Epidemiologist, MBChB, PhD
One advantage of the COVID-19 pandemic is that nowadays, when people ask what my job is, I’m much less likely to get a blank look when I say, ‘I’m an epidemiologist.’ With all the publicity about coronaviruses and vaccinations and epidemic curves, the profile of public health research has never been higher.
Which provides a stark backdrop to the profile of other diseases and conditions that affect so many of us, one of them being migraine disease.
We get an idea of how big an issue migraine is from the Global Burden of Disease study, a huge worldwide collaborative research project that tracks the impact of hundreds of diseases and injuries in several hundred countries, including Aotearoa/New Zealand.
The study measures the impact on both mortality and measures of disability or quality of life, including ‘years of life lived with disability’ or YLD. Migraine is not a fatal disease but it causes significant impairment, so the YLD measure provides a way to quantify the amount and severity of this impairment.
The YLD calculates the number of years that a person lives with impaired function or ‘loss of productive life’, to give a definition that a soulless economist might favour. It combines measures of migraine prevalence (how common the disease is in a population), with the amount of time spent with impaired function (for migraine, which is an intermittent and transient neurological condition, this varies by person, so an average is used) and a number called a ‘disability weight’, which is an admittedly subjective assessment of the relative severity of the impairment, compared to other disabling conditions.
The disability weight is taken from large surveys where participants compare and rate the health status of hypothetical pairs of individuals, with differing levels of disease and disability.
In 2016, the Global Burden of Disease study estimated that there were over one billion people globally with migraine.
Migraine caused the second highest amount of YLD, amounting to 4.1 million years lived with disability. For Aotearoa/New Zealand, it was estimated that 642,000 people had migraine, ranging from 564,000-744,000.
Let me ponder this range for just a moment. Researchers provide these ranges to give us an idea of how sure they are about their results. The wide range around this estimate of migraine prevalence reveals that there is quite a lot of uncertainty. Although even if we take a conservative approach, the lowest estimate is well over half a million people, which is one in ten of our team of five million. But why are we so uncertain about the exact number of people with migraine in Aotearoa?
The short answer is, migraine is not a condition that has received any significant attention by researchers, policy makers or the medical professions for … well, ever?
The Neurological Foundation, which is the leading charity in Aotearoa that supports neurological research, has allocated just $147,000 of its research funds to projects related to migraine over the past 50 years, compared with $4.6 million for Alzheimer’s and dementia, $5.3 million for stroke and $7.6 million for Parkinson’s disease. Grouped together with headache and tinnitus, it received the least funding.
The Health Research Council, which is the primary source of Government funding for health research, spending millions of dollars each year, has an online library of research projects that it has funded over the past ten years. When I searched this library in November 2021, I found one project with relevance to migraine – a study worth $500,000 looking for a new target to treat neurological pain. This study was classified as a ‘rheumatology/arthritis’ study, because its main focus was on low back pain.
By contrast, there were 24 funded projects for dementia, many of them worth well over a million dollars, even though the estimated YLD for dementia is much lower than for migraine; and 42 funded projects for depression, which has a similar estimated YLD as migraine. The most recent estimate of migraine prevalence in Aotearoa comes from the New Zealand Health Survey, which is our primary source of annual data on health conditions, risk factors and access to health care – but the last time this survey asked about migraine was in 2006/07. Clearly not a topical issue, not worth including in our national health survey.
The Global Burden of Disease study does not provide migraine estimates by ethnicity so we don’t know what the burden of migraine disease is in Māori, but research from the United States has found that indigenous people have the highest prevalence of migraine of all ethnic groups, as do people who live in poverty.
Another study found that people of colour were less likely to have their migraine disorder diagnosed and treated. There is no reason to think that things would be different in this country – we have well-documented inequalities in health outcomes for Māori (and Pacific people), much of it attributable to systemic and institutionalised racism and the impacts of colonisation, which has stripped Māori people of resources, mana and opportunities.
In some ways, it is surprising that migraine research has not been a mainstream activity in Aotearoa, or in much of the world. Research from Australia shows that almost everyone with migraine experiences loss of work productivity (not to mention the impact on social activities), and the cost of migraine to Australia is estimated at $35.7 billion.
But migraine is a gendered disease – women are three times more likely to experience migraine than men and it is often more severe in women, perhaps due to hormonal factors.
The value of women’s work has long been unappreciated, so perhaps it is not surprising that the treatment of migraine has not been prioritised, because it disproportionately impacts the lives of women. Women have also traditionally been excluded from health research, for many complicated reasons (check out Gabrielle Jackson’s excellent book Pain and Prejudice for more about how the medical profession has consistently marginalised women’s health issues). So it is hardly surprising that migraine has been overlooked and dismissed, with roots in the nineteenth century, where physicians associated migraine with ‘hysteria’ and an affliction of women weak in mind and body.
At least we no longer treat migraine by drilling a hole in the skull to release evil spirits.
My own experience of migraine exemplifies the lack of knowledge and interest in migraine that pervades the medical system. The first neurologist I consulted, in some desperation as I had tried many preventive medications and none of them had been successful, sent me away with the words, ‘There’s nothing I can do for you.’ This was a devastating pronouncement for a young woman who had no idea how to manage a working life with frequent but inconsiderately unpredictable bouts of severe pain, nausea and cognitive haze. I had already abandoned the idea of practising as a hospital doctor, unable to fathom how I would study for exams on top of a gruelling 60-hour work week, with migraine as my companion. I had tried general practice but had opted to train in public health – this seemed like a profession that was friendlier to those who wanted to, or were forced to, work part time and flexible hours.
As it happened, this first neurologist was wrong, and the second one I consulted gave me more preventive treatments to try, but conceded that migraine, although a ‘fascinating disease’ was severely under-studied. None of his suggested treatments had been developed specifically to treat migraine – they were all drugs for treating other conditions, such as epilepsy, hypertension, or depression. Unfortunately, none of these worked long-term for me either, and my last neurological consult ended with an offer of Botox, which was approved in the United States in 2010 to help prevent chronic migraine, although I would have to pay for it privately at a cost of around $1,200 every 12 weeks.
I did eventually try Botox, but it didn’t have much effect and I hated the feeling of an immobile forehead so much that I actually gave myself a headache from constantly trying to move my eyebrows, in a fight against the paralysis.
I was back to treating the migraine attacks when they came on, rather than trying to reduce their frequency and intensity with a preventive medication.
I find that the most effective treatment for a migraine attack is a triptan, a drug that latches on to receptors for serotonin in the brain and blood vessels. Serotonin is most well known to be the brain chemical that keeps us happy – but it is in fact involved in many bodily functions – digestion, sleep, maintaining bone density, wound healing, sexual function. I’m still not sure exactly how the triptans manage to stave off a migraine attack – some say they constrict blood vessels, or reduce inflammation, or block the transmission of pain signals in the brain – maybe all of these things at once. I’m lucky that the triptans work well for me, most of the time, if I get in early, but there are limits on how often you can take triptans – more than 10 a month is frowned upon, as it could lead to its own type of headache, a medicine-overuse headache. This is a problem for people like me, who have a migraine attack on average 14 days a month (sometimes less, sometimes more).
Sometimes I can abort an attack with caffeine and non-steroidal anti-inflammatories like aspirin and ibuprofen. Sometimes none of this works, and I just have to suck it up and hope I can sleep it off, or wait it out.
This is why I was so excited when I heard about the new migraine treatments – preventive medicines that have been made for people with migraine, not for people with heart disease or mental illness, migraine medicines that are the product of actual science and research into the cause and neurological basis of migraine disease.
These modern, migraine specific medications are the Calcitonin Gene-Related Peptide (CGRP) monoclonal antibodies. CGRP is a small protein involved in the cascade of events that lead to a migraine attack, which helps to transmit pain signals in the brain, ramp up inflammation and dilate blood vessels. The CGRP monoclonal antibodies block this protein, effectively turning off its ability to stimulate the neurological dysfunction that is a migraine attack.
The development of these new medications is the first real hope I have had since that first neurologist told me there was nothing he could do to help me.
Maybe, finally, there will be a treatment that works for me. Even if they only reduce my migraine headaches by 50% (which is the usual kind of effect), I can barely imagine how much better life would be if I only had seven migraine days a month, compared to 14.
But I have heard stories from clinicians overseas about some patients, like me, with treatment-resistant migraine, who have had complete or almost complete remission. That makes me want to cry. I really can’t imagine a life without migraine, but I know it is a life I want.
As well as preventive treatments, there are also new treatments for acute migraine attacks, ones that you might be able to take whenever you need it, without worrying about causing the medicine-overuse headache.
But accessing these new medicines in Aotearoa is a problem. Medsafe has approved two of the new preventive medicines, Aimovig (erenumab) and Emgality (galcanezumab), but they are not funded. Aimovig is delivered as a monthly injection and costs $678 per month. An even greater barrier than the cost is the lack of awareness about them. I had saved up some money and approached my GP in June 2021 to see if I could try Aimovig, and she had never heard of it. Two other GPs I have seen since were similarly in the dark. I did get a prescription for it, but the pharmacist didn’t know what to do with it. He contacted the supplier and got a quote – $5,962.52 for three doses. I didn’t fill the prescription, that was well beyond my budget.
There aren’t many neurologists in Aotearoa who specialise in migraine. The nearest one I could find is around 140km away.
He told me that he can prescribe Aimovig at the more humble, or less humbling, price of $678 a month but only one pharmacy in his region can dispense it. I’m planning on making the trip soon, hopefully on one of the 14 days a month I don’t have a migraine. The hope is so important. I need that hope.
Yet many people with migraine in Aotearoa do not have hope. They are living in silence. Many do not know what their treatment options are, many do not even have a name for this pain and neurological dysfunction that they are labouring under. We don’t have numbers for how many people, as we don’t have this kind of research in Aotearoa. We could guess that we are similar to Australia, and around 10% of people with migraine have chronic migraine (headache on 15 days or more a month), the most debilitating kind. That is at least 50,000 people in Aotearoa, probably more. That is a lot of migraine days.
There’s a lot we need to do to improve the quality of life for people in Aotearoa with migraine. We need to know more about the scale of the problem; we need to have better awareness and understanding about what migraine is and how to manage it, both in the health professions and amongst the public. And we need access to a full range of treatment options, especially those that have been developed to target the exact pain receptors and pain modulators in the brain that cause migraine.
We know now that all this is perfectly possible. The COVID-19 pandemic revealed the extraordinary speed by which data can be gathered, research undertaken, and new preventive and acute treatments developed and funded when faced with a significant health threat.
All we need is strong political, professional and public engagement.
Migraine may not be killing us, but it has significant impacts on functioning, well-being and productivity. Migraine is not a disease of hysterical women; it is not caused by our poor health behaviours; it doesn’t happen to us because we are frail and can’t handle stress and need to relax; it is not a joke-butt headache that we use to excuse ourselves from work or unwanted sex.
Migraine is a neurological condition with a genetic predisposition that causes significant harm and deserves to be taken more seriously.