Table 2. Quality assessment of included studies.

Author	Selection	Comparability	Outcome or Exposure Assessment	Overall
Ahmad et al [9]	3	2	3	Good
Alushi et al [10]	3	2	3	Good
Barbash et al [11]	3	2	2	Good
Keymel et al [12]	4	2	3	Good
Kleczynski et al [13]	4	1	3	Good
Lindman et al [14]	3	1	2	Fair
Masri et al [15]	3	2	2	Good
Mayr et al [16]	3	1	3	Good
Miyamoto et al [17]	3	2	2	Good
Mujeeb et al [18]	3	1	3	Good
Naing et al [19]	4	2	3	Good
O Sullivan et al [20]	3	2	3	Good
Souza et al [21]	3	2	2	Good
Sultan et al [22]	4	1	2	Good
Testa et al [23]	3	2	3	Good