title: Commentary: observation versus intervention--what's different?
authors.affiliation: Division of Epidemiology, Department of Family and Preventive Medicine, University of California, San Diego, La Jolla, CA 92093-0607, USA. ebarrettconnor@ucsd.edu
authors.forename: Elizabeth
authors.initials: E
authors.lastname: Barrett-Connor
mesh_terms: D000367:Age Factors; D003327:Coronary Disease / Q000453:epidemiology* / Q000517:prevention & control; D015340:Epidemiologic Research Design; D015914:Estrogen Replacement Therapy / Q000009:adverse effects; D004967:Estrogens / Q000502:physiology*; D005260:Female; D006304:Health Status; D006801:Humans; D008297:Male; D011372:Progestins / Q000008:administration & dosage; D016032:Randomized Controlled Trials as Topic; D012307:Risk Factors; D012737:Sex Factors
chemical_list: D004967:Estrogens; D011372:Progestins