Epidemiologists have noted for many years that one of the key factors that modifies the relation between alcohol intake and many diseases is the education, income, or other index of socio-economic status (SES) of subjects. While differences in drinking practices (regular moderate versus binge drinking), other more moderate lifestyle factors, better access to health care, etc., have been suggested as potential mechanisms, there has been little research directed at this relation.
The present study is a systematic review of published reports to investigate the relationship between SES and risk of mortality or morbidity for each alcohol-attributable condition and, where feasible, to explore alcohol consumption as a mediating or interacting variable in this relationship. It summarized data from 31 case-control or cohort studies, relating an overall measure of the effects of low SES (variously defined) to the risk of cancers related to alcohol, as well as to liver disease, hypertension, stroke, epilepsy, cardiac arrhythmias, and pancreatitis.
The key findings of the study demonstrate a tendency for greater risk for low-SES subjects than for high-SES subjects to develop a number of diseases that are associated with alcohol consumption. Specifically, the authors report higher and statistically significant increases in risk of head and neck cancer and of stroke associated with alcohol consumption among lower-SES subjects than among higher-SES subjects. There was a tendency for lower risk of breast cancer among lower-SES women, but differences were not significant when adjusted for known confounders. The authors suggest that some of the effects shown may relate to greater total amounts of alcohol consumption by lower-SES subjects, or due to their higher levels of smoking.
Forum members thought this was a valiant attempt of the authors to unravel what has been a mystery: why do people at lower levels of SES seem to have more adverse effects of alcohol consumption than subjects at higher levels of SES. Unfortunately, as the authors admit, current scientific data do not allow firm answers. Suggested theories for reasons why low-SES subjects may have more adverse effects from alcohol include (1) different drinking patterns, with more binge drinking, (2) clustering of poor lifestyle factors, and (3) less access to health care. In some studies, even though the reported total alcohol intake of low- and high-SES subjects may be similar, the latter seem more likely to drink moderate amounts of alcohol on a regular basis, while lower-SES subjects are more likely to binge drink on fewer days per week. However, other studies do not support such a finding. Further, there may be differences according to the type of alcoholic beverage consumed, which was not considered in this study.
Forum members pointed out that differences in factors other than drinking patterns probably contribute to the greater adverse effects among subjects with lower SES. One member suggested that lower SES affects susceptibility to many diseases, most likely due to effect modification of hitherto unrecognized factors. The Forum concluded that there are too many confounders to make a conclusion about this topic, and much more research will be needed to understand how socio-economic factors affect the risk of disease and may modify the relation between alcohol consumption and disease.
Reference: Jones L, Bates G, McCoy E, Bellis MA. Relationship between alcohol-attributable diseaseand socioeconomic status, and the role of alcohol consumption in this relationship: a systematic review and meta-analysis. BMC Public Health 2015;15:400. DOI 10.1186/s12889-015-1720-7. .