Causes and Risk Factors of Migraine

Migraine is more than just a bad headache that occurs from time to time. It’s a neurological disease that typically causes moderate to severe head pain that is often intense, according to the American Migraine Foundation. The pain may cause a throbbing, pounding, or pulsating sensation, and you may experience nausea or vomiting. You may also be sensitive to light, noise, or smells. Migraine may occur with or without aura.

Episodes of migraine symptoms are referred to as migraine attacks, and they can last from four hours to a few days, per the American Migraine Foundation. People with chronic migraine have symptoms at least 15 days per month for at least three months or more.

Chances are, you or someone you care about has migraine: At least 39 million Americans live with migraine, notes the American Migraine Foundation.

Experts are still learning about the complexities of migraine and what causes it. There are things that make you more likely to have migraine, and there are factors that can increase your chances of a migraine attack.

Researchers don't fully understand what causes migraine, but genetics and environmental factors seem to be involved, according to the Mayo Clinic.

Neurotransmitters and Migraine

Changes in the brain stem and how it interacts with the trigeminal nerve, a major pain pathway, might play a role in causing migraine, per the Mayo Clinic.

Imbalances in brain chemicals, including the neurotransmitter serotonin, which affects functions such as mood, sleep, and hunger, may also play a role. Some experts believe that migraine pain occurs because of waves of activity by groups of excitable brain cells, which could cue chemicals such as serotonin to narrow blood vessels, according to Johns Hopkins Medicine.

RELATED: What You Need to Know About Migraine, Depression, and Anxiety

Other neurotransmitters also play a role in the pain of migraine, including calcitonin gene-related peptide (CGRP), per the Mayo Clinic.

There’s also evidence to suggest that dopamine, a neurotransmitter that affects things like motivation and learning, is also involved in migraine. Imaging tests of the brain have revealed that dopamine levels fall and fluctuate at different times during a migraine attack, according to research published April 25, 2017, in Neurology. Physicians and emergency department personnel often give people with migraine dopamine antagonists, which are drugs that block overactive dopamine receptors, to level off big dopamine fluctuations, which can ease migraine attacks. The study found that when people with migraine are between attacks, their dopamine levels were stable and normal, but during the attack, the levels fell significantly.

Blood Proteins and Migraine

A study published May 11, 2022, in Nature Communications found that specific blood proteins may cause migraine, and others can increase your risk for migraine.

Researchers identified that high levels of two proteins, DKK1 and PDGFB, may cause migraine, and lower levels of other proteins may also cause migraine. Study authors posited that this discovery may pave the way for new targeted migraine treatments and therapies.

There are several risk factors for migraine, including genetics, age, sex, and hormonal changes.

Family History or Genetics

Genetics play a fairly significant role in migraine, according to Roderick Spears, MD, the regional medical director of neurology at Penn Medicine in Pennsylvania. “If you have migraine, you have about a 75 percent chance of having a first-degree relative with migraine. It can be passed equally from both the mother’s and the father’s side,” Dr. Spears says, adding that family history is particularly important in migraine with aura, or migraine with accompanying neurological disturbances, most commonly visual.

Age

The onset of migraine can begin at any age, though the initial attack often occurs during adolescence, per the Mayo Clinic. Migraine usually peaks during a person's thirties, after which point the attacks gradually become less severe and less frequent.

Girls are more likely to have the onset of migraine around the time of their first menstrual cycle, with migraine prevalence in women peaking during childbearing years, according to the American Migraine Foundation.

Sex

Women are three times more likely than men to have migraine, which is believed to be due to the role of estrogen. “If you look at children, boys and girls have about the same rate of migraine, but that changes at puberty, with women jumping to a 3 to 1 ratio. The estrogen hormones, specifically, play a pretty significant role in the expression of migraine,” says Spears.

Hormonal Changes

It’s very common for women to have migraine around their menstrual period, according to Nada Hindiyeh, MD, a headache specialist and clinical associate professor at Stanford Medicine in Palo Alto, California. “There are several different types of migraine, and there is a subset of migraine that is related to the menstrual cycle.”

“We believe the reason many women have migraine around their menstrual cycle is because of the drop in estrogen that happens right as the cycle starts. That’s a big trigger for migraine,” says Dr. Hindiyeh.

Conversely, steady levels of estrogen production (as in menopause) or increasing levels (as in pregnancy) may reduce the risk of migraine attacks, according to a review published in Current Opinion in Neurology.

While the underlying cause of most types of migraine — or why one person has migraine and another doesn’t — remains unknown, the various triggers for a migraine attack are better understood.

“The migraine brain is a brain that likes what we call homeostasis; it does not like a lot of change. When there is change in weather, light, noise, even nutrition — those types of situations will tend to trigger migraine attacks,” says Spears.

According to the American Migraine Foundation, the most common migraine triggers include:

• Stress Stress is a trigger for almost 70 percent of people with migraine.
• Changes in sleep schedule Sleeping too much and too little can cause migraine, according to the Sleep Foundation.
• Hormone level changes, particularly in women.
• Caffeine and alcohol Many people find their migraine symptoms worsen after consuming caffeine or alcohol, particularly red wine. (Others say a cup of coffee can relieve their migraine symptoms, and some medications for migraine pain may contain a dose of caffeine.)
• Weather changes Storms, excessive heat, and changes in barometric pressure are common triggers, per the American Migraine Foundation.
• Diet The most common foods known to trigger migraine attacks include foods that contain histamine and MSG, chocolate, cheese and other dairy products, artificial sweeteners (such as aspartame), caffeine, cured meats, and anything with a strong odor.
• Dehydration About one-third of people with migraine say dehydration is a trigger, and for some, even mild dehydration can cause an attack.
• Light Natural, bright light and fluorescent or flickering bulbs can all cause migraine.
• Odors Some smells may activate certain nerve receptors in the nasal passages that may trigger a migraine attack or make one worse, notes the American Migraine Foundation.
• Medication overuse If you take acute medication prescribed by your doctor more than 10 days per month, it can, ironically, cause more migraine attacks, which is known as Medication Overuse Headache (MOH).

Identifying your personal migraine triggers can be difficult, according to Migraine Trust, since it can take numerous triggers to result in a migraine attack and a particular trigger may not lead to an attack every time it occurs.

“We know that it's fairly common to have headache after head trauma,” says Spears. If you have a genetic predisposition for migraine, you have a greater chance of that post-traumatic headache presenting as a migraine-type headache, he adds.

“But there are cases of people who never had headaches, have no family history of headaches, and after head trauma they end up with persistent, severe, migraine-like headaches going forward. They usually don’t have them every day, but they are more prone to them after head trauma,” says Spears.

A study published in 2018 in the Journal of Headache and Pain found that people hospitalized due to a mild head injury were more likely to develop new headache onset or report exacerbation of existing headache compared with the general population.

There is evidence that abuse in childhood is associated with a higher risk of developing migraine later in life, says Spears. Research published in January 2017 in the journal Headache found that children who experienced emotional abuse may be more likely to experience migraine as young adults. Emotional abuse was assessed by asking study participants how often a parent or other adult caregiver said things that really hurt their feelings or made them feel like they were not wanted or loved. Emotional abuse was more strongly linked to the likelihood of future migraine than physical or sexual abuse, according to the study.

An earlier study published in Neurology compared the effects of emotional abuse, emotional neglect, and sexual abuse in childhood. It found that while all of these types of abuse were associated with a higher risk of migraine, the association was strongest for emotional abuse. Emotional abuse was evaluated by asking people how frequently such statements as “People in my family said hurtful, insulting things to me” were true, whereas emotional neglect was evaluated by asking people how frequently such statements as “Someone in my family helped me feel that I was important, special” were true. Sexual abuse was determined by asking people how frequently such statements as “Someone tried to pressure or force me to have unwanted sexual contact” were true.

Episodic migraine is defined as 14 or fewer headache days per month, while chronic migraine is 15 or more days per month of headache with migraine features for at least three months or more, says Spears. “There is a risk of progressing from episodic migraine to chronic migraine that’s in a range of 1.5 percent to 3 percent per year,” he says.

A review published in March 2019 in the journal Headache analyzed 17 studies that looked at risk factors for developing chronic migraine, says Spears. These factors had the strongest evidence for progressing from episodic migraine to chronic migraine:

• Acute medication overuse
• Depression
• Increasing headache day frequency

Increasing headache and acute medication overuse can go together, says Spears. “For example, if you have someone who has two headaches a month, and they notice that increases to more like one headache a week, then two headaches a week, and then they start to treat those headaches with acute medication, which leads to more headache,” he says.

This can turn into a vicious cycle of increased headache days leading to increased treatment days, says Spears. “As you treat more, your risk of progressing to chronic migraine goes up.”

Risk factors that a person doesn’t really have control over are known as nonmodifiable risk factors. For migraine, those would include age, sex, and head injury.

Other risk factors that you can control are known as modifiable risk factors. Spears suggests the following lifestyle modifications to reduce the risk of migraine attack:

• Lose excess weight or prevent the development of obesity. According to the American Migraine Foundation, obesity is associated with episodic migraine progressing to chronic migraine.
• Limit caffeine intake.
• Monitor headache frequency and use of acute medication.

“The thinking is that if you go past two [migraine] days a week, you really need to seek medical care for your headache to get it investigated and potentially get onto a treatment plan to keep the frequency down,” says Spears.

Keeping track of your daily habits — such as when and what you eat or drink, when you sleep, and how much physical activity you get — can also sometimes help identify triggers for migraine so that you can avoid them in the future, according to MedlinePlus. Managing stress and establishing a consistent sleep schedule may also be helpful.