title: Medical problems concerning the control group.
mesh_terms: D000368:Aged; D001145:Arrhythmias, Cardiac / Q000175:diagnosis; D002986:Clinical Trials as Topic; D005260:Female; D005500:Follow-Up Studies; D005860:Germany, West; D006801:Humans; D008297:Male; D008875:Middle Aged; D009369:Neoplasms / Q000175:diagnosis; D010001:Osteitis Deformans / Q000175:diagnosis; D010361:Patients; D010820:Physicians; D012107:Research Design; D013223:Statistics as Topic; D013911:Thorium Dioxide / Q000009:adverse effects*
chemical_list: D013911:Thorium Dioxide