title: Re: Should observational studies be a thing of the past?
authors.forename: Noel S
authors.initials: NS
authors.lastname: Weiss
mesh_terms: D001943:Breast Neoplasms / Q000139:chemically induced* / Q000401:mortality*; D015914:Estrogen Replacement Therapy / Q000009:adverse effects* / Q000379:methods; D005260:Female; D006801:Humans; D019370:Observation; D016032:Randomized Controlled Trials as Topic; D012107:Research Design; D012307:Risk Factors; D013548:Sweden / Q000453:epidemiology