Impact of cesarean section delivery and breastfeeding on infant gut microbiota at one year of age
Bibliographic record
Abstract
The gut microbiota is essential to human health, playing central roles in host metabolism and immunity. In a pilot study, we previously demonstrated that mode of delivery and breastfeeding influence the infant gut microbiota at 4 months of age. Here, we examine the impact of these critical early-life exposures in a larger cohort at 12 months of age. The study comprised a sub-sample of 190 healthy term infants from one centre participating in the Canadian Healthy Infant Longitudinal Development (CHILD) birth cohort study. Mode of delivery was determined from hospital records, and mothers reported infant diet at 3, 6 and 12 months postpartum. Antibiotic exposure was documented from hospital and prescription records. Gut microbiota was characterized by Illumina 16S rRNA sequencing of fecal samples collected at 12 months. Delivery and breastfeeding practices significantly influenced infant gut microbiota composition and diversity at one year of age. Regardless of breastfeeding or antibiotic exposure, infants delivered by emergency cesarean section had higher gut microbiota diversity compared to infants delivered vaginally or by elective cesarean section (p<0.001). Consistent with our pilot results at 4 months, emergency cesarean delivery was associated with lower relative abundance of Bacteroides (p<0.001); this difference was attenuated in breastfed infants. Independent of delivery mode or antibiotic exposure, and contrary to our findings at 4 months, breastfeeding exclusivity (none, partial or full) and duration (never, < 6 months, ≥ 6 months) were associated with progressively higher diversity, and increasing relative abundance of Bifidobacteria (p for trends all <0.01). Other taxa influenced by mode of delivery and breastfeeding included the Family Lachnospiraceae (increased following emergency cesarean delivery) and the Genera Veillonella , Lactobacillus and Megasphera (all increased among breastfed infants). Mode of delivery and breastfeeding are strong determinants of the infant gut microbiota, with persistent and potentially interactive effects throughout the first year of life. Breastfeeding appears to influence microbiota diversity differently at 4 versus 12 months of age, indicating that measures of diversity require cautious interpretation (including consideration of age at assessment), and that a single measure of nutrition may not adequately reflect the diverse exposures that occur during the weaning period. Ongoing research in the CHILD study will address the cumulative and long-term impact of these and other early-life exposures, and associated changes to the gut microbiota, on the development of allergic disease and other health outcomes.
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.001 | 0.003 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.001 | 0.000 |
| Open science | 0.000 | 0.001 |
| Research integrity | 0.000 | 0.001 |
| Insufficient payload (model declined to judge) | 0.001 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".