TABLE 2.

Quality assessment of included cohort studies.

Original studies	Selection				Comparability	Outcome			Total score
	(1) Representa-tiveness of the exposed cohort	(2) Selection of the non-exposed cohort	(3) Ascertainment of exposure	(4) Demonstration that outcome of interest was not present at start of study	(1) Comparability of cohorts on the basis of the design or analysis	(1) Assessment of outcome	(2) Was follow-up long enough for outcomes to occur	(3) Adequacy of follow up of cohorts
Primack et al. (41)	1	1	0	1	2	0	1	1	7
Lucas et al. (46)	0	1	0	1	2	0	1	1	6
Thomée et al. (44)	1	1	0	1	1	0	0	1	5
Thomée et al. (45)	1	1	0	1	1	0	0	1	5
Grøntved et al. (51)	0	1	0	1	2	0	1	0	5
Sui et al. (38)	1	1	0	1	2	0	0	0	5
Padmapriya et al. (43)	1	1	0	0	2	0	0	1	5
Wu et al. (39)	1	1	0	0	2	0	0	1	5
Khouja et al. (40)	1	1	0	0	2	0	0	0	4
Liu et al. (26)	1	1	0	1	2	0	0	1	6
Zink et al. (42)	1	1	0	0	2	0	0	1	5
Choi et al. (49)	1	1	0	1	2	0	1	1	7
Meyer et al. (48)	0	1	0	0	2	0	0	1	4
Sarris et al. (35)	1	1	0	1	2	0	1	0	6
Ayuso-Mateos et al. (52)	1	1	0	0	2	0	0	0	4
Kandola et al. (47)	1	1	0	0	1	0	0	0	3
Liu et al. (36)	1	1	0	1	2	0	0	1	6
Pimenta et al. (50)	1	1	0	1	1	0	1	1	6