Summary: A Canadian study finds that frequent use of household disinfectants is linked to changes in the infant gut microbiome and a higher risk of childhood overweight.
Household disinfectants linked to changes in infant gut microbes and higher BMI in young children, research published in CMAJ finds.
A study using data from the Canadian Healthy Infant Longitudinal Development (CHILD) birth cohort suggests that regular use of common household disinfectants may alter infants’ gut bacteria and is associated with increased body mass index (BMI) by age three. Researchers examined stool samples from 757 infants at 3–4 months and tracked weight outcomes at 1 and 3 years, comparing households that used disinfectants, conventional detergents, or eco-friendly cleaning products.
The team measured infant gut microbial composition and related it to parental reports of home cleaning habits. Analysis using World Health Organization growth charts showed notable differences in microbial communities among infants from homes with different cleaning routines.
Frequent use of disinfectant cleaners, such as multi-surface disinfectants used at least weekly, was associated with reduced abundance of some bacteria (including Haemophilus and Clostridium) and increased abundance of bacteria in the Lachnospiraceae family. Infants from households with weekly disinfectant use were about twice as likely to have higher levels of Lachnospiraceae at 3–4 months. By age three, those same children had higher BMI compared with peers not exposed to heavy disinfectant use during infancy.
By contrast, frequent use of conventional detergents did not show the same pattern of association, and households that reported using eco-friendly cleaning products had distinct microbiota profiles. Infants in eco-cleaner households showed lower levels of Enterobacteriaceae and were less likely to be overweight as toddlers. The investigators emphasize, however, that they did not find evidence that changes in Enterobacteriaceae directly mediated the lower overweight risk, suggesting other behavioral or lifestyle factors may explain this finding.
Anita Kozyrskyj, professor of pediatrics at the University of Alberta and principal investigator on the SyMBIOTA project, summarized the findings: “We found that infants living in households with disinfectants being used at least weekly were twice as likely to have higher levels of the gut microbes Lachnospiraceae at age 3–4 months; when they were 3 years old, their body mass index was higher than children not exposed to heavy home use of disinfectants as an infant.”
In a related commentary, epidemiologists Noel Mueller and Moira Differding of the Johns Hopkins Bloomberg School of Public Health note the biological plausibility of the link. They write that early-life exposure to disinfectants could increase childhood obesity risk through microbially mediated mechanisms, and they call for additional research to explore this possibility.
The study authors and commentators alike emphasize the need for further work that precisely identifies the active ingredients in cleaning products. Kozyrskyj acknowledged that a limitation of the current study was the inability to classify products by specific chemical constituents.
Study details: The research analyzed fecal microbial profiles from 757 infants aged 3–4 months from the CHILD cohort and compared maternal reports of household cleaning product use. The investigators assessed associations between early-life cleaning product exposure, infant gut microbiota composition, and subsequent BMI and overweight status at age 3.
Key findings: Greater frequency of household disinfectant use was associated with increasing abundance of Lachnospiraceae and decreasing abundance of Haemophilus in infant gut samples. Lachnospiraceae abundance significantly mediated the link between high disinfectant use in infancy and higher BMI and greater odds of overweight or obesity at age 3. Use of eco-friendly products correlated with lower odds of overweight by age 3, but this association was not explained by measured changes in infant gut microbes.
Funding: This study was funded by the Canadian Institutes of Health Research (CIHR) with support from the Allergy, Genes and Environment (AllerGen) Network of Centres of Excellence for the CHILD study.
Source: CMAJ. Organized by NeuroscienceNews.com. Original research: “Postnatal exposure to household disinfectants, infant gut microbiota and subsequent risk of overweight in children,” CHILD Study Investigators. Published September 17, 2018. doi: 10.1503/cmaj.170809
MLA: CMAJ. “Household Cleaners May Contribute to Obesity in Kids by Altering the Gut Microbiome.” NeuroscienceNews, 17 September 2018.
APA: CMAJ (2018, September 17). Household Cleaners May Contribute to Obesity in Kids by Altering the Gut Microbiome. NeuroscienceNews.
Chicago: CMAJ. “Household Cleaners May Contribute to Obesity in Kids by Altering the Gut Microbiome.” NeuroscienceNews. Accessed September 17, 2018.
Abstract
Postnatal exposure to household disinfectants, infant gut microbiota and subsequent risk of overweight in children
BACKGROUND: Emerging evidence links household cleaning products with childhood overweight, potentially through effects on the gut microbiome. This study examined whether infant gut microbial profiles mediate associations between home cleaning product use and risk of later overweight.
METHODS: From the CHILD birth cohort, maternal reports of cleaning product use were compared with infant fecal microbial profiles at 3–4 months and overweight outcomes at age 3.
RESULTS: In 757 infants, the abundance of specific gut microbes varied with household disinfectant and eco-friendly product use in a dose-dependent fashion. More frequent disinfectant use correlated with higher Lachnospiraceae abundance (adjusted odds ratio 1.93 for highest vs lowest quintile) and lower Haemophilus abundance (adjusted odds ratio 0.36). Greater eco-friendly product use was linked to lower Enterobacteriaceae (adjusted odds ratio 0.45). Lachnospiraceae abundance significantly mediated the association between top-tier disinfectant use and higher BMI z-scores and greater odds of overweight at age 3. The reduced overweight odds observed with eco-friendly product use were not mediated by Enterobacteriaceae abundance.
INTERPRETATION: Household disinfectant exposure was associated with higher BMI at age 3, mediated in part by infant gut microbial composition. Although eco-friendly cleaning correlated with lower risk of childhood overweight, the mechanism appears independent of the infant gut microbiota measured in this study.