Table 2 Summary of included reviews reporting studies of regulation policy interventions

Brown et al. 2014 [20]

Studies based in a country at stage 4 of the tobacco epidemic or in the WHO European Region, 1995–2013

Smoking restrictions in workplaces and enclosed public places; controls on advertising, promotion and marketing of tobacco; neighbourhood improvement initiative.

Includes 3 studies also identified in Fraser et al. (2016).

Higher quality evidence suggests smoking restrictions in workplaces and enclosed public places leads to a widening of inequalities, with a small amount of evidence of a negative effect of a general neighbourhood improvement initiative. Controls on advertising, promotion and marketing appear to have an equal effect across SES groups.

Frazer et al. 2016 [29]

Cities/States/Countries in New Zealand, Italy, USA; search timeframe – inception to March 2015

Smoking ban in indoor places (e.g. workplaces/bars/ restaurants).

Includes 3 studies also identified in Brown et al. (2014).

Mixed results although some evidence from New Zealand and Italy in particular which suggests a smoking ban may improve health outcomes particularly from those living in deprived areas.

Thomas et al. 2008 [30]

Variety of settings; OECD countries; inception to January 2006

Smoking restrictions in workplaces and other public places; increased enforcement against underage sales in tobacco; and multifaceted interventions (e.g. combined effects of different anti-tobacco laws).

No evidence of differential effects for smoking restrictions in workplaces.

Sumar and McLaren 2011 [31]

Women, no country restrictions, 1990-time of study

Introduction of mandatory fortification policy.

Some support is found for the hypothesis that mandatory fortification policy is less likely than information campaigns to lead to worsening inequalities in health by socioeconomic status or race/ethnicity; however, conclusions were complicated by different outcome variables and different economic and political regimes in which interventions took place.

McGill et al. 2015 [32]

Any age or gender from any country, from 1980 onwards

National salt reduction strategy (whereby manufacturers, retailers, trade associations and the catering sector were committed to salt reduction).

Study based on reformulation of food products found no effect in terms of inequality.

Hillier-Brown et al. 2017 [34]

City/States in the USA. January 1993 – October 2015

Regulation in a major city to control the trans and saturated fat content of fast-food purchases and mandatory menu labelling.

Mean trans-fat per purchase decreased but no difference by the poverty rate of the neighbourhood in which the restaurant was located. Mixed results for equity effects of menu labelling on calories purchased (negative and neutral).

Hendry et al. 2015 [35]

New York City; 1980–2012

Trans-fatty acid ban for all licensed food establishments.

Mean trans-fatty acids decreased. Neighbourhood poverty was not associated with trans-fatty acid purchase.

Olstad et al. 2016 [25]

Range of settings including cities, countries and establishments; Korea, UK, USA, France, Finland and Australia, January 2004–August 2015

A range of nutrition policies (e.g. minimum standards, national diabetes prevention), and menu labelling law.

Most nutrition policy interventions showed negative effects on inequalities. Menu labelling had no effect on health inequalities.

Iheozor-Ejiofor et al. 2015 [36]

Various settings in English areas, start date – 2015

Initiation of water fluoridation.

Although caries and decayed, missing and filled deciduous teeth/surfaces did show improvement following the initiation of water fluoridation, the authors concluded that due to problems with the study designs, results are inconclusive.

Ashton et al. 2009 [37]

More and less deprived cities; UK; 1990–2009

Traffic calming measures documented in two cities.

Significant drop in child pedestrian casualties in more deprived area.

Mulvaney et al. 2015 [38]

City roads, London (UK), various to 2015

The implementation of 20 mph zones.

Study results suggest that 20 mph zones have smaller effects on cycle casualties with increasing levels of social deprivation of the area in which the collision occurred (no evidence demonstrated on adjacent roads). Over the period, the decline in road casualties was greater in less deprived areas despite the 20 mph zones causing socioeconomic inequalities to widen over time.

Benmarhnia et al. 2014 [39]

Specific areas with vulnerable populations, 1980–2013. English language only.

Low emission zones.

Low-emission zones were more beneficial to the wealthiest residents.

Egan et al. 2007 [40]

Privatisation of water industry, UK, 1945–2003

Privatisation of UK’s water industry.

Worsening mental health for clerical and administrative staff (no significant change for manual workers or managers) post intervention. Little change in mean OSI scores for somatic symptoms among any occupation group.

National Collaborating Centre for Women’s and Children’s Health 2009 [26]

Context limited to application to a UK setting; Searches to March 2008, articles published before 1988 were excluded. English language only.

Mandatory immunisations for school entry.

There is evidence of positive effects on inequalities in vaccination rates for regulatory-style interventions.