Table 1.

Characteristics of the included systematic reviews

		AMSTAR 2 confidence rating
Characteristic	Overall, N=124	High, N = 7 (6%)	Moderate, N = 21 (17%)	Low, N = 41 (33%)	Critically low, N = 55 (44%)
Type of intervention studied
Clinical intervention (drug)	26 (21%)	0 (0%)	5 (24%)	12 (29%)	9 (16%)
Clinical intervention (other)	30 (24%)	0 (0%)	9 (43%)	8 (20%)	13 (24%)
Clinical intervention (surgical)	26 (21%)	1 (14%)	1 (5%)	7 (17%)	17 (31%)
Environmental exposure	4 (3%)	2 (29%)	0 (0%)	1 (2%)	1 (2%)
Non-clinical intervention	3 (2%)	0 (0%)	2 (10%)	1 (2%)	0 (0%)
Public health intervention	21 (17%)	2 (29%)	1 (5%)	11 (27%)	7 (13%)
Non-interventional	14 (11%)	2 (29%)	3 (14%)	1 (2%)	8 (15%)
Number of included studies
Median (IQR)	14 (9, 27)	14 (8, 22)	16 (7, 36)	15 (10, 27)	13 (9, 24)
Range	2, 124	3, 29	2, 91	4, 47	2, 124
Funding sources
Academic	2 (2%)	0 (0%)	0 (0%)	0 (0%)	2 (4%)
Foundation/NGO	9 (7%)	0 (0%)	1 (5%)	4 (10%)	4 (7%)
Government	23 (19%)	2 (29%)	4 (19%)	8 (20%)	9 (16%)
Industry	4 (3%)	1 (14%)	0 (0%)	1 (2%)	2 (4%)
Multiple (excl. industry)	11 (9%)	2 (29%)	3 (14%)	3 (7%)	3 (5%)
Multiple (incl. industry)	2 (2%)	0 (0%)	0 (0%)	2 (5%)	0 (0%)
Other	2 (2%)	0 (0%)	0 (0%)	2 (5%)	0 (0%)
None	44 (35%)	2 (29%)	9 (43%)	15 (37%)	18 (33%)
Not reported	27 (22%)	0 (0%)	4 (19%)	6 (15%)	17 (31%)
Competing interests
Academic	11 (9%)	2 (29%)	2 (10%)	5 (12%)	2 (4%)
Industry	15 (12%)	1 (14%)	1 (5%)	7 (17%)	6 (11%)
None	92 (74%)	4 (57%)	16 (76%)	26 (63%)	46 (84%)
Not reported	6 (5%)	0 (0%)	2 (10%)	3 (7%)	1 (2%)
Review included randomized trials	70 (56%)	2 (29%)	16 (76%)	21 (51%)	31 (56%)
Review included meta-analysis	73 (59%)	5 (71%)	7 (33%)	20 (49%)	41 (75%)