7. Comparison 2: Overview of Synthesis and Included Studies (OSIS).

Study name (year)	Study design (individual vs stepped‐wedge vs cluster‐randomised [and unit of randomisation, if applicable])	Country of conduct	Overall risk of bias (arranged low to high)	Key details of intervention (% KCl, LSSS implementation [discretionary, non‐discretionary, both], quantity, provided or purchased, co‐interventions [education, advice])	Key details of the comparator (implementation [discretionary, non‐discretionary, both], quantity, provided or household supply, co‐interventions [education, advice])	Population  (No. of participants randomised [intervention/control], age, gender, hypertensive status, anti‐hypertensive medication use, BMI)	Outcome domains with available data (synthesis method/metric)	Specific outcomes measure	Time point of measurement
Toft 2020	Cluster‐randomised (families)	Denmark	Unclear	< 30% KCl LSSS (per 100 g: approximately 8000 mg sodium; 870 mg Mg and 100 mg‐200 mg K estimated from the technical data sheet)   Non‐discretionary use (LSSS bread products to replace usual consumption), provided to families twice a week   Co‐interventions NR	Regular salt           Non‐discretionary use (regular wholegrain bread products for usual consumption), provided to families twice a week     Co‐interventions NR	40/52   9.5 (4.2)/8.4 (3.5) years   Female, %: 47.5/48.1   Normotensive   N/A   18.0 (2.9)/16.9 (2.8) kg/m2	Change in blood pressure   Change in BMI   24‐h urinary excretion	1. Change in DBP 2. Change in SBP 3. Change in BMI 4. 24‐h urinary sodium excretion 5. 24‐h urinary potassium excretion	1. 4 months 2. 4 months 3. 4 months 4. 4 months 5. 4 months

Abbreviations: 
24‐h: 24‐hour
BMI: body mass index
DBP: diastolic blood pressure
K(Cl): potassium (chloride)
LSSS: low‐sodium salt substitute
Mg: magnesium
N/A: not applicable
NR: not reported