Risk Factors

About 30 million Americans suffer from migraine headaches. They affect about 17% of all women and 6% of men. In fact, 70% of all migraine sufferers are women. Migraine is more prevalent among women throughout the world and in every culture. Although the incidence of migraine is similar for boys and girls during childhood, it increases in girls after puberty. Most people with migraine have 1 - 4 attacks per month.

Hormone Fluctuations in Women. Most migraines in women develop during the hormonally active years between adolescence and menopause. Fluctuations of estrogen and progesterone, rather than their presence, appear to increase the risk for migraines and their severity in some women.

• About half of women with migraines report headaches associated with their menstrual cycle, although true menstrual migraines may actually be less common. True menstrual migraines tend not to have auras and to increase in prevalence between 2 days before and 5 days after the onset of period.
• The first 3 months of pregnancy can worsen migraines in some women, although one study reported that pregnancy had little effect one way or the other on severity in most women with chronic headaches.
• Women whose migraines are affected by pregnancy or menstruation are also likely to have worse migraines if they take oral contraceptives or hormone replacement therapies.

Age

General Age of Onset. More than 20% of adults with migraines report that their headaches started before age 10, and over 45% say they started before age 20. The incidence of migraine declines in both men and women after age 40.

Migraine in Children. Migraine headaches occur in all ages and can appear in children as young as 4 years of age. Migraines in children are equally prevalent in boys and girls. Studies estimate that about 4 – 10% of all children suffer from migraine. Research indicates that overweight children may be especially susceptible to headaches, although this association is most likely due to poor nutrition and lack of exercise rather than excess weight. Children who have sleep problems, especially difficulty falling asleep, may also be more prone to migraines.

A small 2006 study indicated that some adolescents with migraine may eventually grow out of their condition. By the end of the 10-year study, 38% of patients had stopped having migraines, and 20% had transitioned into less severe tension-type headache. Children with a family history of migraine were more likely to continue having migraines.

Migraine Onset in Older Adults. Although uncommon, late-life migraine occurs in about 1% of the population, usually in men. In such cases, it often occurs as migraine with visual disturbances but without headache.

Family History

Migraine headaches can be inherited. If both parents suffer from migraines, their children have a 75% chance of getting them. When only one parent gets migraines, there is a 50% chance that children will be afflicted.

Ethnic Differences

Caucasians have a higher risk than either African-Americans or Asians. Worldwide, one study reported that migraines are most common in North America. They are slightly less prevalent in South America and Europe and far less common in Asia and Africa. Investigators believe that the differences are due to genetic variations, not lifestyle factors.

Other Medical Conditions Associated with Migraines

• Asthma and allergies. These conditions have also been associated with a higher risk for conversion from having periodic migraines attacks to a chronic form (transformed migraines).
• H. pylori infection. People who are infected with the bacteria H. pylori, the major cause of peptic ulcers, are at higher risk for migraines.
• Epilepsy. Patients with epilepsy are twice as likely to have migraines as the general population.
• Fibromyalgia
• Systemic lupus erythematosus
• Raynaud syndrome
• Mitral valve prolapse
• Narcolepsy

Personality Traits

One study suggested that women with migraines tend to over-respond to stressful situations. In the study, they were more likely than other women to be diligent, conscientious, and overly sensitive to pressure from others. More likely, however, a person's family history of migraine, rather than any personality trait, is the important risk factor.

Review Date: 12/21/2006
Reviewed By: Harvey Simon, MD, Associate Professor of Medicine, Harvard Medical School; Physician, Massachusetts General Hospital.

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