In a large new US study, migraine headaches were found to be
more likely to happen to people with lower household incomes, but tended to go
into remission at the same rate for people at all income levels.
It was already well
know that migraines were associated with lower income, said the new study's
lead author Walter Stewart of Sutter Health in Concord, California. His first
research suggesting the idea was published in 1992.
Since most people who get migraines eventually go into
remission, he said, researchers wondered if remission was more common for
people with higher incomes, which would have explained the connection between
headaches and lower earnings.
Stewart and co-authors used data from 162 700 people with
occasional, not chronic, migraines who were interviewed about their symptoms,
including how old they were when the headaches began and the date of their most
For both men and women, migraines became more common as
income decreased. And when participants were grouped by age, more women and men
with migraines had household incomes under $60 000.
For instance, among
women ages 25 to 34, 37% had household incomes under $22,500, while 29% fell
between $22,500 and $59,999 and 20% had household income greater than $60,000. Previously,
some had theorised that migraines cause people to function poorly at work and
in life, gradually driving the headache sufferers from a higher to a lower
income bracket, which is known as the "social selection" hypothesis
explaining the income link.
Based on the current results, that is not a meaningful
explanation, Stewart said. He thinks social causation, in which stress or other
factors related to lower income make someone more prone to migraines, is much
more likely, he told Reuters Health.
"It has been hypothesized that a low socio-economic
status is associated with more stressful life events (such as trauma, poor
healthcare, i.e. financial stress)," Dr Barbara Lee Peterlin, director of
headache research at Johns Hopkins Medicine in Baltimore, told Reuters by email.
"Stress has long been described as a trigger for migraine," both
happy stresses, like marriage, and unhappy stresses, like combat, rape or car
accidents, said Peterlin, who co-authored a commentary published with the new
study in the journal Neurology.
The new results do the most so far to support the idea that
low income or something closely related to low income, causes migraines,
according to Peterlin, but she believes migraines are "simply not
simple", and that environment and genetics probably both play a role.
Stewart's group did not account for several factors that
could influence the onset or remission of migraines, ranging from alcohol and
tobacco use to access to healthcare.
According to 2009 survey data from the Centers for Disease
Control and Prevention, 10% of men and 23% of women reported having had a
migraine in the past three months. Women are three times as likely as men to
get migraines, which often begin to occur in the late teens and early
adulthood, Stewart said.
After sex and age, the most important predictor of migraines
is income, he said. Though Stewart believes his study nixed the theory that
migraines cause changes in income, another study published in the same issue of
the journal links the headaches, especially those accompanied by a so-called
aura, to long-term changes in brain structure.
The review by Dr Asma Bashir from the University of
Copenhagen in Denmark and her colleagues examined 19 previous studies and
determined that migraine sufferers were at increased risk for brain lesions,
structural abnormalities and brain volume changes over time.
Once again, the
researchers point out, more study is needed to determine what is cause and what
is effect, and whether the lesions seen in the brains of migraine sufferers
have any notable effects on brain function.