Gas stoves & childhood asthma in the US

Executive summary

* A four-page paper was widely reported with headlines such as "Gas stove pollution causes 12.7% of childhood asthma, study finds."

* The paper was a modelling exercise, which meant it could only produce estimates. The headlines claimed causation.

* The model used one number from a 2013 paper as its base. The researchers sought and found data since this date, but then ignored it.

* The one number chosen by the researchers was for current asthma. Had they chosen lifetime asthma, or all asthma, or wheeze (the main symptom of asthma), there would have been nothing to report.

* The one number was based on 10 studies, which dated back to 1977. Eight of these found no association between gas cooking and childhood asthma.

* The one number was claimed to be based on three North American and seven European studies, which were pooled together. There were in fact five North American and five European studies, which were pooled together. Since we have no idea how five and five became three and seven, the combined number can’t be dissected.

* The study was funded by an organisation that wants a carbon free world. There was an anti-gas/pro-electric motive from the outset. This was borne out in the methodology and the selection of one number that found something, ignoring vastly more numbers that found nothing.