Familial risk of migraine: Variation by proband age at onset and headache severity

Background: It is well established that migraine aggregates within families. Less is known about the influence of proband characteristics (e.g., age at onset, headache severity) on familial aggregation. Objective: To examine the association between the proband's migraine severity and age at migraine onset and familial aggregation of migraine. Methods: The authors investigated the migraine prevalence in first-degree relatives of 532 persons with migraine and control subjects in a population study. Familial aggregation was expressed as the risk of migraine in family members of probands divided by risk in control family members. Results: The relative risk (RR) of migraine in first-degree relatives of migraine probands was elevated compared with family members of controls (RR = 1.88; 95% CI: 1.30 to 2.72). The RR was also significantly higher for relatives of probands reporting onset of migraine before age 16 (2.50; 95% CI: 1.65 to 3.79) compared with those with onset at age 16 or older (1.44; 95% CI: 0.93 to 2.23). Among probands with very severe average pain scores (i.e., 9 to 10 on a 0 to 10 scale), the RR of migraine in family members was 2.38 (95% CI: 1.56 to 3.62) compared with 1.52 (0.99 to 2.34) for less severe pain (p < 0.05). Conclusion: Early onset of migraine in the proband as well as the severity of migraines are associated with higher levels of family aggregation.