The dose-response relationship between socioeconomic deprivation and alcohol-attributable mortality risk—a systematic review and meta-analysis
Individuals with low socioeconomic status (SES) experience a higher risk of mortality, in general, and alcohol-attributable mortality in particular. However, a knowledge gap exists concerning the dose-response relationships between the level of socioeconomic deprivation and the alcohol-attributable mortality risk.
The researchers conducted a systematic literature search in August of 2020 to update a previous systematic review that included studies published up until February of 2013. Quantitative studies reporting on socioeconomic inequality in alcohol-attributable mortality among the general adult population were included. The researchers used random-effects dose-response meta-analyses to investigate the relationship between the level of socioeconomic deprivation (education, occupation, and income) and the relative alcohol-attributable risk (RR), by sex and indicator of SES (education, income, and occupation).
The researchers identified 25 eligible studies, comprising about 241 million women and 230 million men, among whom there were about 75,200 and 308,400 alcohol-attributable deaths, respectively.
A dose-response relationship between the level of socioeconomic deprivation and the RR was found for all indicators of SES.
The sharpest and non-linear increase in the RR of dying from an alcohol-attributable cause of death with increasing levels of socioeconomic deprivation was observed for education, where, compared to the most educated individuals, individuals at percentiles with decreasing education had the following RR of dying:
- women: 25th: 2.09,
- 50th: 3.43,
- 75th: 4.43,
- 100th: 4.50;
- men: 25th: 2.34,
- 50th: 4.22,
- 75th: 5.87,
- 100th: 6.28.
The findings of this study show that individuals along the entire continuum of SES are exposed to increased alcohol-attributable mortality risk. Differences in the dose-response relationship can guide priorities in targeting public health initiatives.
This study therefore strongly demonstrates the necessity to think about socioeconomic gradients rather than categories where those with a low SES are being perceived as the fringe of the society with elevated risks that are somehow different from the “general population”.
The differences between the dose-response relationships point to distinct causal pathways connecting socioeconomic deprivation to increased alcohol mortality risks.
These pathways need to be studied and accounted for rather than treating education, occupation, and income as equivalent indicators of a single latent variable of SES. Understanding the health benefits of all three indicators independently is integral to reducing health disparities, including but not limited to alcohol-attributable mortality.
The findings suggest that of the three indicators studied, education is a particularly strong indicator of SES concerning impacts on alcohol-attributable mortality.
The relative alcohol-attributable risk (RR) for education is higher overall than the RR for occupation or income.
- Individuals with a medium or low level of education have a three- to fivefold higher alcohol-attributable mortality risk compared to individuals with high education.
- The alcohol-attributable mortality risk is similar for the bottom 20% to 30% of the education distribution.
- Strong gains in lowering the mortality risk can only be expected beyond this range. This may indicate some support of moving everybody beyond the threshold minimal education.
For income, the dose-response relationship showed that at the bottom end of the income distribution even small gains in income can go a long way in reducing the alcohol-attributable mortality risk, for women in particular.
- This has important implications for the social support and welfare system, indicating that moving individuals up the income distribution may have considerable preventive and public health effects.
Relative mortality risks observed for occupation were overall lower. The results showed high sex differences in the relative mortality risks at the bottom end of the occupation spectrum (about twofold higher for men), confirming findings from previous research.
- Factors such as a lower income, child care, and societal standing play a stronger role in influencing risks for women above and beyond the occupation.