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Nghiem N, Teng A, Cleghorn C, McKerchar C, Wilson N. Using household economic survey data to assess food expenditure patterns and trends in a high-income country with notable health inequities. Sci Rep 2022; 12:21703. [PMID: 36522384 PMCID: PMC9753885 DOI: 10.1038/s41598-022-26301-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2022] [Accepted: 12/13/2022] [Indexed: 12/23/2022] Open
Abstract
This study aimed to identify dietary trends in Aotearoa New Zealand (NZ) and whether inequities in dietary patterns are changing. We extracted data from the Household Economic Survey (HES), which was designed to provide information on impacts of policy-making in NZ, and performed descriptive analyses on food expenditures. Overall, total household food expenditure per capita increased by 0.38% annually over this period. Low-income households spent around three quarters of what high-income households spent on food per capita. High-income households experienced a greater increase in expenditure on nuts and seeds and a greater reduction in expenditure on processed meat. There was increased expenditure over time on fruit and vegetables nuts and seeds, and healthy foods in Māori (Indigenous) households with little variations in non-Māori households. But there was little change in processed meat expenditure for Māori households and expenditure on less healthy foods also increased over time. Routinely collected HES data were useful and cost-effective for understanding trends in food expenditure patterns to inform public health interventions, in the absence of nutrition survey data. Potentially positive expenditure trends for Māori were identified, however, food expenditure inequities in processed meat and less healthy foods by ethnicity and income continue to be substantial.
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Affiliation(s)
- Nhung Nghiem
- Department of Public Health, University of Otago, Wellington, New Zealand.
| | - Andrea Teng
- Department of Public Health, University of Otago, Wellington, New Zealand
| | - Christine Cleghorn
- Department of Public Health, University of Otago, Wellington, New Zealand
| | - Christina McKerchar
- Department of Population Health, University of Otago, Christchurch, New Zealand
| | - Nick Wilson
- Department of Public Health, University of Otago, Wellington, New Zealand
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Hoenink JC, Waterlander WE, Mackenbach JD, Mhurchu CN, Wilson N, Beulens JWJ, Nghiem N. Impact of taxes on purchases of close substitute foods: analysis of cross-price elasticities using data from a randomized experiment. Nutr J 2021; 20:75. [PMID: 34493309 PMCID: PMC8424883 DOI: 10.1186/s12937-021-00736-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2021] [Accepted: 08/30/2021] [Indexed: 11/10/2022] Open
Abstract
OBJECTIVE To examine the effects of health-related food taxes on substitution and complementary purchases within food groups, including from unhealthier to healthier alternatives and between brands. METHODS We used data from a virtual supermarket experiment with data from 4,259 shopping events linked to varying price sets. Substitution or complementary effects within six frequently purchased food categories were analyzed. Products' own- and cross-price elasticities were analyzed using Almost Ideal Demand System models. RESULTS Overall, 37.5% of cross-price elasticities were significant (p < 0.05) and included values greater than 0.10. Supplementary and complementary effects were particularly found in the dairy, meats and snacks categories. For example, a 1% increase in the price of high saturated fat dairy was associated with a 0.18% (SE 0.06%) increase in purchases of low saturated fat dairy. For name- and home-brand products, significant substitution effects were found in 50% (n = 3) of cases, but only in one case this was above the 0.10 threshold. CONCLUSIONS/POLICY IMPLICATIONS Given the relatively low own-price elasticities and the limited substitution and complementary effects, relatively high taxes are needed to substantively increase healthy food purchases at the population level. TRIAL REGISTRATION This study included secondary analyses; the original trial was registered in the Australian New Zealand Clinical Trials Registry ACTRN12616000122459 .
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Affiliation(s)
- Jody C Hoenink
- Amsterdam UMC, Vrije Universiteit Amsterdam, Department of Epidemiology and Data Science, Amsterdam Public Health Research Institute, De Boelelaan 1089a, 1081 HV, Amsterdam, the Netherlands. .,Upstream Team, www.upstreamteam.nl, Amsterdam UMC, Amsterdam, The Netherlands.
| | - Wilma E Waterlander
- Amsterdam UMC, Department of Public and Occupational Health, University of Amsterdam, Amsterdam Public Health Research Institute, Meibergdreef 9, Amsterdam, the Netherlands
| | - Joreintje D Mackenbach
- Amsterdam UMC, Vrije Universiteit Amsterdam, Department of Epidemiology and Data Science, Amsterdam Public Health Research Institute, De Boelelaan 1089a, 1081 HV, Amsterdam, the Netherlands.,Upstream Team, www.upstreamteam.nl, Amsterdam UMC, Amsterdam, The Netherlands
| | - Cliona Ni Mhurchu
- National Institute for Health Innovation, University of Auckland, Auckland, New Zealand
| | - Nick Wilson
- Department of Public Health, University of Otago, Wellington, New Zealand
| | - Joline W J Beulens
- Amsterdam UMC, Vrije Universiteit Amsterdam, Department of Epidemiology and Data Science, Amsterdam Public Health Research Institute, De Boelelaan 1089a, 1081 HV, Amsterdam, the Netherlands.,Julius Center for Health Sciences and Primary Care, University Medical Center Utrecht, Utrecht University, Utrecht, the Netherlands
| | - Nhung Nghiem
- Department of Public Health, University of Otago, Wellington, New Zealand
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The effect of food taxes and subsidies on population health and health costs: a modelling study. LANCET PUBLIC HEALTH 2020; 5:e404-e413. [DOI: 10.1016/s2468-2667(20)30116-x] [Citation(s) in RCA: 30] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/30/2020] [Revised: 05/03/2020] [Accepted: 05/06/2020] [Indexed: 11/17/2022]
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Blakely T, Nghiem N, Genc M, Mizdrak A, Cobiac L, Mhurchu CN, Swinburn B, Scarborough P, Cleghorn C. Modelling the health impact of food taxes and subsidies with price elasticities: The case for additional scaling of food consumption using the total food expenditure elasticity. PLoS One 2020; 15:e0230506. [PMID: 32214329 PMCID: PMC7098589 DOI: 10.1371/journal.pone.0230506] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2019] [Accepted: 03/03/2020] [Indexed: 11/24/2022] Open
Abstract
Background Food taxes and subsidies are one intervention to address poor diets. Price elasticity (PE) matrices are commonly used to model the change in food purchasing. Usually a PE matrix is generated in one setting then applied to another setting with differing starting consumptions and prices of foods. This violates econometric assumptions resulting in likely mis-estimation of total food consumption. In this paper we demonstrate this problem, canvass possible options for rescaling all consumption after applying a PE matrix, and illustrate the use of a total food expenditure elasticity (TFEe; the expenditure elasticity for all food combined given the policy-induced change in the total price of food). We use case studies of: NZ$2 per 100g saturated fat (SAFA) tax, NZ$0.4 per 100g sugar tax, and a 20% fruit and vegetable (F&V) subsidy. Methods We estimated changes in food purchasing using a NZ PE matrix applied conventionally, and then with TFEe adjustment. Impacts were quantified for pre- to post-policy changes in total food expenditure and health adjusted life years (HALYs) for the total NZ population alive in 2011 over the rest of their lifetime using a multistate lifetable model. Results Two NZ studies gave TFEe’s of 0.68 and 0.83, with international estimates ranging from 0.46 to 0.90 (except a UK outlier of 0.04). Without TFEe adjustment, total food expenditure decreased with the tax policies and increased with the F&V subsidy–implausible directions of shift given economic theory and the external TFEe estimates. After TFEe adjustment, HALY gains reduced by a third to a half for the two taxes and reversed from an apparent health loss to a health gain for the F&V subsidy. With TFEe adjustment, HALY gains (in 1000’s) were: 1,805 (95% uncertainty interval 1,337 to 2,340) for the SAFA tax; 1,671 (1,220 to 2,269) for the sugar tax; and 953 (453 to 1,308) for the F&V subsidy. Conclusions If PE matrices are applied in settings beyond where they were derived, additional scaling is likely required. We suggest that the TFEe is a useful scalar, but we also encourage other researchers to examine this issue and propose alternative options.
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Affiliation(s)
- Tony Blakely
- Population Interventions Unit, Melbourne School of Population and Global Health, University of Melbourne, Melbourne, Australia
- Burden of Disease Epidemiology, Equity and Cost Effectiveness Programme, Department of Public Health, University of Otago, Wellington, New Zealand
- * E-mail:
| | - Nhung Nghiem
- Burden of Disease Epidemiology, Equity and Cost Effectiveness Programme, Department of Public Health, University of Otago, Wellington, New Zealand
| | - Murat Genc
- Department of Economics, University of Otago, Dunedin, New Zealand
| | - Anja Mizdrak
- Burden of Disease Epidemiology, Equity and Cost Effectiveness Programme, Department of Public Health, University of Otago, Wellington, New Zealand
| | - Linda Cobiac
- Nuffield Department of Population Health, Oxford University, Oxford, United Kingdom
| | - Cliona Ni Mhurchu
- National Institute of Health Innovation, University of Auckland, Auckland, New Zealand
| | - Boyd Swinburn
- School of Population Health, University of Auckland, Auckland, New Zealand
| | - Peter Scarborough
- Nuffield Department of Population Health, Oxford University, Oxford, United Kingdom
| | - Christine Cleghorn
- Burden of Disease Epidemiology, Equity and Cost Effectiveness Programme, Department of Public Health, University of Otago, Wellington, New Zealand
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Waterlander WE, Jiang Y, Nghiem N, Eyles H, Wilson N, Cleghorn C, Genç M, Swinburn B, Mhurchu CN, Blakely T. The effect of food price changes on consumer purchases: a randomised experiment. LANCET PUBLIC HEALTH 2019; 4:e394-e405. [DOI: 10.1016/s2468-2667(19)30105-7] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/26/2018] [Revised: 05/30/2019] [Accepted: 06/03/2019] [Indexed: 10/26/2022]
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Siegrist M, Ung CY, Zank M, Marinello M, Kunz A, Hartmann C, Menozzi M. Consumers' food selection behaviors in three-dimensional (3D) virtual reality. Food Res Int 2019; 117:50-59. [DOI: 10.1016/j.foodres.2018.02.033] [Citation(s) in RCA: 72] [Impact Index Per Article: 14.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2017] [Revised: 02/09/2018] [Accepted: 02/13/2018] [Indexed: 11/28/2022]
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Mizdrak A, Waterlander WE, Rayner M, Scarborough P. Using a UK Virtual Supermarket to Examine Purchasing Behavior Across Different Income Groups in the United Kingdom: Development and Feasibility Study. J Med Internet Res 2017; 19:e343. [PMID: 28993301 PMCID: PMC5653905 DOI: 10.2196/jmir.7982] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2017] [Revised: 06/18/2017] [Accepted: 06/27/2017] [Indexed: 01/08/2023] Open
Abstract
BACKGROUND The majority of food in the United Kingdom is purchased in supermarkets, and therefore, supermarket interventions provide an opportunity to improve diets. Randomized controlled trials are costly, time-consuming, and difficult to conduct in real stores. Alternative approaches of assessing the impact of supermarket interventions on food purchases are needed, especially with respect to assessing differential impacts on population subgroups. OBJECTIVE The aim of this study was to assess the feasibility of using the United Kingdom Virtual Supermarket (UKVS), a three-dimensional (3D) computer simulation of a supermarket, to measure food purchasing behavior across income groups. METHODS Participants (primary household shoppers in the United Kingdom with computer access) were asked to conduct two shopping tasks using the UKVS and complete questionnaires on demographics, food purchasing habits, and feedback on the UKVS software. Data on recruitment method and rate, completion of study procedure, purchases, and feedback on usability were collected to inform future trial protocols. RESULTS A total of 98 participants were recruited, and 46 (47%) fully completed the study procedure. Low-income participants were less likely to complete the study (P=.02). Most participants found the UKVS easy to use (38/46, 83%) and reported that UKVS purchases resembled their usual purchases (41/46, 89%). CONCLUSIONS The UKVS is likely to be a useful tool to examine the effects of nutrition interventions using randomized controlled designs. Feedback was positive from participants who completed the study and did not differ by income group. However, retention was low and needs to be addressed in future studies. This study provides purchasing data to establish sample size requirements for full trials using the UKVS.
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Affiliation(s)
- Anja Mizdrak
- Burden of Disease Epidemiology, Equity and Cost-Effectiveness Programme (BODE3), Department of Public Health, University of Otago, Wellington, Wellington, New Zealand
| | | | - Mike Rayner
- Centre on Population Approaches for Non-Communicable Disease Prevention, Nuffield Department of Population Health, University of Oxford, Oxford, United Kingdom
| | - Peter Scarborough
- Centre on Population Approaches for Non-Communicable Disease Prevention, Nuffield Department of Population Health, University of Oxford, Oxford, United Kingdom
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Ploydanai K, van den Puttelaar J, van Herpen E, van Trijp H. Using a Virtual Store As a Research Tool to Investigate Consumer In-store Behavior. J Vis Exp 2017. [PMID: 28784959 DOI: 10.3791/55719] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/31/2022] Open
Abstract
People's responses to products and/or choice environments are crucial to understanding in-store consumer behaviors. Currently, there are various approaches (e.g., surveys or laboratory settings) to study in-store behaviors, but the external validity of these is limited by their poor capability to resemble realistic choice environments. In addition, building a real store to meet experimental conditions while controlling for undesirable effects is costly and highly difficult. A virtual store developed by virtual reality techniques potentially transcends these limitations by offering the simulation of a 3D virtual store environment in a realistic, flexible, and cost-efficient way. In particular, a virtual store interactively allows consumers (participants) to experience and interact with objects in a tightly controlled yet realistic setting. This paper presents the key elements of using a desktop virtual store to study in-store consumer behavior. Descriptions of the protocol steps to: 1) build the experimental store, 2) prepare the data management program, 3) run the virtual store experiment, and 4) organize and export data from the data management program are presented. The virtual store enables participants to navigate through the store, choose a product from alternatives, and select or return products. Moreover, consumer-related shopping behaviors (e.g., shopping time, walking speed, and number and type of products examined and bought) can also be collected. The protocol is illustrated with an example of a store layout experiment showing that shelf length and shelf orientation influence shopping- and movement-related behaviors. This demonstrates that the use of a virtual store facilitates the study of consumer responses. The virtual store can be especially helpful when examining factors that are costly or difficult to change in real life (e.g., overall store layout), products that are not presently available in the market, and routinized behaviors in familiar environments.
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Affiliation(s)
- Kunalai Ploydanai
- Wageningen University and Research; Marketing Consumer Behaviour Group;
| | | | - Erica van Herpen
- Wageningen University and Research; Marketing Consumer Behaviour Group
| | - Hans van Trijp
- Wageningen University and Research; Marketing Consumer Behaviour Group
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Brimblecombe J, Ferguson M, Chatfield MD, Liberato SC, Gunther A, Ball K, Moodie M, Miles E, Magnus A, Mhurchu CN, Leach AJ, Bailie R. Effect of a price discount and consumer education strategy on food and beverage purchases in remote Indigenous Australia: a stepped-wedge randomised controlled trial. LANCET PUBLIC HEALTH 2017; 2:e82-e95. [PMID: 29253401 DOI: 10.1016/s2468-2667(16)30043-3] [Citation(s) in RCA: 70] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/09/2016] [Revised: 12/01/2016] [Accepted: 12/13/2016] [Indexed: 11/27/2022]
Abstract
BACKGROUND Evidence is mounting that price discounts can be effective in improving diet. This study examined the effectiveness of a 20% price discount on food and drink purchases with and without consumer education in remote Indigenous Australia. METHODS A 20% discount on fruit, vegetables, water, and artificially sweetened soft drinks was applied for 24 weeks in 20 communities in remote Indigenous Australia where the community store was managed by the Arnhem Land Progress Aboriginal Corporation (ALPA) or Outback Stores (OBS) in a stepped-wedge randomised trial. Communities were randomly allocated to a fixed framework of five sets of four stratified by store association; ten stores (two in each set) were randomly assigned to receive consumer education. A store from each of the ALPA and OBS store groups (contained in separate opaque envelopes) was selected, and stores in turn continued to be consecutively allocated to the fixed store set framework, starting with the first store slot in the first store set, until all stores had been allocated. The effect of the discount on the weight of fruit and vegetables purchased (the primary endpoint) was assessed using weekly store sales data and mixed models per protocol. We did sensitivity analyses by repeating the analyses with the outliers included and repeating the analyses for the primary outcome measure removing each store one at a time. This trial was registered with Australian New Zealand Clinical Trials Registry, number ACTRN12613000694718. FINDINGS Weekly store sales data on all food and drink products sold in 20 stores were collected from July 1, 2012, to Dec 28, 2014. Price discount alone was associated with a 12·7% (95% CI 4·1-22·1) increase in purchases in grams of fruit and vegetables combined (primary outcome), and a 19·8% (6·2-35·1) increase post discount (after vs before); an effect of 12 g and 18 g per capita per day. Sensitivity analyses did not modify the results for the primary outcome measure. INTERPRETATION A 20% discount can only increase fruit and vegetable purchases to help protect against obesity and diet related disease to a certain extent. Large discounts might have a greater impact than small discounts. Creative merchandising approaches to consumer education could also be considered alongside fiscal interventions to achieve marked improvements in diet. FUNDING Australian National Health and Medical Research Council.
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Affiliation(s)
- Julie Brimblecombe
- Wellbeing and Preventable Chronic Diseases Division, Royal Darwin Hospital Campus, Tiwi, NT, Australia.
| | - Megan Ferguson
- Wellbeing and Preventable Chronic Diseases Division, Royal Darwin Hospital Campus, Tiwi, NT, Australia; Centre for Population Health Research, School of Health Sciences, University of South Australia, Adelaide, SA Australia
| | - Mark D Chatfield
- Wellbeing and Preventable Chronic Diseases Division, Royal Darwin Hospital Campus, Tiwi, NT, Australia
| | - Selma C Liberato
- Wellbeing and Preventable Chronic Diseases Division, Royal Darwin Hospital Campus, Tiwi, NT, Australia
| | - Anthony Gunther
- Wellbeing and Preventable Chronic Diseases Division, Royal Darwin Hospital Campus, Tiwi, NT, Australia
| | - Kylie Ball
- Institute for Physical Activity and Nutrition, School of Exercise and Nutrition Sciences, Deakin University, Geelong, Australia, Geelong, VIC, Australia
| | - Marj Moodie
- Deakin Health Economics, Centre for Population Health Research, Faculty of Health, Deakin University, Geelong, Australia, Geelong, VIC, Australia
| | - Edward Miles
- Indigenous Community Volunteers, 1/67 Townshend Street, Phillip, ACT, Australia
| | - Anne Magnus
- Deakin Health Economics, Centre for Population Health Research, Faculty of Health, Deakin University, Geelong, Australia, Geelong, VIC, Australia
| | - Cliona Ni Mhurchu
- National Institute for Health Innovation, School of Population Health, University of Auckland, Auckland, New Zealand
| | - Amanda Jane Leach
- Child Health Division, Menzies School of Health Research, Royal Darwin Hospital Campus, Tiwi, NT, Australia
| | - Ross Bailie
- University Centre for Rural Health North Coast, University of Sydney, Lismore, NSW, Australia
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