Fig. 1From: A study to investigate the prevalence of headache disorders and migraine among people registered in a health insurance association in JapanDescription of the study population. *1 Insured: Insured persons and their dependents. *2 Persons in the population that have registered information and claims information if they have visited medical institution. *3 Survey responses, claims information, and registration information can be merged with registered ID. *4 Among 21,704 survey respondents, 21,480 people were included in the analysis population. A total of 224 respondents were excluded from the analysis population as their age and gender did not match the claims dataBack to article page