Appendix 2

2.a   More on the Strong Association between Breastfeeding Rate and Diagnosed Autism

    1)   In a U.S. study provided on the NIH website (Shamberger, 2011), looking at the correlation between autism and breastfeeding rates, observation of all 50 states as well as 51 counties revealed findings that "exclusive breast-feeding shows a direct epidemiological relationship to autism" and also, "there was a direct correlation (of increased autism rates) with the increasing percentage of women exclusively breast-feeding."(1) (parenthetical expressions added)


     2)  A study of interest (Whitely and colleagues) was conducted regarding 1189 children age 3 to 11 formally diagnosed with various forms of Autism Spectrum Disorder, residing in the U.K. and Republic of Ireland, drawing on records received between 2002 and 2007.  The records showed that 65% of the children with those conditions had been “exclusively breastfed” for over four weeks.(2)  After doing a search of available sources for a comparison figure for exclusive breastfeeding for over four weeks for the U.K. as a whole for the period in which those children would have been newborns, this author has come up with data from two different sources, which are consistent in leading to a figure of about 28%.(2)  So the children who turned out to be autistic had been breastfed at a rate over twice as high as what the comparable figure would have been for the U.K. as a whole. 


      3)  In an investigation of rates of breastfeeding among 45 Kentucky children diagnosed with autism (Williams et al.), the percent of ASD-diagnosed patients who had been breastfed at 6 months was 37%, as compared with 13% in the control group (or 14% in the general Kentucky population).(3)  The authors (two MD's) determined a "P value" regarding the above finding of .003, meaning the odds of that difference resulting purely from chance, as opposed to from a causal relationship, are 3 out of 1000.  The odds that the greatly increased level of autism found in the Whitely study (with a 26-times larger study group) resulted merely from chance would probably have been even smaller than 3 out of 1000.  And since those two studies provide the only data findable in an extensive web search in September of 2012 regarding this kind of comparison, the odds appear to be extremely small that those studies would find compatible findings indicating strong correlations between breastfeeding and autism unless there were an actual causal relationship there. 


     4)  A 2010 Canadian study, drawing data from a population-basedclinically-rich perinatal database,” investigated a very large cohort of nearly 130,000 births.  In that respect, it was second only to the Shamberger study, in studies on this topic.  Data from almost 127,000 of those children (those without identified genetic risk of autism) went into the study’s finding that there was a 25% increased risk of autism among children who were breastfed at discharge from the hospital, compared with those who were not.(4)


Note above what appear to be effects’ varying in relation to duration of exposure:  When the dividing line for comparison purposes was at discharge from the hospital, the increase in autism for breastfed infants was 25%.  When the cutoff was at four weeks, the increase in autism was 132% (65% divided by 28%).  When the cutoff was at six months, the increase was 185% (37% divided by 13%).   That same kind of "direct correlation (of increased autism rates) with the increasing percentage of women exclusively breast-feeding" was also found in the Shamberger study. 



For considerably more evidence concerning the relationship between breastfeeding and autism, go to


To read an interesting set of comments from mothers of autistic children about their breastfeeding histories, as were posted on a blog of the Autism Speaks organization, together with this author's observation about the merits of the blog to which they were responding, go to .



1)  Autism rates associated with nutrition and the WIC program.  Shamberger R.J., Phd, FACN, King James Medical Laboratory, Cleveland, OH  J Am Coll Nutr. 2011 Oct;30(5):348-53.  Abstract at  The full text, including the quoted passages, can be purchased for $7 or reference librarians at local libraries could probably obtain it at no charge.

2)  Trends in Developmental, Behavioral and Somatic Factors by Diagnostic Sub-group in Pervasive Developmental Disorders: A Follow-up Analysis, Table 9, and pp. 10, 14   Paul Whiteley (Department of Pharmacy, Health & Well-being, Faculty of Applied Sciences, University of Sunderland, UK), et al.  Autism Insights 2009:1 3-17;  go to the following link and find the link for this study close above the bottom of the list of studies at  Whitely et al. looked at a comparison figure of 54%, but that figure was unrealistically high for the general UK population, since it came from a study (Pontin et al.) of breastfeeding by mothers who were largely from “more affluent families”, in the words of that study’s authors; more affluent mothers are well known to breastfeed at unusually high rates in the U.K, U.S. and certain other countries.  For breastfeeding prevalence data that would apply to the general U.K. population, the authors of the Pontin study referred the reader to Infant Feeding 1995 (Foster et al.), which they say shows a 21% figure for exclusive breastfeeding for the next period following the first month; examination of the data in that book reveals that the 21% figure would apply at about eight weeks after birth, and that a figure in the upper 20%’s would apply at just after four weeks.  That is also compatible with a figure of about 28% for exclusive breastfeeding at four weeks provided in the 2010 update of the U.K.’s Infant Feeding publication in the U.K. Infant Feeding Survey - UK, 2010 Publication date: November 20, 2012, Chapter 2, at  An almost identical figure was found in the next-earlier U.K. Infant Feeding Survey (2005).

3)  Breastfeeding and Autism  P. G. Williams, MD, Pediatrics, University of Louisville, and L. L. Sears, MD, presented at International Meeting for Autism Research, May 22, 2010, Philadelphia Marriot

4)  Dodds et al., The Role of Prenatal, Obstetric and Neonatal Factors in the Development of Autism, J Autism Dev Disord (2011) 41:891–902  DOI 10.1007/s10803-010-1114-8, Table 6, at