Table 6:
Cross-sectional studies with references
| Reference | Population | Exposure source | Exposure level | Methodology | Findings |
|---|---|---|---|---|---|
| (39) | Case group:156; Control group:186 |
Tile Industry | Case group SPL>82 dB(A); Control group SPL<82 dB(A) |
Noise measurement; Audiometric | The average hearing threshold was higher for Case group than control group. In the right ear, there was significant difference in frequency 3000 Hz( P value =0.02), 4000 Hz ( P value =0.04) |
| (5) | Case group: 55; Control group:55 |
Oil industry | case group SPL=91.8 dB(A); Control group: office staffs |
Noise measurement; Audiometric | Significant difference in the hearing threshold of Case and control group, frequencies 500,1000,2000,4000,8000 Hz ( P value <0.001) |