title: Hospital or population controls: a discussion.
mesh_terms: D000328:Adult; D004812:Epidemiologic Methods; D005260:Female; D006202:Hair Dyes; D006203:Hair Preparations; D006760:Hospitalization; D006801:Humans; D008875:Middle Aged; D009864:Ontario
chemical_list: D006202:Hair Dyes; D006203:Hair Preparations