Sturm 2015.

Methods	Design: CBA Timing: Retrospective Allocation to group: Quote: "The intervention group is respondents living in South Los Angeles, that is, the area targeted by the Fast‐Food Ban (...). The comparison groups are either respondents living in other parts of the city of Los Angeles (...) or living in other parts of Los Angeles County" Number of clusters or sites: An unspecified number of fast‐food restaurants in parts of South Los Angeles (including Baldwin Hills, Leimert Park, and portions of South Los Angeles and Southeast Los Angeles) (the IG), and in other parts of the city of Los Angeles and Los Angeles County (the CG) Number of individuals: This was a repeat cross‐sectional analysis, and the baseline sample size was 467 in the IG and 15,420 in the CG; the follow‐up sample size was 535 in the IG and 11,286 in the CG Length of intervention: 3 ‐ 4 years (no exact dates for follow‐up data collection reported)
Participants	General description of participants: Residents of the city of Los Angeles and Los Angeles County, USA Age: Adults (all age groups were exposed to the intervention, but data were collected only from adults aged 18 years or older) Inclusion criteria: Quote: "Diet and obesity measures come from the 2007, 2009, and 2011–2012 waves of the California Health Interview Survey (CHIS), a random‐digit‐dial telephone survey of California’s non‐institutionalized population. We use the restricted files that identify a survey respondent’s residential address. In the three waves, a total of 141,597 adults ages 18 years and older were interviewed. The sampling weights provided by CHIS account for unequal sampling probabilities and non‐response. We exclude pregnant women (0.5%), respondents whose information was provided through a proxy interview (0.5%), and residents of areas defined as rural (1.7%)" Exclusion criteria: See inclusion criteria Recruitment: See inclusion criteria Weight status at baseline: Mean BMI was 29.9 in the IG at baseline, and 26.7 and 26.3 in the 2 CGs. Baseline prevalence of obesity was 32% in the IG and 17% and 22% in the CGs. Baseline prevalence of overweight and obesity combined was 63% in the IG and 57% and 55% in the CGs SSB consumption at baseline: Baseline intake frequency of soft drinks was 3.23 in the IG, and 2.3 and 2.1 in the 2 control groups (unclear if these numbers refer to servings/day or some other unit) Equity considerations: The area in which the intervention was implemented (South Los Angeles) is described as relatively low‐income and as having a high proportion of minority inhabitants. Quotes: "There is a widespread belief that low‐income or minority neighborhoods have an overconcentration of fast food chains. This belief was enshrined in the justification for the interim regulation (...) Prior to the regulation, South Los Angeles had more small retail stores, but not more (if anything fewer) large fast‐food restaurants than wealthier areas of Los Angeles per capita. Consistent with the business structure, residents in South LA also had a higher consumption of discretionary calories from candy, cookies, and soda"
Interventions	Intervention: A zoning regulation that restricts opening or expanding stand‐alone fast‐food restaurants. (Quote: "The Los Angeles Fast‐Food Ban was introduced as a draft ordinance in the Los Angeles City Council in 2007 and after an extended debate was passed unanimously in July 2008. It became effective on September 14, 2008, initially as a temporary ordinance, but the City Council made it a permanent amendment to the city’s General Plan in December 2010. Despite its nickname, the policy is a zoning regulation that restricts opening or expanding a ‘stand‐alone fast‐food restaurant’ in Baldwin Hills, Leimert Park, and portions of South Los Angeles and Southeast Los Angeles; the paper refers to this area as South Los Angeles. Fast‐food restaurants are defined as ‘any establishment which dispenses food for consumption on or off the premises, and which has the following characteristics: a limited menu, items prepared in advance or prepared or heated quickly, no table orders, and food served in disposable wrapping or containers.’ The regulation prevents new drive‐through windows, new stand‐alone fast food restaurants, or expanding floor space. It does not affect interior remodeling or exterior changes that do not increase the floor space. For example, a fast food restaurant that shares a building in a strip mall would not be subject to the regulation") Behavioural co‐intervention: None reported Control: No intervention
Outcomes	Measures of SSB intake: Intake frequency of soft drinks (excluding diet drinks), assessed with data from the California Health Interview Survey, a routine population health survey, at baseline and 3 ‐ 4 years follow‐up" Measures of intake of alternatives to SSB: N/R Anthropometric measures: Assessed in this study but not included in our review due to confounding by non‐beverage specific intervention components Adverse outcomes: The study does not report how data on adverse outcomes were collected, and if adverse outcomes were observed or not Other outcomes: None included in this review
Context and implementation	Setting: Fast‐food restaurants Sector: Food service/urban planning Country: USA Year(s) when implemented: 2008 ‐ 2012 Mode of implementation: Mandatory government regulation Level of implementation: Policy‐level intervention
Declarations	COI: No information provided by study authors (the study's primary report does not contain a COI section) Funding: "This project was supported by grant no. 1R03CA173040‐01 from the National Cancer Institute" Trial registration: N/R Protocol availability: N/R
Notes	See section on 'Potential biases in the review process' for a discussion of issues related to the minimum number of intervention and control sites
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	High risk	This was a CBA, and allocation was not random and not concealed
Allocation concealment (selection bias)	High risk	This was a CBA, and allocation was not random and not concealed
Similarity of baseline outcome measurements (selection bias)	Unclear risk	Baseline outcome measurements differed substantially (baseline intake frequency of SSB was 3.23 in the IG, and 2.3 and 2.1 in the 2 control groups). While this was taken into account in the analysis, it may hint at unobserved baseline differences. Quote: "We assess crosssectional differences between areas and difference‐in‐differences (DID, whether secular changes in diet or obesity in South Los Angeles differ from secular changes in other areas)"
Similarity of other baseline characteristics (selection and performance bias)	Unclear risk	There were differences in baseline characteristics, which were taken into account in the analysis. However, given the magnitude of differences it seems plausible that unobserved baseline differences may have existed, which could not be adjusted for. Quote: "Our main statistical analysis uses regression analysis to address potentially confounding variables at the individual and neighborhood level (including socio‐demographic changes that may differ across areas): gender, age, race/ethnicity, household size, annual household income, education, and marital status at the individual level; population density, median household income, and proportion of non‐Hispanic Whites of residential census tract from the 2010 Census as neighborhood‐level covariates"
Incomplete outcome data (attrition bias) All outcomes	Unclear risk	Data were repeat‐cross‐sectional. While precautions were taken to ensure representativeness of the sample at each time point, representativeness may not be given at the neighbourhood level. Quote: "Diet and obesity measures come from the 2007, 2009, and 2011–2012 waves of the California Health Interview Survey (CHIS), a random‐digit‐dial telephone survey of California’s non‐institutionalized population. We use the restricted files that identify a survey respondent’s residential address. In the three waves, a total of 141,597 adults ages 18 years and older were interviewed. The sampling weights provided by CHIS account for unequal sampling probabilities and non‐response. We exclude pregnant women (0.5%), respondents whose information was provided through a proxy interview (0.5%), and residents of areas defined as rural (1.7%)"
Blinding (performance and detection bias) Subjective outcomes	Low risk	This study is based on a retrospective analysis of routinely‐collected population health monitoring data. Bias due to lack of blinding is unlikely
Contamination (performance bias)	Unclear risk	Given the potential mobility of residents between the different parts of Los Angeles, contamination seems possible
Selective reporting (reporting bias)	Low risk	The study does not provide information on trial registration or the public availability of a protocol, but all outcomes mentioned in the Methods sections, and all outcomes which one would expect in a study of this kind are reported
Other bias	Low risk	No other concerns