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Published on: August 7, 2017
Thirdhand smoke associations with the gut microbiomes of infants admitted to a neonatal intensive care unit: An
Thomas F Northrup1, Angela L Stotts2, Robert Suchting3
1Department of Family and Community Medicine, The University of Texas Health Science Center at Houston (UTHealth), McGovern Medical School, 6431 Fannin, JJL 324, Houston, TX, 77030, USA.
Insights
Thirdhand smoke (THS) exposure impacts hospitalized infants' gut microbiomes, altering bacterial diversity and abundance. This study highlights the need for further research into tobacco residue
Area of Science:
- Environmental Health
- Microbiology
- Neonatal Medicine
Background:
- Adult smokers exhibit microbiome differences compared to non-smokers.
- The impact of thirdhand smoke (THS), or post-combustion tobacco residue, on infant gut microbiomes is largely unexplored.
- Hospitalized infants in Neonatal Intensive Care Units (NICUs) are particularly vulnerable to environmental exposures.
Purpose of the Study:
- To investigate gut microbiome variations in infants admitted to the NICU based on their exposure to THS.
- To identify specific bacterial genera and overall microbiome diversity associated with THS exposure markers.
Main Methods:
- Studied 43 mother-infant dyads with varying household smoking habits.
- Collected carbon monoxide breath samples, bedside furniture nicotine wipes, infant urine samples (for cotinine), and stool samples for 16S rRNA gene sequencing.
- Utilized negative binomial regression to model bacterial abundances and microbiome diversity, controlling for confounding factors.
Main Results:
- Infants from non-smoking homes or with lower surface nicotine levels had greater microbiome alpha-diversity.
- Seven of eight modeled bacterial genera showed associations with THS exposure markers (household smoking, surface nicotine, urine cotinine).
- Lower Bifidobacterium abundance was linked to increased nicotine exposure via furniture, urine cotinine, and household smoking.
Conclusions:
- Thirdhand smoke exposure is associated with altered gut microbiome composition and diversity in NICU-admitted infants.
- Findings suggest that even post-combustion tobacco residue can significantly affect the developing infant gut microbiome.
- Further research is warranted to understand the long-term effects of tobacco-related exposures on infant gut microbiome development.
Introduction:
Microbiome differences have been found in adults who smoke cigarettes compared to non-smoking adults, but the impact of thirdhand smoke (THS; post-combustion tobacco residue) on hospitalized infants' rapidly developing gut microbiomes is unexplored. Our aim was to explore gut microbiome differences in infants admitted to a neonatal ICU (NICU) with varying THS-related exposure.
Methods:
Forty-three mother-infant dyads (household member[s] smoke cigarettes, n = 32; no household smoking, n = 11) consented to a carbon monoxide-breath sample, bedside furniture nicotine wipes, infant-urine samples (for cotinine [nicotine's primary metabolite] assays), and stool collection (for 16S rRNA V4 gene sequencing). Negative binomial regression modeled relative abundances of 8 bacterial genera with THS exposure-related variables (i.e., household cigarette use, surface nicotine, and infant urine cotinine), controlling for gestational age, postnatal age, antibiotic use, and breastmilk feeding. Microbiome-diversity outcomes were modeled similarly. Bayesian posterior probabilities (PP) ≥75.0% were considered meaningful.
Results:
A majority of infants (78%) were born pre-term. Infants from non-smoking homes and/or with lower NICU-furniture surface nicotine had greater microbiome alpha-diversity compared to infants from smoking households (PP ≥ 75.0%). Associations (with PP ≥ 75.0%) of selected bacterial genera with urine cotinine, surface nicotine, and/or household cigarette use were evidenced for 7 (of 8) modeled genera. For example, lower Bifidobacterium relative abundance associated with greater furniture nicotine (IRR<0.01 [<0.01, 64.02]; PP = 87.1%), urine cotinine (IRR = 0.08 [<0.01,2.84]; PP = 86.9%), and household smoking (IRR<0.01 [<0.01, 7.38]; PP = 96.0%; FDR p < 0.05).
Conclusions:
THS-related exposure was associated with microbiome differences in NICU-admitted infants. Additional research on effects of tobacco-related exposures on healthy infant gut-microbiome development is warranted.
