Background.— Migraine aggregates within families. Nonetheless the familial aggregation of chronic daily headaches (CDH) and of episodic headaches of different frequencies has been very poorly studied. Accordingly herein we test the hypothesis that frequency of primary headaches aggregates in the family.
Methods.— Sample consisted of 1994 children (5-12 years) identified in the population. Validated questionnaires were used to interview the parents. Crude and adjusted prevalences of low-frequency (1-4 headache days/month), intermediate-frequency (5-9 days/month), high-frequency (10-14 headache days/month), and CDH (15 or more headache days/month) in children were calculated as a function of headaches in the mother.
Results.— Frequency of headaches in the mother predicted frequency of headaches in the children; when the mother had low frequency headaches, the children had an increased chance to have low or intermediate headache frequency (relative risk = 1.4, 1.2-1.6) but not CDH. When the mother had CDH, risk of CDH in the children was increased by almost 13-fold, but the risk of infrequent headaches was not increased. In multivariate models, headaches in the children were independently predicted by headaches in the mother (P < .001); headache frequency in the children was also predicted by frequency in the mother (P < .001).
Conclusions.— Frequency of headaches in children is influenced by frequency of headaches in the mother and seems to aggregate in families. Future studies should focus on the determinants of headache aggregation, including genetic and non-genetic factors.