izindaba

Ubuthi bomthofu obungapheli buyingozi enkulu yesifo senhliziyo nemithambo yegazi kubantu abadala kanye nokukhubazeka kwengqondo ezinganeni, futhi kungabangela ukulimala ngisho nasemazingeni omthofu ayebhekwa njengephephile ngaphambili. Ngo-2019, ukuchayeka komthofu kwaba necala lokufa kwabantu abayizigidi ezi-5.5 emhlabeni jikelele kanye nokulahlekelwa okuphelele kwamaphoyinti e-IQ ayizigidi ezingama-765 ezinganeni unyaka ngamunye.
Ukuchayeka komthofu cishe kuyo yonke indawo, kuhlanganise nopende onomthofu, uphethiloli omthofu, amanye amapayipi amanzi, izitsha zobumba, izimonyo, amakha, kanye nokuncibilikisa, ukukhiqizwa kwamabhethri nezinye izimboni, ngakho-ke amasu asezingeni labantu abalulekile ukuze kuqedwe ubuthi bomthofu.

Ubuthi bomthofu yisifo sasendulo. UDioscorides, udokotela ongumGreki nesazi semithi eRoma lasendulo, wabhala uDe
I-Materia Medica, umsebenzi obaluleke kakhulu kwezemithi emashumini eminyaka edlule, yachaza izimpawu zobuthi bomthofu obuningi cishe eminyakeni eyizi-2 000 edlule. Abantu abanoshevu womthofu osobala babhekana nokukhathala, ikhanda elibuhlungu, ukucasuka, amajaqamba esiswini, nokuqunjelwa. Lapho ukugcwala komthofu wegazi kudlula ku-800 μg/L, ubuthi bomthofu obabazekayo bungabangela ukudlikizeka, i-encephalopathy, nokufa.
Ubuthi bomthofu obungapheli baqashelwa eminyakeni engaphezu kwekhulu edlule njengembangela ye-atherosclerosis kanye ne-gout “enobuthi bomthofu”. Ekuhlolweni kwesidumbu, iziguli ezingu-69 kwezingu-107 ezine-gout ebangelwa umthofu “zaziqina udonga lwemithambo yegazi ngenxa yezinguquko ze-atheromatous.” Ngo-1912, uWilliam Osler (uWilliam Osler)
Utshwala, ukuhola, kanye ne-gout kudlala indima ebalulekile ku-pathogenesis ye-arteriosclerosis, nakuba izindlela eziqondile zokwenza aziqondi kahle," kubhala u-Osler. Umugqa womthofu (idiphozithi eluhlaza okwesibhakabhaka ye-lead sulfide emaphethelweni ezinsini) iyisici soshevu womthofu ongapheli kubantu abadala.
Ngo-1924, i-New Jersey, i-Philadelphia kanye ne-New York City yavala ukuthengiswa kukaphethiloli onomthofu ngemuva kokuthi amaphesenti angama-80 abasebenzi abakhiqiza i-tetraethyl lead kwa-Standard Oil eNew Jersey kutholakale ukuthi banoshevu womthofu, abanye babo bashona. NgoMeyi 20, 1925, uHugh Cumming, udokotela ohlinzayo jikelele wase-United States, wabiza ososayensi nabamele imboni ukuze banqume ukuthi kuphephile yini ukwengeza umthofu we-tetraethyl kuphethiloli. U-Yandell Henderson, isazi sokusebenza komzimba nochwepheshe ezimpini zamakhemikhali, waxwayisa ngokuthi “ukwengezwa komthofu we-tetraethyl kuzodalula kancane kancane inani elikhulu labantu ebusheni bomthofu nokuqina kwemithambo yegazi”. URobert Kehoe, isikhulu sezokwelapha se-Ethyl Corporation, ukholelwa ukuthi izikhungo zikahulumeni akufanele zivimbe umthofu we-tetraethyl ezimotweni kuze kube yilapho sekutholakale ukuthi unobuthi. “Umbuzo awukona ukuthi umthofu uyingozi yini, kodwa ukuthi umthofu othile uyingozi yini,” kusho uKehoe.
Nakuba ukumba izimayini zomthofu sekuyiminyaka eyizi-6,000, ukucutshungulwa komthofu kwanda kakhulu ekhulwini lama-20. Umthofu uyinsimbi ethambile, eqinile esetshenziselwa ukuvimbela uphethiloli ekushiseni ngokushesha, ukunciphisa “ukushayisa kwenjini” ezimotweni, ukuthutha amanzi okuphuza, amathini okudla athengiswayo, ukwenza upende ukhanye umude futhi ubulale izinambuzane. Ngeshwa, umthofu omningi osetshenziselwa lezi zinhloso uphelela emizimbeni yabantu. Esiqongweni somqedazwe wobuthi bomthofu e-United States, amakhulu ezingane alaliswa esibhedlela ihlobo ngalinye ngenxa ye-leencephalopathy yomthofu, futhi ingxenye yesine yazo yafa.
Abantu okwamanje basengozini yokuhola emazingeni angaphezu kwamazinga angemuva emvelo. Ngawo-1960, isazi sokuma komhlaba uClair Patterson, owasebenzisa ama-isotopes omthofu ukuze alinganisele ubudala boMhlaba eminyakeni eyizigidi eziyizinkulungwane ezingu-4.5.
U-Patterson wathola ukuthi izimayini, ukuncibilikisa kanye nokukhishwa kwezimoto kubangele ukufakwa komthofu osemkhathini ngokuphindwe izikhathi eziyi-1,000 kunamazinga angemuva emvelo kumasampuli ayinhloko yeqhwa. UPatterson waphinde wathola ukuthi ukugcwala komthofu emathanjeni abantu emazweni anezimboni kwakuphakeme ngokuphindwe izikhathi eziyi-1 000 kunabantu ababephila ezikhathini zangaphambi kwezimboni.
Ukuchayeka komthofu kwehle ngaphezu kwama-95% kusukela ngeminyaka yawo-1970, kodwa isizukulwane samanje sisathwele umthofu ophindwe ka-10-100 ngaphezu kwabantu abaphila ezikhathini zangaphambi kwezimboni.
Ngaphandle kokumbalwa, okunjengokuhola kuphethiloli wendiza nezinhlamvu namabhethri aneasidi eholayo ezimotweni, umthofu awusasetshenziswa e-United States naseYurophu. Odokotela abaningi bakholelwa ukuthi inkinga kashevu womthofu isiyinto yesikhathi esidlule. Nokho, upende womthofu ezindlini ezindala, uphethiloli womthofu ofakwe enhlabathini, umthofu okhishwe emapayipini amanzi, nesisi esikhishwa ezimbonini zezimboni nasezishibhini konke kunomthelela ekuchayekeni komthofu. Emazweni amaningi, umthofu ukhishwa ekuncibilikisweni, ekukhiqizweni kwebhethri kanye ne-e-waste, futhi uvame ukutholakala kumapende, izitsha zobumba, izimonyo namaphunga. Ucwaningo luqinisekisa ukuthi ubuthi bomthofu obungapheli obusezingeni eliphansi buyingozi yesifo senhliziyo nemithambo yegazi kubantu abadala kanye nokukhubazeka kwengqondo ezinganeni, ngisho nasemazingeni ayebhekwa njengephephile noma angenabungozi. Lesi sihloko sizofingqa imiphumela yobuthi bomthofu obungapheli obusezingeni eliphansi

Ukuchayeka, ukumuncwa kanye nomthwalo wangaphakathi
Ukumunca ngomlomo kanye nokuhogela kuyizindlela eziyinhloko zokuchayeka komthofu. Izinsana ezikhula ngokushesha nokukhula zingamunca kalula umthofu, futhi ukuntuleka kwe-iron noma ukuntuleka kwe-calcium kungakhuthaza ukumuncwa komthofu. I-calcium elingisa umthofu, insimbi, ne-zinc ingena kuseli ngamashaneli e-calcium nezithuthi zensimbi njengesithuthi sensimbi se-divalent 1[DMT1]. Abantu abane-polymorphisms yofuzo ekhuthaza ukumuncwa kwe-iron noma i-calcium, njengalezo ezibangela i-hemochromatosis, baye bandisa ukumuncwa komthofu.
Uma usumuncwe, u-95% womthofu oyinsalela emzimbeni womuntu ugcinwa emathanjeni; U-70% wensalela yomthofu emzimbeni wengane ugcinwa emathanjeni. Cishe i-1% yawo wonke umthamo womthofu emzimbeni womuntu uzungeza egazini. U-99% womthofu osegazini usemangqamuzaneni abomvu egazi. Ukugxiliswa komthofu wegazi lonke (umthofu osanda kumunca kanye nomthofu okhishiwe ethanjeni) yi-biomarker esetshenziswa kakhulu yeleveli yokuchayeka. Izinto ezishintsha umzimba wethambo, njengokunqamuka kokuya esikhathini kanye ne-hyperthyroidism, zingakhulula umthofu oqoqwe emathanjeni, okubangele ukuthi amazinga omthofu wegazi anyuke.
Ngo-1975, lapho umthofu wawusangezwa kuphethiloli, uPat Barry wenza ucwaningo lwe-autopsy kubantu baseBrithani abangu-129 futhi wabala umthamo wabo ophelele womthofu. Isamba esimaphakathi somthwalo emzimbeni wendoda singu-165 mg, okulingana nesisindo sesiqeshana sephepha. Umthwalo womzimba wamadoda anoshevu womthofu wawungu-566 mg, okuwumthwalo ophindwe kathathu kuphela kunomthwalo ojwayelekile wesampula yonke yabesilisa. Uma kuqhathaniswa, isilinganiso esiphelele somthwalo emzimbeni wesifazane singu-104 mg. Kokubili abesilisa nabesifazane, ukugcwala okuphezulu komthofu ezicutshini ezithambile kwakuse-aorta, kanti kwabesilisa ukugxila kwakuphakeme kuma-atherosclerotic plaque.
Ezinye izakhamuzi zisengozini enkulu yokuba noshevu womthofu uma kuqhathaniswa nenani labantu elivamile. Izinsana nezingane ezincane zisengozini enkulu yokungenisa umthofu ngenxa yokuziphatha kwazo komlomo okungawudli, futhi kungenzeka zimunce umthofu kunezingane ezindala nabantu abadala. Izingane ezincane ezihlala ezindlini ezinganakekelwa kahle ezakhiwa ngaphambi kuka-1960 zisengozini yokungenwa ushevu womthofu ngokudla izicucu zikapende nothuli lwasendlini olunomthofu. Abantu abaphuza amanzi kampompi aphuma emapayipini anomthofu noma abahlala eduze kwezindiza noma ezinye izindawo ezinomthofu basengozini enkulu yokuba noshevu wezinga eliphansi lomthofu. E-United States, ukugxila komthofu emoyeni kuphezulu kakhulu emiphakathini ehlukene kunemiphakathi ehlanganisiwe. Izisebenzi ezimbonini ezincibilikisayo, ezigaya kabusha amabhethri kanye nezokwakha, kanye nalabo abasebenzisa izibhamu noma abanezicucu zezinhlamvu emizimbeni yabo, nabo basengozini enkulu yokungenwa ushevu womthofu.
Umthofu uyikhemikhali yokuqala enobuthi elinganiswe ku-National Health and Nutrition Examination Survey (NHANES). Ekuqaleni kwesigaba sokuphuma kukaphethiloli onomthofu, izinga lomthofu egazini lehla lisuka ku-150 μg/L ngo-1976 laya ku-90 ngo-1980.
μg/L, inombolo engokomfanekiso. Amaleveli omthofu wegazi athathwa njengabangase abe yingozi ehliswe izikhathi ezimbalwa. Ngo-2012, i-Centers for Disease Control and Prevention (CDC) yamemezela ukuthi izinga eliphephile lomthofu egazini lezingane alikanqunywa. I-CDC yehlise izinga lamazinga omthofu wegazi ngokweqile ezinganeni - ngokuvamile okusetshenziselwa ukukhombisa ukuthi kufanele kuthathwe isinyathelo ukuze kuncishiswe ukuchayeka komthofu - ukusuka ku-100 μg/L kuya ku-50 μg/L ngo-2012, futhi kuya ku-35 μg/L ngo-2021. Ukwehliswa kwezinga lokuhola kwegazi ngokweqile kwaba nomthelela esinqumweni sethu sokuthi leli phepha lizosebenzisa amaleveli omthofu amaningi esikhundleni seyunithi yegazi. kusetshenziswe i-μg/dL, ebonisa ubufakazi obuningi bobuthi bomthofu emazingeni aphansi.

Ukufa, ukugula nokukhubazeka
UPaul Mushak no-Annemarie F. Crocetti, bobabili bengamalungu eNational Board of Air Quality eqokwe uMongameli Jimmy Carter, embikweni weCongress ngo-1988, bathi: “Ikhono lokulinganisa amazinga omthofu egazini, emazinyweni nasemathanjeni lembula uchungechunge lwezinkinga zezokwelapha ezihlobene nobuthi obunganqamuki obusezingeni eliphansi emazingeni avame ukutholakala emzimbeni womuntu. Amazinga aphansi kashevu womthofu ayisici esiyingozi sokuzalwa ngaphambi kwesikhathi, kanye nokukhubazeka kwengqondo kanye ne-attention deficit hyperactivity disorder (ADHD), ukwanda komfutho wegazi kanye nokuncipha kokuhlukahluka kwesilinganiso senhliziyo ezinganeni. Kubantu abadala, amazinga aphansi kashevu womthofu ayisici esiyingozi sokwehluleka kwezinso okungapheli, umfutho wegazi ophakeme kanye nesifo senhliziyo nemithambo yegazi

Ukukhula kanye neurodevelopment
Emazingeni omthofu ovame ukutholakala kwabesifazane abakhulelwe, ukuchayeka komthofu kuyisici esiyingozi sokuzalwa ngaphambi kwesikhathi. Kuqembu elizoba yiqembu lokuzalwa laseCanada, ukwenyuka okungu-10 μg/L kumazinga okuhola egazini likamama kwahlotshaniswa nengozi eyandayo engama-70% yokuzalwa okuzenzakalelayo ngaphambi kwesikhathi. Kwabesifazane abakhulelwe abanamazinga e-serum kavithamini D angaphansi kuka-50 mmol/L namazinga okuhola egazini akhuphuka ngo-10 μg/L, ingozi yokuzalwa okuzenzakalelayo ngaphambi kwesikhathi yanda yafinyelela izikhathi ezintathu.
Ocwaningweni lwangaphambili oluyingqopha-mlando lwezingane ezinezimpawu zomtholampilo zobuthi bomthofu, u-Needleman et al. ithole ukuthi izingane ezinamazinga aphezulu omthofu maningi amathuba okuba zithole ukushoda kwe-neuropsychological kunezingane ezinamazinga aphansi omthofu, Futhi zazingase zithathwe njengezimpofu ngothisha ezindaweni ezifana nokuphazamiseka, amakhono enhlangano, ukuthatheka kanye nezinye izici zokuziphatha. Eminyakeni eyishumi kamuva, izingane eziseqenjini elinamazinga aphezulu omthofu we-dentin zazinethuba eliphindwe izikhathi ezingu-5.8 lokuba ne-dyslexia kanye namathuba angu-7.4 okuyeka isikole kunezingane eziseqenjini elinamazinga omthofu aphansi.
Isilinganiso sokwehla kwengqondo ekwenyukeni kwamazinga omthofu sasisikhulu ezinganeni ezinamaleveli omthofu aphansi. Ekuhlaziyweni okuhlanganisiwe kwamaqembu ayisikhombisa azoba khona, ukwanda kwamazinga omthofu wegazi ukusuka ku-10 μg/L kuya ku-300 μg/L kwakuhlotshaniswa nokwehla ngamaphuzu angu-9 ku-IQ yezingane, kodwa ukwehla okukhulu kakhulu (ukwehla ngamaphuzu angu-6) kwenzeka lapho amazinga okuhola egazini eqala ukwanda ngo-100 μg/L. Amajika okuphendula umthamo ayefana nokuncipha kwengqondo okuhlotshaniswa namazinga okuhola alinganisiwe ethanjeni naseplasma.

Ukuchayeka komthofu kuyisici esiyingozi sezinkinga zokuziphatha ezifana ne-ADHD. Ocwaningweni olumele izwe lonke lwase-US lwezingane ezineminyaka engu-8 kuya kwengu-15, izingane ezinamazinga omthofu wegazi angaphezu kuka-13 μg/L zazinethuba eliphindwe kabili lokuba ne-ADHD kunalezo ezinamazinga omthofu wegazi ku-quintile ephansi kakhulu. Kulezi zingane, cishe isigameko esi-1 kwezi-5 ze-ADHD singabalelwa ukuchayeka komthofu.

Ukuchayeka komthofu wezingane kuyisici esiyingozi sokuziphatha okungahambisani nomphakathi, okuhlanganisa nokuziphatha okuhlotshaniswa nokuphazamiseka kokuziphatha, ubuhlongandlebe, nokuziphatha kobugebengu. Ekuhlaziyweni kwemeta yezifundo eziyi-16, amazinga aphezulu okuhola egazini ayelokhu ehlotshaniswa nokuphazamiseka kokuziphatha ezinganeni. Ezifundweni ezimbili ezingase zibe yiqembu, amazinga aphezulu okuhola igazi noma i-dentin ebuntwaneni aye ahlotshaniswa namazinga aphezulu obuhlongandlebe kanye nokuboshwa lapho esekhulile.
Ukuchayeka okuphakeme komthofu ebuntwaneni kwakuhlotshaniswa nokuncipha komthamo wobuchopho (okungenzeka ngenxa yokuncipha kosayizi we-neuron kanye ne-dendrite branching), kanye nokuncipha komthamo wobuchopho kwaqhubeka kwaze kwaba umuntu omdala. Ocwaningweni olubandakanya abantu abadala asebekhulile, amazinga aphezulu egazi noma amathambo ayehlotshaniswa nokwehla okushesha kwengqondo, ikakhulukazi kulabo ababephethe i-APOE4 allele. Ukuchayeka komthofu kwasebuntwaneni kungase kube isici esiyingozi sokuthola isifo i-Alzheimer's esiqala sekwephuzile, kodwa ubufakazi abucaci.

I-Nephropathy
Ukuchayeka komthofu kuyisici esiyingozi sokuthuthukisa isifo sezinso esingamahlalakhona. Imiphumela ye-nephrotoxic yomthofu ibonakala emizimbeni yokufakwa kwe-intranuclear yama-proximal renal tubules, i-tubule interstitial fibrosis kanye nokwehluleka kwezinso okungapheli. Phakathi kwalabo ababambe iqhaza ocwaningweni lwe-NHANES phakathi kuka-1999 no-2006, abantu abadala abanamazinga omthofu wegazi angaphezu kuka-24 μg/L babenethuba elingama-56% lokuba nesilinganiso sokuhlunga kwe-glomerular esincishisiwe (<60 mL/[min·1.73 m2]) kunalabo abanamazinga omthofu wegazi angaphansi kuka-11 μg/L. Ocwaningweni oluzoba yiqembu, abantu abanamazinga omthofu wegazi angaphezu kuka-33 μg/L babenengozi engamaphesenti angu-49 ephakeme yokuba nesifo sezinso esingamahlalakhona kunalabo abanamazinga aphansi omthofu wegazi.

Isifo senhliziyo
Izinguquko zeselula ezibangelwa umthofu ziyisici somfutho wegazi ophakeme kanye ne-atherosclerosis. Ezifundweni zaselabhorethri, amazinga aphansi njalo okuchayeka komthofu andisa ukucindezeleka kwe-oxidative, anciphisa amazinga e-bioactive nitric oxide, futhi enze i-vasoconstriction ngokwenza kusebenze i-protein kinase C, okuholela ekucindezelekeni komfutho wegazi oqhubekayo. Ukuchayeka komthofu kwenza i-nitric oxide isebenze, kwandisa ukwakheka kwe-hydrogen peroxide, kuvimbela ukulungiswa kwe-endothelial, kukhinyabeze i-angiogenesis, kuthuthukise i-thrombosis, futhi kuholele ku-atherosclerosis (Umfanekiso 2).
Ucwaningo lwe-in vitro lubonise ukuthi amangqamuzana e-endothelial akhuliswe endaweni ene-lead concentration ka-0.14 kuya ku-8.2 μg/L amahora angu-72 abangela ukulimala kolwelwesi lwamaseli (izinyembezi ezincane noma ukubhobozwa okubonwa ngokuskena i-electron microscopy). Lolu cwaningo luhlinzeka ngobufakazi obunamandla bokuthi umthofu osanda kumunca noma umthofu osanda kungena egazini usuka ethanjeni ungabangela ukungasebenzi kahle kwe-endothelial, okuwushintsho olubonakalayo lwakuqala emlandweni wemvelo wezilonda ze-atherosclerotic. Ekuhlaziyweni kwezingxenye ezihlukene zesampula elimele abantu abadala abanezinga lokuhola kwegazi eliphakathi kuka-27 μg/L futhi ongenawo umlando wesifo senhliziyo nemithambo yegazi, amazinga okuhola egazini anyuke ngo-10%.
Ku-μg, isilinganiso sezinkinga zokubala okuqinile komthambo we-coronary (okungukuthi, isikolo se-Agatston >400 ngebanga lamaphuzu angu-0[0 angabonisi ukubalwa] kanye nezikolo eziphakeme ezibonisa ububanzi bokubala okukhulu) sasingu-1.24 (isikhawu sokuzethemba esingu-95% esingu-1.01 kuya ku-1.53).
Ukuchayeka komthofu kuyingozi enkulu yokufa ngenxa yesifo senhliziyo nemithambo yegazi. Phakathi kuka-1988 no-1994, abantu abadala baseMelika abangu-14 000 babamba iqhaza ocwaningweni lwe-NHANES futhi kwalandelwa iminyaka engu-19, okwafa abangu-4,422 kuyo. Umuntu oyedwa kwabahlanu ubulawa isifo senhliziyo. Ngemva kokulungiswa kwezinye izici eziyingozi, ukukhuphuka kwamazinga omthofu wegazi ukusuka ku-10th percentile kuya ku-90th percentile kwakuhlotshaniswa nokuphindwa kabili kwengozi yokufa ngenxa yesifo senhliziyo. Ingozi yesifo senhliziyo nemithambo yegazi nokufa kwenhliziyo ikhuphuka kakhulu lapho amazinga omthofu engaphansi kuka-50 μg/L, kungekho mkhawulo ocacile (Izibalo 3B kanye no-3C). Abacwaningi bakholelwa ukuthi ingxenye yesine yesigidi yokufa ngaphambi kwesikhathi kwemithambo yenhliziyo unyaka ngamunye ibangelwa ubuthi bomthofu obungapheli obusezingeni eliphansi. Kulaba, abangu-185,000 babulawa isifo senhliziyo.
Ukuchayeka komthofu kungase kube esinye sezizathu ezenza ukufa kwesifo senhliziyo kuqale kwenyuka kwase kwehla ekhulwini leminyaka elidlule. E-United States, amazinga okufa kwesifo senhliziyo enyuke kakhulu engxenyeni yokuqala yekhulu lama-20, afinyelela umvuthwandaba ngo-1968, abese ehla kancane kancane. Manje ingamaphesenti angama-70 ngaphansi kwenani eliphakeme lango-1968. Ukuchayeka komthofu kuphethiloli oholayo kwakuhlotshaniswa nokwehla kokushona kwabantu ngenxa yesifo senhliziyo (Umfanekiso 4). Phakathi kwalabo ababambe iqhaza ocwaningweni lwe-NHANES, olwalandelwa iminyaka efika kweyisishiyagalombili phakathi kuka-1988-1994 no-1999-2004, u-25% wokuncipha okuphelele kwezigameko zesifo senhliziyo kwakungenxa yokuncipha kwamazinga omthofu wegazi.

Eminyakeni yokuqala yokuqedwa kukaphethiloli omthofu, izinga lomfutho wegazi ophakeme e-United States lehla kakhulu. Phakathi kuka-1976 no-1980, amaphesenti angu-32 abantu abadala baseMelika ayenomfutho wegazi ophakeme. Ngo-1988-1992, ingxenye yayingama-20% kuphela. Izici ezivamile (ukubhema, imishanguzo yomfutho wegazi, ukukhuluphala, ngisho nobukhulu obukhulu bekhafu elisetshenziselwa ukukala umfutho wegazi kubantu abakhuluphele) azikuchazi ukwehla komfutho wegazi. Kodwa-ke, izinga lokuhola kwegazi eliphakathi e-United States lehla lisuka ku-130 μg/L ngo-1976 laya ku-30 ​​μg/L ngo-1994, liphakamisa ukuthi ukwehla kokuchayeka komthofu kungesinye sezizathu zokwehla komfutho wegazi. Esifundweni Somndeni Senhliziyo Eqinile, esihlanganisa iqembu lamaNdiya aseMelika, amazinga okuhola kwegazi ehle ngo-≥9 μg/L kanye nomfutho wegazi we-systolic wehle ngesilinganiso esingu-7.1 mm Hg (inani elilungisiwe).
Imibuzo eminingi isalokhu ingaphenduliwe mayelana nemiphumela yokuchayeka komthofu esifweni senhliziyo nemithambo yegazi. Ubude besikhathi sokuchayeka obudingekayo ukuze kubangele umfutho wegazi ophakeme noma isifo senhliziyo nemithambo yegazi abuqondwa ngokugcwele, kodwa ukuchayeka komthofu okwesikhathi eside okukalwa emathanjeni kubonakala kunamandla okubikezela anamandla kunokuchayeka kwesikhashana okukalwa egazini. Nokho, ukunciphisa ukuchayeka komthofu kubonakala kunciphisa umfutho wegazi kanye nethuba lokufa ngenxa yesifo senhliziyo nemithambo yegazi phakathi nonyaka owodwa kuya kwemibili. Unyaka ngemva kokuvinjelwa kukaphethiloli oholayo emjahweni we-NASCAR, imiphakathi eseduze nethrekhi ibe namazinga aphansi kakhulu okufa kwesifo senhliziyo uma kuqhathaniswa nemiphakathi eminingi eseduze. Okokugcina, kunesidingo sokutadisha imiphumela yesikhathi eside yenhliziyo nemithambo yegazi kubantu abachayeke emazingeni omthofu angaphansi kuka-10 μg/L.
Ukuncipha kokuchayeka kwamanye amakhemikhali anobuthi nakho kube nomthelela ekwehleni kwesifo senhliziyo. Ukuqedwa kukaphethiloli onomthofu kusukela ngo-1980 kuya ku-2000 kwehlisa izinhlayiya ezindaweni zamadolobha amakhulu angu-51, okubangele ukwanda ngamaphesenti angu-15 esikhathini sokuphila. Bambalwa abantu ababhemayo. Ngo-1970, cishe amaphesenti angu-37 abantu abadala baseMelika ayebhema; Ngo-1990, amaphesenti angu-25 kuphela abantu baseMelika ayebhema. Ababhemayo banamazinga omthofu aphezulu kakhulu egazini kunabangabhemi. Kunzima ukuhlekisa ngemiphumela yomlando neyomanje yokungcoliswa komoya, intuthu kagwayi kanye nomthofu ku-coronary heart disease.
Isifo senhliziyo siyimbangela ehamba phambili yokufa emhlabeni wonke. Ucwaningo olungaphezu kweshumi nambili luye lwabonisa ukuthi ukuchayeka komthofu kuyingozi enkulu futhi evame ukunganakwa yokufa ngenxa yesifo senhliziyo. Ekuhlaziyweni kwe-meta, u-Chowdhury et al wathola ukuthi amazinga aphezulu okuhola egazini ayingxenye ebalulekile yengozi yesifo senhliziyo. Ezifundweni eziyisishiyagalombili ezizoba khona (ezinengqikithi yabahlanganyeli abangu-91,779), abantu abanomthofu wegazi ku-quintile ephakeme kakhulu babe nengozi ephezulu engama-85% ye-non-fetal myocardial infarction, ukuhlinzwa kwe-bypass, noma ukufa ngenxa yesifo senhliziyo kunalabo abasesigabeni esiphansi kakhulu se-quintile. Ngo-2013, i-Environmental Protection Agency (EPA)
I-Protection Agency yaphetha ngokuthi ukuchayeka komthofu kuyingozi yesifo senhliziyo; Eminyakeni eyishumi kamuva, i-American Heart Association yasigunyaza leso siphetho.