School as a risk factor.
Ockel
Edith
E
D000293:Adolescent; D002648:Child; D005260:Female; D005858:Germany / Q000453:epidemiology; D006261:Headache / Q000175:diagnosis* / Q000453:epidemiology* / Q000523:psychology; D006801:Humans; D007899:Leisure Activities; D008297:Male; D010287:Parent-Child Relations; D015995:Prevalence; D018570:Risk Assessment; D012307:Risk Factors; D017678:Sex Distribution