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Study flow diagram showing the number of abstracts identified (n = 522); abstracts not meeting criteria (n = 438); full-text articles retrieved (n = 84); full-text articles excluded after screening (n = 53); full-text articles added from grey literature search (n = 6); full-text articles suggested by key informants (n = 2); full-text articles meeting study eligibility criteria (n = 39); eligible randomized controlled trials (n = 32), and observational studies (n = 7).
