“Bleach” by Incase is licensed under CC BY 2.0

Could Household Cleaners Be Making Children Overweight?

MedicalResearch.com Interview with:

Dr. Kozyrskyj

Anita Kozyrskyj PhD
Professor in Pediatrics
Faculty of Medicine & Dentistry
School of Public Health
University of Alberta

MedicalResearch.com: What is the background for this study?

Response: Data for this study were collected in the Canadian Healthy Infant Longitudinal Development (CHILD) cohort of over 3,500 full-term infants born between 2009 and 2012. When infants were 3-4 months of age, parents provided a sample of their poop. At that time, parents checked-off responses to questions about their home, including type and frequency of cleaning product use. The infant poop was initially frozen, then thawed later to extract DNA from the sample and identify microbes on the basis of their DNA sequence. 

MedicalResearch.com: What are the main findings? 

Response: Frequent home use of disinfectants, as high as once daily, increased the chance of an infant having high levels of Lachnospiraceae in their gut microbiota and becoming overweight at age 3. This results suggest that gut microbiota were the culprit.

We took the statistical analysis one step further by conducting a mediation test. Using this mediation method, the higher levels of the Lachnospiraceae bacteria were found to be responsible for the association between disinfectant use and child overweight.

MedicalResearch.com: What should readers take away from your report?

Response: We know that cleaning products with antibacterial ingredients such as bleach or hydrogen peroxide, kill certain bacteria. That’s how they work. However, when some bacteria are killed, others which are not sensitive to the antibacterial agent increase in numbers.

This is a first study to show that frequent cleaning with disinfectants affects the composition of gut microbiota of infants living in these homes, such that some bacteria are reduced, for example Hemophilus, while others like the Lachnospiraceae increase in number.

Our study shows that infants are twice more likely to have high levels of Lachnospiraceae in their gut following heavy home use of disinfectants versus infrequent use. These findings could not be explained by other factors such as infant antibiotic use or birth method. The fact that we observed a dose-relationship between how often disinfectants were used versus concentrations of Lachnospiraceae is highly suggestive that the disinfectants were the culprit.

Findings from piglet studies also show similar changes to gut microbiota after continuous exposure to a disinfectant. From other animal experiments, we have learned that the Lachnospiraceae bacteria promote higher body fat and insulin resistance.

These changes to infant gut microbiota were not observed when households cleaned with eco-products.

MedicalResearch.com: What recommendations do you have for future research as a result of this work?

Response: These findings suggest we should not overuse disinfectants since they may harm our human microbiota. When infants are implicated, changing the composition of microbiota at a critical time of development may affect the immune system. An alternative would be to clean with eco-products. 

Disclosures: This study was funded by CIHR and AllerGen NCE. 


Mon H. Tun, Hein M. Tun, Justin J. Mahoney, Theodore B. Konya, David S. Guttman, Allan B. Becker, Piush J. Mandhane, Stuart E. Turvey, Padmaja Subbarao, Malcolm R. Sears, Jeffrey R. Brook, Wendy Lou, Tim K. Takarao, James A. Scott, Anita L. Kozyrskyj. Postnatal exposure to household disinfectants, infant gut microbiota and subsequent risk of overweight in children. Canadian Medical Association Journal, 2018; 190 (37): E1097 DOI: 10.1503/cmaj.170809

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Last Updated on September 20, 2018 by Marie Benz MD FAAD