Table 3. Study characteristics.

CHARACTERISTICS	TOTAL NO. OF STUDIES N=65 (%)	TOTAL SAMPLE SIZE N=28921
Continent Africa Asia Europe South America	20 (30.7) 9 (13.8) 35 (53.8) 1 (1.5)	7539 2801 18442 139
WHO Region African Eastern Mediterranean Western Pacific European Americas	18 (27.7) 2 (3.0) 9 (13.8) 35 (53.8) 1 (1.5)	7271 268 2801 18442 139
Income group Low-income Lower-middle-income Upper-middle-income Mixed setting	2 (3.0) 5 (7.6) 57 (87.6) 1 (1.5)	402 1924 25510 1303
Study design Case control Cohort Cross-sectional	7 (10.7) 50 (76.9) 8 (12.3)	449 26071 2619
Study setting Hospital-based Community-based Both	58 (89.2) 5 (7.6) 2 (3.0)	25757 2874 508
Urbanization Rural Urban Both	4 (6.1) 58 (89.2) 3 (4.6)	1813 25455 1871