ABSTRACT
BACKGROUND: The association between occupational noise exposure and hypertension is inconsistent because of an exposure bias caused by outer-ear measurements of noise levels among workers. This study used hearing loss values (HLVs) measured at 4 kHz and 6 kHz in both ears as a biomarker to investigate the chronic effects of noise exposure on hypertension in 790 aircraft-manufacturing workers. METHODS: Participants were divided into a high hearing loss (HL) group (n = 214; average HLVs ≥ 30 decibel [dB] at 4 kHz or 6 kHz bilaterally; 83.1 ± 4.9 A-weighted decibel [dBA]), a median HL group (n = 302; 15 ≤ average HLVs < 30 dB at 4 kHz or 6 kHz bilaterally; 83.1 ± 4.4 dBA) and a low HL group (n = 274; average HLVs < 15 dB at 4 kHz or 6 kHz bilaterally; 82.2 ± 5.1 dBA) based on the results of pure tone audiometry. Multivariate logistic regressions were used to estimate the risk of hypertension between groups. RESULTS: The prevalence rates of hypertension were significantly higher in the high HL (43.5%; p = 0.021) and median HL (42.1%; p = 0.029) groups than in the low HL group (33.2%). The high HL and median HL workers had 1.48-fold (95% confidence interval [95%CI] = 1.02-2.15; p = 0.040) and 1.46-fold (95%CI = 1.03-2.05; p = 0.031) higher risks of hypertension relative to the low HL workers. Employment duration was significantly and positively correlated with the risk of hypertension among workers with average HLVs ≥ 15 dB at 4 kHz (p < 0.001) and 6 kHz (p < 0.001) bilaterally. CONCLUSIONS: Our findings suggest that high-frequency hearing loss is a good biomarker of occupational noise exposure and that noise-induced hearing loss may be associated with the risk of hypertension.
Subject(s)
Hearing Loss, High-Frequency/epidemiology , Hypertension/etiology , Noise, Occupational/adverse effects , Occupational Diseases/epidemiology , Aircraft , Biomarkers , Cross-Sectional Studies , Hearing Loss, High-Frequency/etiology , Hearing Loss, Noise-Induced/epidemiology , Hearing Loss, Noise-Induced/etiology , Humans , Hypertension/epidemiology , Logistic Models , Male , Occupational Diseases/etiology , Occupational Exposure/adverse effects , Prevalence , Risk Factors , TaiwanABSTRACT
Many volatile organic compounds (VOCs) are emitted during the manufacturing of thin film transistor liquid crystal displays (TFT-LCDs), exposure to some of which has been reported to be associated with kidney dysfunction, but whether such an effect exists in TFT-LCD industry workers is unknown. This cross-sectional study aimed to investigate the association between exposure to VOCs and kidney dysfunction among TFT-LCD workers. The results showed that ethanol (1811.0+/-1740.4 ppb), acetone (669.0+/-561.0 ppb), isopropyl alcohol (187.0+/-205.3 ppb) and propylene glycol monomethyl ether acetate (PGMEA) (102.9+/-102.0 ppb) were the four dominant VOCs present in the workplace. The 63 array workers studied had a risk of kidney dysfunction 3.21-fold and 3.84-fold that of 61 cell workers and 18 module workers, respectively. Workers cumulatively exposed to a total level of isopropyl alcohol, PGMEA and propylene glycol monomethyl ether> or =324 ppb-year had a significantly higher risk of kidney dysfunction (adjusted OR=3.41, 95% CI=1.14-10.17) compared with those exposed to <25 ppb-year after adjustment for potential confounding factors. These findings indicated that array workers might be the group at greatest risk of kidney dysfunction within the TFT-LCD industry, and cumulative exposure to specific VOCs might be associated with kidney dysfunction.
