Increases and decreases in childhood obesity as related to corresponding earlier increases and decreases in breastfeeding


(This is a supplement to information presented in Part 4 at


Regarding the relationship between breastfeeding and childhood obesity, there has been only one study of the type that is acknowledged to be the “gold standard” type (a large randomized controlled trial, or RCT); that study found that obesity at age 16 was significantly increased among children who had been more breastfed.5  In addition to that, substantial scientific evidence indicates that PCBs, which are exceptionally high in typical human milk,1 cause obesity.  An animal study found that various kinds of PCBs promote fat cell development and increase the size of fat cells.19  Another study team, summarizing previous research, stated that "PCBs exposure is closely associated with obesity and diabetes."20  Another study found that low-level exposure of mice to PCB resulted in "marked deposition" of lipid within the abdominal cavity as well as increase in body weight and adipose mass.22  


It is also of interest to consider effects of PCBs on activity levels, since inactivity is a known risk factor for obesity.  Several human studies and at least four experiments with animals have found reduced activity (often greatly reduced) to be an effect of exposure to PCBs.16,54  At least one of the human studies found reduced activity to be associated with higher PCB levels in a population considered to have only normal background exposures to PCBs.54 




Amid the general increases of childhood obesity in Europe, there has been a small number of multi-year national declines of child obesity; and there has also been a small number of multi-year national declines in breastfeeding, along with the generally increasing trend in that feeding type; and the declines in breastfeeding appear to have always preceded the declines in obesity by a number of years that corresponds to the ages of the increasingly-obese children.  It appears that, in every case of significant national decline of childhood obesity in Western or Northern Europe, any existing high-quality national data about breastfeeding history has shown a corresponding decline in the earlier breastfeeding.


Increases and declines in obesity in Europe and corresponding earlier increases and declines in breastfeeding: 

 Given the high levels of PCBs in human milk in recent decades1 and the strong evidence linking PCB exposures with obesity (see earlier), it is of interest to see (below) a chart showing trends in breastfeeding since 1980 for the European region.

 Fig. 3


 (Above chart downloaded from WHO/Europe HFA website, Jan. 2013.)


It is easy to see in this chart a predominantly upward general trend in breastfeeding at 6 months in Europe.  That increase began in about 1970.142


(Odd places in this chart: the steeply-dropping blue line on the left, for Bulgaria, was probably related to curtailment of breastfeeding out of concern for transmission of fallout from the 1986 Chernobyl nuclear accident.153  The magnitude of the rise for Hungary in the middle is apparently greatly exaggerated as a result of changes in data collection methods; other, recent evidence from WHO and Hungary shows Hungarian breastfeeding rates to be merely average.137)

 When observing the above chart, we should bear in mind that there has also been a strong upward trend in childhood obesity in Europe in recent decades.83  As indicated in combined data for 2-19-year-olds, the increase appears to have started to become detectable in the early 1980s,154 about a decade after breastfeeding began to increase.142  This seems to be another example of the pattern seen in the U.S. (Figure 2 at, of childhood obesity increasing after breastfeeding began increasing.  A closer look at details within the overall picture can be especially interesting (see below).

A recent, different version of the above chart is shown below.  Although less complete, it is better for enabling a close look at certain details.

   Fig. 4


For helpful instructions on use of the WHO European Health Information Gateway, see reference no. 159


The decline of breastfeeding in Germany after 2002 is a notable example of the relationship between changing breastfeeding rates and later changes in childhood obesity.  Figure D-3 just below shows an enlargement of the relevant section from Figure D-2 above.  A study team observed that, although overweight and obesity among 12-16-year-old boys were increasing between 2004 and 2008, a significant decline was taking place among the 4-8-year-old age group during those same years.89  So it is of interest to mark off the birth years of the 12-16-year-olds (1988-1996,  “A” below) as well as the birth years of the 4-8-year-old group (1996-2004, “B” below).

Fig. 5

.Changing breastfeeding trends in Germany


 It is easy to see an increase in breastfeeding across the span of the birth years of the A group and a decline of breastfeeding across the birth years of the B group.  That increase and that decrease in breastfeeding may be related to later changes that took place in obesity in those same age groups, as follows:

   a) a later increase of obesity that took place in children born when breastfeeding was increasing, and

   b) a later decline of obesity that took place in children born when breastfeeding was declining.


Both of the above obesity trends were reported in the above-mentioned study.89


There was another age group intermediate in age between the oldest group, with increasing rates of both breastfeeding and obesity, and the youngest group with declining rates of both.  No change in obesity was observed in the intermediate group.


Updates to the above data, from other studies, are also of interest.  Data through 2009/10 showed that breastfeeding at 6 months was at a slightly higher level than the 2004-5 low.166  And later obesity data showed that children born around 2009-10 grew to have slightly more obesity than children born around 2004-05.167  This constituted the third leg of a changing course of obesity, parallel with a similar, earlier changing course of breastfeeding, providing additional support for the following generalization:  Changing trends in obesity have tracked well with earlier changing trends in breastfeeding.



Among 2-to-5-year-old children in the Netherlands between 1992-96 and 1997-2001, obesity declined 26%.169  So it is relevant that breastfeeding in the Netherlands declined between 1990 and 1997. (See Figure D-2 above and also reference no. 168.)   Most of the 2-to-5-year-olds whose obesity was declining in 1992-2001 would have been born in the years when breastfeeding is shown (above) to have declined.


There is considerable additional evidence of decreases in childhood obesity having followed declines in breastfeeding, providing still more examples of health improvements that took place when decreasingly-breastfed children grew older.  See Additional examples below.


All of the above might be dismissed as a surprising number of coincidences except for the facts that

  a) they are completely in line with what would be predicted on the basis of the highest-quality evidence about the effects of breastfeeding in relation to obesity; bear in mind the results of the PROBIT RCT study mentioned in part 1 for the highest-quality evidence, and remember the reasons why observational evidence (the only kind that has shown favorable effects of breastfeeding) is authoritatively considered to be of low quality (part 2);

   b) the numerous examples (above and to follow) of increasing or declining obesity following increasing or declining breastfeeding apparently include all of the cases in which there is data of sufficiently high quality to permit establishing reliable trends in breastfeeding.  Notice that, although there are many data points that could be connected with lines for individual countries (as WHO had done in 2013, for Figure D-1), WHO now only shows trend lines for countries that have annual survey results (see Figures 4 and 5).  That is probably in recognition of problems in representativeness and comparability of the data when surveys are only carried out every several years.  Substantial internet research has indicated that, in every case in which a national percentage of childhood obesity has declined for several years, any annual data for 6-month breastfeeding for earlier years for that country shows corresponding declines in breastfeeding that preceded the later declines in obesity.  The ages of the children with declining obesity have always been appropriate for linking with declines in breastfeeding that were taking place during the children’s birth years, in the many examples provided above and below.


Additional examples of declines in breastfeeding and corresponding later declines in obesity:


Sweden:  A section of Figure D-1 has been snipped out and inserted below, to facilitate focusing on details.  Spans of years have been marked and labeled, to permit observation of changes in Swedish breastfeeding during specific time periods, for comparison with corresponding later changes in child obesity.




A study team investigated changing trends in obesity in various Swedish child age groups between 2004 and 2015 and found that changes in trends differed among the various age groups.139  So it is of interest to subtract the groups’ ages from the years of the 2004-2015 period to see when the children in the various groups were born, as depicted in the above chart. The marked timespans (A through D) indicate the birth years of the children who were 17, 14, 11, or 4 years old, respectively, at the beginning and end of the 2004-2015 period.  As is obvious, there were increases in breastfeeding across the birth timespans of each of the three oldest groups (A, B, and C). And increasing trends in obesity were observed in the data for each of those increasingly-breastfed age groups when the children grew older.139  The increase of obesity was greatest in the A group, in accord with that group’s having undergone the greatest increase in breastfeeding.


On the other hand, breastfeeding was clearly declining when the 4-year-olds (the D group) were being born, between 2000 and 2011.  And by the time these children became four years old, the trend of their obesity was also found to be declining.139  Even though the direction had changed, the trend of obesity again turned out to be in the same direction as the trend in breastfeeding had been moving during the children’s birth years.



A decline in obesity was reported among 6-13-year-olds in Switzerland between 2002 and 2007.155  Again, there is good evidence of substantial decline of breastfeeding taking place in that country during the years when most of those children were being born, mainly in the 1990s.  In a 1994 study carried out for the Swiss Federal Office of Public Health, it was found that 80% of babies were breastfed exclusively for at least one month, based on a survey with a high participation rate.156  But a later study found that, in 2000, only 35.9% of infants were being exclusively breastfed even while the mothers and infants were still in the hospital.157  That indicated a major decline in the most intensive type of breastfeeding during the birth years of most of the children whose obesity percentage was declining in the 2000s.



There was apparently a decline of breastfeeding in Norway between 2006 and 2013, as can be seen in Figure D-2.  Very little has been published regarding childhood obesity trends in Norway following those years, but one study did find a decline in BMI z-scores (a normal metric for overweight and/or obesity) of 2-to-6-year-old overweight children In Norway during the 2014-2016 period.158  Those authors found less BMI decline among older children;158

that means that more decline of obesity took place among the children whose birth years occurred farther along in the decline of breastfeeding that took place between 2006 and 2013.


In a study that compared trends in childhood obesity in 11 European countries from 2007 to 2017, Greece, Italy, and Portugal were reported to have had declines in obesity.161  Unfortunately, it is difficult to establish past trends in breastfeeding in many countries because of differing definitions and survey methods that have been used in breastfeeding surveys.162,163







-   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  


 5) Martin et al., Effects of promoting longer-term and exclusive breastfeeding on adolescent adiposity, JAMA Pediatr, 2017, at


- 16) 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  See last paragraph above Method 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  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


-  20) Su S et al., Oleanolic acid attenuates PCBs-induced adiposity and insulin resistance via HNF1b-mediated regulation of redox and PPARγ signaling, J Free Radical Biology and Medicine, 2018,


-  22) Arsenescu et al., Polychlorinated Biphenyl-77 Induces Adipocyte Differentiation and Proinflammatory Adipokines and Promotes Obesity and Atherosclerosis, Environ Health  Perspect, 2008,


-  54) U.S. ATSDR:  Toxicological Profile for Polychlorinated Biphenyls (PCBs), 2000, p. 185 at


-  83) Wickramasinghe K et al., Childhood overweight and obesity abatement policies in Europe, Obesity Reviews, 2021,


 -  89) Bluher S et al., Age-specific stabilization in obesity prevalence in German children: A cross-sectional study from 1999 to 2008, International Journal of Pediatric Obesity, 2011, at


-  133) WHO Country Profile (for Malta) on Nutrition, Physical Activity and Obesity, citing a 2012 WHO source; see second bar chart; at

-  137) Six-month breastfeeding in Hungary appears in Figure D-1 to have been outstandingly high in the most recent decades, including well over twice as high as in Malta in 2007; but Hungary was shown in other WHO data (of 2012) to have an exclusive breastfeeding rate at 6 months merely equal to that of Malta.133  Official Hungarian data (Central Statistics Office, 2009) indicates breastfeeding at 4-5 months of age to be only 43.8%. (Elmadfa I et al., European Nutrition and Health Report 2009, Karger, 2009, p. 317, There have been various different definitions of breastfeeding and different methods of data collection that have been applied at different times.  Data such as in Figures 3 and 4 may not be suitable for some purposes.


-  139) Eriksson M et al., Trends in prevalence of thinness, overweight and obesity among Swedish children and adolescents between 2004 and 2015, Acta Paediatrica, 2018, at


-  142) Re early increases of breastfeeding in Europe:  See Figure D-1 for period after 1980. For the 1970s for France, see Differential trends in breastfeeding according to maternal and hospital characteristics, Acta Paediatrica, 2007,; the proportion of newborns breastfed in maternity units increased regularly throughout the 1970s;

for Norway, see Fig. 11 in The Resurgence of Breastfeeding, 1975-2000, The transcript of a Witness Seminar, Edited by S M Crowther et al.

  For Germany, “a steady increase since an historic low point in the middle of the 1970s,” Kersting M and Dulon M, Assessment of breast-feeding promotion in hospitals and follow-up survey, Public Health Nutrition, 2001, DOI:   10.1079/PHN2001321

 For elsewhere since about 1970:  Cable N et al., Gender differences in the effect of breastfeeding on adult psychological well-being, European Journal of Public Health, 2012, “Breastfeeding has been increasing since 1970.”, at  

  Also Zetterstrom, Breastfeeding and infant-mother interaction, Acta Paediatrica, 2007, p. 76,



-  153) Marples DR, The Social Impact of the Chernobyl Disaster, Mcmillan Press Ltd., 1988, p. 48


-  154) Ng M et al., Global, regional, and national prevalence of overweight and obesity in children and adults during 1980-2013: a systematic analysis for the Global Burden of Disease Study 2013, The Lancet, 2014, at

Figure 2b shows obesity history for children at ages 2-19, indicating a barely perceptible increase taking place in 1980-83 and then slowly continuing upward until more rapid increase begins after 1995.


-  155) Aeberli I et al., Decrease in the prevalence of paediatric adiposity in Switzerland from 2002 to 2007, Public Health Nutrition, 2009, at


-  156) Conzelmann-Auer and Ackermann-Liebrich U, Frequency and duration of breast-feeding in Switzerland, Soz Praventivmed, 1995, DOI:, at


-  157) Merten S and Ackermann-Liebrich U, The Baby-Friendly Hospital Initiative in Switzerland: Trends over a 9-Year Period, Journal of Human Lactation, 2013, DOI: 10.1177/0890334413483923 jhl.sagepub.c,



-  158) Westergren T et al., Prevention of overweight and obesity in a Norwegian public health care context: a mixed-methods study, BMC Public Health, 2021, at


-  159) Go to Click on HFA Explorer, then on Select Indicators.  Then scroll well down to bold heading, "Maternal and child health," then select Proportion of infants breastfed at (6) months. Then Select countries. 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. (Identification of countries may require entering only a few countries at a time.)


  160) Colen CG and Ramey DM, Is Breast Truly Best? Estimating the Effect of Breastfeeding on Long-term Child Wellbeing in the United States Using Sibling Comparisons, So Sci Med, 2014, at

-  161) Buoncristiano M, Childhood overweight and obesity in Europe: Changes from 2007 to 2017, Obesity Reviews, 2021 (see Figures 1 and 2),  at 


-  162) Elmadfa I et al., European Nutrition and Health Report 2009, Karger, 2009, p. 200,


-  163) Cattaneo A et al., Are data on the prevalence and duration of breastfeeding reliable? The case of Italy. Acta Paediatr 89, 2000


-  166) Weissenborn A et al., Breastfeeding frequency and duration of breastfeeding in Germany, a systematic overview, Healthcare, 2016, Abb. (figure) 3, at


-  167) Kess A et al., Further stabilization and even decrease in the prevalence rates of overweight and obesity in German children and adolescents from 2005 to 2015, Public Health Nutrition, 2017.  Table 1. See the column for 4-7.99-year-olds, noting that those whose obesity data is shown for 2015 would have been born in or close to 2010


-  168) As well as Figure D-2, also see Yngve and Sjostrom, Breastfeeding in countries of the European Union and EFTA: current and proposed recommendations, rationale, prevalence, duration and trends, Public Health Nutrition, 2001, p. 640  DOI: 10.1079/PHN2001147


-  169) Cattaneo A et al., Overweight and obesity in infants and pre-school children in the European Union: a review of existing data, Obesity Reviews, 2009, doi: 10.1111/j.1467-789X.2009.00639.x  Table 4.