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Simpson's Paradox and the Association Between Vitamin D Deficiency and Increased Heart Disease

  • William K. Chan
    Affiliations
    Department of Medicine, University of Toronto, Toronto, Ontario, Canada

    Institute for Clinical Evaluative Sciences in Ontario, Toronto, Ontario, Canada
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  • Donald A. Redelmeier
    Correspondence
    Corresponding author: Tel: 416-480-6999; fax: 416-480-6048
    Affiliations
    Department of Medicine, University of Toronto, Toronto, Ontario, Canada

    Institute for Clinical Evaluative Sciences in Ontario, Toronto, Ontario, Canada

    Clinical Epidemiology Program, Sunnybrook Health Sciences Centre, Toronto, Ontario, Canada

    Center for Leading Injury Prevention Practice Education & Research, Toronto, Ontario, Canada
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      Several recent investigations have highlighted a potential link between vitamin D deficiency and increased heart disease. Observational studies suggest cardioprotective benefits related to supplementation, but randomized trials remain to be conducted. This report adds a caution based on a statistical paradox that is rarely mentioned in formal medical training or in common medical journals. Insight into this phenomenon, termed Simpson's paradox, may prevent clinicians from drawing faulty conclusions about vitamin D deficiency and heart disease.
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      References

        • Lavie C.J.
        • Lee J.H.
        • Milani R.V.
        Vitamin D and cardiovascular disease will it live up to its hype?.
        J Am Coll Cardiol. 2011; 58: 1547-1556
        • Julious S.A.
        • Mullee M.A.
        Confounding and Simpson's paradox.
        BMJ. 1994; 309: 1480-1481
        • Simpson E.
        The interpretation of interaction in contingency tables.
        R Stat Soc Ser B (Methodol). 1951; 13: 238-241
        • Bickel P.J.
        • Hammel E.A.
        • O'Connell J.W.
        Sex bias in graduate admissions: data from Berkeley.
        Science. 1975; 187: 398-404
        • Morris M.C.
        • Tangney C.C.
        A potential design flaw of randomized trials of vitamin supplements.
        JAMA. 2011; 305: 1348-1349
        • Pavlides M.G.
        • Perlman M.D.
        How likely is Simpson's paradox?.
        Am Stat. 2009; 63: 226-233
        • Normand S.L.
        • Sykora K.
        • Li P.
        • Mamdani M.
        • Rochon P.A.
        • Anderson G.M.
        Readers guide to critical appraisal of cohort studies: 3.
        BMJ. 2005; 330: 1021-1023
        • Anderson J.L.
        • May H.T.
        • Horne B.D.
        • Bair T.L.
        • Hall N.L.
        • Carlquist J.F.
        Relation of vitamin D deficiency to cardiovascular risk factors, disease status, and incident events in a general healthcare population.
        Am J Cardiol. 2011; 106: 963-968
        • Lee J.H.
        • Gadi R.
        • Spertus J.A.
        • Tang F.
        • O'Keefe J.H.
        Prevalence of vitamin D deficiency in patients with acute myocardial infarction.
        Am J Cardiol. 2011; 107: 1636-1638
        • Reddy Vanga S.
        • Good M.
        • Howard P.A.
        • Vacek J.L.
        Role of vitamin D in cardiovascular health.
        Am J Cardiol. 2010; 106: 798-805
        • Vacek J.L.
        • Vanga S.R.
        • Good M.
        • Lai S.M.
        • Lakkireddy D.
        • Howard P.A.
        Vitamin D deficiency and supplementation and relation to cardiovascular health.
        Am J Cardiol. 2012; 109: 359-363
        • Cobb L.A.
        • Killip T.
        • Lambrew C.T.
        • MacLeod B.A.
        • Rackley C.E.
        • Selker H.P.
        Glucose-insulin-potassium infusion and mortality in the CREATE-ECLA trial.
        JAMA. 2005; 293: 2597
        • Bongartz T.
        • Sutton A.J.
        • Sweeting M.J.
        • Buchan I.
        • Matteson E.L.
        • Montori V.
        Anti-TNF antibody therapy in rheumatoid arthritis and the risk of serious infections and malignancies: systematic review and meta-analysis of rare harmful effects in randomized controlled trials.
        JAMA. 2006; 295: 2275-2285

      Linked Article

      • Mixing of Confounding and Non-Collapsibility: A Notable Deficiency of the Odds Ratio
        American Journal of CardiologyVol. 111Issue 2
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          We read with interest the report by Chan and Redelmeier1 about Simpson's paradox in medical studies. Using a hypothetical example, the investigators aimed to draw clinicians' attention to this paradox in medical research. We would like to remind readers that the discrepancy between a crude and a stratified odds ratio (OR) actually conflates 2 different components, namely, a confounding bias and a noncollapsibility effect.2
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