An epidemiologic study of headaches in Brazilian schoolchildren with a focus on pain frequency.

The purpose of this study was to assess the prevalence and frequency of the headaches in Brazilian schoolchildren. A cross-sectional study was conducted between March and November 2004 in São José do Rio Preto, São Paulo State, Brazil. A sample of 5,232 children from elementary schools was selected using proportional stratified sampling method. To collect data, a questionnaire was handed out in the schools to the schoolchildren to be answered by parents or guardians. From the total answers received, 84.2% reported headache complaints during the last year. There were significant complaint differences between males and females. Females were reported as having more frequent headaches than males with daily ones occurring twice as many times. A greater headache frequency was also reported for increasing age. The study has shown that headache prevalence was high, with a predominantly higher frequency (monthly, weekly and daily) with girls and older age groups.