Table 2. Means and 95% confidence intervals of occupational noise exposure by participants characteristics.

Characteristic	No.	Occupational noise (dBA), mean (95% C.I.)		p-value a
Age (year)				<0.001
10–29	2356	85.8	(85.6–86.0)
30–39	6995	87.9	(87.8–88.1)
40–49	10062	89.2	(89.1–89.3)
≥50	10659	90.7	(90.6–90.8)
Sex				<0.001
Male	27857	89.0	(89.0–89.1)
Female	2215	90.8	(90.5–91.0)
Body mass index (kg/m2)				<0.001
<25	20991	89.3	(89.3–89.4)
≥25	9081	88.7	(88.6–88.8)
Hypertension				<0.001
No	25199	89.1	(89.0–89.1)
Yes	4873	89.6	(89.5–89.8)
Occupational exposure to heavy metals				<0.001
Non exposure	27382	89.4	(89.4–89.5)
Exposure	2690	86.1	(85.9–86.3)
Occupational exposure to organic solvents				<0.001
Non exposure	22164	89.0	(88.9–89.0)
Exposure	7908	89.7	(89.6–89.8)

CI, confidence interval

^a t-test for binominal groups and trend-P for ordinal categorical groups were used.