求!帮我大致翻译一下这篇文章吧~~（英译中—）Anewstudyhasfoundnoevidencethatsunscreen,commonlyusedtoreducetheriskofskincancer,actuallyincreasetherisk.ResearchersfromtheUniversityofIowabasedtheirfindings

　　求!帮我大致翻译一下这篇文章吧~~（英译中—）

　　Anewstudyhasfoundnoevidencethatsunscreen,commonlyusedtoreducetheriskofskincancer,actuallyincreasetherisk.

　　ResearchersfromtheUniversityofIowabasedtheirfindingsonareviewof18earlierstudiesthatlookedattheassociationbetweensunscreenuseandmelanoma(黑素瘤).Theysaidthattheyfoundflawsinstudiesthathadreportedassociationsbetweensunscreenuseandhigherriskofmelanoma.

　　Mosthealthexpertsbelievethatbyprotectingtheskinfromtheharmfuleffectsofthesun,sunscreenhelpspreventskincancer,whichisincreasinginincidence(发生率)fasterthananyothercancerintheUnitedStates.

　　Butquestionshasbeenraisedaboutsunscreenandwhetheritmayhasoppositeeffect,perhapsbyallowingpeopletoremainexposedtothesunlongerwithoutburning.

　　Theresearcherssaidthatamongtheproblemswithsomeearlierstudiesisthattheyoftenfailedtotakeintoaccountthatthosepeoplemostatriskforskincancer---peoplewithfairskinandfreckles(雀斑),forexample---aremorelikelytousesunscreen.Asaresult,itmayappearthatsunscreenusersgetcancermoreoften.

　　Thestudies,whichgenerallyreliedonvolunteerstorecalltheirsunscreenuse,werealsounabletoprovehowwelltheproductshadbeenapplied,saidthenewstudy.