Review · 2011
Healthy user and related biases in observational studies of preventive interventions: a primer for physicians
W. H. Shrank, A. R. Patrick, M. A. Brookhart. Journal of General Internal Medicine.
The primer on Healthy User Bias: people who take preventive pills are different in a hundred ways that look like treatment effects. The right citation for 'supplement users have better jobs'.
Open sourcedoi:10.1007/s11606-010-1609-1PMID 21203857
Edges that cite this paper
- Money buys bottles. Reverse causation is the whole trick of the wellness-to-wealth genre.
- Fish-oil buyers are not a random sample of the labor force.
- People who buy vitamins look more employed because they already differ in ways that keep jobs, not because the pill caused the job. Shrank (2011) named that healthy-user bias. Simpson (2006) measured the same selection as death, not employment: in 21 studies and 46,847 people, good adherence, including to placebo, had an odds ratio of 0.56 for mortality.
Cite this page
What Causes What. “Healthy user and related biases in observational studies of preventive interventions: a primer for physicians.” https://whatcauseswhat.org/papers/p-shrank-2011 (atlas updated 2026-09-02).