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 source doi:10.1007/s11606-010-1609-1 PMID 21203857

Edges that cite this paper

The archetypal smoke. Control for education, parental SES, and baseline income and the supplement→career effect goes to zero.
Fish-oil buyers are not a random sample of the labor force.
Money buys bottles. Reverse causation is the whole trick of the wellness-to-wealth genre.

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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 2026-08-31).

https://whatcauseswhat.org/papers/p-shrank-2011