2021
Estimating the natural indirect effect and the mediation proportion via the product method
Cheng C, Spiegelman D, Li F. Estimating the natural indirect effect and the mediation proportion via the product method. BMC Medical Research Methodology 2021, 21: 253. PMID: 34800985, PMCID: PMC8606099, DOI: 10.1186/s12874-021-01425-4.Peer-Reviewed Original ResearchConceptsInterval estimatorsApproximate estimatorExact estimatorMultivariate delta methodFinite sample performanceProduct methodNon-negligible biasBinary outcomesRare outcome assumptionExact expressionDelta methodVariance estimationEmpirical performanceEstimatorCommon data typesBootstrap approachBinary mediatorNatural indirect effectSample sizeswdpwr: A SAS macro and an R package for power calculations in stepped wedge cluster randomized trials
Chen J, Zhou X, Li F, Spiegelman D. swdpwr: A SAS macro and an R package for power calculations in stepped wedge cluster randomized trials. Computer Methods And Programs In Biomedicine 2021, 213: 106522. PMID: 34818620, PMCID: PMC8665077, DOI: 10.1016/j.cmpb.2021.106522.Peer-Reviewed Original ResearchConceptsWedge clusterIntracluster correlation coefficientContinuous outcomesCross-sectional cohortBinary outcomesExchangeable correlation structureWedge designPublic health intervention evaluationsHealth services researchClosed cohort designPower calculationCohort designClosed cohortStudy designIntracluster correlationIntervention evaluationNeeds of investigatorsOutcomesTrialsCohortServices researchInvestigatorsPrevious studiesSWD
2009
Power and sample size calculations for longitudinal studies comparing rates of change with a time‐varying exposure
Basagaña X, Spiegelman D. Power and sample size calculations for longitudinal studies comparing rates of change with a time‐varying exposure. Statistics In Medicine 2009, 29: 181-192. PMID: 19899065, PMCID: PMC3772653, DOI: 10.1002/sim.3772.Peer-Reviewed Original Research
2003
Fruits, vegetables and lung cancer: A pooled analysis of cohort studies
Smith‐Warner S, Spiegelman D, Yaun S, Albanes D, Beeson WL, van den Brandt PA, Feskanich D, Folsom AR, Fraser GE, Freudenheim JL, Giovannucci E, Goldbohm RA, Graham S, Kushi LH, Miller AB, Pietinen P, Rohan TE, Speizer FE, Willett WC, Hunter DJ. Fruits, vegetables and lung cancer: A pooled analysis of cohort studies. International Journal Of Cancer 2003, 107: 1001-1011. PMID: 14601062, DOI: 10.1002/ijc.11490.Peer-Reviewed Original ResearchConceptsLung cancer riskCancer riskVegetable consumptionLung cancerRelative riskLung cancer risk factorsStudy-specific relative risksIncident lung cancer casesTotal fruitCancer risk factorsLung cancer incidenceLung cancer casesTotal vegetable consumptionRandom-effects modelCohort studyCurrent smokersSmoking habitsProspective studyQuintiles 2Pooled analysisLowest quintileResidual confoundingInverse associationRisk factorsCancer incidence
1999
Rationale and Design of the Tanzania Vitamin and HIV Infection Trial
Fawzi W, Msamanga G, Spiegelman D, Urassa E, Hunter D. Rationale and Design of the Tanzania Vitamin and HIV Infection Trial. Contemporary Clinical Trials 1999, 20: 75-90. PMID: 10027501, DOI: 10.1016/s0197-2456(98)00045-2.Peer-Reviewed Original ResearchConceptsHIV infectionVitamin APregnant womenPolymerase chain reactionVitamin supplementsHIV-positive pregnant womenVertical transmissionHIV Infection TrialInfant immune functionEligible pregnant womenPlacebo-controlled trialClinical staging systemHIV-positive womenGenital tract secretionsUse of supplementsHIV diseaseMost HIVPrevention trialsViral loadMain endpointBreast milkStaging systemCohort retentionPosttest counselingTract secretions
1997
Power and Sample Size Calculations for Case-Control Studies of Gene-Environment Interactions with a Polytomous Exposure Variable
Foppa I, Spiegelman D. Power and Sample Size Calculations for Case-Control Studies of Gene-Environment Interactions with a Polytomous Exposure Variable. American Journal Of Epidemiology 1997, 146: 596-604. PMID: 9326439, DOI: 10.1093/oxfordjournals.aje.a009320.Peer-Reviewed Original Research