Implications for policy
These findings carry several implications for policy. One is that, the most compelling evidence of a negative (desirable) social gradient in effectiveness is for the price of tobacco products. Increasing the price of tobacco is the population-level intervention for which there is strongest evidence as a measure for reducing smoking-related inequalities in health.
However, effects of increasing tobacco taxation may be undermined by tax evasion or tax avoidance measures such as smuggling and cross-border shopping. The Acheson Inquiry
and other commentators have also raised concern about the long-term effect of price rises on disadvantaged households, where smokers are more likely to be nicotine dependent and for whom living in hardship is the primary deterrent to quitting. The policy steer on this point is that extra measures to support cessation among low-income households would be needed, alongside any intensification of pricing policy.
Nonetheless, there is certainly more consistent evidence to support increasing the price of tobacco products as a means of reducing social inequalities in smoking than for other more visible interventions, such as health warnings and advertising restrictions, where differential effects appear under-explored. It should also be noted that although interventions such as health warnings and advertising restrictions may not in themselves impact upon inequalities, they may be important as part of a wider tobacco control strategy if they help to elicit public support for other measures.
In children and young people, restrictions on sales may be effective in deterring younger smokers, though their effectiveness depends on enforcement. Un-enforced voluntary
agreements with retailers are less effective in reducing sales. Pricing may be less effective among younger children, perhaps because they obtain cigarettes from non-commercial
sources. Among this group, restrictions in schools (which affect consumption) and health warnings (which affect attitudes to smoking) may be more productive. Appropriately-enforced restrictions on sales to minors may offer the greatest promise as part of a strategy for tackling inequalities. While combinations of interventions are also likely to be an important part of the policy armoury, the differential effects of such combinations largely remains an area for further research, though they may hold promise for reducing smoking initiation in young people.
Aside from identifying interventions which are effective in reducing inequalities, it is also important to identify measures which have the potential to increase inequalities. Here the
message from our review is encouraging, as there was little evidence that the interventions we examined had adverse effects in this regard. One possible exception was restrictions on smoking in the workplace, which may be more effective among higher occupational grades and among staff with higher levels of educational attainment. This suggests that the
implementation of such policies should be accompanied by measures to mitigate adverse effects on inequalities, such as measures to support adherence across all occupational
grades. The potential for workplace restrictions is therefore dependent on their effective implementation in blue-collar settings. This supports the case for legislating for mandatory
workplace bans, rather than relying on willing employers to introduce voluntary bans.
Implications for research
We currently know little about the differential effects of the following interventions stratified by income group:
Health warnings on tobacco products
Restrictions on tobacco advertising
Restrictions on smoking in schools
Restrictions on sales of tobacco to minors.
With respect to the pricing of tobacco products, a relatively well-researched field, we need to know more about:
The effects of price increases on adolescents from lower-income households, and on adolescents and young people in general compared to adults; and
The effects of price increases on lower-income adults, who are more likely to be dependent on nicotine.
Other aspects of the social gradient are under-represented in the evidence-base, in particular;
The differential effects of most interventions by ethnicity; and
The differential effects between boys and girls in school restrictions, health warnings,
advertising restrictions and pricing.
Further primary research is indicated in each of these areas. Perhaps most important to note is that most of the existing evidence derives from the US. The greatest research priority should therefore be to develop relevant interventions for other country contexts with a focus on behavioural outcomes. The introduction of new population-level tobacco control policies - such as the restrictions on smoking in public places now introduced in all the countries of the UK and elsewhere – provides such an opportunity.