Study Highlights Relationship Between Alcohol Use, Socioeconomic Status, and IHD Mortality Risk

Researchers have discovered that light-to-moderate drinking seemed to offer more protection against ischemic heart disease (IHD) mortality for wealthier individuals than those with lower socioeconomic status (SES).

It is known that individuals with lower SES often face greater health risks from alcohol-related conditions than those with higher SES, even if they have similar or lower levels of alcohol intake. This phenomenon, often called the alcohol-harm paradox, highlights the complexity of alcohol's impact on health outcomes. Research has indicated a U-shaped relationship between alcohol consumption and IHD, where light-to-moderate drinking without heavy episodic drinking (HED) is linked to lower IHD risk but HED and higher alcohol consumption levels are associated with increased risk. However little was known about how this relates specifically to heart disease in the US prior to this study, which was published in JAMA Network Open.

“To the best of our knowledge, this cohort study is the first to have analyzed, at the individual level, the socioeconomic gradient in the association of alcohol use with IHD mortality in the US, with a more pronounced protective association with light-to-moderate drinking identified in the high-SES group,” the authors said. “This specific protective association should be considered in the context of other known harms from drinking at even low levels, such as cancers, and other studies that do not show an all-cause mortality benefit.”

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The cohort study analyzed data from the National Health Interview Survey spanning 1997 to 2018 to explore how alcohol consumption impacts IHD mortality across different SES in the country, including more than half a million participants 25 years and older in the study with a mean (SD) age of 50.3 (16.2) years.

When compared with lifetime abstinence from alcohol, the researchers found that drinking less than 20 grams of alcohol per day (light-to-moderate drinking) was associated with a lower risk of IHD mortality, particularly in individuals with higher SES. For men in the high-SES group, light-to-moderate drinking had a statistically significant 22% higher protective effect against IHD mortality compared with abstinence (interaction term HR, 1.22; 95% CI, 1.02-1.45), whereas women in the high-SES group saw a significant 35% higher protective effect (interaction term HR, 1.35; 95% CI, 1.09-1.67).

The disparities in the impact of light-to-moderate drinking on IHD mortality based on SES were evident solely among individuals who engaged in HED less than monthly (interaction term HR, 1.20; 95% CI, 1.01-1.43 in men; HR, 1.34; 95% CI, 1.08-1.67 in women), with no significant variation observed among those with monthly or more frequent HED episodes.

Among women, there was a stronger protective effect of light-to-moderate drinking on IHD mortality in the high SES group compared with the middle SES group, as indicated by an interaction term HR of 1.35 (95% CI, 1.06-1.72). Conversely, the harmful association of consuming more than 60 grams of alcohol per day with IHD mortality in the low-SES group was largely explained by other behavioral risk factors like smoking and body mass index in men.

These findings underscore the importance of considering socioeconomic factors in public health interventions related to alcohol consumption, as what may be considered safe levels of alcohol intake for preventing IHD can vary across different sociodemographic groups. The authors noted that the more protective effect among women is possibly due to the limited number of women consuming an average alcohol intake exceeding 40 grams per day in the study. Therefore, the association primarily stemmed from women who consumed between 20 to 40 grams per day.

According to the authors, the weaker protective effect of moderate alcohol consumption against IHD mortality among individuals with low SES could be attributed to limited access to health care services and higher levels of chronic stress, which elevate blood pressure and increase the risk of IHD mortality. Additionally, low SES may coincide with other risk factors or unhealthy behaviors that, when combined with alcohol consumption, negate the benefits of moderate drinking or amplify the adverse effects of heavy drinking. On the other hand, individuals with higher SES may be more able to adopt healthier lifestyles, possess greater awareness of the risks of heavy drinking, and have stronger support systems or coping mechanisms.

“Public health interventions on alcohol use should account for different socioeconomic backgrounds when assessing the level of risk related to alcohol exposure, bearing in mind that levels of consumption deemed safe regarding a specific outcome such as IHD may indeed be less safe or not safe across all sociodemographic groups,” the authors said.

Reference

Zhu Y, Llamosas-Falcón L, Kerr W, Puka K, Probst C. Differential associations of alcohol use with ischemic heart disease mortality by socioeconomic status in the US, 1997-2018. JAMA Netw Open. 2024;7(2):e2354270. doi:10.1001/jamanetworkopen.2023.54270