参阅：
美国疾病控制和预防中心：美国40％癌症病例与超重肥胖有关
肥胖是如何促进乳腺癌生长及其转移的？（obesityandbreastcancer）
历时18年对22万人的研究表明，成人超重，患癌的风险增加
至少40%的癌症可以通过改变生活方式来预防
-*-*-*-*-*-
视频
-*-*-*-*-*-
视频中文字
ObesityandCancer
Theprevalenceofoverweight(bodymassindexof25to30kg/2)andobesity(bodymassindex≥30kg/m2)inmostdevelopedcountries(andinurbanareasofmanylessdevelopedcountries)hasincreasedmarkedlyduringthepast2decades.
IntheUnitedStates,morethanonethirdofthepopulationisnowclassifiedasobese.Althoughobesityhaslongbeenrecognizedasanimportantcauseofdiabetesandcardiovasculardisease,therelationshipbetweenobesityandcancerhasreceivedlessattention.
Epidemiologicstudiesindicatethatadipositycontributestotheincreasedincidenceofanddeathfromcancersofthecolon,breast(inpostmenopausalwomen),endometrium,kidney(renalcell),esophagus(adenocarcinoma),gastriccardia,pancreas,gallbladder,andliver(hepatocellularcarcinoma).
Ithasbeenestimatedthat15%to20%ofallcancerdeathsintheUnitedStatescanbeattributedtooverweightandobesity.Themechanismsbywhichobesityincreasescancerriskappeartoinvolvethemetabolicandendocrineeffectsofobesitythroughtheiralterationsinlevelsofpeptideandsteroidhormones.
Forexample,greateramountsofadiposetissueleadtoincreasedcirculatinglevelsoffreefattyacids.Thisinturncausesliver,muscle,andothertissuestoincreasetheiruseoffatsforenergyproduction,therebyreducingtheirneedforuptakeandmetabolismofglucoseandeventuallyleadingtohyperglycemia.
Thisfunctionalinsulinresistanceforcesanincreaseinpancreaticinsulinsecretion.Epidemiologicandexperimentalevidencesuggeststhatchronichyperinsulinemiaincreasestheriskofcancersofthecolonandendometriumandprobablyothertumors(e.g.,thoseofthepancreasandkidney).
Circulatinglevelsofestrogensarestronglyrelatedtoadiposity.Forcancersofthebreast(inpostmenopausalwomen)andendometrium,theeffectsofoverweightandobesityoncancerriskarelargelymediatedbyincreasedestrogenlevels.
Forpatientswithbreastcancer,adiposityhasbeenassociatedwithbothpoorersurvivalandincreasedlikelihoodofrecurrence,aneffectthatpersistedafteradjustmentfortumorstageandgrade,hormonereceptorstatus,andadjuvanttherapy.
-*-*-*-*-*-
参考译文：
肥胖与癌症
在过去20年中，大多数发达国家（以及许多欠发达国家的城市地区）的超重（体重指数为25至30公斤/平方米）和肥胖（体重指数≥30公斤/平方米）的患病率显著增加。
在美国，超过三分之一的人口现在被归类为肥胖。虽然肥胖一直被认为是糖尿病和心血管疾病的重要病因，但肥胖与癌症的关系却很少受到
