Noise exposure is associated with elevated blood pressure, but the effects on susceptible workers have not been reported. This repeated-measure study investigated the effects of noise exposure on 24-h ambulatory blood pressure among hypertensive, pre-hypertensive, and normotensive adults.
We enrolled 113 volunteers in an occupational cohort in 2009. Individual noise exposure and personal blood pressure were measured simultaneously over 24 h on working and non-working days. Linear mixed-effects regressions were used to estimate the effects on SBP and DBP by controlling for potential confounders.
Each A-weighted decibel (dBA) increase in a 30-min time-lagged exposure was associated with transient elevations of work-time SBP [0.30 (95% confidence interval: 0.06, 0.54) mmHg] on working days as well as sleep-time SBP [0.39 (0.12, 0.66) mmHg] and DBP [0.33 (0.14, 0.51) mmHg] on non-working days among 19 hypertensive adults. In contrast, 46 normotensive workers had transient increases in work-time SBP [0.16 (0.03, 0.29) mmHg] and DBP [0.25 (0.15, 0.34) mmHg] on working days as well as sleep-time SBP [0.17 (0.06, 0.29) mmHg] and DBP [0.21 (0.14, 0.29) mmHg] on non-working days caused by a 1-dBA increase in the current exposure. All groups had sustained increases in 24-h average ambulatory SBP and DBP induced by noise exposure on 2 days, but the hypertensive workers had the most pronounced increase in SBP.
Hypertensive adults are more susceptible to noise exposure with a greater effect on ambulatory SBP. These results suggest a need for more protection for this subpopulation.
aDepartment of Occupational Safety and Health, College of Public Health, China Medical University
bDepartment of Family Medicine, China Medical University Hospital
cSchool of Medicine, College of Medicine, China Medical University
dDepartment of Pharmacy, College of Pharmacy, China Medical University, Taichung
eInstitute of Labor, Occupational Safety and Health, Ministry of Labor, Executive Yuan, Taipei, Taiwan, ROC.
Correspondence to Ta-Yuan Chang, Department of Occupational Safety and Health, College of Public Health, China Medical University, 91 Hsueh-Shih Road, Taichung, Taiwan 40402, ROC.Tel: +886 4 22053366 ext 6203; fax: +886 4 22079225; e-mail: firstname.lastname@example.org
Abbreviations: CI, confidence interval; dBA, A-weighted decibel; LDL, low-density lipoprotein; Leq, equivalent sound level; TWA, time-weighted average
Received 8 April, 2014
Revised 10 September, 2014
Accepted 10 September, 2014