Habitual Sleep Duration and the Colonic Mucosa-Associated Gut Microbiota in Humans—A Pilot Study
, Hashem B. El-Serag 4,5,6,7,9, Joseph F. Petrosino 2,6,7 and Li Jiao 4,5,6,7,8,9,*,†Round 1
Reviewer 1 Report
Healthy subjects with self-reported sleep duration – either short (n=16) or normal sleep length (n=47) -were compared on colonic microbiota. The subjects with short self-reported sleep duration were found to have a lower relative abundance of Sutterella and a higher relative abundance of Pseudomonas.
This seems not to be a hypothesis-driven study. What is a rationale for searching this associations? What kinds of results were expected?
It is post hoc division of study participants into two groups that are profoundly different in size.
The difference between weekday and weekend sleep duration and some other additional sleep times, e.g., weekend sleep duration, were not compared in two groups. Did the groups significantly overlap on weekend sleep duration?
Previous studies (ref 17-19) were not discussed in the light of the authors’ results.
It need not include a ref. (43) in Conclusions.
Supplementary Figures were included in the main text.
Author Response
Please see attached file.
Author Response File: 
Author Response.pdf
Reviewer 2 Report
Associations between microbiota and host acquire increasing attention recently, particularly interesting are time-related interactions since microbiota was shown to have rhythmicity of its own and feedback with the circadian rhythms and sleep of the host.
The reviewed paper presents some interesting and novel findings on human sleep habits in association with the colonic mucosa-associated gut microbiota. Results are presented clearly and supported with adequate statistics.
It seems like the paper can be published; however, several concerns are issued below:
- Authors discuss associations between colonic mucosa-associated gut microbiota with sleep duration, any associations between microbiota and habitual sleep phase/chronotype were left off-scope. This information is particularly important since metabolism, body mass index, risk of diabetes, and bad habits all have been shown repeatedly to be related to the later chronotype/sleep phase.
- Table 1 (Basic characteristics of the participants) provide information on age, sex, body mass index, two comorbidities (hypertension, and type 2 diabetes), alcohol, and smoking status, and ethnicity with no information on eating behavior of the participants: such information was most important considering the main topic of this study.
- Information regarding the prior history of antibiotics administration longer (longer, not just three months as indicated in Methods) especially related to investigated microbiota is essential for correct interpretations of the results.
- The authors provided no information on the exact timing of sampling, which is also crucial as rhythms of the gut microbiota have been demonstrated previously, and authors themselves mentioned it in Introduction and Discussion.
Author Response
Please see attached file
Author Response File: Author Response.pdf
Round 2
Reviewer 1 Report
The authors have addressed most of my previous comments. I support the publication of this manuscript.
Reviewer 2 Report
This paper provides some novel results, comments were appropriately addressed, recommended for publication.
