Background
Methods
Study design
Search strategy
Study selection and inclusion criteria
Include | Exclude |
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Participants
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Healthy populations (any age or gender), from any country | Studies including participants that were not representative of the population were excluded (e.g. sub categories such as obese participants in weight loss trials, participants with diabetes, pregnant women). |
Interventions
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Studies evaluating the effects of intervention to promote healthy eating that were implemented experimentally; or due to local or national policies. These could include a range of actions to improve healthy eating (in terms of the dietary factors of salt, sugar, trans fats, saturated fat, total fat, fruit and vegetables and calories). | Interventions with no change in healthy eating outcomes quantitatively stratified by SEP. |
Actions initiated by industry. | |
Comparators
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Studies were only included in the review provided that the authors made a quantitative comparison of differential effects of policy interventions to improve healthy eating by at least one measure of SEP. | Studies which did not report the effects of actions to improve healthy eating by SEP |
Outcomes
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The primary outcome of interest was dietary intake. Secondary outcomes included: changes in clinical/physiological indicators related to NCD, behaviours associated with a healthy diet e.g. change in BMI. | Process evaluations reporting on implementation of interventions/policies without any outcome data; data only on costs, or feasibility or acceptability without an assessment of intake; reviews/studies of under-nutrition. |
Studies with no mention of SEP. | |
Study design
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We included studies of any design, including RCTs, cohort studies and modelling studies. We explicitly included modelling studies to better capture analysis of fiscal measures such as taxes, subsidies, or economic incentives | Opinion articles; purely qualitative evaluations with no quantitative assessment; data/statistics from monitoring and surveillance not directly linked to a policy intervention |
Data extraction and management
Assessment of methodological quality of included studies
Data synthesis
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Price – fiscal measures such as taxes, subsidies, or economic incentives
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Place – environmental measures in specific settings such as schools, work places (e.g. vending machines) or planning (e.g. location of supermarkets and fast food outlets) or community-based health education
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Product – modification of food products to make them healthier/less harmful e.g. reformulation, additives, or elimination of a specific nutrient
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Prescriptive – restrictions on advertising/marketing through controls or bans, labelling, recommendations or guidelines
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Promotion – mass media public information campaigns
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Person –Individual-based information and education (e.g. cooking lessons, tailored nutritional education/counselling, or nutrition education in the school curriculum).
Socioeconomic inequalities in impact
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Intervention likely to reduce inequalities: the intervention preferentially improved healthy eating outcomes in people of lower SEP
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Intervention likely to widen inequalities: the intervention preferentially improved healthy eating outcomes in people of higher SEP
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Intervention which had no preferential impact by SEP (this also includes interventions where there was an overall benefit but where there was no effect on healthy eating outcomes for any SEP sub-group).
Sensitivity analyses
Results
Impact on socioeconomic inequalities by “P” category
Price interventions (taxes, subsidies, or economic incentives)
Author | Study | Setting | Intervention | Quality∆ | Outcome measured | SEP measurement | Effect on SEP inequalities† |
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Modelling study | France | 10% Tax on high energy density food: | 2 | Change in fat consumed (%) | Household income |
↓
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Modelling study | USA | 1% Subsidy on fruit and vegetables | 2 | CHD incidence | Household income |
↑*
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Modelling study | France | 5.5% to 2.1% Subsidy on fruit and vegetables | 2 | Change in mean fruit and vegetable consumption (g/d) | Household income |
↔*
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Food stamp program for fruit and vegetables |
↓*
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Finkelstein [41] | Modelling study | Canada | 20% Tax on high energy density food | 2 | Mean change in energy intake from all beverages | Household income |
↔*
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40% tax on carbonated sugar sweetened beverages |
↔*
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20% tax on all sugar sweetened beverages |
↔*
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40% tax on all sugar sweetened beverages |
↔*
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RCT | Holland | 50% Tax on high energy density food | 5 | % change in calories purchased in lean individuals | Food budget |
↓*
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Modelling study | UK | 17.5% tax on high energy density foods | 2 | % change in calorie intake | Household income |
↔*
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17.5% tax on food classified as ‘less healthy’ by nutrient profiling |
↓*
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Combined the taxation on ‘less healthy’ foods with a 17.5% subsidy on fruit and vegetables |
↓*
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As above with a 32.5% subsidy on fruit and vegetables |
↓*
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Modelling study | Australia | 20% tax on sugar sweetened beverages | 2 | Mean net change in body weight in kg | Household income |
↑*
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Modelling study | Denmark | 5% tax on fatty meat and dairy products with subsidies on fruit and vegetables, potatoes and grain products | 2 | Change in nutrient demand of saturated fat (%) | Social class |
↓
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7.89 DKK/kg tax on saturated fats with subsidies on fibre |
↓
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7.89 DKK/kg tax on saturated fats with subsidies on fibre with an additional 10.3 DKK/kg tax on sugar |
↓
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Modelling study | UK | 1% Tax on fatty food for every % saturated fat content with a matching subsidy on fruit and vegetables | 2 | % change in energy intake | Occupation |
↓
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Place interventions (environmental measures in specific settings)
Author | Study | Setting | Intervention | Quality∆ | Outcome measured | SEP measurement | Effect on SEP inequalities† |
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Place
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Campbell [43] | RCT | USA | Church based intervention | 5 | Mean change in portions of fruit and vegetables consumed | Household income |
↔*
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Cross sectional survey | England | School based intervention | 4 | Change in portions of fruit and vegetables consumed | Index of Multiple Deprivation |
↓*
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RCT | New Zealand | School based intervention | 3 | Change in BMI standard deviation score in 5–7 year olds | Household income |
↔*
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RCT | USA | Work based intervention | 5 | % change in those achieving 5 a day | Occupation |
↓*
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RCT | USA | Work based intervention | 5 | Change in geometric mean grams of fibre per 1000 kcals | Occupation |
↓*
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Cohort study | Holland | Area based intervention | 4 | Difference in mean energy intake between intervention and control (MJ/d) | Education level |
↓*
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Product
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Observational study | England | Salt reformulation | 3 | Salt intake (g/d) | Social class |
↔*
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Prescriptive
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No studies were identified examining the potential SEP differentials effects of restrictions on advertising/marketing through controls or bans; labelling, recommendations or guidelines
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Promotion
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Modelling study | UK | Health information campaign (5 a day) | 2 | Change in fruit and vegetable intake (portions) | Household income |
↓*
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Modelling study | France | Health information campaign (fruit and vegetable promotion) | 2 | Change in fruit and vegetable consumption (g/d) | Household income |
↔*
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Cohort study | France | Health information campaign (5 a day) | 2 | % of males consuming ≥ five portions of fruit and vegetable per day | Education level |
↑*
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Cross sectional survey | USA | Health information campaign (5 a day) | 2 | Change in portions of fruit and vegetables consumed | Poverty Index Ratio |
↔*
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Product interventions (modification of food products to make them healthier/less harmful)
Prescriptive interventions (restrictions on advertising/marketing)
Promotion interventions (mass media public information campaigns)
Person interventions (Individual-based information and education)
Author | Study | Setting | Intervention | Quality∆ | Outcome measured | SEP measurement | Effect on SEP inequalities† |
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Cross sectional survey | USA | Health education: Community based education | 3 | % change of the % of people who consume five portions of fruit and vegetables per day | Education level |
↓
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RCT | Switzerland | Health education: Healthy nutrition program aimed at children | 5 | Mean BMI (kg/m2) | Parental education level |
↔*
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RCT | USA | Health education: Tailored feedback and self-help dietary intervention. | 5 | Mean fruit and veg intake score (Score out of 3, 3 = less F/V intake, 1 = more F/V intake) | Education level |
↓*
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RCT | USA | Dietary counselling intervention | 3 | Change in serum cholesterol (mg/dl) | Household income |
↑
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Randomised parallel groups comparison study | UK | Health education: Cooking fair with cooking lessons accompanying personalised dietary goal settings | 3 | % change in mean food energy from fat | Quintile of Deprivation Index |
↓*
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RCT | Republic of Ireland | Health education: Healthy nutrition program aimed at children (“Hearty heart”) | 2 | Change in % of children consuming >4 portions of fruit and veg per day | Area level deprivation |
↔*
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RCT | Belgium | Health education: adapted computer tailored dietary intervention for children. | 4 | Change in mean dietary fat intake (g/d) | Education level |
↔*
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RCT | USA | Health education: Healthy nutrition program aimed at adult women | 5 | Change in mean daily servings consumed of fruit and vegetables | Education level |
↑*
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RCT | USA | Dietary counselling intervention | 5 | % change in fruit and vegetables consumed | Education level |
↑*
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RCT | Norway | Dietary counselling intervention | 5 | % change in cholesterol | Social class |
↑
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RCT | USA | Health education: Community based education | 3 | Mean weight change in women (lb) | Household income |
↔*
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Health education: Community based education with an additional prize lottery |
↔*
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RCT | France | Health education: Healthy nutrition program aimed at children | 4 | Change in % of children overweight | Area level deprivation |
↓*
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Cohort study | UK | Health education: Healthy nutrition program aimed at children | 3 | % change in vegetables observed consumed | Free school meal entitlement |
↑
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RCT | Germany | Health education: Healthy nutrition program aimed at children | 5 | Change in % prevalence of overweight | Parental education level |
↑*
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RCT | USA | Health education: Healthy nutrition program aimed at children | 3 | Portions of fruit and vegetables consumed | Household income |
↑*
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RCT | Australia | Health education: Healthy nutrition program aimed at adults | 4 | Change in fat density consumed (g/4200 kcal) | The Daniel Scale of Occupational Prestige |
↓
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RCT | Denmark | Dietary counselling intervention | 4 | Change in amount of fruit eaten by men (g/week) | Education level |
↑*
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