Last Updated: February 27, 2019
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Big Idea: There is some evidence that early childhood exposure to certain environmental asthma triggers can cause asthma.
- Scientists have found that specific environmental exposures in early childhood appear to cause asthma, including: house dust mites, cockroaches, mold, tobacco smoke exposure, and outdoor air pollution.
- For example, there is evidence showing that exposure to tobacco smoke can cause asthma, making a child exposed to his or her mother’s smoking in utero 10 times more likely to get asthma and increasing the chance of other respiratory illnesses. One 2016 study found that exposure, in utero and in early childhood, can alter DNA methylation (the signaling tool that turns off genes) to result in the onset of asthma and allergies and a persistence of asthma later in adult life. (Potaczek et al, 2016.)