title: Understanding mechanisms: opening the "black box" in observational studies.
authors: Petter
authors: P
authors: Kristensen
authors: Odd O
authors: OO
authors: Aalen
mesh_terms: D005260:Female; D006304:Health Status; D006801:Humans; D008297:Male; D012179:Retirement / Q000706:statistics & numerical data*; D062707:Return to Work / Q000706:statistics & numerical data*; D014478:Unemployment / Q000706:statistics & numerical data*