Prospective StudiesCohort StudiesRisk FactorsFollow-Up StudiesIncidenceProportional Hazards ModelsQuestionnairesTreatment OutcomeRisk AssessmentTime FactorsMultivariate AnalysisPregnancyMulticenter Studies as TopicLongitudinal StudiesAge FactorsLogistic ModelsNetherlandsInfant, NewbornRiskPrognosisUnited StatesEpidemiologic MethodsRetrospective StudiesPredictive Value of TestsOdds RatioSmokingPrevalenceDenmarkSeverity of Illness IndexBody Mass IndexConfidence IntervalsSex Factors