Measurement error as an explanation for the alcohol harm paradox: analysis of eight cohort studies

Volume of alcohol intake, heavy episodic drinking, and all-cause mortality in Spain: A longitudinal population-based study

INTRODUCTION

The impact of alcohol consumption on health, particularly in low quantities, remains controversial. Our objective was to assess the association between alcohol volume and heavy episodic drinking (HED) with all-cause mortality, while minimizing many of the known methodological issues.

METHODOLOGY

This longitudinal study used data from the 2011-2012 National Health Survey and the 2014 European Health Survey in Spain. Data from 43,071 participants aged ≥ 15 years were linked to mortality records as of December 2021. Alcohol consumption categories were defined based on intake volume and frequency: never-drinkers, former drinkers, infrequent occasional drinkers (≤once/month), frequent occasional drinkers ( once /month). Regular drinkers (≥once/week) were further classified by volume: >0-10 g/day, >10-20 g/day, >20-40 g/day, and > 40 g/day. Heavy Episodic Drinking (HED) was defined as ≥ 6 and ≥ 5 standard drinks (10 g) within 4-6 h for men and women, respectively. Hazard ratios (HR) were calculated using Cox regression, adjusting for sociodemographic variables, lifestyle factors, health status, and alcohol volume or HED.

RESULTS

Compared to infrequent occasional drinkers, HRs for never-drinkers and former drinkers were 1.30 (95 %CI:1.14-1.47) and 1.32 (95 %CI:1.15-1.50), respectively. No differences in mortality risk were observed for intakes up to 20 g/day, but it increased for consumptions > 20-40 g/day and > 40 g/day (HR = 1.29; 95 %CI:1.05-1.58 and HR = 1.57; 95 %CI:1.14-2.17, respectively). The HR of weekly HED vs. never was 1.31 (95 %CI:0.98-1.75).

CONCLUSIONS

Compared to infrequent occasional drinking, consuming low amounts of alcohol had no impact on mortality risk. However, never-drinkers, former drinkers, individuals with regular consumption > 20 g/day, and those engaging in weekly HED, experienced higher mortality risk.

The Alcohol Harm Paradox in Periodontitis

Individuals of lower socioeconomic position (SEP) experience a greater rate of alcohol-related harms, yet they consume equal or lower amounts of alcohol than higher-SEP individuals. This phenomenon, called the "alcohol harm paradox" (AHP), gained attention recently, and different mechanisms have been proposed to explain it. Since both SEP and alcohol have been suggested to be associated with periodontitis risk, we conducted a secondary analysis using data from the National Health and Nutrition Examination Survey 2011 to 2012 and 2013 to 2014 cycles, aiming to examine 1) whether the association between alcohol consumption and periodontitis is modified by SEP and 2) the extent to which the effect of SEP inequalities on periodontitis is mediated by and/or interacts with alcohol consumption. We set educational attainment as the main SEP proxy and tested the poverty income ratio in subsequent sensitivity analyses. Effect measure modification analysis was employed, considering heavy drinking as exposure, and causal mediation analysis based on the potential outcome's framework decomposed the effect of SEP on periodontitis in proportions attributable to mediation and interaction. Models were fitted using binary logistic regression and adjusted for sex, ethnicity, age, body mass index, smoking status, diabetes, binge drinking, and regular preventive dental visits. The analytical sample comprised 4,057 participants. After adjusting for covariates, less educated heavy drinkers presented 175% (odds ratio, 2.75; 95% confidence interval [CI], 2.04-3.72) higher odds of periodontitis than their counterparts, and super-additive associations were found (relative excess risk due to interaction: 1.35; 95% CI, 0.49-2.20). Additionally, -69.5% (95% CI, -122.1% to -16.8%) of the effects of education on periodontitis were attributable to interaction with heavy drinking, consistent with the AHP. No contribution was found for the mechanism of mediation. Heavy drinking disproportionately impacts the occurrence of periodontitis in lower-SEP individuals. Lower-SEP individuals seem to experience differential effects of heavy drinking on periodontitis.

The Joint Effect of Education and Alcohol Use on 100% Alcohol-attributable Hospitalization or Death in Canada

BACKGROUND

Individuals with low socioeconomic position (SEP) experience disproportionately greater alcohol-attributable harm than individuals with high SEP despite similar or less alcohol use (i.e., the alcohol harm paradox). We examined the sex/gender- specific independent and joint effects of education and heavy drinking or volume of alcohol use on 100% alcohol-attributable hospitalization or death.

METHODS

We conducted a cohort study among 199,125 current and former alcohol users aged 15-64 years from population-representative Canadian Community Health Surveys (2000-2008) linked to hospitalization and mortality records through 2017. We estimated the sex/gender-specific associations between education and heavy drinking or volume of alcohol use and incident 100% alcohol-attributable hospitalization or death using multivariable Fine and Gray subdistribution hazard models with competing risk (non-100% alcohol-attributable deaths), assessing additive interactions using the Synergy Index (S).

RESULTS

Overall, heavy drinking prevalence and volume of alcohol use were similar or lower in individuals with lower education compared with higher education. Lower education levels compared with a bachelor's degree or above were associated with increased 100% alcohol-attributable hospitalization or death [e.g., less than high school, men: hazard ratio (HR) = 2.78; 95% CI = 2.17, 3.56; women: HR = 2.98; 95% CI = 2.00, 4.44]. We found superadditive joint effects between low education and heavy drinking (men: S = 1.22; 95% CI = 1.14, 1.30; women: S = 1.34; 95% CI = 0.88, 2.04) and low education and higher volume of alcohol use (e.g., excess volume, men: S = 1.30; 95% CI = 1.05, 1.62; women: S = 1.41; 95% CI = 0.77, 2.58), with larger inequities in women than men with similar alcohol use.

CONCLUSIONS

Our study is consistent with the hypothesis that increased vulnerability to alcohol use among individuals with lower education partially explains the alcohol harm paradox in Canada.

The alcohol harm paradox and tooth loss among Brazilian older adults

OBJECTIVE

To investigate whether the association between alcohol consumption and tooth loss is modified across socioeconomic positions (SEPs) in Brazilian older adults.

METHODS

We conducted a secondary analysis using data of The Brazilian Longitudinal Study of Ageing (ELSI-Brazil 2015-2016). Effect Measure Modification (EMM) analyses using multivariable Poisson regression models tested whether the association between heavy drinking and lack of functional dentition (FD) varies in magnitude and direction according to levels of Household Wealth index (HWI) and educational attainment, assessed by the Relative Excess Risk due to Interaction (RERI). Sensitivity analyses using lifetime exposure to alcohol were performed.

RESULTS

The analytical sample comprised 8078 participants. Heavy drinkers living in low-wealth households and with lower education presented 7% (95% CI: 1.01-1.14) and 36% (95% CI: 1.28-1.44) higher prevalence of lack of FD, respectively, than their counterparts, and super-additive associations were detected [RERI for HWI: 0.12 (95% CI: 0.02-0.21); RERI for educational attainment: 0.20 (95% CI: 0.09-0.30)]. The associations were also super-additive in the sensitivity analyses when controlling for abstainer reference group bias.

CONCLUSION

We suggest that alcohol consumption disproportionately impacts the prevalence of tooth loss in Brazilian older adults from lower SEP groups.

Socioeconomic inequalities in alcohol-related harm in adolescents: a prospective cohort study of 68,299 Danish 15-19-year-olds

Background

Evidence shows that similar levels of alcohol consumption lead to greater harm in adults with low socioeconomic position (SEP) compared to high SEP. We investigated if SEP is associated with alcohol-related hospital contacts in adolescents, and whether differences in risk can be explained by differences in levels of alcohol consumption, drinking pattern, and substance use.

Methods

This is a prospective cohort study of 68,299 participants aged 15-19 years old from the Danish National Youth Cohort 2014. SEP was operationalised as parent educational level, family income and perceived financial strain in the family. Data were linked to national registers and participants were followed up for five years from 2014 to 2019. Outcomes were hospital contacts due to alcohol. Multilevel Poisson regression was used to estimate incidence rates (IR) and incidence rate ratios (IRR).

Findings

During 280,010 person years of follow-up, 872 participants had an alcohol-attributable hospital contact; intoxications (n = 778, 89%) were the most common diagnosis. Low as compared to high SEP was associated with higher IRR of alcohol-attributable hospital contacts for all three SEP measures. The adjusted IRR of harm was 1.73 (95% CI: 1.29-2.33) for elementary school as the highest parent education compared to longer parent education and 1.57 (95% CI: 1.30-1.89) for family financial strain compared to those without financial strain. Adjustment for weekly alcohol intake, drinking pattern and substance use did not substantially change results. Cubic spline analysis of the association between family income and alcohol-attributable hospital contacts revealed a dose-response relationship with decreasing risk of alcohol-related harm with higher income.

Interpretation

Our findings suggested that alcohol-related harm is more common in socioeconomically disadvantaged adolescents despite similar levels of alcohol consumption, regardless of differences in drinking pattern or substance use. Future preventive strategies should prioritise young adolescents, including those who are most disadvantaged.

Funding

Tryg Foundation (ID: 153539).

"Harm per litre" as a concept and a measure in studying determinants of relations between alcohol consumption and harm

The term "harm per litre" has been increasingly used in alcohol research in recent years as a concept and a comparative measure of alcohol-attributable harm in comparisons between environments, circumstances, and patterns of drinking. This essay discusses the origins of the term in connection with analyses in terms of patterns as well as levels of drinking and with concerns about differential harms from drinking different beverage types. Also discussed is the term's current primary usage, in the context of epidemiological concerns about differentially severe harms for poorer persons who drink. It is noted that these same concerns have been discussed, particularly in Britain, using the phrase "alcohol harm paradox". "Harm per litre" was initially most often used in comparisons between rates of alcohol-attributable harm by beverage type. After 2010, the expression was applied more broadly, particularly after its use in various World Health Organization-related discussions and documents. In addition, and especially from 2018 onwards when most of the papers using this term were published, it has been used in comparisons by socioeconomic status at the individual level, and by level of socioeconomic development at the country level. Almost all the findings indicate that people with lower socioeconomic status, and countries with lower average income, e.g., low income and lower-middle income countries, incur considerably higher harm per litre (with harm being expressed in disease burden and mortality) than upper middle-income and high-income countries. "Harm per litre" is a practicable and easy-to-understand concept to compare groups of individuals or countries, and to quantify health inequalities. The next important step will need to be elucidating a better causal understanding of the processes underlying these inequalities, with an emphasis on factors which can be most easily changed by interventions.

Educational Gradients in Drinking Amount and Heavy Episodic Drinking among Working-Age Men and Women in Spain

Alcohol-related harm decreases as socioeconomic position increases, although sometimes the opposite happens with alcohol intake. The objective was to know the educational gradient in monthly measures of drinking amount and heavy episodic drinking (HED) among people aged 25−64 years in Spain from 1997−2017. Such gradient was characterized with the relative percent change (PC) in drinking measures per year of education from generalized linear regression models after adjusting for age, year, region, marital status and immigration status. Among men, the PCs were significantly positive (p < 0.05) for prevalence of <21 g alcohol/day (2.9%) and 1−3 HED days (1.4%), and they were negative for prevalences of 21−40 g/day (−1.1%), >40 g/day (−6.0%) and ≥4 HED days (−3.2%), while among women they ranged from 3.6% to 5.7%. The gradient in prevalences of >40 g/day (men) and >20 g/day (women) was greatly attenuated after additionally adjusting for HED, while that of ≥4 HED days was only slightly attenuated after additionally adjusting for drinking amount. Among women, the gradients, especially in HED measures, seem steeper in 2009−2017 than in 1997−2007. Educational inequality remained after additional adjustment for income and occupation, although it decreased among women. These results can guide preventive interventions and help explain socioeconomic inequalities in alcohol-related harm.

Reaction Time and Visual Memory in Connection to Hazardous Drinking Polygenic Scores in Schizophrenia, Schizoaffective Disorder and Bipolar Disorder

The purpose of this study was to explore the association of cognition with hazardous drinking Polygenic Scores (PGS) in 2649 schizophrenia, 558 schizoaffective disorder, and 1125 bipolar disorder patients in Finland. Hazardous drinking PGS was computed using the LDPred program. Participants performed two computerized tasks from the Cambridge Automated Neuropsychological Test Battery (CANTAB) on a tablet computer: the 5-choice serial reaction time task, or Reaction Time (RT) test, and the Paired Associative Learning (PAL) test. The association between hazardous drinking PGS and cognition was measured using four cognition variables. Log-linear regression was used in Reaction Time (RT) assessment, and logistic regression was used in PAL assessment. All analyses were conducted separately for males and females. After adjustment of age, age of onset, education, household pattern, and depressive symptoms, hazardous drinking PGS was not associated with reaction time or visual memory in male or female patients with schizophrenia, schizoaffective, and bipolar disorder.

Reaction Time and Visual Memory in Connection to Alcohol Use in Persons with Bipolar Disorder

The purpose of this study was to explore the association of cognition with hazardous drinking and alcohol-related disorder in persons with bipolar disorder (BD). The study population included 1268 persons from Finland with bipolar disorder. Alcohol use was assessed through hazardous drinking and alcohol-related disorder including alcohol use disorder (AUD). Hazardous drinking was screened with the Alcohol Use Disorders Identification Test for Consumption (AUDIT-C) screening tool. Alcohol-related disorder diagnoses were obtained from the national registrar data. Participants performed two computerized tasks from the Cambridge Automated Neuropsychological Test Battery (CANTAB) on A tablet computer: the 5-choice serial reaction time task, or reaction time (RT) test and the Paired Associative Learning (PAL) test. Depressive symptoms were assessed with the Mental Health Inventory with five items (MHI-5). However, no assessment of current manic symptoms was available. Association between RT-test and alcohol use was analyzed with log-linear regression, and eβ with 95% confidence intervals (CI) are reported. PAL first trial memory score was analyzed with linear regression, and β with 95% CI are reported. PAL total errors adjusted was analyzed with logistic regression and odds ratios (OR) with 95% CI are reported. After adjustment of age, education, housing status and depression, hazardous drinking was associated with lower median and less variable RT in females while AUD was associated with a poorer PAL test performance in terms of the total errors adjusted scores in females. Our findings of positive associations between alcohol use and cognition in persons with bipolar disorder are difficult to explain because of the methodological flaw of not being able to separately assess only participants in euthymic phase.