Table 1. Quality assessment of studies (NOS score of included studies).

Authors (Year)	S1: Representativeness of the sample	S2: sample size	S3: Non-respondents	S4: Ascertainment of exposure	Ca: Study controls for most important factor	Cb: Study controls for additional factor	O1: Ax of outcome	O2: Statistical test	Total
Choi & Chung (2023)	★	★	★	★★	★	★	★★		9/10 stars
Ueda et al. (2020)	★	★	★	★★	★	★	★★	★	10/10 stars
Hunter et al. (2020)	★	★	★	★★	★		★★	★	9/10 stars
Land, Gordon & Watt (2017)	★	★	★	★★	★	★	★★	★	10/10 stars
Kolber et al. (2017)	★	★	★	★★	★		★★	★	9/10 stars
Theisen et al. (2010)	★		★	★★	★	★	★★	★	9/10 stars
Erol, Özçakar & Çeliker (2008)	★		★	★★	★		★★		7/10 stars
McClure, Michener & Karduna (2006)	★			★★	★	★	★★		7/10 stars

Notes.

NOS, Newcastle Ottawa Scale.