J-Shaped Curves and Public Health.

Interventions that alter population-level risk exposure haveyieldedanumberof improvements inpublichealth. Tobaccotaxesareanexampleofsuchpopulation-basedapproachestodiseaseprevention. Inthecaseoftobacco,the harmsofshiftingtotalpopulationexposurethroughtaxationareminimal,becausethereisnosafelevelofconsumption. However, other risk factors do not exhibit the same linear relationshipbetweenexposureandmortality—and thereforemayintroducenewcomplexitiesincommunicatingwith individualsandthepublic. Inparticular,manyrisk factors, such as alcohol consumption, exhibit a J-shaped associationwhenplottinghealth effects likemortality on the vertical axis against the magnitude of the risk factor on thehorizontal axis (Figure). Settingasidepopulationrisk,anyclinicianwhohastried tocounselapatientaboutalcoholusehasencounteredthe question: “But I thoughta coupleofdrinksanight is good for my health?” In this way, the strategies of preventive medicine—bothindividualandpopulationbased—thathave provenquitesuccessful fortobaccocontrolmaybelesseffectivewhen confronting the epidemiologic andperceptional challengespresentedby the J-shapedcurve.