explains that studies of identical twins ‘‘ indicate that migraine has a significant genetic component’’. Stark says people ‘‘ are born with a susceptibility to migraine, and the cause is predominantly genetic’’.
Lorimer’s grandmother, mother and sisters all suffer from migraine. However, Matthies- son is the only sufferer in her family.
Nearly 10 years ago Nyholt published an article in Human Molecular Genetics (1998;7;459-463) proposing that there was a gene on the X chromosome that predisposed people, especially women, to migraine. Because women have two X chromosomes, compared to men who only have one, it made sense that women would have a higher chance of getting migraines.
In a study of the DNA of 103 Australians from three large families he found several genes on the X chromosome that were potential sites for the ‘‘ migraine gene’’. But Nyholt now believes we will have a definitive answer to whether there is a migraine gene on the X chromosome in a year or two.
Stark says there is very likely to be a gene in the X chromosome, but there are likely to be genes on other, non-gender-specific chromosomes. It looks like the X chromosome is not the X-factor explaining why women are more affected by migraines than men.
The most difficult part about studying migraines is the inconsistent symptoms of migraineurs, which makes it tricky to diagnose and investigate the disease. Research is clearly showing that there is a scientific basis to explain why women suffer from migraines more than men. The research also shows that migraines aren’t just dehydration headaches that some people can’t handle; they are debilitating and affect individuals worldwide.
Crippling: Amy Lorimer’s blinding headaches completely disable her