France.

Methods	Uncontrolled pre‐post
Participants	Individual and National Food Consumption Survey (INCA1) 1998‐1999 (a): nationally representative, stratified, random sample of individuals 15 years of age and older. *Study considers only adults 18 to 79 years of age to be comparable with INCA2 Individual and National Food Consumption Survey (INCA1) 1998‐1999 (b): “The sampling design used to select nationally representative samples of adults and children living in French households included a stratification by region of residence and community size and a distribution according to age, gender, household size and head of household socio‐professional status by the quota method” Individual and National Food Consumption Survey (INCA2) 2006‐2007: nationally representative, stratified, random sample of individuals 18 to 79 years of age
Interventions	Salt reduction initiative began in 2001. Efforts included: public information/education campaign; food product reformulation; and food procurement policy in specific settings.
Outcomes	INCA1 1998‐1999 (a): mean sodium intake (milligrams/d) estimated via 7‐day open‐ended food records INCA1 1998‐1999 (b): mean sodium intake (mmol/d) estimated via 7‐day open‐ended food records INCA2 2006‐2007: mean sodium intake (milligrams/d) estimated via 7‐day open‐ended food records
Axes of inequality	INCA1 1998‐1999 (a): gender INCA1 1998‐1999 (b): gender, place of residence and occupation INCA2 2006‐2007: gender
Sample size and response rate	INCA1 1998‐1999 (a): n = 1985; unknown RR Analysis performed on n = 1345 (613 M; 732 W) INCA1 1998‐1999 (b): n = 1985; unknown RR Analysis performed on n = 1474 (672 M; 802 W) INCA2 2006‐2007: n = 2624; 63% RR Analysis performed on n = 1922 (840 M; 1082 W)
Funding source / Conflict of Interest (COI)	INCA1 1998‐1999 (a): "The INCA1 survey was supported by a grant from the Ministries for Health, Agriculture and Consumer Affairs"/Study authors declare no COI INCA1 1998‐1999 (b): INCA1 was performed by the French Food Safety Agency. “Joel Menard received funding from the Association Robert Debre ´pour la Recherche Medicale and Pierre Meneton from the Institut National pour la Sante´ et la Recherche Medicale”/Study authors declare no COI 2006‐07: “INCA2 [was supported] by a grant from the French Food Safety Agency (AFSSA)”/Study authors declare no COI
Notes	Sources of data points and references: see France INCA1 1998‐1999 (a): France country questionnaire 2014: *Dubuisson C, Lioret S, Touvier M, Dufour A, Calamassi‐Tran G, Volatier J‐L, Lafay L. Trends in food and nutritional intakes of French adults from 1999 to 2007: results from the INCA surveys. British Journal of Nutrition 2010;103:1035‐1048 INCA1 1998‐1999 (b): France country questionnaire 2014: Meneton P, Lafay L, Tard A, Dufour A, Ireland J, Ménard J, Volatier JL. Dietary sources and correlates of sodium and potassium intakes in the French general population. European Journal of Clinical Nutrition 2009;63:1169‐1175 INCA2 2006‐2007: France country questionnaire 2014: *Dubuisson et al., 2010 (see full citation above) *Indicates main publication used for in‐text citation purposes
Risk of bias
Bias	Authors' judgement	Support for judgement
Sampling	Low risk	Representative samples through stratification and “quota method” were used for INCA1 1998‐1999. Random samples used multi‐stage cluster sampling for INCA2 2005‐2007
Confounding	High risk	Uncontrolled pre‐post designs always score 'high'
Reliability/validity of outcome measure	Low risk	Dietary surveys were used for both time points and used comparable methods. Convincing text suggests protocols were adhered to, and that the method was properly carried out for both years
Blinding of outcome assessment (detection bias) All outcomes	Low risk	Pre‐existing data were used to evaluate the initiative
Representativeness of sample	Low risk	“Two independent samples… were made representative of the French population through stratification and use of the quota method” (pg. 1036). No indication that the sample differed from the population
Selective reporting (reporting bias)	Low risk	Means and standard deviations were reported for both men and women for all measures
Other bias	Low risk	No other obvious sources of bias to report