Environmental toxicants in breast milk of Norwegian mothers and gut bacteria composition and metabolites in their infants at 1 month

Study information

Reviewed Marked as Reviewed by Claregrieve1 on 2023-5-24

study design

prospective cohort

Citation

PMID PubMed identifier for scientific articles.

30813950

DOI Digital object identifier for electronic documents.

10.1186/s40168-019-0645-2

URI

Authors

Iszatt N, Janssen S, Lenters V, Dahl C, Stigum H, Knight R, Mandal S, Peddada S, González A, Midtvedt T, Eggesbø M

Journal

Microbiome

Year

2019

Keywords:

Birth cohort, Breast milk, Infant gut microbiome, Short-chain fatty acids, Toxicants

BACKGROUND: Early disruption of the microbial community may influence life-long health. Environmental toxicants can contaminate breast milk and the developing infant gut microbiome is directly exposed. We investigated whether environmental toxicants in breastmilk affect the composition and function of the infant gut microbiome at 1 month. We measured environmental toxicants in breastmilk, fecal short-chain fatty acids (SCFAs), and gut microbial composition from 16S rRNA gene amplicon sequencing using samples from 267 mother-child pairs in the Norwegian Microbiota Cohort (NoMIC). We tested 28 chemical exposures: polychlorinated biphenyls (PCBs), polybrominated flame retardants (PBDEs), per- and polyfluoroalkyl substances (PFASs), and organochlorine pesticides. We assessed chemical exposure and alpha diversity/SCFAs using elastic net regression modeling and generalized linear models, adjusting for confounders, and variation in beta diversity (UniFrac), taxa abundance (ANCOM), and predicted metagenomes (PiCRUSt) in low, medium, and high exposed groups. RESULTS: PBDE-28 and the surfactant perfluorooctanesulfonic acid (PFOS) were associated with less microbiome diversity. Some sub-OTUs of Lactobacillus, an important genus in early life, were lower in abundance in samples from infants with relative "high" (> 80th percentile) vs. "low" (< 20th percentile) toxicant exposure in this cohort. Moreover, breast milk toxicants were associated with microbiome functionality, explaining up to 34% of variance in acetic and propionic SCFAs, essential signaling molecules. Per one standard deviation of exposure, PBDE-28 was associated with less propionic acid (- 24% [95% CI - 35% to - 14%] relative to the mean), and PCB-209 with less acetic acid (- 15% [95% CI - 29% to - 0.4%]). Conversely, PFOA and dioxin-like PCB-167 were associated with 61% (95% CI 35% to 87%) and 22% (95% CI 8% to 35%) more propionic and acetic acid, respectively. CONCLUSIONS: Environmental toxicant exposure may influence infant gut microbial function during a critical developmental window. Future studies are needed to replicate these novel findings and investigate whether this has any impact on child health.

Experiment 1

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Reviewed Marked as Reviewed by Claregrieve1 on 2023-5-25

Curated date: 2021/01/10

Curator: WikiWorks

Revision editor(s): WikiWorks, Claregrieve1

Subjects

Location of subjects: Norway

Host species Species from which microbiome was sampled. Contact us to have more species added.: Homo sapiens

Body site Anatomical site where microbial samples were extracted from according to the Uber Anatomy Ontology: Feces Cow dung,Cow pat,Droppings,Dung,Excrement,Excreta,Faeces,Fecal material,Fecal matter,Fewmet,Frass,Guano,Matières fécales@fr,Merde@fr,Ordure,Partie de la merde@fr,Piece of shit,Porción de mierda@es,Portion of dung,Portion of excrement,Portion of faeces,Portion of fecal material,Portion of fecal matter,Portion of feces,Portion of guano,Portion of scat,Portionem cacas,Scat,Spoor,Spraint,Stool,Teil der fäkalien@de,Feces

Condition The experimental condition / phenotype studied according to the Experimental Factor Ontology: environmental exposure measurement environmental exposure measurement

Group 0 name Corresponds to the control (unexposed) group for case-control studies: one-month age infants exposed to low chemical breast milk (<20th percentile)

Group 1 name Corresponds to the case (exposed) group for case-control studies: one-month age infants exposed to high chemical breast milk

Group 1 definition Diagnostic criteria applied to define the specific condition / phenotype represented in the case (exposed) group: infants with high chemical exposure (≥ 80th percentile breast milk toxicant exposure)

Group 0 sample size Number of subjects in the control (unexposed) group: 45

Group 1 sample size Number of subjects in the case (exposed) group: 45

Antibiotics exclusion Number of days without antibiotics usage (if applicable) and other antibiotics-related criteria used to exclude participants (if any): 2 weeks

Lab analysis

Sequencing type: 16S

16S variable region One or more hypervariable region(s) of the bacterial 16S gene: V4

Sequencing platform Manufacturer and experimental platform used for quantifying microbial abundance: Illumina

Statistical Analysis

Data transformation Data transformation applied to microbial abundance measurements prior to differential abundance testing (if any).: relative abundances

Statistical test: Mann-Whitney (Wilcoxon)

Significance threshold p-value or FDR threshold used for differential abundance testing (if any): 0.05

MHT correction Have statistical tests be corrected for multiple hypothesis testing (MHT)?: Yes

Confounders controlled for Confounding factors that have been accounted for by stratification or model adjustment: gestational age

Alpha Diversity

Shannon Estimator of species richness and species evenness: more weight on species richness: increased

Signature 1

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Reviewed Marked as Reviewed by Claregrieve1 on 2023-5-25

Curated date: 2021/01/10

Curator: Shaimaa Elsafoury

Revision editor(s): Fatima, LGeistlinger, WikiWorks

Source: Figure 2

Description: Differentially abundant sequences in the high vs. low chemical exposure groups.

Abundance in Group 1: increased abundance in one-month age infants exposed to high chemical breast milk

NCBI	Quality Control	Links
Clostridium
Enterococcus
Streptococcaceae

Revision editor(s): Fatima, LGeistlinger, WikiWorks

Signature 2

Edit History Delete

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Reviewed Marked as Reviewed by Claregrieve1 on 2023-5-25

Curated date: 2021/01/10

Curator: Shaimaa Elsafoury

Revision editor(s): WikiWorks

Source: Figure 2

Description: Differentially abundant sequences in the high vs. low chemical exposure groups.

Abundance in Group 1: decreased abundance in one-month age infants exposed to high chemical breast milk

NCBI	Quality Control	Links
Lactobacillus
Veillonella

Revision editor(s): WikiWorks