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Association of overtime work and hypertension in a Japanese working population: a cross-sectional study
Teppei Imai1, Keisuke Kuwahara, Akiko Nishihara
1Azbil Corporation , Tokyo , Japan .
Insights
Longer working hours were linked to a lower prevalence of hypertension (high blood pressure) in Japanese workers. This study analyzed health data from over 50,000 employees, finding an inverse relationship between overtime and hypertension risk.
Area of Science:
- Occupational Health
- Cardiovascular Epidemiology
- Public Health
Background:
- Long working hours are a known risk factor for cardiovascular disease.
- The specific relationship between overtime and hypertension is not well-established.
- Understanding this link is crucial for workplace health interventions.
Purpose of the Study:
- To investigate the association between overtime work and the presence of hypertension.
- To analyze data from a large cohort of Japanese workers.
- To determine if increased overtime correlates with hypertension prevalence.
Main Methods:
- Utilized health check-up and self-reported overtime data from 52,365 workers across four Japanese companies.
- Defined hypertension based on blood pressure readings (≥140/90 mmHg) or antihypertensive medication use.
- Employed logistic regression analysis, adjusting for age, sex, company, smoking status, and body mass index.
Main Results:
- Hypertension prevalence decreased as overtime hours increased: 17.5% (<45h/month) to 9.1% (≥100h/month).
- Adjusted odds ratios for hypertension showed a significant inverse trend with increasing overtime (OR=0.58 for ≥100h/month vs. <45h/month).
- This inverse association remained significant after adjusting for additional confounders in a sub-cohort.
Conclusions:
- The study suggests an inverse association between overtime work and the presence of hypertension among Japanese workers.
- Findings indicate that increased overtime may be linked to a lower likelihood of having hypertension.
- Further research is needed to explore the mechanisms behind this unexpected association.
Abstract:
Long working hours have been associated with an increased risk of cardiovascular disease, but its relationship with hypertension remains unclear. The objective of this study is to examine the relationship between overtime and presence of hypertension using data from a large-scale multi-company study in Japan. Participants were 52 365 workers of four companies that provided both health-checkup data and self-reported data on overtime worked. Hypertension was defined as systolic blood pressure ≥140 mmHg, diastolic blood pressure ≥90 mmHg, and/or the use of antihypertensive drug. Logistic regression analysis was performed to determine the odds ratio for hypertension for each category of overtime work (<45, 45-79, 80-99 or ≥100 h/month) with adjustments for age, sex, company, smoking status and body mass index. The prevalence of hypertension tended to decrease with increasing overtime work: 17.5, 12.0, 11.1 and 9.1% for the shortest (<45 h/month) through the longest overtime category (≥100 h/month). The age-, sex- and company-adjusted odds ratios (95% confidence interval) were 1.00 (reference), 0.81 (0.75-0.86), 0.73 (0.62-0.86), 0.58 (0.44-0.76), respectively (p for linear trend <0.001). In a sub-cohort, the inverse association remained statistically significant after an additional adjustment for other potential confounders. Results of the present large-scale study among Japanese workers suggest an inverse association between overtime work and presence of hypertension.
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