“…Most studies were conducted in China (10 studies) 23,27,34–36,40,42,43,46,47 and in the United States (nine studies) 5,8,24–26,29,30,33,41 . Most studies were cross‐sectional (26 studies) 4–7,21–23,25–29,31,32,35–46 . The studies were conducted more frequently in the community (15 studies) 6,22,23,25,28,31,32,36–38,41,42,44–46 and in outpatient clinics (five studies) 29,33,35,39,40 .…”