Comprehensive analysis of gut microbiota of a healthy population and covariates affecting microbial variation in two large Japanese cohorts

Abstract

Background Inter-individual variations in gut microbiota composition are observed even among healthy populations. The gut microbiota may exhibit a unique composition depending on the country of origin and race of individuals. To comprehensively understand the link between healthy gut microbiota and host state, it is beneficial to conduct large-scale cohort studies. The aim of the present study was to elucidate the integrated and non-redundant factors associated with gut microbiota composition within the Japanese population by 16S rRNA sequencing of fecal samples and questionnaire-based covariate analysis. Results A total of 1596 healthy Japanese individuals participated in this study via two independent cohorts, NIBIOHN cohort (n = 954) and MORINAGA cohort (n = 642). Gut microbiota composition was described and the interaction of these microorganisms with metadata parameters such as anthropometric measurements, bowel habits, medical history, and lifestyle were obtained. Thirteen genera, including Alistipes, Anaerostipes, Bacteroides, Bifidobacterium, Blautia, Eubacterium halli group, Faecalibacterium, Fusicatenibacter, Lachnoclostridium, Parabacteroides, Prevotella_9, Roseburia, and Subdoligranulum were predominant among the two cohorts. On the basis of univariate analysis for overall microbiome variation, 18 matching variables exhibited significant association in both cohorts. A stepwise redundancy analysis revealed that there were four common covariates, Bristol Stool Scale (BSS) scores, gender, age, and defecation frequency, displaying non-redundant association with gut microbial variance. Conclusions We conducted a comprehensive analysis of gut microbiota in healthy Japanese individuals, based on two independent cohorts, and obtained reliable evidence that questionnaire-based covariates such as frequency of bowel movement and specific dietary habit affects the microbial composition of the gut. To our knowledge, this was the first study to investigate integrated and non-redundant factors associated with gut microbiota among Japanese populations.

Typing of the Gut Microbiota Community in Japanese Subjects

“…Nishijima et al [ 12 ] also demonstrated that the gut microbiome structure in a Japanese population was considerably different from that of other populations, with at least one of the differences being the rich abundance of the genus Bifidobacterium . Park et al [ 18 ] also described the high abundance of Bifidobacterium as a feature of the gut microbiota of 1596 healthy Japanese individuals. Thus, a high abundance of Bifidobacterium seems to be notable in the structure of Japanese gut microbiota, representign an important genus, independent of the presence or absence of various diseases.…”

Altered gut microbiota and its association with inflammation in patients with chronic thromboembolic pulmonary hypertension: a single-center observational study in Japan

“…Hemodynamic data in all patients were assessed using right heart catheterization. The control participants were selected from the database at the National Institutes of Biomedical Innovation, Health and Nutrition and matched with patients with CTEPH in terms of age, sex, and body mass index (BMI) [ 24 ].…”

Average gut flora in healthy Japanese subjects stratified by age and body mass index

“…To date, several studies have aimed to elucidate gut microbiota in the healthy Japanese population and provided intriguing evidence regarding the average gut microbiota [ 14 , 15 , 17 , 18 ], although the numbers of subjects were relatively small compared with our study (367 [ 14 ], 516 [ 15 ], 277 [ 17 ] and 1,946 [ 18 ]). When comparing our results with those of previous studies, we found both consistency and inconsistency in our findings.…”

“…Furthermore, elucidation of outlier gut microbiota may lead to the identification of hidden factors, including specific diseases. However, reports analyzing the gut microbiotas of healthy populations, especially the Japanese population, are limited, and the sample sizes have been too small [ 13 , 14 , 15 , 16 , 17 , 18 ].…”