Altering the Availability of Healthier vs. Less Healthy Items in Vending Machines

NCT03252158 | Completed

• 1 other identifier: PRE.2017.029
• Study Type: interventional
• Target: 10
• Locations: 1 country
• Sites: 1

Brief Summary

Background: While there is some evidence that increasing the range of healthier foods and drinks and/or decreasing the range of less healthy options may increase healthier choices, more work is needed to establish the reproducibility of any effect. The current study aims to investigate the impact of altering the availability of healthier and less healthy foods and cold beverages in hospital vending machines. Methods: An adapted multiple treatment reversal design will be used, in which all standard vending machines serving snack foods and/or cold beverages in one hospital in England change the number of slots containing (i) less healthy items and (ii) healthier items over eight 4-week periods. Changes will take place in a two-step process whereby decreases are implemented in a separate study period prior to increases in the contrasting food group. Following a 4-week baseline period, all vending machines will be standardised to have 75% healthier drinks and/or 25% healthier snacks (study period 1). Vending machines (n=9) will be randomly allocated to the order in which they: (1) decrease less healthy foods and increase healthier foods or (2) decrease healthier foods and increase less healthy foods (study periods 2\&3 and 5\&6). After each decrease-increase pair, machines will return to the standardised 75% healthier drinks and 25% healthier snacks (study periods 4 and 7). Sales data will be obtained via records of machine restocking. Planned Analysis: The impact of the availability intervention will be assessed in separate linear mixed models for cold drinks and snacks, examining the impact on total energy (kcal) purchased, per restocking interval, with random effects for vending machine.

Conditions

Healthy Diet

Outcome Measures

Primary Outcomes (1)

• Energy purchased

  Energy purchased (kcal) per restocking interval from intervention (standard-fare) vending machines

  Restocking interval (between 2-4 days; restocking occurs on set weekdays for each machine, to match usual restocking)

Secondary Outcomes (3)

• Number of items sold

  Restocking interval (between 2-4 days; restocking occurs on set weekdays for each machine, to match usual restocking)

• Energy purchased (healthier alternative machines)

  Restocking interval (between 2-4 days; restocking occurs on set weekdays for each machine, to match usual restocking)

• Number of items sold (healthier alternative machines)

  Restocking interval (between 2-4 days; restocking occurs on set weekdays for each machine, to match usual restocking)

Study Arms (2)

Decrease less healthy item availability

EXPERIMENTAL

Intervention: Availability of healthier vs. less healthy foods Remove less healthy items in 20% of slots, then fill the empty slots with healthier items.

Behavioral: Availability of healthier vs. less healthy foods

Decrease healthier item availability

EXPERIMENTAL

Intervention: Availability of healthier vs. less healthy foods Remove healthier items in 20% of slots, then fill the empty slots with less healthy items.

Behavioral: Availability of healthier vs. less healthy foods

Interventions

Availability of healthier vs. less healthy foods BEHAVIORAL

Altering the number of slots containing (a) healthier and (b) less healthy foods or beverages in hospital vending machines. Changes follow a 2-step process whereby decreases are implemented in a separate study period prior to increases in the contrasting group. Following a 4-week baseline period, all vending machines will be standardised to have 75% healthier drinks and/or 25% healthier snacks (study period 1). Vending machines will be randomly allocated to the order in which they: (1) decrease less healthy foods and increase healthier foods or (2) decrease healthier foods and increase less healthy foods (study periods 2\&3 and 5\&6). After each decrease-increase pair, machines will return to the standardised 75% healthier drinks / 25% healthier snacks (study periods 4 and 7).

Decrease healthier item availability; Decrease less healthy item availability

Eligibility Criteria

• Sex: all
• Healthy Volunteers: Yes
• Age Groups: Child (0-17), Adult (18-64), Older Adult (65+)

You may qualify if:

• All vending machines at one UK hospital selling standard-fare (i.e. not healthier alternatives) cold beverages and snack foods

You may not qualify if:

• Healthier alternative vending machines; vending machines selling hot drinks or meals

Sponsors & Collaborators

• University of Cambridge: lead
• Oxford University Hospitals NHS Trust: collaborator

Study Sites (1)

University of Cambridge

Cambridge, Cambridgeshire, CB2 0SR, United Kingdom

Location

Study Officials

• Rachel Pechey, PhD

  University of Cambridge

  PRINCIPAL INVESTIGATOR

Study Design

• Study Type: interventional
• Phase: not applicable
• Allocation: RANDOMIZED
• Masking: NONE
• Purpose: BASIC SCIENCE
• Intervention Model: CROSSOVER
• Sponsor Type: OTHER
• Responsible Party: PRINCIPAL INVESTIGATOR
• PI Title: Senior Research Associate

Model Details: An adapted multiple treatment reversal design will be used, in which the number of slots containing (i) less healthy items and (ii) healthier items are altered over eight 4-week periods. Vending machines will be randomly allocated to one of two groups: (1) decreasing less healthy foods first or (2) decreasing healthier foods first.

Study Record Dates

• First Submitted: August 9, 2017
• First Posted: August 17, 2017
• Study Start: August 17, 2017
• Primary Completion: March 28, 2018
• Study Completion: March 28, 2018
• Last Updated: May 3, 2018

Record last verified: 2018-05

Locations

GB (1)