Editing DDT (section)

==Human health==
[[File:DDT WWII soldier.jpg|thumb|A U.S. soldier is demonstrating DDT hand-spraying equipment. DDT was used to control the spread of [[typhus]]-carrying [[lice]].]]
[[File:ASC Leiden - Coutinho Collection - 27 09 - Ziguinchor hospital, Senegal - Cleaning the hospital and the hospital beds - 1973.tif|thumb|Spraying hospital beds with DDT, [[PAIGC]] hospital of [[Ziguinchor]], 1973]]
[[File:The build up of toxins in a food chain.svg|thumb|upright=1.0|[[Biomagnification]] is the build up of toxins in a food chain. The DDT concentration is in parts per million. As the trophic level increases in a food chain, the amount of toxic build up also increases. The X's represent the amount of toxic build up accumulating as the trophic level increases. Toxins build up in organism's tissues and fat. Predators accumulate higher toxins than the prey.]]

DDT is an [[endocrine disruptor]].<ref>{{cite web |url= http://www.fws.gov/contaminants/issues/endocrinedisruptors.cfm |title= Endocrine (Hormone) Disruptors |work= [[United States Fish and Wildlife Service]] |access-date= 8 April 2015 |archive-date= October 8, 2015 |archive-url= https://web.archive.org/web/20151008032722/http://www.fws.gov/contaminants/issues/EndocrineDisruptors.cfm |url-status= dead }}</ref><ref>{{cite web | url = http://gewa.mpcer.nau.edu/files/endocrine-disruptors.pdf | title = Endocrine Disruptors |work=[[National Institute of Environmental Health Sciences]] | date = 2007 | access-date = April 8, 2015 | archive-url = https://web.archive.org/web/20160305203707/http://gewa.mpcer.nau.edu/files/endocrine-disruptors.pdf | archive-date = March 5, 2016 |via= George Washington Birthplace National Monument}}</ref>  It is considered likely to be a human [[carcinogen]] although the majority of studies suggest it is not directly [[Genotoxicity|genotoxic]].<ref>{{cite web |url=http://www.efsa.europa.eu/sites/default/files/scientific_output/files/main_documents/433.pdf |title=European Food Safety Administration – DDT |access-date=2014-10-29 |archive-date=June 3, 2018 |archive-url=https://web.archive.org/web/20180603023020/http://www.efsa.europa.eu/sites/default/files/scientific_output/files/main_documents/433.pdf |url-status=dead }}</ref><ref name=NTP-DDT>{{cite web |url=http://ntp.niehs.nih.gov/ntp/roc/content/profiles/dichlorodiphenyltrichloroethane.pdf |work=National Toxicology Program |title=DDT |access-date=2014-10-29 |archive-date=May 22, 2016 |archive-url=https://web.archive.org/web/20160522013510/http://ntp.niehs.nih.gov/ntp/roc/content/profiles/dichlorodiphenyltrichloroethane.pdf |url-status=live }}</ref><ref>{{cite book |url=http://monographs.iarc.fr/ENG/Monographs/vol53/mono53-9.pdf |title=IARC – DDT |year=1992 |isbn=9789283212539 |access-date=2014-10-29 |archive-date=October 29, 2014 |archive-url=https://web.archive.org/web/20141029134721/http://monographs.iarc.fr/ENG/Monographs/vol53/mono53-9.pdf |url-status=live }}</ref>  [[Dichlorodiphenyldichloroethylene|DDE]] acts as a weak [[androgen receptor]] [[receptor antagonist|antagonist]], but not as an [[estrogen]].<ref>{{Cite journal|last1=Kelce|first1=William R.|last2=Stone|first2=Christy R.|last3=Laws|first3=Susan C.|last4=Gray|first4=L. Earl|last5=Kemppainen|first5=Jon A.|last6=Wilson|first6=Elizabeth M.|date=1995|title=Persistent DDT metabolite p,p'–DDE is a potent androgen receptor antagonist|url=http://www.nature.com/articles/375581a0|journal=Nature|language=en|volume=375|issue=6532|pages=581–585|doi=10.1038/375581a0|pmid=7791873|bibcode=1995Natur.375..581K|s2cid=4344932|issn=0028-0836|access-date=October 14, 2020|archive-date=November 17, 2020|archive-url=https://web.archive.org/web/20201117150457/https://www.nature.com/articles/375581a0|url-status=live}}</ref> ''p'',''p{{'}}''-DDT, DDT's main component, has little or no androgenic or estrogenic activity.<ref name="Cohn07">{{cite journal | vauthors = Cohn BA, Wolff MS, Cirillo PM, Sholtz RI | title = DDT and breast cancer in young women: new data on the significance of age at exposure | journal = Environmental Health Perspectives | volume = 115 | issue = 10 | pages = 1406–1414 | date = October 2007 | pmid = 17938728 | pmc = 2022666 | doi = 10.1289/ehp.10260 | bibcode = 2007EnvHP.115.1406C }}</ref> The minor component ''o'',''p{{'}}''-DDT has weak estrogenic activity.

===Acute toxicity===
DDT is classified as "moderately toxic" by the U.S. [[National Toxicology Program]] (NTP) and "moderately hazardous" by WHO, based on the rat oral {{LD50}} of 113&nbsp;mg/kg.<ref name = "zvgfrt">World Health Organization, [https://www.who.int/ipcs/publications/pesticides_hazard_rev_3.pdf ''The WHO Recommended Classification of Pesticides by Hazard''] {{Webarchive|url=https://web.archive.org/web/20210704154307/https://www.who.int/ipcs/publications/pesticides_hazard_rev_3.pdf |date=July 4, 2021 }}, 2005.</ref> Indirect exposure is considered relatively non-toxic for humans.<ref name="Agarwal">{{cite journal | vauthors = Agarwal A, Aponte-Mellado A, Premkumar BJ, Shaman A, Gupta S | title = The effects of oxidative stress on female reproduction: a review | journal = Reproductive Biology and Endocrinology | volume = 10 | issue = 1 | pages = 49 | date = June 2012 | pmid = 22748101 | pmc = 3527168 | doi = 10.1186/1477-7827-10-49 | quote = In general, incidental human exposure to DDT has been considered relatively non-toxic, but prolonged exposure has long been recognized to adversely affect reproduction. | doi-access = free }}</ref>

=== Chronic toxicity ===
Primarily through the tendency for DDT to build up in areas of the body with high lipid content, chronic exposure can affect reproductive capabilities and the embryo or fetus.<ref name="Agarwal"/>
* A review article in ''[[The Lancet]]'' states: "research has shown that exposure to DDT at amounts that would be needed in malaria control might cause preterm birth and early weaning&nbsp;... toxicological evidence shows [[endocrine disruptor|endocrine-disrupting]] properties; human data also indicate possible disruption in semen quality, menstruation, gestational length, and duration of lactation".<ref name=Rogan05/>
* Other studies document decreases in [[semen]] quality among men with high exposures (generally from [[indoor residual spraying]]).<ref>{{cite journal | vauthors = Jurewicz J, Hanke W, Radwan M, Bonde JP | s2cid = 6681999 | title = Environmental factors and semen quality | journal = International Journal of Occupational Medicine and Environmental Health | volume = 22 | issue = 4 | pages = 305–329 | date = January 2010 | pmid = 20053623 | doi = 10.2478/v10001-009-0036-1 | doi-broken-date = November 11, 2024 }}</ref>
* Studies are inconsistent on whether high blood DDT or DDE levels increase time to pregnancy.<ref name="PineRiver"/> In mothers with high DDE blood serum levels, daughters may have up to a 32% increase in the probability of conceiving, but increased DDT levels have been associated with a 16% decrease in one study.<ref name="Eskenazi">{{cite journal | vauthors = Eskenazi B, Chevrier J, Rosas LG, Anderson HA, Bornman MS, Bouwman H, Chen A, Cohn BA, de Jager C, Henshel DS, Leipzig F, Leipzig JS, Lorenz EC, Snedeker SM, Stapleton D | title = The Pine River statement: human health consequences of DDT use | journal = Environmental Health Perspectives | volume = 117 | issue = 9 | pages = 1359–1367 | date = September 2009 | pmid = 19750098 | doi = 10.1289/ehp.11748 | quote = Overall, the few studies conducted to date suggest that DDT exposure may affect time to pregnancy, but more research is needed. | pmc=2737010| bibcode = 2009EnvHP.117.1359E }}</ref>
* Indirect exposure of mothers through workers directly in contact with DDT is associated with an increase in spontaneous abortions.<ref name="Agarwal"/>
* Other studies found that DDT or DDE interfere with proper thyroid function in pregnancy and childhood.<ref name="PineRiver"/><ref>{{cite journal | vauthors = Chevrier J, Eskenazi B, Holland N, Bradman A, Barr DB | title = Effects of exposure to polychlorinated biphenyls and organochlorine pesticides on thyroid function during pregnancy | journal = American Journal of Epidemiology | volume = 168 | issue = 3 | pages = 298–310 | date = August 2008 | pmid = 18550560 | pmc = 2727265 | doi = 10.1093/aje/kwn136}}</ref>
* Mothers with high levels of DDT circulating in their blood during pregnancy were found to be more likely to give birth to children who would go on to develop autism.<ref>{{Cite journal|last=Reardon|first=Sara|date=2018-08-16|title=Autism and DDT: What one million pregnancies can – and can't – reveal|url=https://www.nature.com/articles/d41586-018-05994-1|journal=Nature|doi=10.1038/d41586-018-05994-1|s2cid=81471566|issn=0028-0836|access-date=August 17, 2018|archive-date=August 19, 2018|archive-url=https://web.archive.org/web/20180819095150/https://www.nature.com/articles/d41586-018-05994-1|url-status=live}}</ref><ref>{{cite journal | vauthors = Brown AS, Cheslack-Postava K, Rantakokko P, Kiviranta H, Hinkka-Yli-Salomäki S, McKeague IW, Surcel HM, Sourander A | title = Association of Maternal Insecticide Levels With Autism in Offspring From a National Birth Cohort | journal = The American Journal of Psychiatry | volume = 175 | issue = 11 | pages = 1094–1101 | date = November 2018 | pmid = 30111184 | pmc = 6377859 | doi = 10.1176/appi.ajp.2018.17101129 }}</ref>

=== Carcinogenicity ===
In 2015, the [[International Agency for Research on Cancer]] classified DDT as Group 2A "probably carcinogenic to humans".<ref>{{Cite web|url=http://www.iarc.fr/en/media-centre/pr/2015/pdfs/pr236_E.pdf|title=IARC Monographs evaluate DDT, lindane, and 2,4-D|access-date=August 13, 2015|archive-date=April 13, 2020|archive-url=https://web.archive.org/web/20200413043943/http://www.iarc.fr/en/media-centre/pr/2015/pdfs/pr236_E.pdf|url-status=live}}</ref> Previous assessments by the U.S. [[National Toxicology Program]] classified it as "reasonably anticipated to be a carcinogen" and by the EPA classified DDT, DDE and DDD as class B2 "probable" [[carcinogen]]s; these evaluations were based mainly on animal studies.<ref name="ATSDRc5"/><ref name=Rogan05/> <!--In 2002, the [[Centers for Disease Control and Prevention]] reported, "Overall, in spite of some positive associations for some cancers within certain subgroups of people, there is no clear evidence that exposure to DDT/DDE causes cancer in humans."<ref name="ATSDRc5"/> -->

A 2005 Lancet review stated that occupational DDT exposure was associated with increased [[pancreatic cancer]] risk in 2 case control studies, but another study showed no DDE dose-effect association. Results regarding a possible association with [[liver cancer]] and biliary tract cancer are conflicting: workers who did not have direct occupational DDT contact showed increased risk. White men had an increased risk, but not white women or black men. Results about an association with multiple myeloma, prostate and testicular cancer, endometrial cancer and colorectal cancer have been inconclusive or generally do not support an association.<ref name=Rogan05/> A 2017 review of liver cancer studies concluded that "organochlorine pesticides, including DDT, may increase [[hepatocellular carcinoma]] risk".<ref>{{cite journal | vauthors = VoPham T, Bertrand KA, Hart JE, Laden F, Brooks MM, Yuan JM, Talbott EO, Ruddell D, Chang CH, Weissfeld JL | title = Pesticide exposure and liver cancer: a review | journal = Cancer Causes & Control | volume = 28 | issue = 3 | pages = 177–190 | date = March 2017 | pmid = 28194594 | pmc = 5336347 | doi = 10.1007/s10552-017-0854-6 }}</ref>

A 2009 review, whose co-authors included persons engaged in DDT-related litigation, reached broadly similar conclusions, with an equivocal association with testicular cancer. [[Case–control studies]] did not support an association with leukemia or lymphoma.<ref name="PineRiver"/>

====Breast cancer====
The question of whether DDT or DDE are [[Risk factors for breast cancer|risk factors in breast cancer]] has not been conclusively answered. Several meta analyses of observational studies have concluded that there is no overall relationship between DDT exposure and breast cancer risk.<ref>{{cite journal | vauthors = Park JH, Cha ES, Ko Y, Hwang MS, Hong JH, Lee WJ | title = Exposure to Dichlorodiphenyltrichloroethane and the Risk of Breast Cancer: A Systematic Review and Meta-analysis | journal = Osong Public Health and Research Perspectives | volume = 5 | issue = 2 | pages = 77–84 | date = April 2014 | pmid = 24955316 | pmc = 4064641 | doi = 10.1016/j.phrp.2014.02.001 }}</ref><ref>{{cite journal | vauthors = Ingber SZ, Buser MC, Pohl HR, Abadin HG, Murray HE, Scinicariello F | title = DDT/DDE and breast cancer: a meta-analysis | journal = [[Regulatory Toxicology and Pharmacology]] | volume = 67 | issue = 3 | pages = 421–433 | date = December 2013 | pmid = 24021539 | doi = 10.1016/j.yrtph.2013.08.021 | doi-access = free | pmc = 11298241 }}</ref> The United States Institute of Medicine reviewed data on the association of breast cancer with DDT exposure in 2012 and concluded that a causative relationship could neither be proven nor disproven.<ref>{{cite journal | vauthors = Smith-Bindman R | title = Environmental causes of breast cancer and radiation from medical imaging: findings from the Institute of Medicine report | journal = Archives of Internal Medicine | volume = 172 | issue = 13 | pages = 1023–1027 | date = July 2012 | pmid = 22688684 | pmc = 3936791 | doi = 10.1001/archinternmed.2012.2329 }}</ref>

A 2007 case-control study<ref name="Cohn07"/> using archived blood samples found that breast cancer risk was increased 5-fold among women who were born prior to 1931 and who had high serum DDT levels in 1963. Reasoning that DDT use became widespread in 1945 and peaked around 1950, they concluded that the ages of 14–20 were a critical period in which DDT exposure leads to increased risk. This study, which suggests a connection between DDT exposure and breast cancer that would not be picked up by most studies, has received variable commentary in third-party reviews. One review suggested that "previous studies that measured exposure in older women may have missed the critical period".<ref name="PineRiver"/><ref>{{cite journal | vauthors = Clapp RW, Jacobs MM, Loechler EL | title = Environmental and occupational causes of cancer: new evidence 2005–2007 | journal = Reviews on Environmental Health | volume = 23 | issue = 1 | pages = 1–37 | year = 2008 | pmid = 18557596 | pmc = 2791455 | doi = 10.1515/REVEH.2008.23.1.1 | bibcode = 2008RvEH...23....1C }}</ref> The National Toxicology Program notes that while the majority of studies have not found a relationship between DDT exposure and breast cancer that positive associations have been seen in a "few studies among women with higher levels of exposure and among certain subgroups of women".<ref name=NTP-DDT/>

A 2015 case control study identified a link (odds ratio 3.4) between ''in-utero'' exposure (as estimated from archived maternal blood samples) and [[breast cancer]] diagnosis in daughters. The findings "support classification of DDT as an endocrine disruptor, a predictor of breast cancer, and a marker of high risk".<ref>{{cite journal | vauthors = Cohn BA, La Merrill M, Krigbaum NY, Yeh G, Park JS, Zimmermann L, Cirillo PM | title = DDT Exposure in Utero and Breast Cancer | journal = The Journal of Clinical Endocrinology and Metabolism | volume = 100 | issue = 8 | pages = 2865–2872 | date = August 2015 | pmid = 26079774 | pmc = 4524999 | doi = 10.1210/jc.2015-1841 }}</ref>