What explanations for the Alcohol Harm Paradox are proposed in the literature? A Systematic Review - Final Protocol October 2019

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What explanation for the Alcohol Harm Paradox are proposed in the literature?
A Systematic Review.
Final Protocol: October 2019
Lead Investigator: Jennifer Boyd (jeboyd1@sheffield.ac.uk)
Co-investigators: Robin Purshouse, Colin Angus, Petra Meier, Olivia Sexton, John
Holmes
Institution: ScHARR, University of Sheffield
1. Introduction
Alcohol is known to play a causal role in over 200 disease and injury conditions,
accounting for 5.3% of deaths and 5.1% of the burden of disease and injury globally
(1). There is evidence to suggest alcohol-related harm is not equitably distributed
across socioeconomic position (SEP). Disadvantaged groups in society
disproportionately suffer from alcohol related harm compared with advantaged
groups, despite reporting similar or lower levels of consumption (2,3). This consistent
finding has been termed the alcohol harm paradox (AHP) (4). Although previous
research has focused on establishing the existence of this phenomenon, there is a
paucity of evidence which attempts to understand the underlying causes.
Several reviews and meta-analyses have been published with a primary aim of
establishing socioeconomic differences in alcohol-related or attributable harms
based on existing evidence or available survey data (3,5–8). A subset also focused
on the role of levels or patterns of alcohol consumption (5,7,8). Overall, elevated risk
did exist for low SEP groups and differences in consumption could not completely
explain this relationship – it did attenuate the relationship for some disease specific
outcomes (7). Each review discussed potential causes of the AHP, but this was often
brief. Therefore, scope exists to conduct a review which synthesizes causal
explanations for the AHP.
Previous research investigating the causes of the AHP has focused on
methodological and behavioural explanations. In terms of methodological
explanations, it is often argued that the AHP is the result of low SEP groups
underreporting their alcohol consumption (4). However, there is evidence to suggest
that high SEP groups also underreport their consumption (9). Therefore, it remains
unclear whether methodological issues are the cause. Cross-sectional studies have
empirically tested differences in drinking patterns, behavioural clustering, drinking
histories and underreporting between SEP groups (9,10). While average alcohol
consumption is similar or less (typically across the week or annually) for low SEP
groups, there is evidence that they tend to drink more per occasion (engaging in
binge drinking) and engage in multiple risky health behaviours (9,10) – these studies
do not test harm outcomes. A more recent study highlighted that low SEP was
associated with elevated alcohol related harm relative to high SEP after adjusting for
weekly consumption, binge drinking, BMI, and smoking (11). Therefore, it is clear
behavioural factors do not adequately explain the AHP. Although behavioural factors
may play a role (4), other explanations have been neglected.

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Given previous research has narrowly focused on using proximal individual-level
factors to explain the AHP, this review aimed to comprehensively identify proposed
explanations for the paradox used within the relevant literature. This literature
includes papers explicitly exploring the causes of the AHP, in addition to those
testing the relationship between SEP, consumption and harm. Secondary aims of the
review were to explore any relationships between these explanations and provide an
overview of the existing evidence for these explanations taken from the included
papers.
2. Detailed methodology
2.1 Rationale for literature review
The existing empirical evidence has been dominated by behavioural and
methodological explanations for the AHP, while wider determinants (e.g. living and
working conditions, social networks) have been largely ignored. Our review will
therefore consider explanations for the existence of the AHP not only tested in
empirical research but also those explored hypothetically in the discussion sections
of these papers and more broadly in secondary research, debate/discussion papers
and the grey literature. The key focus is on what has been suggested as an
explanation for the AHP from a wide range of literature.
2.2 Research aims and objectives
The primary aim of this review was to identify proposed explanations for the AHP
from the existing literature. Secondary aims were to understand the relationships
between these explanations and the provide an overview of the evidence base for
these explanations. This will be achieved through the following objectives:
1. To identify academic and grey literature which either a) discusses or
investigates the existence or explanations for the AHP or b) explores the
relationship between socioeconomic position (SEP), alcohol consumption and
alcohol-related harm.
2. Use thematic analysis to collate and summarise existing explanations
presented in the literature.
3. Assess whether explanations fit within wider domains and whether there are
relationships between explanations.
4. Summarise the evidence base for explanations which have been empirically
tested.
5. Discuss the findings of the review and consider any implications for future
research and policy, including how the findings should inform the alcohol-
harm research agenda.
2.3 Search Strategy
Academic Literature
A comprehensive search strategy will be implemented across 3 electronic
bibliographic databases: MEDLINE, EMBASE and PsycINFO. Two main blocks of
search terms will be used, one covering socioeconomic inequalities and the other

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alcohol consumption (see Appendix A for list of search terms); eligible articles must
appear in both.
The results of a preliminary scoping searches in MEDLINE and PsycINFO are
displayed in Table 1 (search conducted in 05 October 2019). Given these findings,
this study will not restrict included papers to the UK setting given the aim of this
paper is to identify a broad range of explanations for the AHP, which is shown to not
only exist in the UK but also in other countries, for example Finland (12) and
Australia (13). However, when screening studies, only those set in the global north
as defined by the OECD (14) will be selected for full text screening. This is due to
stark differences in drinking culture between the global north and south.
Table 1: Search results for preliminary scoping searches
Search term blocks
Database
MEDLINE
PsycINFO
All
11,831
3,286
UK only
1,162
566
Grey literature
Grey literature pertaining to this topic will be identified in three main ways. Firstly,
expert opinion will be solicited to identify key relevant papers. I will supplement the
database searches with searches of Google/Google Scholar using the search terms:
socioeconomic, inequalities, alcohol-related harm, deprivation, morbidity, mortality.
This will also include searching for reports on the websites of key organisations and
charities (e.g. Institute of Alcohol Studies UK, The Foundation for Alcohol Research
and Education (FARE) Australia).
2.4 Study eligibility criteria
Studies that meet this specified criterion will be eligible for inclusion:
• Aim to investigate the existence and/or explanations for the alcohol harm
paradox
OR
• Any investigation of the relationship between alcohol related harm,
socioeconomic status, and alcohol consumption
o Any type of alcohol related physical health harm- morbidity and
mortality associated with alcohol use both wholly and partially
attributable causes and general physical health complaints -
OR
o social harm (e.g. victimisation)
OR
o clinical diagnosis of alcohol use disorder using ICD codes/ DSM-IV
manual

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AND
o Any measure of socioeconomic status; deprivation score, education,
occupation, income, etc.
AND
o Any measure of alcohol consumption
AND
● Empirical studies: cross-sectional or longitudinal; or theoretical papers, or
commentaries and/or reports produced by agencies and organisations
AND
● Full papers
Studies will be excluded if they meet any of the following criteria:
● Studies exclusively looking at countries outside of the global north as defined by
OECD (14)
● Non-English language papers
● Treatment/Intervention studies
2.5 Literature Screening
Abstract and title screening will initially be undertaken by one reviewer (JB) to
identify relevant references which investigate the topic of socioeconomic inequalities
in alcohol-related harm (both explicitly and implicitly). Full paper screening will then
be conducted by the same reviewer (JB). This process will be done for both
academic and grey literature.
2.6 Data extraction and quality appraisal
A data extraction matrix has been developed with headings appropriate to the
research question. This was done in collaboration with co-authors (RP & JH). For
each included study, the following details will be extracted: Author, Year of
Publication, Country, Study Design, Year of data collection, Population, Sample size,
Unit of analyses (e.g. area level etc.), Age of participants, Hypothesis/Aim, Alcohol
harm measure, socioeconomic position measure, alcohol consumption measure,
evidence of the AHP (yes/no), main findings, how to the researchers attempt to
explain the AHP and theoretical propositions used to explain the AHP. The studies
will be quality appraised, the checklist used for this will depend on the study design,
for example cross-sectional studies will be appraised with the AXIS checklist (15).
Data extraction and quality appraisal will be undertaken by JB. An independent
reviewer (OS) will crosscheck a subset of included papers (approx. 20%) against
both the inclusion criteria and for extraction.

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2.7 Approach to synthesis
Given that the research question is of a qualitative nature, we do not intend to
conduct a meta-analysis. Initially a narrative synthesis will be presented to gain an
understanding of the studies included in the review. To address Objective 2, a
thematic analysis will be conducted which aims to group the explanations into broad
themes. Any relationships between explanations (instances of authors combining or
relating explanations). Finally, a narrative synthesis will be presented which
summarises the findings from the studies which have empirically tested
explanations. Research cited within the included papers to support or oppose
explanations will also be synthesized.
3. Research Outputs
This systematic review will be submitted as an academic article to an academic
journal, expected submission date August 2020.
4. Timeline
Oct 2019: Finalise search strategy and data extraction/quality appraisal proforma
Oct-Nov 2020: Run systematic searches
Solicit expert opinion/online search for grey literature
Title/Abstract screening
Dec-Jan 2020: Full text screen for eligibility criteria
Data extraction and quality appraisal
Feb-Mar 2020: Data analysis and synthesis
Apr-Jul 2020: Prepare manuscript for publication
Jul 2020: Rerun systematic searches
Aug 2020: Submit paper for publication

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References
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Alcohol Harm Paradox: A population based survey of adults in England. PLoS One.
2016;11(9):1–17.
3. Probst C, Roerecke M, Behrendt S, Rehm J. Socioeconomic differences in alcohol-
attributable mortality compared with all-cause mortality: A systematic review and
meta-analysis. Int J Epidemiol. 2014;43(4):1314–27.
4. Smith BK, Global R, Health P. Alcohol , Health Inequalities and the Harm Paradox :
Why some groups face greater problems despite consuming less alcohol A summary
of the available evidence. 2014;
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Alcohol Res Curr Rev. 2016;38(1):83–94.
6. Probst C, Roerecke M, Behrendt S, Rehm J. Gender differences in socioeconomic
inequality of alcohol-attributable mortality: A systematic review and meta-analysis.
Drug Alcohol Rev. 2015;34(3):267–77.
7. Jones L, Bates G, McCoy E, Bellis MA. Relationship between alcohol-attributable
disease and socioeconomic status, and the role of alcohol consumption in this
relationship: A systematic review and meta-analysis. BMC Public Health. 2015;15(1).
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differences in the experience of alcohol-related problems. Alcohol Alcohol.
2012;47(5):597–605.
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paradox: Using a national survey to explore how alcohol may disproportionately
impact health in deprived individuals. BMC Public Health [Internet]. 2016;16(1):1–10.
Available from: http://dx.doi.org/10.1186/s12889-016-2766-x
10. Lewer D, Meier P, Beard E, Boniface S, Kaner E. Unravelling the alcohol harm
paradox: A population-based study of social gradients across very heavy drinking
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http://dx.doi.org/10.1186/s12889-016-3265-9
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[cited 2019 Mar 9]. Available from:
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Appendix A: Search Terms
Table S1. Systematic search strategy
Concept
Search terms
Alcohol
(.mp.) (MEDLINE &
Embase)
Alcohol* adj3 drink*
Heavy adj3 drink*
Binge drink*
*alcohol consumption/ or
*binge drinking/ or
*heavy drinking
Alcohol*.ti.
Alcohol (PsychInfo)
Alcohol* adj3 drink* (.mp.)
Alcohol drinking
patterns/
Heavy adj3 drink* (.mp.)
*alcohol consumption/
OR *binge drinking/ OR
*heavy drinking/
Alcohol*.ti.
Health Inequalities
(MEDLINE &
Embase)
Health Status Disparities/ or
exp Socioeconomic Factors/
Health adj2 inequalit*
(.mp.)
Socioeconomic or socio-
economic (.mp.)
Health Inequalities
(PsychInfo)
Health status disparities
(.mp.)
Socioeconomic status/
Health adj2 inequalit*
(.mp.)
Socioeconomic
Status (MEDLINE &
Embase)
Disadvantage* OR inequit*
OR inequal* OR poverty OR
low income OR unemploy*
OR employ
High income OR
deprived OR social class
OR upper class OR
middle class OR working
class
Deprivation (.mp.)
Socioeconomic
Status (PsychInfo)
Disadvantage* OR inequit*
OR inequal* OR poverty OR
low income OR unemploy*
OR employ (.mp.)
High income OR
deprived OR social class
OR upper class OR
middle class OR working
class (.mp.)
Deprivation (.mp.)
*social class/ OR
*socioeconomic status/
Exclusions for:
MEDLINE & Embase
Therapeutics/ OR
psychotherapy/ OR
intervention.ti. OR brief
intervention.ab. OR
effectiveness.ti.
(Gestat* OR fet* OR
child* OR adolescen*
OR you* OR matern*
OR birth* OR parent*
OR preg* OR
prenatal).ti.
(Brain OR bacter* OR
pathogen* OR methyl*
OR memor* OR cortex
OR neur* OR
temporal).ti.
(Africa* OR chin* OR
india* OR Russia* OR
thai* OR vietn* OR
Uganda OR brazil OR
Nepal).ti.
Addiction.ti. OR
rehabilitation.mp. OR
disorder.ti. OR psych*.ti.
OR rats.mp. OR
vehicle.mp.
Exclusions for:
PsycInfo
(Addiction OR rehabilitation
OR alcoholi*).ti.
Therapeutics/ OR
psychotherapy/ OR
intervention.ti. OR brief
intervention.ab. OR
effectiveness.ti. OR
case-control.ti.
(Gestat* OR fetal OR
child* OR adolescen*
OR young OR matern*
OR birth* OR preg* OR
parent* OR school OR
college).ti.

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