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.