Links between carcinogens in human milk and later cancer in the child and adult.

 

(Author's note:  This article was originally part of a larger article, which became too long for convenient reading in its original form.  Therefore the contents below were separated out from that article and included here.  The Introduction below summarizes some background information from the original article, which can be found at http://www.breastfeeding-questions.info.)

 

Introduction:

Human milk has been authoritatively found to contain both PCBs and dioxins in concentrations that far exceed established safety standards.1  Both of those chemicals have been recognized as carcinogenic to humans.2 Considering the special vulnerabilities of infants, the EPA applies a 10-fold risk adjustment factor for exposures to such toxins for children younger than age two.8  

 

Studies have found that various kinds of PCBs promote fat cell development, increase the size of fat cells, and result in marked deposition of fat within the abdominal cavity.6,7, Many studies have found reduced activity (often greatly reduced) to be an effect of exposure to PCBs.5,10  Both obesity and inactivity are known risk factors for cancer.

 

PCBs taken in during breastfeeding have been found to continue to be still circulating in the body well into the teenage years, at levels typically 70% and more above levels found in non-breastfed children.11

 

PCBs, dioxins, and various cancers: 

Colon cancer:  Both obesity and inactivity are considered to be risk factors for colon cancer.  In two separate meta-analyses, inactivity was found to be associated with colon cancer in dose-response relationships.12  

Stomach cancer:  Obesity and inactivity (since it leads to obesity) are also risk factors for stomach cancer.76 

Since PCB exposures have been found to lead to both obesity and inactivity (see Introduction), PCBs are an especially significant risk factor for colon and stomach cancers.  Regarding the other principal carcinogen in human milk (dioxin), multiple studies have concurred in showing an appreciable excess risk of cancer due to relatively small increases in dioxin above background levels, such as increases that could result from dioxin in normal foods.9   In a 1997 evaluation of the International Agency for Research on Cancer (IARC), dioxin was unprecedented in that it was judged to cause an increase in cancers at all sites rather than at only a few specific sites.65

 

Cancer increases:  Given the above, it should not be surprising that there have been serious increases in U.S. cancer rates that have aligned with the increases in breastfeeding that have taken place since the 1960s (Figure 1):  

  -- overall childhood cancer incidence in the U.S. increased 40% between 1975 and 2018;23 the increases appear to have been strongest among younger children, which is in line with occurrence of exposures to carcinogens during infancy;26

  -- the U.S. National Cancer Institute reported in 2020 that colorectal cancer incidence among adults younger than 50 had more than doubled since the 1990s;22 (bear in mind the approximate 20-year minimum latency of colorectal cancer34)

  -- overall cancer in younger U.S. women increased 24% during the years 1995-2015;36 (males are less affected by PCBs and dioxins than females98)

  -- stomach cancer incidence among women born in 1983 was twice that of women born in 1951.77  Note that breastfeeding in the majority U.S. population was over twice as high in the 1980s as it had been in the 1950s (Figure 1);

  -- in contrast with the major cancer increases among people born when breastfeeding was increasing (above), incidences of both colorectal and stomach cancers have been stable or declining among people born before 1955,13,77 when breastfeeding was declining; (Figure 1 below)

 

……………….

 

Separate trend lines for whites and blacks:  It is of interest to take a close look at the breastfeeding history after the 1960s, in the data below.  Compare where the bottoms of the trends occurred for blacks versus for whites, when the trends changed from downward to upward:

 

Fig, 1


 

 The above can be found at https://deepblue.lib.umich.edu/handle/2027.42/133367 

 

Notice that, during the 1970s, breastfeeding was increasing in the majority population but still declined among blacks.  In relation to that, and considering the normal latent period for such cancer (20 or more years34), note the following colorectal cancer information for 1992-2005:  incidence of that cancer was increasing in the majority of the population but not for blacks, among whom it still declined.19 

 

Then consider the subsequent pair of earlier-and-later periods:  blacks came together with the overall upward trend in breastfeeding in the U.S. as of the 1980s (Fig. 1 and ref. 33); and there were long-term increases in young-adult colorectal cancer in all race/ethnic groups as of the 2000s.32,66  As before, the early breastfeeding exposure accurately predicted the corresponding later cancer incidence, with an intervening period equal to a normal period of latency. 

 

……………………

 

Matching demographic characteristics:  Based on 2004-2015 data from the U.S. National Cancer Database, a research team20 pointed out four demographic characteristics that they had observed regarding the increasing young-adult colorectal cancer cases:

  (a) cases were at their highest proportions in the highest-income areas; possibly related to that, a document of the U.S. Surgeon General shows that college graduates are far more likely to breastfeed than women with less education,31 and four studies have found that low-income mothers tend to be less likely to breastfeed than higher-income mothers;24

  (b) cancer cases were diagnosed at lower rates in rural areas; of interest in that regard, a publication of the U.S. Surgeon General pointed out that women in rural areas are less likely to breastfeed than women in urban areas;31

  (c) patients with private insurance became an increasing proportion of the young cases over time; this may be related to the facts that higher-income mothers are more likely to breastfeed than low-income mothers,24,31 and breastfeeding has been increasing;

  (d) cancer cases had been increasing in both sexes only among non-Hispanic whites; of interest (in a publication of the U.S. Institute of Medicine), data shows that whites were in second place in breastfeeding rates among ethnic groups in 1966-70 but as of 1989 had advanced to far out in front (Tables 3-1 and 3-2 in ref. 25).

 

Another research team, publishing their research in 2018, observed four demographic characteristics that applied especially to the increasing numbers of younger patients with stomach cancer:  two of the characteristics (disproportionately white and of middle or higher income)77 align with those of mothers who breastfeed at higher rates, as discussed above.  Another characteristic -- increases occurring in the cancer among younger people while decreases were taking place in the older population -- is understandable in terms of birth years having been when breastfeeding was either increasing or decreasing, as discussed earlier. (see Cancer increases)

 

The fourth demographic characteristic found in the stomach cancer incidence study was far greater increases among younger women than among younger men.  This could well be related to the considerable evidence indicating that women are far more vulnerable to carcinogenic (and other) effects of PCBs and dioxins than men are.98,97,99,100  In relation to that, bear in mind the high levels of PCBs and dioxins in human milk in developed countries,1 as well as the increases that were taking place in breastfeeding during the birth decades of the younger people.

 

Note that the above were not selected from larger lists of such characteristics; they were the only demographic characteristics that were reported to stand out in younger cancer patients in two separate studies of those cancers.  It is worth noting that all of them appear to be very compatible with possible origins of the cancers in carcinogens transferred via breastfeeding.

 

Other risk factors for these cancers:  Several research teams have, with minimal success, addressed the question of why young-onset colorectal and stomach cancers have been increasing.  One team acknowledged that their suggested risk factors (obesity, inactivity, etc.) are inadequate to explain the increases of colorectal cancer among young adults, since those factors have also been increasing in people over age 50, in whom this cancer has been declining.46  Four research teams have pointed out that increases in screening are inadequate as an explanation for the increases that have been taking place,68,70,78 especially because "the most rapid gains are for individuals in their 20s and 30s, who are least likely to be screened." 52  Regarding the various possible causes that they have suggested, authors have generally said nothing about past changing trends in those risk factors,46,29,51 which would be needed in order to be compatible with the past historical trends in incidences of the cancers among younger people.36,77,52,23 (see below)

 

Variations in stomach cancer incidence in relation to variations in exposures to dioxins and PCBs during infancy:

Fig. 2


 
  (Above can be found at https://doi.org/10.1093/jnci/djx262, clicking on link for Supplementary Figure 2)

 

 

  Reasonable explanations for all of the trends and major turns in stomach cancer seen above could include the following: 

  a) In the early 20th century, there was a long-term decline in prevalence of breastfeeding, which transfers high concentrations of carcinogenic dioxins (Fig. 1 and reference no. 1);

  b) beginning mid-century, there were major increases in the general environment of dioxins plus the relatively new carcinogens, PCBs;,4
  c) beginning in the 1970s, there were major increases in breastfeeding, with accompanying transfers of high concentrations of dioxins and PCBs (Fig. 1 and ref. no. 1);

  d) in the late 1980s, a multi-year dip interrupted the long-term increases in breastfeeding.31

 

In addition, the greater increase of cancer among females compared with males (see red symbols above) supports the role of PCBs and dioxins as causes of the cancer represented above, since those specific toxins have been found to affect females more than males.98,97  Judging by substantial searches on PubMed and Google Scholar, greater female vulnerability to carcinogens occurs very rarely, or possibly never, except when PCBs or dioxins are the relevant carcinogens.  So an exposure that is known to contain very high concentrations of both PCBs and dioxins (such as human milk1) would be especially likely to lead to a cancer that is distinctly high among women.  Note how well the down-and-up-and-down variations in breastfeeding according to birth years (a, c, and d in text above) have aligned with later down-and-up-and-down variations in this cancer according to birth years (chart above).

 

……………….

 

Significance of changes in colorectal cancer incidence in other high-income countries in recent decades:

 

After many years of decline or lack of increase, breastfeeding rates in most high-income countries began a long-term increase that started in the early 1970s.111,Fig. 4, 95  Knowing the high levels of carcinogens in human milk in developed countries,1 it would be reasonable to focus on the early 1970s as a time of beginning of increases in carcinogenic exposures; and then (to that) add 20 years -- the approximate minimum latency of colorectal cancer after exposures until symptoms become apparent.34  And then look for what happened in cancer incidence beginning in the early 1990s.  See below.

 

Fig. 3


 

Above can be found at  https://doi.org/10.1016/S2468-1253(19)30147-5

 

Note that the chart for the 20-34 age group showed strong, long-term upturns in cancer incidence beginning at a time that could be related to the 1970s increases in breastfeeding, taking into account the normal minimum latency for colorectal cancer.

That study also showed histories for colon cancer with upward (although less marked) turns beginning among younger people at about that same time.112  Those upturns provided separate evidence of cancers' increasingly originating at about the same time as when breastfeeding was increasing.

  

Rationale for lactational transfer of dioxins and PCBs as leading cause of the increases of cancer among younger people:  

 

As an explanation for the increases of cancer among younger people, it appears that none of the published, proposed alternative risk factors (see part 5) compare well with an exposure that contains two known carcinogens, each in concentrations far exceeding established safety standards.1,2  And those two carcinogens are ingested by infants at a life stage of exceptional vulnerability.8  

Also, it appears that there have been no exposure histories of the other suggested risk factors that have tracked with the changing course of cancer among younger people, much less have they tracked well, as has been the case with breastfeeding. (Part 3

 

Moreover, when sequences are known, changing and increasing rates of the cancers have come after corresponding changes and increases in rates of breastfeeding; normal periods of latency for the cancers have transpired between the earlier exposures and the corresponding later cancer incidences.  For specifics, see (a) "Separate trend lines for whites and blacks" earlier and (b) Figures 2 and 3 and accompanying texts regarding cancer incidence rates' being in line with exposures during infancy.

 In addition, demographic characteristics of younger population groups with specific variations in cancer incidence rates (higher/lower etc.) have almost entirely aligned well with demographic characteristics of mothers who have been found to breastfeed with corresponding variations in rates. (see "Matching demographic characteristics" earlier)

 

Other risk factors for these cancers:  Several research teams have, with minimal success, addressed the question of why young-onset colorectal and stomach cancers have been increasing.  One team acknowledged that their suggested risk factors (obesity, inactivity, etc.) are inadequate to explain the increases of colorectal cancer among young adults, since those factors have also been increasing in people over age 50, in whom this cancer has been declining.46  Four research teams have pointed out that increases in screening are inadequate as an explanation for the increases that have been taking place,68,70,78 especially because "the most rapid gains are for individuals in their 20s and 30s, who are least likely to be screened." 52  Regarding the various possible causes of increases that they have suggested, authors have generally said nothing about past changing trends in those risk factors,46,29,51 which would be needed in order to be compatible with the past changing trends in incidences of the cancers among younger people.36,77,52,23

 

Clustering of high-breastfeeding countries in the highest ranks of colorectal cancer incidence:  Breastfeeding rates in various countries in recent decades, compared with cancer rates in those countries, are of interest:

The countries with the seven highest rates of colorectal cancer in the world (Norway, Hungary, Denmark, Portugal, Slovenia, Slovakia, and South Korea) have all had very unusually high breastfeeding rates. (see chart and text below for details)

This might be considered to be merely remarkably coincidental except for the many good reasons to see a causal link between breastfeeding and cancer, as discussed earlier in this article.

Fig. 4

  Breastfeeding in Europe, 1980-2011


 .

Source:  WHO European Health Information Gateway at https://gateway.euro.who.int/en. Click on HFA Explorer, then on Select Indicators. Uncheck the indicator categories other than HFA. Then scroll well down to bold heading, "Maternal and child health," then select Proportion of infants breastfed at (3) months. Then Select countries/ Select by country group:  Members of the European Union. Then select Norway.  Finally, click on the "line chart" icon at the left end of the row at the top of the chart area.  Pass the cursor across the chart to see countries identified.

 

 Norway, regularly the highest or close to the highest in European breastfeeding rates (above), was reported in 2018 to have the highest rate of colorectal cancer among women in an international ranking of that cancer; the data source was for 185 countries, from a service owned by the IARC.55  Hungary, apparently with the highest breastfeeding rates among European countries in the most recent decades (above), had the highest overall colorectal cancer rate in the ranking provided by the source mentioned above.  Portugal (see above) had the highest rate of rectal cancer among men.56  Denmark (above) was found in 2011 data to have the highest overall cancer rates in the world, although other risk factors are considered to have contributed to that.57  Slovakia and Slovenia, both of which are also among the seven countries with the highest rates of colorectal  cancer,55 have been found in other surveys to have rates of breastfeeding similar to those of Norway (see above).60,61  Separate data showed South Korea's breastfeeding at 6 months to be even higher than that of Norway,60 and the IARC data showed South Korea to have the second highest rate of colorectal cancer in the world.55

The above unusually high-breastfeeding countries were all of the countries found to have the seven highest rates of colorectal cancer in the world.55  

 

 

Comments and questions are welcome.  E-mail to  dm@pollutionaction.org

 

* About the author:

As the author of the above, my role has been to read through very large amounts of scientific research that has already been completed on the subjects of environmental toxins and infant development, and then to summarize the relevant findings; my aim has been to put this information into a form that enables readers to make better-informed decisions related to these matters.  The original research articles and government reports on this subject (my sources) are extremely numerous, often very lengthy, and are usually written in a form and stored in locations such that the general public is normally unable to learn from them. 

 

My main qualification for writing these publications is ability to find and pull together large amounts of scientific evidence from authoritative sources and to condense the most significant parts into a form that is sufficiently accurate to be useful to professionals and at the same time reasonably understandable to the general public.  My educational background included challenging courses in biology and chemistry in which I did very well, but at least as important has been an ability to correctly summarize in plain English large amounts of scientific material.  I scored in the top one percent in standardized tests in high school, graduated cum laude from Oberlin College, and stood in the top third of my class at Harvard Business School.  

 

There were important aspects of the business school case-study method that have been helpful in making my work more useful than much or most of what has been written on this subject, as follows:   After carefully studying large amounts of printed matter on a subject, one is expected to come up with well-considered recommendations that can be defended against criticisms from all directions.  The expected criticisms ingrain the habits of (a) maintaining accuracy in what one says, and (b) not making recommendations unless one can support them with good evidence and logical reasoning.  Established policies receive little respect if they can’t be well supported as part of a free give-and-take of conflicting evidence and reasoning. 

 

When a brief summary of material that conflicts with their breastfeeding positions is repeatedly presented to the physicians’ associations, along with a question or two about the basis for their breastfeeding recommendations, those associations never respond.  That says a great deal about how well their positions on breastfeeding can stand up to scrutiny.

 

The credibility of the contents of the above article is based on the authoritative sources that are referred to in the references:  The sources are mainly U.S. government health-related agencies and academic researchers writing in peer-reviewed journals; those sources are essentially always referred to in footnotes that follow anything that is said in the text that is not common knowledge.  In most cases a link is provided that allows easy referral to the original source(s) of the information.  If there is not a working link, you can normally use your cursor to select a non-working link or the title of the document, then copy it (control - c usually does that), then “paste” it (control - v) into an open slot at the top of your browser, for taking you to the website where the original, authoritative source of the information can be found.  

 

The reader is strongly encouraged to check the source(s) regarding anything he or she reads here that seems to be questionable, and to notify me about anything said in my text that does not seem to accurately represent what was said by the original source, as well as about any source that does not seem to be authoritative.  E-mail to the address shown below.  I will quickly correct anything found to be inaccurate.

 

For a more complete statement about the author and Pollution Action, please go to www.pollutionaction.org

 

Don Meulenberg

Pollution Action

Virginia, USA

Email:  dm@pollutionaction.org.

 

 

 

 References:

 

   1) van den Berg et al., WHO/UNEP Global Surveys of PCDDs, PCDFs and DDTs in human milk and benefit-risk evaluation breastfeeding, Arch Toxicol. 2017, at https://pubmed.ncbi.nlm.nih.gov/27438348/  

 

  2) ATSDR:  Polychlorinated Biphenyls (PCBs) Toxicity:  What Are Adverse Health Effects of PCB Exposure?  See Carcinogenic Effects section, scroll down to IARC findings, at

https://www.atsdr.cdc.gov/csem/polychlorinated-biphenyls/adverse_health.html

   Dioxins are well known to be human carcinogens.

 

  4) Fig. 1 and accompanying text in http://www.breastfeeding-questions.info

 

  5) Jacobson et al., Effects of Exposure to PCBs and Related Compounds on Growth and Activity in Children, Neurotoxicology and Teratology, 1990, Vol. 12, pp. 319-326, at https://www.sciencedirect.com/science/article/abs/pii/089203629090050M  See last paragraph above Methods section re several other studies.

    Chen et al., A 6-Year Follow-Up of Behavior and Activity Disorders in the Taiwan Yu-cheng Children, American Journal of Public Health, Mar. 1994, Vol. 84 No. 3,  at https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1614813/pdf/amjph00454-0081.pdf.  This study refers to three animal studies with findings of reduced activity as effects of early PCB exposures (p. 418 bottom right and p. 419 top left).

    Also Johansen et al., Postnatal exposure to PCB 153 and PCB 180, but not to PCB 52, produces changes in activity level and stimulus control in outbred male Wistar Kyoto rats, Behavioral and Brain Functions, BioMed Central Ltd. 2011, at https://behavioralandbrainfunctions.biomedcentral.com/articles/10.1186/1744-9081-7-18

  6) Also Kim HY et al., Polychlorinated biphenyls exposure-induced insulin resistance is mediated by lipid droplet enlargement through Fsp27, Arch Toxicol, 2017, DOI: 10.1007/s00204-016-1889-2  Animal study showing that both dioxin-like and non-dioxin-like PCBs promote fat cell development and increase the size of fat cells.

 

  7) Arsenescu et al., Polychlorinated Biphenyl-77 Induces Adipocyte Differentiation and Proinflammatory Adipokines and Promotes Obesity and Atherosclerosis, Environ Health  Perspect, 2008, https://doi.org/10.1289/ehp.10554

 

  8) EPA: Supplemental Guidance for Assessing Susceptibility from Early-Life Exposure to Carcinogens, 2005, pp. 32-33, at https://www.epa.gov/sites/production/files/2013-09/documents/childrens_supplement_final.pdf

 

  9) Cancer Research UK: Cancer Incidence Statistics:  Cancer incidence for all cancers combined, at https://www.cancerresearchuk.org/health-professional/cancer-statistics/incidence#heading-Zero

 

  10) U.S. ATSDR:  Toxicological Profile for Polychlorinated Biphenyls (PCBs), 2000, p. 185 at http://www.atsdr.cdc.gov/toxprofiles/tp17.pdf ,

 

  11) Gascon et al., Temporal trends in concentrations and total serum burdens of organochlorine compounds from birth until adolescence and the role of breastfeeding, Environment International, 2015,

https://doi.org/10.1016/j.envint.2014.10.010

 

  12) Boyle et al., Physical Activity and Risks of Proximal and Distal Colon Cancers: A Systematic Review and Meta-analysis, JNCI: Journal of the National Cancer Institute, 2012, at https://academic.oup.com/jnci/article/104/20/1548/970705?login=true 

 

   13) Stoffel and Murphy, Epidemiology and Mechanisms of the Increasing Incidence of Colon and Rectal Cancers in Young Adults, Gastroenterology, 2020, at https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6957715/  See Fig. 2

 

  19) Siegel et al., Increase in Incidence of Colorectal Cancer Among Young Men and Women in the United States, Cancer Epidemiology Biomarkers & Prevention, 2009, Table 1, at https://cebp.aacrjournals.org/lens/cebp/18/6/1695

 

  20) Virostko et al., Recent trends in age at diagnosis of colorectal cancer in the United States National Cancer Database, 2004 -2015, Cancer, 2019, at https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6788938/ 

 

  22) NIH National Cancer Institute:  Why Is Colorectal Cancer Rising Rapidly among Young Adults? Nov. 2020, at https://www.cancer.gov/news-events/cancer-currents-blog/2020/colorectal-cancer-rising-younger-adults

 

  23) In the NIH National Cancer Institute SEER Explorer web page at seer.cancer.gov/explorer , Get Started with "All Cancer Sites Combined" and "SEER Incidence," select "Long-Term Trends" tab, and compare by Both Sexes and Age/Ages<15

 

  24) Guttman and Zimmerman, Low-income mothers' views on breastfeeding, Social Science and Medicine, 2000, at https://www.sciencedirect.com/science/article/pii/S0277953699003871

 

  25) Institute of Medicine (US) Committee on Nutritional Status During Pregnancy and Lactation, Ch. 3, Who Breastfeeds in the United States? Page 30 and Table 3-2, National Academies Press (US); 1991. at https://www.ncbi.nlm.nih.gov/books/NBK235588/#__NBK235588_dtls__

  

  26) Gurney JG et al., Trends in Cancer Incidence among Children in the US, American Cancer Society, 1996

 

  29) REACCT Collaborative:  Characteristics of Early-Onset vs Late-Onset Colorectal Cancer: A Review, JAMA Surg., 2021, at https://pubmed.ncbi.nlm.nih.gov/34190968/

  

  31) The Surgeon General's Call to Action to Support Breastfeeding, 2011, Office of the Surgeon General (US), CDC.   Re rural breastfeeding, see section, "Disparities in Breastfeeding Practices," and Table 2 re college graduates, and also below Table 2;  re dip in breastfeeding in 1980s, see Figure 1.

https://www.ncbi.nlm.nih.gov/books/NBK52681/#ratesof.s1

 

  32) Muller et al., Disparities in Early-Onset Colorectal Cancer, Cells, 2021, at https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8146231/Figure 2 re long-term increases

 

  33) For breastfeeding rates by ethnic group as of 1989, see Table 3-2 in Nutrition During Lactation. Institute of Medicine (US) Committee on Nutritional Status During Pregnancy and Lactation. National Academies Press (US); 1991, at https://www.ncbi.nlm.nih.gov/books/NBK235588/table/ttt00004/?report=objectonly

and for higher breastfeeding rates in 2000s see Progress in Increasing Breastfeeding and Reducing Racial/Ethnic Differences, United States, 2000-2008 Births, CDC Morbidity and Mortality Weekly Report (MMWR), Feb. 8, 2013  at https://www.cdc.gov/mmwr/preview/mmwrhtml/mm6205a1.htm

 

  34) Gamble JF, Asbestos and Colon Cancer: A Weight-of-the-Evidence Review, Environmental Health Perspectives, 1994, at https://ehp.niehs.nih.gov/doi/10.1289/ehp.941021038

  Weiss W, The Lack of Causality between Asbestos and Colorectal Cancer, Journal of Occupational and Environmental Medicine, 1995.  https://www.jstor.org/stable/44995127 . Of the studies reviewed for which latency data was provided, the large majority indicated 20 years as the only latency considered.

  Caygill CP, et al., Increased risk of cancer at multiple sites after gastric surgery for peptic ulcer. Gut 1987;28:924-928, https://gut.bmj.com/content/28/8/924.abstract

Assessment after 15 years of exposures found no increase in cancer mortality, but did find such as the 20-year assessment.

 

  36) Figure 1 in Kehm et al., 40 Years of Change in Age- and Stage-Specific Cancer Incidence Rates in US Women and Men, JNCI Cancer Spectrum, 2019. Figure 1 (All-cancer incidence among U.S. women aged 25-39:  1.15%/yr times 21 yrs =24% for 1995-2015);  At https://academic.oup.com/jncics/article/3/3/pkz038/5513366

 

  42) Carpenter and Bushkin-Bedient, Exposure to Chemicals and Radiation During Childhood and Risk for Cancer Later in Life, Journal of Adolescent Health, 2013, https://doi.org/10.1016/j.jadohealth.2013.01.027

 

  46) Ahnen et al., The Increasing Incidence of Young-Onset Colorectal Cancer: A Call to Action, Mayo Clinic Proceedings, 2014, at https://www.sciencedirect.com/science/article/pii/S0025619613008227

 

  61) IBFAN web page at http://breastfeedingandhr.blogspot.com/2013/06/breastfeeding-situation-in-slovenia.html

 

  65) Steenland et al., Dioxin Revisited: Developments Since the 1997 IARC Classification of Dioxin as a Human Carcinogen, Environ Health Perspect, 2004, at https://ehp.niehs.nih.gov/doi/full/10.1289/ehp.7219

 

  66) Austin et al., Changes in colorectal cancer incidence rates in young and older adults in the United States: what does it tell us about screening, Cancer Causes Control, 2014, at https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4394895/

 

  68) Lansdorp-Vogelaar et al., Contribution of Screening and Survival Differences to Racial Disparities in Colorectal Cancer Rates, Cancer Epidemiology Biomarkers & Prevention, 2012, DOI: 10.1158/1055-9965.EPI-12-0023

 

  73) NIH/National Cancer Institute, Surveillance, Epidemiology, and End Results Program:  Health Policy: Colorectal Cancer - Landmark Studies, 2003, at https://seer.cancer.gov/archive/studies/endresults/study27.html

 

  76) Cancer.net web pages at https://www.cancer.net/cancer-types/stomach-cancer/risk-factors  and https://www.cancer.net/cancer-types/stomach-cancer/statistics

 

  77) Anderson et al., The Changing Face of Noncardia Gastric Cancer Incidence Among US Non-Hispanic Whites, JNCI: Journal of the National Cancer Institute, 2018, https://doi.org/10.1093/jnci/djx262  (see Results section re incidence among younger vs older)

 

  78) Mayo Clinic, Many younger patients with stomach cancer have a distinct disease, Science Daily, Dec. 30, 2019, at https://www.sciencedaily.com/releases/2019/12/191230104803.htm

 

   80) IARC Monographs Volume 107: Polychlorinated Biphenyls and Polybrominated Biphenyls, IARC.

  McGregor et al., An IARC evaluation of polychlorinated dibenzo-p-dioxins and polychlorinated dibenzofurans as risk factors in human carcinogenesis, at https://pubmed.ncbi.nlm.nih.gov/9599727/

 

  95) WHO/UNICEF:  Breastfeeding Policy Brief 5, Global Nutrition Targets 2025, WHO/NMH/NHD/14.7. at https://apps.who.int/nutrition/publications/globaltargets2025_policybrief_breastfeeding/en/index.html

  "Between 1985 and 1995, global rates of exclusive breastfeeding increased from 14% to 38% over 10 years.  25 countries increased their rates of exclusive breastfeeding by 20 percentage points or more after 1995..."

 

  96) World Cancer Research Fund web page, Lactation (breastfeeding) at https://www.wcrf.org/dietandcancer/lactation-breastfeeding/

  97) Dziubanek et al., Preliminary study of possible relationships between exposure to PCDD/Fs and dl-PCBs in ambient air and the length of life of people, Science of the Total Environment, 2017, at https://www.sciencedirect.com/science/article/abs/pii/S0048969717308203?via%3Dihub

  98) Ćwieląg-Drabek et al., Non-Dioxin-Like PCBs --the Key Air Pollutant Associated with Lung Cancer in 15 Cities in Silesia, Pol. J. Environ Stud., 2020, DOI: 10.15244/pjoes/102786, at https://www.cancer.gov/about-nci/organization/cgh/publications/non-dioxin-like-pbcs.pdf

  111) Infant Feeding Guidelines, National Health and Medical Research Council (Australia), 2012, nHmRc Publication reference: n56; see part 1.1 (p. 11) at https://www.eatforhealth.gov.au/sites/default/files/files/the_guidelines/n56_infant_feeding_guidelines.pdf

"In the early 1970s, breastfeeding rates started to rise again in Australia and comparable overseas countries,"  

  Mirindi BM, Interventions for promoting breastfeeding in the Nordic countries -- a scoping review, Bachelor's thesis, Vasa (University), 2020, https://www.theseus.fi/bitstream/handle/10024/342185/Mirindi_Blandine.pdf?sequence=2&isAllowed=y  "...breastfeeding rates in the Nordic countries have slowly increased from the 1970s...." (p. 3)

   Liestol et al., Breast-feeding practice in Norway 1860-1984, Journal of Biosocial Science, 2008, at https://www.cambridge.org/core/journals/journal-of-biosocial-science/article/abs/breastfeeding-practice-in-norway-18601984/D49B0F73ACB5A7427A183657D22BF8CF 

   “…late 1960s, when only about 30% lactated for 3 months or more. The duration then increased quickly,…”

   An international comparison study into the implementation of the WHO code and other breastfeeding initiatives, The University of Sydney, NHMRC Clinical Trials Centre, 2011.  See p. 36 re Canada. https://www1.health.gov.au/internet/main/publishing.nsf/Content/int-comp-whocode-bf-init

   Rogers IS et al., The incidence and duration of breast feeding, Early Human Development, 1997, Institute of Child Health, London, UK  at https://pubmed.ncbi.nlm.nih.gov/9363417/  See part 2, S46 re increase in England after 1975.

   Ladewig EL et al., The influence of ethnicity on breastfeeding rates in Ireland: a cross-sectional study, Journal of Epidemiology and Community Health, 2014, https://www.jstor.org/stable/43281743

  New Zealand Ministry of Health:  Breastfeeding in New Zealand | Whāngote ki Aotearoa, updated 2020, at https://www.health.govt.nz/our-work/life-stages/breastfeeding/national-breastfeeding-strategy-new-zealand-aotearoa-rautaki-whakamana-whangote/further-reading-panui-atu/breastfeeding-new-zealand-whangote-ki-aotearoa

 

  112) Araghi M et al., Changes in colorectal cancer incidence in seven high-income countries: a population-based study, The Lancet Gastroenterology & Hepatology, 2019, https://doi.org/10.1016/S2468-1253(19)30147-5

 

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