Methods used to conceptualize dimensions of health equity impacts of public health interventions in systematic reviews

OBJECTIVES

Our aims were to, first, identify and summarize the use of methods, frameworks, and tools as a conceptual basis for investigating dimensions of equity impacts of public health interventions in systematic reviews including an equity focus. These include PROGRESS-Plus, which identifies key sociodemographic characteristics that determine health outcomes. Second, we aimed to document challenges and opportunities encountered in the application of such methods, as reported in systematic reviews.

STUDY DESIGN AND SETTING

We conducted a methodological study, comprising an overview of systematic reviews with a focus on, or that aimed to assess, the equity impacts of public health interventions. We used electronic searches of the Cochrane Database of Systematic Reviews, the Database of Promoting Health Effectiveness Reviews (DoPHER), and the Finding Accessible Inequalities Research in Public Health Database, supplemented with automated searches of the OpenAlex dataset. An active learning algorithm was used to prioritize title-abstract records for manual screening against eligibility criteria. We extracted and analyzed a core dataset from a purposively selected sample of reviews, to summarize key characteristics and approaches to conceptualizing investigations of equity.

RESULTS

We assessed 322 full-text reports for eligibility, from which we included 120 reports of systematic reviews. PROGRESS-Plus was the only formalized framework used to conceptualize dimensions of equity impacts. Most reviews were able to apply their intended methods to at least some degree. Where intended methods were unable to be applied fully, this was usually because primary research studies did not report the necessary information. A general rationale for focusing on equity impacts was often included, but few reviews explicitly justified their focus on (or exclusion of) specific dimensions. In addition to practical challenges such as data not being available, authors highlighted significant measurement and conceptual issues with applying these methods which may impair the ability to investigate and interpret differential impacts within and between studies. These issues included investigating constructs that lack standardized operationalization and measurement, and the complex nature of differential impacts, with dimensions that may interact with one another, as well as with particular temporal, personal, social or geographic contexts.

CONCLUSION

PROGRESS-Plus is the predominant framework used in systematic reviews to conceptualize differential impacts of public health interventions by dimensions of equity. It appears sufficiently broad to encompass dimensions of equity examined in most investigations of this kind. However, PROGRESS-Plus does not necessarily ensure or guide critical thinking about more complex pathways, including interactions between dimensions of equity, and with wider contextual factors, and important practical, measurement and conceptual challenges remain. The findings from investigations of equity impacts in systematic reviews could be made more useful through more explicitly rationalized and considered approaches to the design, conduct and reporting of both primary research and the reviews themselves.

Using the Past to Understand the Future of U.S. and Global Smoking Disparities: A Birth Cohort Perspective

U.S. smoking-related disparities persist, but data evaluating how smoking patterns across diverse populations have changed by birth cohort are lacking. Worldwide, smoking continues to exact harm, especially to low- and middle-income nations with less historical data for smoking analyses. The Cancer Intervention and Surveillance Modeling Network (CISNET) Lung Working Group previously generated smoking histories for the whole U.S. population using an age, period, and birth cohort (APC) methodological framework. These inputs have been used in numerous models to simulate future patterns of smoking and to evaluate the potential impact of policies. However, the absence of detailed model-ready inputs on smoking behaviors for diverse U.S. populations has been a barrier to research evaluating future trends in smoking-related disparities or the projected impacts of policies across sociodemographic groups. This supplement issue provides new estimates of smoking behaviors with detailed historical data by race/ethnicity, educational attainment, family income, and for each of the 50 U.S. states and Washington, DC. All-cause mortality relative risks associated with smoking by race/ethnicity and educational attainment are also available for the first time. Finally, the supplement issue presents comprehensive smoking histories for Brazil, demonstrating the application of this methodology to resource-limited settings. Collectively, these data aim to offer insight into future U.S. and global smoking disparities and accelerate research on tobacco control policies that advance health equity. This effort will allow tobacco simulation models to account comprehensively for population diversity, thereby enabling researchers to develop more sophisticated analyses of tobacco use and control interventions.

A systematic review of inequalities in the uptake of, adherence to, and effectiveness of behavioral weight management interventions in adults

The extent to which behavioral weight management interventions affect health inequalities is uncertain, as is whether trials of these interventions directly consider inequalities. We conducted a systematic review, synthesizing evidence on how different aspects of inequality impact uptake, adherence, and effectiveness in trials of behavioral weight management interventions. We included (cluster-) randomized controlled trials of primary care-applicable behavioral weight management interventions in adults with overweight or obesity published prior to March 2020. Data about trial uptake, intervention adherence, attrition, and weight change by PROGRESS-Plus criteria (place of residence, race/ethnicity, occupation, gender, religion, education, socioeconomic status, social capital, plus other discriminating factors) were extracted. Data were synthesized narratively and summarized in harvest plots. We identified 91 behavioral weight loss interventions and 12 behavioral weight loss maintenance interventions. Fifty-six of the 103 trials considered inequalities in relation to at least one of intervention or trial uptake (n = 15), intervention adherence (n = 15), trial attrition (n = 32), or weight outcome (n = 34). Most trials found no inequalities gradient. If a gradient was observed for trial uptake, intervention adherence, and trial attrition, those considered "more advantaged" did best. Alternative methods of data synthesis that enable data to be pooled and increase statistical power may enhance understanding of inequalities in behavioral weight management interventions.

Socioeconomic inequalities in secondhand smoke exposure before, during and after implementation of Quebec's 2015 'An Act to Bolster Tobacco Control'

BACKGROUND

To better understand whether tobacco control policies are associated with changes in secondhand smoke (SHS) exposure across socioeconomic groups, we monitored differences in socioeconomic inequalities in SHS exposure in households and private vehicles among youth and adults before, during and after adoption of Quebec's 2015 An Act to Bolster Tobacco Control.

METHODS

Using data from the Canadian Community Health Survey, we examined the prevalence of daily exposure to SHS in households and private vehicles among youth (ages 12 to 17) and adults (ages 18+) across levels of household education and income (separately) in 2013/2014, 2015/2016 and 2017/2018. We tested differences in the magnitude of differences in outcomes over time across education and income categories using logistic models with interaction terms, controlling for age and sex.

RESULTS

We detected inequalities in SHS exposure outcomes at each time point, most markedly at home among youth (OR of SHS exposure among youth living in the 20% poorest households vs the 20% richest=4.9, 95% CI 2.7 to 6.2). There were decreases in SHS exposure in homes and cars in each education/income group over time. The magnitude of inequalities in SHS exposure in homes and cars, however, did not change during this period.

CONCLUSIONS

The persistence of socioeconomic inequalities in SHS exposure despite implementation of new tobacco control laws represents an increasingly worrisome public health challenge, particularly among youth. Policymakers should prioritise the reduction of socioeconomic inequalities in SHS exposure and consider the specific needs of socioeconomically disadvantaged populations in the design of future legislation.

Inequalities in the uptake of, adherence to and effectiveness of behavioural weight management interventions: systematic review protocol

INTRODUCTION

It has been suggested that interventions focusing on individual behaviour change, such as behavioural weight management interventions, may exacerbate health inequalities. These intervention-generated inequalities may occur at different stages, including intervention uptake, adherence and effectiveness. We will synthesise evidence on how different measures of inequality moderate the uptake, adherence and effectiveness of behavioural weight management interventions in adults.

METHODS AND ANALYSIS

We will update a previous systematic literature review from the United States Preventive Services Taskforce to identify trials of behavioural weight management interventions in adults aged 18 years and over that were, or could feasibly be, conducted in or recruited from primary care. Medline, Cochrane database (CENTRAL) and PsycINFO will be searched. Only randomised controlled trials (RCTs) and cluster-RCTs will be included. Two investigators will independently screen articles for eligibility and conduct risk of bias assessment. We will curate publication families for eligible trials. The PROGRESS-Plus acronym (place of residence, race/ethnicity, occupation, gender, religion, education, socioeconomic status, social capital, plus other discriminating factors) will be used to consider a comprehensive range of health inequalities. Data on trial uptake, intervention adherence, weight change and PROGRESS-Plus-related data will be extracted. Data will be synthesised narratively. We will present a Harvest plot for each PROGRESS-Plus criterion and whether each trial found a negative, positive or no health inequality gradient. We will also identify potential sources of unpublished original research data on these factors which can be synthesised through a future individual participant data meta-analysis.

ETHICS AND DISSEMINATION

Ethical approval is not required as no primary data are being collected. The completed systematic review will be disseminated in a peer-reviewed journal, at conferences, and contribute to the lead author's PhD thesis. Authors of trials included in the completed systematic review may be invited to collaborate on a future individual participant data meta-analysis.

PROSPERO REGISTRATION NUMBER

CRD42020173242.