Review for 10.1186/s12876-024-03467-6 (2024)

Title: Birth Characteristics and Risk of Colorectal Cancer
Version: 1 Date: 17 Aug 2024
Reviewer:  Luís Carlos MacHado Junior
Reviewer's report:
GENERAL COMMENTS
The article focuses an issue of clinical relevance, and can contribute to the knowledge about this
issue. But some modifications can make it more suitable for publication.
FORMAL ASPECTS
- Introduction, third paragraph,  “Consequently we also included other birth lengths, placental
weights and other birth characteristics .  .  .”; change to “Consequently we also included birth
lengths, placental weights and other birth characteristics .  .  .”
- In Results, “Effect of low birth weight on colorectal cancer”, in the first line, you write “ .  .  . to
analyze the relationship between high birth weight .  .  . ”. please correct to “low birth weight”.
- In Discussion, last paragraph, seventh line, “ .  .  . according to the classification method
included in the study.”; it is better “ .  .  . according to the classification method adopted in
each study.”.
- In table 1, it lacks the explanation for the expression “NA”.
- In table 2, I suppose that “NOS” mean Newcastle-Ottawa Quality Assessment Scale. But what
I mean is that it is not só obvious. Make it clear in the table. I also recommend you to write
under the table how this scale is built and what is considered a good score. I agree that reading
the text, it is possible to understand the tables, but there is a traditional recommendation that the
reader could be able to understand the tables without having to look again at the text.
- In the Abstract, Results, the expression “fetal dysplasia” is not recommendable. It is very
confusing. I would like to write “fetal growth restriction” (see comments below), but it is not
possible to be sure about this. I suggest “fetal environment”.
METHODS
- I recommend, in Methods or even in Results, to explain the meaning of “ponderal index”.
- The variable birthweight, especially low birth weight, encompasses more than one condition.
Low birth weight may result from preterm birth, from fetal growth restriction (FGR), or from
both. Nowadays, with an adequate prenatal follow up, especially if early ultrasould evaluation
of gestational age is available, it is possible to distinguish these both causes of low birth weight.
But I understand that the authors of the articles you revised, accessing the weight of neonates
born 40 years ago or even more, were not able to make this distinction. Indeed, after reading
the present article, I conducted myself a quick search with the terms ”fetal growth restriction
colorectal cancer”, and it retrieved almost nothing. What happens is that it is possible that these
both causes of low birthweight have distinct influences in colorectal cancers (1).
The more recent literature about fetal origins of noncommunicable diseases in adulthood (“fetal
programming”)  has been giving more emphasis in FGR, instead of birthweight (1 – 3, to
cite only a few). It is possible that part of the contradictory results you have found in your
study is because of these distinct causes for low birthweight. The finding of a significant
association between low placental weight and cancer is suggestive of the effect of FGR, because
low placental weight is common in this condition. I recommend you to include this issue in
Discussion, and suggest you to discuss if this could be one of the reasons fot the contradictory
results.
OTHER ASPECTS
You authors comment that the results you found are somehow contradictory, and I agree with
you. Taking this into account, I recommend you to write a final paragraph in Discussion, not
necessarily as distinct section, giving a sinthesis of your conclusions. In the present form, the
reader needs to read the Discussion some two or three times, with attention, to have his sinthesis
in mind.
1-Barbara T Alexander, John Henry Dasinger, Suttira Intapad. Fetal programming and
cardiovascular pathology. Compr Physiol. 2015 Apr;5(2):997-1025. doi: 10.1002/cphy.c140036
2-José Alfredo Aguayo-Guerrero, Sonia León-Cabrera, Galileo Escobedo. Molecular
mechanisms involved in fetal programming and disease origin in adulthood. J Pediatr Endocrinol
Metab. 2023 May 29;36(7):615-627. doi: 10.1515/jpem-2022-0491.
3-Julia E Heck, Di He, Carla Janzen, Noah Federman, Jorn Olsen, Beate Ritz, Johnni Hansen.
Fetal programming and Wilms tumor. Pediatr Blood Cancer.. 2019 Jan;66(1):e27461. doi:
10.1002/pbc.27461. Epub 2018 S