Growing our understanding of pyloric stenosis

If you look up information about infant pyloric stenosis (PS) on the web or in a book, you may well come across the word “idiopathic”, meaning that PS “arises spontaneously or from an obscure or unknown cause”.

Sadly, this is medical jargon being used to cover up the facts that despite –
knowing since 1717 that babies have died of PS or gone to surgery for it,
– PS being the most frequent reason for infant surgery, and
– PS affecting between one and five (or even more) babies and their families in every 1,000 births
we haven’t yet done enough research to agree on what causes PS and how we can reduce its incidence.  Using a “big word” (idiopathic) may also be a convenient way of saving words and time to explain what we do know about PS.

breastfeeding1There is on the web a recently published medical journal editorial article with the title Beyond the Firstborn Son that argues that PS is not “idiopathic” at all.  Sadly, this editorial and the major report on a PS research project are two of countless valuable articles that lay people like me and most of our interested readers cannot afford to access: only the first page of the editorial and a brief abstract of the major report are freely available, but even these I recommend as “good reads”.

The editorial article’s subtitle also uses medical language which is worth working out: Epidemiology to enlighten the Parthenogenesis of Hypertrophic Pyloric Stenosis means: studying the incidence, distribution, and possible control of PS can help us to understand its causes.

The 21 October 2013 issue of this medical Journal features the major study by a Seattle team to which I referred in a previous post.  It studied 714 confirmed PS babies over 7 years (2003 – 09) to map what they had in common and compared these results with a 10 times larger control group: a very large project.

Among the discoveries made or confirmed –
– the incidence of PS declined during these 7 years from 1.4 to 0.9 per thousand births;
– during these years breastfeeding increased from 80% to 94%;
– compared with the controls, PS babies were more likely to be bottle feeding after birth (19.5% vs 9.1%),
– any duration or proportion of bottle feeding affected the risk factor,
– smoking (identified as a risk factor in previous work) was found to increase the risk of PS 1.5 fold,
– firstborns (and thus younger mothers) run a 1.8 fold higher risk, and
– older mothers’ risk of having a PS infant is halved.

Bottle feeding1These and other comparisons led the team to conclude that especially bottle feeding is associated with an increased risk of HPS, and that this effect seems to be strongest in older women and mothers of more than one child.  It was also found that although smoking increases the risk of a baby having PS it did not change the risk factor of the way the baby was fed.

This study and the large Danish study published in 2012 came to much the same conclusions.  They are also examples of the fact that discovering the causes of many medical conditions will likely be a slow and laborious process akin to assembling a huge jigsaw puzzle!

What can we conclude from the Danish and US studies showing the value of breastfeeding in lowering the risk of a baby having PS?

Mother and baby31                    It shows the way for more studies.  We know that PS is multi-factorial and the more we know about each risk factor, the better we can research whether and how these interact.  The findings about bottle feeding and smoking mentioned above are an example of this.

2                    The Seattle study confirmed previous findings that PS has been a Caucasian malady by a considerable margin, and that older mothers do not have a higher chance of having a PS baby (despite earlier studies coming to the opposite conclusion).

3                    The editorial points out that studies between 1975 and 1983 noted a rising rate of breastfeeding and incidence of PS and drew link between the two.  This new and large study has given significant reason to reject the earlier correlation.

4                    It is noted in the editorial that “bottle feeding” is difficult to define for the purposes of research.  I have mentioned the matter of the duration and proportion of bottle feeding.  The formula is another variable which could play a significant role in the acidity that is a key factor in the development of PS, as Dr Ian Rogers has shown (as reported in several posts).

5                    It does seem possible to conclude that the feeding mode of the first 6 months is more influential than the age of the mother, smoking, and how many children she has had.

6                    The editorial states: For a disease as common as pyloric stenosis, it is of benefit to have precise estimates of the common risk factors.  I might add that all the risk factors identified and quantified in these two studies are worthy of parents’ consideration.  However, other risk factors such as genetics or inheritance cannot be reduced by us – although I have come across at least two couples who knowingly grew their risk profile: both partners had a PS history – and of course had PS children.

It must be clear that although these two studies on the relationship between how an infant is fed and its chance of developing PS only deal with a small number of risk factors and issues around PS and infant surgery.  They are nevertheless significant to us all in several ways, and especially to new parents, to the pediatric medical community, and to those like me who would like to understand PS better and work to see its incidence fall.

2 thoughts on “Growing our understanding of pyloric stenosis

  1. Wendy

    Very enlightening. The bottle feeding issue is complex, isn’t it? In any case, it seems clear that breastfeeding is the way to go. My mother breastfed me until the surgery. She was also an older mother–40. Smoking, however, was not an issue. But surely, not smoking is something a mother can do to reduce the PS risk if only by a small percent. Love what you write about the word “idiopathic.” Another word for, “we really don’t know” and, in my opinion, haven’t cared enough to find out. Can’t wait for Dr. Ian Rogers to get the word out about his theories and the research that’s being done to support his ideas. May be able to get hold of that JAMA article next week. Will share it if I find it.

  2. Fred Vanderbom Post author

    Thanks for these comments, Wendy. I have never seen my mother smoke and after the trauma of spending World War 2 in a German occupied country, I doubt she had the means to smoke or to choose to not breastfeed in 1945!
    Each of these and other factors may represent just a small risk, but it’s so good that today’s parents can reduce their risk profile if they are aware of having one.
    I too am so very grateful for Dr Rogers’ interest in our work and willing to associate himself with it.


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