Fisher 2012

Methods	Study design: Cluster‐randomised controlled trial Funding: “This work was funded by an investigator‐initiated grant to J.O.F. from the Clorox Company, which owns the Hidden Valley, The Original Ranch brand of dressing used in this research. The authors attest to having full scholarly authority over this work and responsibility for the research design and methods, the integrity of the data, the analyses, and the interpretation of the findings.”
Participants	Description: Preschool‐aged children in Head Start classrooms and their parent N (Randomised): 155 parent‐child dyads Age: Child: 3 to 5 years (mean = 4 years) Parent: not specified % Female: Child: 48% Parent: not specified SES and ethnicity: “predominately Hispanic (88%) children” “Of participating parents, close to a majority (n=89) reported being married and slightly greater than one‐third (n=51) reported schooling beyond high school.” Inclusion/exclusion criteria: No explicit inclusion criteria stated for this trial Exclusion criteria: “Exclusion criteria included severe food allergies and/or other medical conditions (e.g., diabetes) that might influence the ability to participate in an as‐desired snack and absences at 75% or more of the vegetable exposure trials.” Recruitment: “To achieve a target sample size of 37 children per experimental dip condition, eight preschool classrooms within three Head Start Centers were approached to participate. Parents of 166 children were sent letters to request written consent for their own and their child’s participation in the study.” Recruitment rate: Parent‐child dyads = 93% (155/166) Region: Houston, TX (USA)
Interventions	Number of experimental conditions: 4 Number of participants (analysed): Plain = 39, Regular = 39, Light = 36, Sauce = 38 142 parents (not specified by group) Description of intervention: “At each trial, raw broccoli was presented with 2% milk (8 oz [246 g]) to children in the condition to which they were assigned. Children were instructed to eat as much or as little as desired.” Plain: “broccoli was served without dressing.” Regular: “broccoli was served with 2.5 oz of a regular ranch‐flavored salad dressing.” Light: “broccoli was served with 2.5 oz of a reduced‐energy/fat ranch‐flavored salad dressing.” Sauce: “2.5 oz of the regular dressing was mixed together with broccoli as a sauce” Duration: 7 weeks Number of contacts: “Thirteen exposure trials (twice per week) took place in children’s classrooms across a 7‐week period.” Setting: Preschool Modality: Face‐to‐face Interventionist: Trained research staff Integrity: No information provided Date of study: 2008 Description of control: N/A
Outcomes	Outcome relating to children's fruit and vegetable consumption: Child’s consumption of target vegetables (broccoli) (grams) with/without dressing/sauce. “Weights of broccoli, milk, and the salad dressing (except in the plain condition) were recorded to the nearest 0.1 g once a stable reading was indicated using a calibrated, research grade digital electronic balance before and following the snacks. In the sauce condition, broccoli and the dressing intakes were estimated from the amount of the mixture consumed based on the proportionate contributions of each to the total pre‐weight.” Outcome relating to absolute costs/cost effectiveness of interventions: Not reported Outcome relating to reported adverse events: Not reported Length of follow‐up from baseline: 7 weeks Length of follow‐up post‐intervention: Immediately Subgroup analyses: None Loss to follow‐up: Overall = 2% (not specified by group) Analysis: Adjusted for clustering Sample size calculation was performed
Notes
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Unclear risk	(Authors describe as a quasi‐experimental design although appear to have randomised classrooms). Randomly allocated to experimental group but the random sequence generation procedure is not described
Allocation concealment (selection bias)	Unclear risk	(Authors describe as a quasi‐experimental design although appear to have randomised classrooms). There is no information provided about allocation concealment and therefore it is unclear if allocation was concealed
Blinding of participants and personnel (performance bias) All outcomes	Low risk	Vegetable intake (objective): Objective measure of child’s vegetable intake and unlikely to be influenced by performance bias
Blinding of outcome assessment (detection bias) All outcomes	Low risk	Vegetable intake (objective): Objective measure of child’s vegetable intake and whether those who weighed the food were blinded is unlikely to have an impact on detection bias
Incomplete outcome data (attrition bias) All outcomes	Low risk	152/155 (98%) completed the study and therefore risk of attrition bias is low
Selective reporting (reporting bias)	Unclear risk	There is no study protocol therefore it is unclear if there was selective outcome reporting
Other bias	Unclear risk	There is insufficient information about baseline imbalances and whether clustering was adjusted for in the analyses