Noise exposure in occupational setting associated with elevated blood pressure in China.

BACKGROUND: Hypertension is the primary out-auditory adverse outcome caused due to occupational noise exposure. This study investigated the associations of noise exposure in an occupational setting with blood pressure and risk of hypertension. METHODS: A total of 1,390 occupational noise-exposed workers and 1399 frequency matched non-noise-exposed subjects were recruited from a cross-sectional survey of occupational noise-exposed and the general population, respectively. Blood pressure was measured using a mercury sphygmomanometer following a standard protocol. Multiple logistic regression was used to calculate the odds ratio (OR) and 95% confidence interval (CI) of noise exposure adjusted by potential confounders. RESULTS: Noise-exposed subjects had significantly higher levels of systolic blood pressure(SBP) (125.1 ± 13.9 mm Hg) and diastolic blood pressure (DBP) (77.6 ± 10.7 mm Hg) than control subjects (SBP: 117.2 ± 15.7 mm Hg, DBP: 70.0 ± 10.5 mm Hg) (P < 0.001). Significant correlations were found between noise exposure and blood pressure (SBP and DBP) (P < 0.001). However, the linear regression coefficients with DBP appeared larger than those with SBP. The prevalence of hypertension was 17.8% in subjects with noise exposure and 9.0% in control group (P < 0.001). Compared with the control group, the subjects with noise exposure had the risk of hypertension with an OR of 1.941 (95% CI = 1.471- 2.561) after adjusting for age, sex, smoking, and drinking status. Dose-response relationships were found between noise intensity, years of noise exposure, cumulative noise exposure and the risk of hypertension (all P values < 0.05). No significant difference was found between subjects wearing an earplug and those not wearing an earplug, and between steady and unsteady noise categories (P > 0.05). CONCLUSIONS: Occupational noise exposure was associated with higher levels of SBP, DBP, and the risk of hypertension. These findings indicate that effective and feasible measures should be implemented to reduce the risk of hypertension caused by occupational noise exposure.

Associations of genetic variations in EYA4, GRHL2 and DFNA5 with noise-induced hearing loss in Chinese population: a case- control study.

BACKGROUND: Both environmental and genetic factors are attributable to the incidence of noise-induced hearing loss (NIHL). The purpose of this study was to examine the associations between genetic variations in the EYA4, GRHL2 and DFNA5 genes and the risk to noise-induced hearing loss (NIHL) in a Chinese population. METHODS: A case-control study was conducted with 476 NIHL workers and 475 normal hearing workers matched with gender, years of noise exposure, and intensity of noise exposure. Twelve tag single-nucleotide polymorphisms (SNP) in the EYA4, GRHL2 and DFNA5 genes were genotyped using nanofluidic dynamic arrays on the Fluidigm platform. Multiple logistic regression was used to analyze the associations of genetic variations with NIHL adjusted by age, smoking/drinking status, and cumulative noise exposure and their interactions with noise exposure. RESULTS: The SNPs of rs3777781and rs212769 in the EYA4 gene were significantly associated with NIHL risk. In rs3777781, comparing with the subjects carrying with TT types, the carriers with AT and AA genotypes had the decreased risk of NIHL (OR = 0.721, 95% CI = 0.522 - 0.996). In rs212769, the AG and AA carriers had increased NIHL risk (OR = 1.430, 95% CI = 1.014 - 2.016) compared with the subjects with GG genotype. Rs666026 in the associated GRHL2 gene and rs2521758 in the DFNA5 gene were marginally t associated with NIHL (P = 0.065 and 0.052, respectively). Rs2521758 and rs212769 had significantly interacted with noise exposure (P < 0.05). CONCLUSIONS: Genetic variations in the EYA4, GRHL2 and DFNA5 genes and their interactions with occupational noise exposure may play an important role in the incidence of NIHL.

[Toxic effects of mixture of volatile organic compounds on mice testis related enzymes and hormones].

OBJECTIVE: To evaluate the toxic effects of mixture of volatile organic compounds (VOCs) on Mice Testis related enzymes and hormones. METHODS: After determining the median lethal dose (LD50) of VOCs using the acute toxicity test, 40 male clean inbred Kunming mice were assigned to 1/8 LD50 VOCs exposure group, 1/4 LD50 VOCs exposure group, and 1/2 LD50 VOCs exposure group, as well as positive control group with cyclophosphamide (60 mg/kg) and negative control group with tea oil, with 8 mice in each group. The mice were intraperitoneally injected with respective agents for 5 days. The levels of testis testosterone, estradiol, follicle stimulating hormone, and luteinizing hormone were determined by ELISA. Meanwhile, the activity of testicular marked enzymes such as lactate dehydrogenase, gamma-glutamyl transpeptidase, acid phosphatase, and glucose-6-phosphate dehydrogenase were examined. RESULTS: Compared with the negative control group, the 1/8 LD50 exposure group had a significantly increased testis coefficient (P<0.05). Both the activity of testicular marked enzymes and the levels of testicular sex hormones in all exposure groups showed significant downward trends with increasing VOC doses compared with those in the negative control group (P<0.05). CONCLUSION: VOCs have obvious toxicity to mouse testis by changing the levels of testicular sex hormones and the activity of testicular marked enzymes.

[Observation of immunity level of pertussis-diphtheria-tetanus in healthy people in Hangzhou City during 1995-2006].

OBJECTIVE: To study the pertussis-diphtheria-tetanus immunity level of healthy people in Hangzhou. METHODS: Pertussis antibody, diphtheria antitoxin and tetanus antitoxin were tested. We carried out surveillance in different counties among the people at 2-4, 6-8, 13-15, 25-39 age group during 1995-2006. RESULTS: It showed that the pertussis antibody positive rate of 1942 persons was 93.87%, GMT 1: 1037.36 IU/ml, the antibody of people in countryside for the people at 2-4 age group was lower than that of other groups and the difference was significant compared with 6-8, 13-15 age group (chi2 = 8.80, 6.13, P < 0.01). The diphtheria antitoxin positive rate of 2141 persons was 91.59%, with the GMT was 0.2911 IU/ml. The tetanus antitoxin positive rate of 2141 persons was 72.35%, GMT 0.095 IU/ml. CONCLUSIONS: We need to strengthen the EPI work in rural areas.