Occupational use of disinfectants during pregnancy is associated with allergic diseases in children, suggests a new study from Japan.

For this study, researchers analysed data from 80,000 pairs of mothers and their children from the Japan Environment and Childrens Study enrolled between January 2011 and March 2014. Information about occupational use of disinfectants and diagnosed allergic diseases such as asthma, eczema and food allergies in children at 3 years of age was provided by the mothers. Majority of mothers (88%) reported no exposure to disinfectant during pregnancy; 5% reported exposure one to three times per month; another 5% reported exposure one to six times per week. Daily exposure was reported by 1.7% of mothers. “Outcomes were adjusted for family allergy history, exposure to indoor cigarette smoke and alcohol consumption during pregnancy, maternal stress, night shift work, occupation (healthcare worker or not) during pregnancy, household income, the presence of older siblings, exclusive breastfeeding, and daycare attendance at 1 year of age”.

Overall, 7.7% of mothers had their children diagnosed with asthma at 3 years of age; 7.3% reported eczema, while 6.3% reported food allergies.

Compared to mothers who did not use disinfectants at all, those who used them daily had a greater likelihood of their children being diagnosed with asthma by 3 years of age with an adjusted odds ratio (aOR) of 1.26. Those who used them one to six times in a week were also more likely to have children with asthma with aOR of 1.18. The probability of eczema was 1.29 times higher in women exposed to disinfectants minimum once in a week and 1.16 times higher in women with exposure one to six times per week. No significant association was noted between food allergy and maternal exposure to disinfectant.

This association persisted even after adjusting for maternal occupation given that nearly 21% of the mothers were healthcare professionals.

Mothers who tend to clean too much should take caution. This study has linked prenatal use of disinfectants by mothers to increased risk of asthma and eczema in their children, a finding which is of public health importance. Considering their significant place in prevention of infectious diseases, particularly in light of the ongoing pandemic, the authors also call for larger studies to validate their findings and to also study the mechanisms responsible for this association. The current study hypothesizes that this association could be due to alteration in the gut microbiota of the newborn which is affected by change in the dermal flora of the mother because of the use of disinfectant. Or, it may be due to modification of the fetal immune system because of exposure to volatile organic compounds during pregnancy.

 Reference

1. Kojima R, et al. Prenatal occupational disinfectant exposure and childhood allergies: the Japan Environment and Children’s study. Occupational and Environmental Medicine. 28 March 2022. doi: 10.1136/oemed-2021-108034