title: Price promotions on healthier compared with less healthy foods: a hierarchical regression analysis of the impact on sales and social patterning of responses to promotions in Great Britain.
abstract: BACKGROUND
  There is a growing concern, but limited evidence, that price promotions contribute to a poor diet and the social patterning of diet-related disease.
  
  
  OBJECTIVE
  We examined the following questions: 1) Are less-healthy foods more likely to be promoted than healthier foods? 2) Are consumers more responsive to promotions on less-healthy products? 3) Are there socioeconomic differences in food purchases in response to price promotions?
  
  
  METHODS
  With the use of hierarchical regression, we analyzed data on purchases of 11,323 products within 135 food and beverage categories from 26,986 households in Great Britain during 2010. Major supermarkets operated the same price promotions in all branches. The number of stores that offered price promotions on each product for each week was used to measure the frequency of price promotions. We assessed the healthiness of each product by using a nutrient profiling (NP) model.
  
  
  RESULTS
  A total of 6788 products (60%) were in healthier categories and 4535 products (40%) were in less-healthy categories. There was no significant gap in the frequency of promotion by the healthiness of products neither within nor between categories. However, after we controlled for the reference price, price discount rate, and brand-specific effects, the sales uplift arising from price promotions was larger in less-healthy than in healthier categories; a 1-SD point increase in the category mean NP score, implying the category becomes less healthy, was associated with an additional 7.7-percentage point increase in sales (from 27.3% to 35.0%; P < 0.01). The magnitude of the sales uplift from promotions was larger for higher-socioeconomic status (SES) groups than for lower ones (34.6% for the high-SES group, 28.1% for the middle-SES group, and 23.1% for the low-SES group). Finally, there was no significant SES gap in the absolute volume of purchases of less-healthy foods made on promotion.
  
  
  CONCLUSIONS
  Attempts to limit promotions on less-healthy foods could improve the population diet but would be unlikely to reduce health inequalities arising from poorer diets in low-socioeconomic groups.
authors.affiliation: From the Behaviour and Health Research Unit, University of Cambridge, Cambridge, United Kingdom (RN, MS, SAJ, RP, and TMM); the Health Economics Group, Norwich Medical School, University of East Anglia, Norwich, United Kingdom (RN and MS); the Centre for Health Economics, University of York, York, United Kingdom (RN and MS); the UKCRC Centre for Diet and Activity Research, Cambridge, United Kingdom (RN and MS); the Nuffield Department of Primary Care Health Sciences, University of Oxford, Oxford, United Kingdom (SAJ); and the Medical Research Council Human Nutrition Research, Elsie Widdowson Laboratory, Cambridge, United Kingdom (EA-R).
authors.forename: Ryota
authors.initials: R
authors.lastname: Nakamura
authors.affiliation: From the Behaviour and Health Research Unit, University of Cambridge, Cambridge, United Kingdom (RN, MS, SAJ, RP, and TMM); the Health Economics Group, Norwich Medical School, University of East Anglia, Norwich, United Kingdom (RN and MS); the Centre for Health Economics, University of York, York, United Kingdom (RN and MS); the UKCRC Centre for Diet and Activity Research, Cambridge, United Kingdom (RN and MS); the Nuffield Department of Primary Care Health Sciences, University of Oxford, Oxford, United Kingdom (SAJ); and the Medical Research Council Human Nutrition Research, Elsie Widdowson Laboratory, Cambridge, United Kingdom (EA-R).
authors.forename: Marc
authors.initials: M
authors.lastname: Suhrcke
authors.affiliation: From the Behaviour and Health Research Unit, University of Cambridge, Cambridge, United Kingdom (RN, MS, SAJ, RP, and TMM); the Health Economics Group, Norwich Medical School, University of East Anglia, Norwich, United Kingdom (RN and MS); the Centre for Health Economics, University of York, York, United Kingdom (RN and MS); the UKCRC Centre for Diet and Activity Research, Cambridge, United Kingdom (RN and MS); the Nuffield Department of Primary Care Health Sciences, University of Oxford, Oxford, United Kingdom (SAJ); and the Medical Research Council Human Nutrition Research, Elsie Widdowson Laboratory, Cambridge, United Kingdom (EA-R).
authors.forename: Susan A
authors.initials: SA
authors.lastname: Jebb
authors.affiliation: From the Behaviour and Health Research Unit, University of Cambridge, Cambridge, United Kingdom (RN, MS, SAJ, RP, and TMM); the Health Economics Group, Norwich Medical School, University of East Anglia, Norwich, United Kingdom (RN and MS); the Centre for Health Economics, University of York, York, United Kingdom (RN and MS); the UKCRC Centre for Diet and Activity Research, Cambridge, United Kingdom (RN and MS); the Nuffield Department of Primary Care Health Sciences, University of Oxford, Oxford, United Kingdom (SAJ); and the Medical Research Council Human Nutrition Research, Elsie Widdowson Laboratory, Cambridge, United Kingdom (EA-R).
authors.forename: Rachel
authors.initials: R
authors.lastname: Pechey
authors.affiliation: From the Behaviour and Health Research Unit, University of Cambridge, Cambridge, United Kingdom (RN, MS, SAJ, RP, and TMM); the Health Economics Group, Norwich Medical School, University of East Anglia, Norwich, United Kingdom (RN and MS); the Centre for Health Economics, University of York, York, United Kingdom (RN and MS); the UKCRC Centre for Diet and Activity Research, Cambridge, United Kingdom (RN and MS); the Nuffield Department of Primary Care Health Sciences, University of Oxford, Oxford, United Kingdom (SAJ); and the Medical Research Council Human Nutrition Research, Elsie Widdowson Laboratory, Cambridge, United Kingdom (EA-R).
authors.forename: Eva
authors.initials: E
authors.lastname: Almiron-Roig
authors.affiliation: From the Behaviour and Health Research Unit, University of Cambridge, Cambridge, United Kingdom (RN, MS, SAJ, RP, and TMM); the Health Economics Group, Norwich Medical School, University of East Anglia, Norwich, United Kingdom (RN and MS); the Centre for Health Economics, University of York, York, United Kingdom (RN and MS); the UKCRC Centre for Diet and Activity Research, Cambridge, United Kingdom (RN and MS); the Nuffield Department of Primary Care Health Sciences, University of Oxford, Oxford, United Kingdom (SAJ); and the Medical Research Council Human Nutrition Research, Elsie Widdowson Laboratory, Cambridge, United Kingdom (EA-R).
authors.forename: Theresa M
authors.initials: TM
authors.lastname: Marteau
mesh_terms: D000328:Adult; D000329:Advertising / Q000379:methods*; D001628:Beverages / Q000191:economics; D003430:Cross-Sectional Studies; D004032:Diet / Q000191:economics; D005069:Evaluation Studies as Topic; D005191:Family Characteristics; D005260:Female; D058870:Food, Organic / Q000191:economics*; D006293:Health Promotion / Q000191:economics*; D006801:Humans; D008297:Male; D008875:Middle Aged; D008962:Models, Theoretical; D012044:Regression Analysis; D012959:Socioeconomic Factors; D006113:United Kingdom
keywords: Great Britain; food purchasing; price promotion; public health; public policy
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