title: Tibolone and breast cancer risk: effects of selection bias cannot be eliminated in observational studies.
authors.forename: A
authors.initials: A
authors.lastname: Coomarasamy
mesh_terms: D001943:Breast Neoplasms / Q000139:chemically induced*; D015331:Cohort Studies; D020847:Estrogen Receptor Modulators / Q000009:adverse effects*; D005260:Female; D006801:Humans; D009652:Norpregnenes / Q000009:adverse effects*; D012307:Risk Factors; D015983:Selection Bias
chemical_list: D020847:Estrogen Receptor Modulators; D009652:Norpregnenes; C027385:tibolone