TABLE 1.

Summary of the quality-assessment metrics for included studies investigating the sources of dietary salt across the globe¹

	Continent
	Africa	Asia	Europe	North America	Oceania	South America	Total
Year of data collection
Last 5 y	0	5	3	2	0	1	11
5–10 y ago	1	7	9	6	7	3	33
10–15 y ago	0	0	2	7	4	0	13
>15 y ago	1	4	6	6	0	1	18
Missing	0	1	1	0	1	0	3
Total	2	17	21	21	12	5	78
Representativeness
National	0	6	7	11	5	2	31
Subnational	0	2	0	0	0	1	3
Urban	1	2	0	1	1	1	6
Rural	0	1	0	0	0	0	1
Not representative	1	6	14	9	6	1	37
Total	2	17	21	21	12	5	78
Risk of bias
Low risk	0	8	7	8	4	4	31
Moderate risk	2	9	13	10	8	0	42
High risk	0	0	1	1	0	1	3
Unknown risk	0	0	0	2	0	0	2
Total	2	17	21	21	12	5	78

¹The number of studies in each continent belonging to each quality metric is shown. Two studies (22, 26) reported data from >1 country and are not included in this table.