Chronic Headache and Comorbibities: A Two‐Phase,Population‐Based,Cross‐Sectional Study

Background.— Studies using resources of a public family health program to estimate the prevalence of chronic daily headaches (CDH) are lacking. Objectives.— To estimate the 1‐year prevalence of CDH, as well as the presence of associated psychiatric and temporomandibular disorders (TMD) comorbidities, on the entire population of a city representative of the rural area of Brazil. Methods.— This was a cross‐sectional, population‐based, 2‐phase study. In the first phase, health agents interviewed all individuals older than 10 years, in a rural area of Brazil. In the second stage, all individuals who reported headaches on 4 or more days per week were then evaluated by a multidisciplinary team. CDH were classified according to the second edition of the International Classification of Headache Disorders (ICHD‐2). Medication overuse headache was diagnosed, as per the ICHD‐2, after detoxification trials. Psychiatric comorbidities and TMD were diagnosed based on the DSM‐IV and on the Research Diagnostic Criteria for Temporomandibular Disorders criteria, respectively. Results.— A total of 1631 subjects participated in the direct interviews. Of them, 57 (3.6%) had CDH. Chronic migraine was the most common of the CDH (21, 36.8%). Chronic tension‐type headache (10, 17.5%), medication overuse headache (13, 22.8%) and probable medication overuse headache (10, 17.5%) were also common. Psychiatric disorders were observed in 38 (67.3%) of the CDH subjects. TMD were seen in 33 (58.1)% of them. Conclusions.— The prevalence of CDH in the rural area of Brazil is similar to what has been reported in previous studies. A significant proportion of them have psychiatric comorbidities and/or TMD. In this sample, comorbidities were as frequent as reported in convenience samples from tertiary headache centers. (Headache 2010;50:1306‐1312)