This study included 1527 subjects (case group, 509 individuals; control group, 1018 individuals). The mean age was similar between the case and control groups (29.23±5.72 and 29.26±5.84 years, respectively; P>0.05). However, heart rate and BMI were significantly higher in the case group than in the control group (86±13 vs. 79±11 beats/min and 27.29±3.73 and 23.96±3.61 kg/m2, respectively; both P<0.05).
Correlation of noise and other occupational factors with hypertension among workers in modern enterprises
In the present study, table 1 shhows that the hypertension group and normal blood pressure group had been exposed to significantly different levels of noise intensity (P<0.05). The risk of hypertension was 2.54 times higher in workers exposed to noise intensity ≥80 dB than in those exposed to noise intensity <80 dB (95% CI 2.02–3.19). The difference in CNE between the two groups was statistically significant (P<0.05). The risk of hypertension in those with CNE ≥80 dB was 1.56 times higher than that in those with CNE <80 dB (95% CI 1.24–1.97). However, there was no significant difference in the nature of noise between the two groups (P>0.05).
Table 1 Relationship between noise exposure levels and hypertension.
Noise factor
|
N
|
Case group(n=509)
|
Control group(n=1018)
|
P
|
OR(95%CI)
|
Noise intensity
|
≥80dB
|
445
|
216(42.4)
|
229(22.5)
|
<0.05
|
2.54(2.02-3.19)
|
<80dB
|
1082
|
293(57.6)
|
789(77.5)
|
Cumulative noise exposure (CNE)
|
≥80dB
|
957
|
355(71.1)
|
602(61.2)
|
<0.05
|
1.56(1.24-1.97)
|
<80dB
|
526
|
144(28.9)
|
382(38.8)
|
Noise nature
|
steady-state noise
|
1506
|
503(98.8)
|
1003(98.5)
|
0.64
|
1.25(0.48-3.25)
|
impulse noise
|
21
|
6(1.2)
|
15(1.5)
|
Table 2(At the end of the manuscript)shows the hypertension and normal blood pressure groups showed significant differences in the duration of noise exposure (P<0.05). The risk of hypertension among individuals who had been working in noisy environments for >1 year was 1.31 times (95% CI 1.05–1.64) higher than that among those who had been working in noisy environments for ≤1 year. The two groups also showed significant differences in toxin exposure (P<0.05), with the risk of hypertension being 2.47 times higher among those with toxin exposure (95% CI 1.96–3.12). Similarly, the two groups showed significantly different levels of dust exposure (P<0.05), and individuals with dust exposure showed a 0.79-fold (95% CI 0.64–0.98) difference in the risk of hypertension compared with those with no dust exposure. The two groups also appeared to be involved in different types of work and workshops, and these differences were statistically significant (P<0.05).
Table 2 Relationship between levels of exposure to other occupational factors and hypertension
Occupational factor
|
N
|
Case group(n=509)
|
Control group(n=1018)
|
P
|
OR(95%CI)
|
length of service
|
>1year
|
963
|
342(67.2)
|
621(61.0)
|
<0.05
|
1.31(1.05-1.64)
|
≤1year
|
564
|
167(32.8)
|
397(39.0)
|
|
|
|
|
|
|
|
poison
|
Yes
|
923
|
377(74.1)
|
546(53.6)
|
<0.05
|
2.47(1.96-3.12)
|
No
|
604
|
132(25.9)
|
472(46.4)
|
|
|
|
|
|
|
|
dust
|
Yes
|
881
|
274(53.8)
|
607(59.6)
|
<0.05
|
0.79(0.64-0.98)
|
No
|
646
|
235(46.2)
|
411(40.4)
|
|
|
|
|
|
|
|
Type of work
|
Quality Management
|
3
|
2(0.4)
|
1(0.1)
|
<0.05
|
1
|
Logistics
|
3
|
0(0)
|
3(0.3)
|
0
|
repairs
|
64
|
22(4.3)
|
42(4.1)
|
0.26(0.02-3.05)
|
driver
|
146
|
45(8.8)
|
101(9.9)
|
0.22(0.02-2.52)
|
fitter
|
26
|
9(1.8)
|
17(1.7)
|
0.26(0.02-3.33)
|
painting
|
35
|
19(3.7)
|
16(1.6)
|
0.59(0.05-7.17)
|
polishing
|
17
|
8(1.6)
|
9(0.9)
|
0.44(0.03-5.88)
|
machining
|
3
|
1(0.2)
|
2(0.2)
|
0.26(0.01-7.45)
|
welding
|
118
|
28(5.5)
|
90(8.8)
|
0.16(0.01-1.78)
|
rework
|
18
|
1(0.2)
|
17(1.7)
|
0.03(0-0.68)
|
Section leader
|
15
|
3(0.6)
|
12(1.2)
|
0.13(0.01-1.88)
|
Electric welding
|
4
|
2(0.4)
|
2(0.2)
|
0.50(0.02-11.09)
|
Electrician
|
13
|
2(0.4)
|
11(1.1)
|
0.09(0.01-1.55)
|
Operator
|
1062
|
367(72.1)
|
695(68.3)
|
0.26(0.02-2.92)
|
|
|
|
|
|
|
|
workshop
|
final assembly
|
1321
|
427(83.9)
|
894(87.8)
|
<0.05
|
1.20(0.46-3.10)
0.36(0.06-2.07)
1.95(0.72-5.26)
1
|
body
|
169
|
74(14.5)
|
95(9.3)
|
painting
|
16
|
2(0.4)
|
14(1.4)
|
stamping
|
21
|
6(1.2)
|
15(1.5)
|
In this study, table 3 shows that the prevalence of abnormal lung function was found to differ significantly between the hypertension and normal blood pressure groups (P<0.05). The risk of hypertension in workers with abnormal lung function was 2.14 times (95% CI 1.30–3.53) higher than that in workers with normal lung function. There was no significant difference in the rate of hearing loss between the two groups (P>0.05).
Table 3 Relationship between occupational injuries and hypertension
Other disease factors
|
N
|
Subgroup(number (%))
|
p
|
OR(95%CI)
|
Case group(n=509)
|
Control
group(n=1018)
|
Abnormal lung function
|
Yes
|
65
|
33(6.5)
|
32(3.2)
|
<0.05
|
2.14(1.30-3.53)
|
No
|
1456
|
473(93.5)
|
983(96.8)
|
Hearing loss
|
Yes
|
84
|
25(4.9)
|
59(5.8)
|
0.48
|
0.84(0.52-1.36)
|
No
|
1443
|
484(95.1)
|
959(94.2)
|
Stratified analysis based on factors related to hypertension
To explore whether other factors influence the correlation of noise intensity and CNE with hypertension, factors found to show a statistically significant effect on the occurrence of hypertension were used for stratified analysis. The study population was stratified according to factors such as duration of work, workshop environment, and exposure to dust. However, given that the types of work were too numerous and the sample size of the abnormal lung function group was too small, these factors could not be used for stratified analyses.
Table 4(At the end of the manuscript) shows that regardless of the duration of work in noisy environments and combined exposure to dust and toxins, noise intensity levels were significantly different (P<0.05) between the hypertension and normal blood pressure groups. Noise intensity levels in the two groups were different in different workshops. The two groups showed statistically significant differences (P<0.05) in the proportion of assembly workshop workers.
Table 4 Relationship between noise intensity and hypertension under different levels of exposure to related factors.
Stratification factors
|
Noise intensity level
|
N
|
subgroup(number (%))
|
P
|
OR(95%CI)
|
Case group(n=509)
|
Control group(n=1018)
|
Length of service
|
>1year
|
≥80dB
|
363
|
177(51.8)
|
186(30.0)
|
<0.05
|
2.51(1.9-3.30)
|
<80dB
|
600
|
165(48.2)
|
435(70.0)
|
≤1year
|
≥80dB
|
82
|
39(23.4)
|
43(10.8)
|
<0.05
|
2.51(1.56-4.05)
|
<80dB
|
482
|
128(76.6)
|
354(89.2)
|
Workshop
|
Final assembly
|
≥80dB
|
337
|
171(40.0)
|
166(18.6)
|
<0.05
|
2.92(2.26-3.78)
|
<80dB
|
983
|
256(60.0)
|
727(81.4)
|
Body
|
≥80dB
|
84
|
40(54.1)
|
44(46.3)
|
0.32
|
1.36(0.74-2.51)
|
<80dB
|
85
|
34(45.9)
|
51(53.7)
|
Application
|
≥80dB
|
4
|
0(0)
|
4(28.6)
|
1.00
|
|
<80dB
|
12
|
2(100.0)
|
10(71.4)
|
|
Stamping
|
≥80dB
|
20
|
5(83.3)
|
15(100.0)
|
0.29
|
|
<80dB
|
1
|
1(16.7)
|
0(0)
|
|
Dust
|
Yes
|
≥80dB
|
216
|
90(32.8)
|
126(20.8)
|
<0.05
|
1.87(1.36-2.57)
|
<80dB
|
665
|
184(67.2)
|
481(79.2)
|
No
|
≥80dB
|
229
|
126(53.6)
|
103(25.1)
|
<0.05
|
3.46(2.46-4.86)
|
<80dB
|
417
|
109(46.4)
|
308(74.9)
|
Poison
|
Yes
|
≥80dB
|
295
|
166(44.0)
|
129(23.6)
|
<0.05
|
2.54(1.92-3.38)
|
<80dB
|
628
|
211(56.0)
|
417(76.4)
|
No
|
≥80dB
|
150
|
50(37.9)
|
100(21.2)
|
<0.05
|
2.27(1.50-3.44)
|
<80dB
|
454
|
82(62.1)
|
372(78.8)
|
Table 5(At the end of the manuscript) shows that when the duration of noise exposure was ≤1 year, the CNE was significantly different between the two groups (P<0.05). When the two groups were compared, CNE levels were found to be significantly different between final assembly workshop workers (P<0.05), workers who were not exposed to dust (P<0.05), and workers exposed to toxins (P<0.05).
Table 5 Relationship between CNE levels and hypertension under different levels of exposure to related factors.
Stratification factor
|
Cumulative noise intensity level
|
N
|
subgroup(number (%))
|
P
|
OR(95%CI)
|
Case group(n=509)
|
Control group (n=1018)
|
Length of service
|
>1
|
≥80dB
|
881
|
318(93.0)
|
563(90.7)
|
0.22
|
1.36(0.83-2.24)
|
<80dB
|
82
|
24(7.0)
|
58(9.3)
|
|
|
≤1
|
≥80dB
|
76
|
37(23.6)
|
39(10.7)
|
<0.05
|
2.56(1.56-4.21)
|
<80dB
|
444
|
120(76.4)
|
324(89.3)
|
|
|
Workshop
|
Final assembly
|
≥80dB
|
799
|
295(70.1)
|
504(58.3)
|
<0.05
|
1.68(1.31-2.15)
|
<80dB
|
487
|
126(29.9)
|
361(41.7)
|
|
|
Body
|
≥80dB
|
126
|
54(77.1)
|
72(79.1)
|
0.76
|
0.89(0.42-1.89)
|
<80dB
|
35
|
16(22.9)
|
19(20.9)
|
|
|
Application
|
≥80dB
|
13
|
1(50.0)
|
12(85.7)
|
0.35
|
0.17(0.01-3.89)
|
<80dB
|
3
|
1(50.0)
|
2(14.3)
|
|
|
Stamping
|
≥80dB
|
18
|
5(83.3)
|
13(100.0)
|
0.32
|
|
<80dB
|
1
|
1(16.7)
|
0(0)
|
|
|
Dust
|
Yes
|
≥80dB
|
533
|
170(64.2)
|
363(61.8)
|
0.52
|
1.10(0.82-1.49)
|
<80dB
|
319
|
95(35.8)
|
224(38.2)
|
|
|
No
|
≥80dB
|
424
|
185(79.1)
|
239(60.2)
|
<0.05
|
2.50(1.72-3.63)
|
<80dB
|
207
|
49(20.9)
|
158(39.8)
|
|
|
poisons
|
Yes
|
≥80dB
|
566
|
262(70.6)
|
304(56.5)
|
<0.05
|
1.85(1.40-2.45)
|
<80dB
|
343
|
109(29.4)
|
234(43.5)
|
|
|
No
|
≥80dB
|
391
|
93(72.7)
|
298(66.8)
|
0.21
|
1.32(0.85-2.04)
|
<80dB
|
183
|
35(27.3)
|
148(33.2)
|
|
|
In order to explore the factors influencing hypertension development among workers in modern enterprises, we conducted multivariate unconditional logistic regression analysis. The dependent variable was the presence of hypertension after noise exposure. The independent variables included noise intensity, CNE, nature of noise, duration of work in noisy environments, work in production workshops, dust exposure, toxin exposure, family history, lung function, body mass index(BMI), and heart rate. Table 6 shows that noise intensity, BMI >23.9 kg/m2, heart rate >100 beats/min, toxin exposure, and abnormal lung function were found to influence the development of hypertension in workers exposed to noise in modern enterprises.
Table 6 Adjusted risk of hypertension based on noise and other occupational factors
source
|
B
|
S.E.
|
Wald
|
AdjustedOR
|
OR95%CI
|
Noise intensity
body mass index (BMI)>23.9 kg/m2
|
0.80
2.39
|
0.16
0.56
|
24.41
18.50
|
2.23
10.90
|
(1.62-3.06)
(3.67-32.39)
|
Toxin exposure
|
1.24
|
0.16
|
61.26
|
3.45
|
(2.53-4.71)
|
Body workshop
|
0.91
|
0.22
|
17.73
|
2.49
|
(1.63-3.79)
|
Lung function
|
1.05
|
0.30
|
11.93
|
2.86
|
(1.58-5.19)
|
Heart rate>100 beats/min
|
1.79
|
0.27
|
44.61
|
5.98
|
(3.54-10.11)
|