The other comment betrays the reason: because the numbers are bogus and are artificially inflated to be high by making a query too broad (it includes marbles, BB balls, batteries, etc).
Just another example of the FUD spread by CPSC which people ended up eating wholesale.
Which query are you referring to? It's important to understand that the first step in a systematic review is to identify all the potentially relevant literature (the "search"), only after which are the studies found screened for inclusion. We're conservative in the direction of over-inclusion during the "search", but in the opposite direction during the "screen".
We - are you one of the authors? Perhaps you can clarify the following paragraph from [1], page 8:
>Inclusion Criteria and Variable Classification:
>Subjects from 0-17 years old were included using a primary search term for diagnosis of “ingested object” from the time period of 2002-2015. Cases of ingested
objects were classified as “suspected magnet ingestion” (SMI) if the term “magnet” appeared anywhere in the narrative section of the database.
Where's the screening part you mention? I didn't find anywhere that the inclusion criteria implied that magnets have actually been ingested - or that the results were filtered in any way other than a keyword search.
E.g.: "Child ingested a marble, parent worries that it could have been a magnet" would pass this inclusion criterion.
Just another example of the FUD spread by CPSC which people ended up eating wholesale.