Study selection
A total of 434 studies from six databases were identified through electronic and manual searches. Nineteen duplicate studies were excluded, and 371 studies did not pass the title and abstract screening. From 44 studies eligible for full-text assessment, 36 were excluded due to deviation from the PICO, of which two papers were excluded due to the study subjects having concomitant diseases and allergies.31-32 One study was a duplicate, and the full-text of one study could not be retrieved despite maximal efforts. An additional 3 studies were identified through manual search of relevant articles. Finally, nine studies were included in this SR/NMA (Figure 1).