title: Differential Responses to Food Price Changes by Personal Characteristic: A Systematic Review of Experimental Studies.
abstract: BACKGROUND
  Fiscal interventions to improve population diet have been recommended for consideration by many organisations including the World Health Organisation and the United Nations and policies such as sugar-sweetened beverage taxes have been implemented at national and sub-national levels. However, concerns have been raised with respect to the differential impact of fiscal interventions on population sub-groups and this remains a barrier to implementation.
  
  
  OBJECTIVE
  To examine how personal characteristics (such as socioeconomic status, sex, impulsivity, and income) moderate changes in purchases of targeted foods in response to food and beverage price changes in experimental settings.
  
  
  METHODS
  Systematic review.
  
  
  METHODS
  Online databases (PubMed, EMBASE, Web of Science, EconLit and PsycInfo), reference lists of previous reviews, and additional data from study authors.
  
  
  METHODS
  We included randomised controlled trials where food and beverage prices were manipulated and reported differential effects of the intervention on participant sub-groups defined according to personal characteristics.
  
  
  METHODS
  Where possible, we extracted data to enable the calculation of price elasticities for the target foods by personal characteristic.
  
  
  RESULTS
  8 studies were included in the review. Across studies, the difference in price elasticity varied from 0.02 to 2.43 between groups within the same study. 11 out of the total of 18 comparisons of own-price elasticity estimates by personal characteristic differed by more than 0.2 between groups. Income related factors were the most commonly considered and there was an indication that own-price elasticity estimates do vary by income but the direction of this effect was not clear.
  
  
  CONCLUSIONS
  Experimental studies provide an opportunity to examine the differential effects of fiscal measures to improve population diets. Patterns in price sensitivity by personal characteristics are complex. General conclusions pertaining to the effects of personal characteristics on price sensitivity are not supported by the evidence, which shows heterogeneity between studies and populations.
  
  
  BACKGROUND
  PROSPERO CRD42014009705.
authors.affiliation: British Heart Foundation Centre on Population Approaches for Non-Communicable Disease Prevention, Nuffield Department of Population Health, University of Oxford, Oxford, United Kingdom.
authors.forename: Anja
authors.initials: A
authors.lastname: Mizdrak
authors.affiliation: British Heart Foundation Centre on Population Approaches for Non-Communicable Disease Prevention, Nuffield Department of Population Health, University of Oxford, Oxford, United Kingdom.
authors.forename: Peter
authors.initials: P
authors.lastname: Scarborough
authors.affiliation: National Institute for Health Innovation, School of Population Health, University of Auckland, Auckland, New Zealand.
authors.forename: Wilma E
authors.initials: WE
authors.lastname: Waterlander
authors.affiliation: British Heart Foundation Centre on Population Approaches for Non-Communicable Disease Prevention, Nuffield Department of Population Health, University of Oxford, Oxford, United Kingdom.
authors.forename: Mike
authors.initials: M
authors.lastname: Rayner
mesh_terms: D001628:Beverages / Q000191:economics; D003132:Commerce / Q000191:economics*; D016208:Databases, Factual; D005502:Food / Q000191:economics*; D006801:Humans