The association between population drinking and ischemic heart disease mortality in educational groups

A large number of observational studies have found a J-shaped relationship between alcohol intake and ischemic heart disease (IHD) risk. However, some studies suggest that the alleged cardio-protective effect may be an artifact in the way that the elevated risk for abstainers is due to self-selection on risk factors for IHD.
A paper estimated the association between alcohol and IHD-mortality on the basis of aggregate time-series data, where the problem with selection effects is not present. In addition, the researchers analysed SES-specific mortality to investigate whether there is any socio-economic gradient in the relationship at issue.
SES was measured by educational level. IHD-mortality in three educational groups was used as the outcome. Per capita alcohol consumption was proxied by Systembolaget’s alcohol sales (litres of alcohol 100% per capita 15+). Swedish quarterly data on mortality and alcohol consumption spanned the period 1991Q1-2020Q4. Survey data were used to construct an indicator of heavy SES-specific episodic drinking.
The estimated association between per capita consumption and IHD-mortality was positive and statistically significant in the two groups with primary and secondary education, but not in the group with postsecondary education. The association was significantly stronger the lower the educational group. Although the associations were generally stronger for males than for females, these differences were not statistically significant. The researchers say that their findings suggest that the detrimental impact of per capita consumption on IHD-mortality was stronger the lower the educational group.
Source: Thor Norström, Jonas Landberg, The association between population drinking and ischemic heart disease mortality in educational groups, Alcohol and Alcoholism, Volume 58, Issue 4, July 2023, Pages 385–392,