Association between family income to poverty ratio and severe headache/migraine in the American adults: data from NHANES 1999-2004.

Background: The relationship between family income to poverty ratio (PIR) and severe headache/migraine remains unclear.

Methods: Data for this cross-sectional study were obtained from NHANES 1999-2004. PIR was the exposure variable, and severe headache/migraine was the dependent variable.