Association between long working hours and poor cardiovascular health assessed by the American Heart Association's "Life's essential 8": findings from a nationally representative sample of Korean workers (2014-2021).

Background: Long working hours represent a major public health concern. We explored the association between working hours and the American Heart Association's "Life's Essential 8 (LE8)."

Methods: A nationwide sample comprising 21 062 Korean workers was analyzed. The LE8 scores (range 0-100) were calculated based on the following cardiovascular disease risk factors: diet, physical activity, nicotine exposure, sleep health, body mass index, blood lipid levels, blood glucose levels, and blood pressure. Cardiovascular health (CVH) was categorized as low (LE8: 0-49), intermediate (LE8: 50-59), and high (LE8: 80-100). Linear regression and multinomial logistic regression models were used for statistical analyses.

Results: The means of the LE8 scores for those working <35 h, 35-40 h, 41-48 h, 49-54 h, and ≥ 55 h per week were 69.4, 68.2, 66.8, 64.7, and 61.9, respectively. Among men, working 49-54 h per week [β: -1.43; 95% confidence interval (CI): -2.40, -0.45] and ≥55 h per week (β: -3.23; 95% CI: -4.11, -2.35) were associated with lower LE8 scores. Similarly, among women, working 49-54 h per week (β: -1.62; 95% CI: -2.72, -0.52) and ≥55 h per week (β: -2.88; 95% CI: -3.88, -1.88) had negative associations with LE8 scores. Working ≥55 h per week was associated with a 2.03-fold increase (95% CI: 1.53, 2.68) in the odds of low CVH among men and a 2.02-fold increase (95% CI: 1.37, 2.98) among women.

Conclusion: Long working hours are associated with poor CVH, emphasizing the necessity of mitigating excessive working hours. Key message What is already known on this topic-The American Heart Association recently introduced "Life Essential 8 (LE8)," a metric assessing cardiovascular health. This study explored the association between long working hours and poor cardiovascular health among Korean adult workers. What this study adds-This study demonstrates that compared with working 35-40 h per week, working ˃48 h per week is associated with a reduced LE8 score. Specifically, working 49-54 h and ≥55 h per week are associated with increased odds of having poor cardiovascular health in both men and women, compared with working 35-40 h per week. Notably, long working hours showed a strong association with the health behavior factors of LE8. How this study might affect research, practice, or policy-This study suggests that promoting cardiovascular health based on the LE8 framework can be beneficial in mitigating the health burdens of long working hours.