Population tobacco control interventions and their effects on social inequalities in smoking: systematic review

Abstract

Objective: To assess the effects of population tobacco control interventions on social inequalities in smoking.

Data sources: Medical, nursing, psychological, social science and grey literature databases, bibliographies, hand-searches and contact with authors.

Study selection: Studies were included (n = 84) if they reported the effects of any population-level tobacco control intervention on smoking behaviour or attitudes in individuals or groups with different demographic or socioeconomic characteristics.

Data extraction: Data extraction and quality assessment for each study were conducted by one reviewer and checked by a second.

Data synthesis: Data were synthesised using graphical ("harvest plot") and narrative methods. No strong evidence of differential effects was found for smoking restrictions in workplaces and public places, although those in higher occupational groups may be more likely to change their attitudes or behaviour. Smoking restrictions in schools may be more effective in girls. Restrictions on sales to minors may be more effective in girls and younger children. Increasing the price of tobacco products may be more effective in reducing smoking among lower-income adults and those in manual occupations, although there was also some evidence to suggest that adults with higher levels of education may be more price-sensitive. Young people aged under 25 are also affected by price increases, with some evidence that boys and non-white young people may be more sensitive to price.

Conclusions: Population-level tobacco control interventions have the potential to benefit more disadvantaged groups and thereby contribute to reducing health inequalities.

Figure 2. Evidence for social gradients in effects of interventions. A „supermatrix” covering all categories of intervention consisting of six rows (one for each dimension of inequality) and three columns (one for each of the three competing hypotheses about the differential effects of each category of intervention). Each study is represented by a mark in each row for which that study had reported relevant results. Studies with hard behavioural outcome measures are indicated with full-tone (black) bars, and studies with intermediate outcome measures with half-tone (grey) bars. The suitability of study design is indicated by the height of the bar, where the highest bars represent the most suitable study designs (categories A and B) and the lowest bars represent the least suitable (category D). Each bar is annotated with the number of other methodological criteria (maximum six) met by that study.

Figure 1. Process of study selection.