The Cardiovascular Effects of Occupation Status and 12-hour Shift Work
Date Issued
2005
Date
2005
Author(s)
Su, Ta-Chen
DOI
zh-TW
Abstract
Abstract
Occupational cardiovascular diseases increased in association with the industrialization and globalization of working environments. However, the identification of work-related cardiovascular disease was often overlooked. This study was designed to investigate the cardiovascular effects of occupational status and 12-hour shift work.
The first study: The relationship between time factors of elevated blood pressure (BP) and carotid atherosclerosis (CA) is still unclear. The associations between time-weighted average 24-hour ambulatory systolic BP (TWA-SBP), duration of hypertension in years (hypertension-year), and CA were investigated in a petrochemical company sample of 95 executives and 91 gender- and age-matched non-executives employees. Intima-media thickness (IMT) and plaque scores of extracranial carotid artery (ECCA) were determined bilaterally by high-resolution B-mode ultrasound. The determinants of segment-specific carotid IMT and odds ratios for CA, in terms of thicker IMT (IMT ≥75th percentile) and ECCA score ≥3, were evaluated by multivariate regression analysis. Results revealed TWA-SBP and hypertension-year were two major determinants of IMT at common carotid artery (CCA) and carotid bulb by using mixed regression models. However, TWA-DBP was a negative determinant of IMT at CCA and carotid bulb. Meanwhile, the executives were found to be a negative association with IMT at carotid bulb. Measurements at both internal carotid artery and bulb identified duration of diabetes mellitus as significant determinant of IMT. After controlling covariates, multivariate logistic regression analysis identified TWA-SBP and hypertension-year as the important determinants for thicker IMT and ECCA were determined bilaterally by high-resolution B-mode ultrasound. The determinants of segment-specific carotid IMT and odds ratios for CA, in terms of thicker IMT (IMT≧75th percentile) and ECCA score≧3, were evaluated by multivariate regression analysis. Results revealed TWA-SBP and hypertension-year were two major determinants of IMT at common carotid artery (CCA) and carotid bulb by using mixed regression models. However, TWA-DBP was a negative determinant of IMT at CCA and carotid bulb. Meanwhile, the executives were found to be a negative association with IMT at carotid bulb. Measurements at both internal carotid artery and bulb identified duration of diabetes mellitus as significant determinant of IMT. After controlling covariates, multivariate logistic regression analysis identified TWA-SBP and hypertension-year as the important determinants for thicker IMT and ECCA≧3. And, TWA-DBP was found as a negative determinant for CA. In conclusion, both TWA-SBP and hypertension-year were two major determinants for carotid IMT and CA, which seem to imply that both short-term and long-term durations of elevated BP are probably crucial in the pathogenesis of CA.
The second study: Shift work has been associated with increased risk for cardiovascular disease. This study is designed to determine the hemodynamic effects during12-hour (12-h) shifts and changes in blood pressure (BP) and heart rate variability (HRV) for a 36-hour rest time following 12-h shifts. We recruited 15 male shift workers with a mean age of 32.9 years from a semiconductor factory. Ambulatory BP (AmBP) monitoring was performed for a total of 48-h for each participant. Forty-eight hours of Holter electrocardiogram monitoring was also performed in six workers each in day or night shifts. Paired self-comparison was used to estimate the difference between two hourly measurements using the same timetable intraindividually. Mixed models were constructed to estimate the effect of 12-h shift on delayed recovery of BP and heart rate (HR) in seven workers completed 96-h’s AmBP monitoring, including a 48-h night shift and another day shift period. Results showed compared with the effects of 12-h day shift work on the corresponding resting time, 12-h night shift work was found to have a persistent elevation of systolic and diastolic BP (SBP and DBP), and HR and a decrease in HRV. The delayed recovery of SBP and DBP also was found on the first 12-h rest time in night shift workers and was further demonstrated on the second 12-h rest time after adjustment for possible confounders through mixed models. In conclusions, 12-h night shift work may elevate BP, HR, and decrease HRV, and is associated with delayed recovery in SBP and DBP.
Subjects
職業
12小時輪班工作
心臟血管效應
Occupation
12-hour Shift work
Cardiovascular effects
SDGs
Type
thesis
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