Occupational noise and genetic variants in stress hormone biosynthesis-based genes and rates of blood lipid changes in China: A five-year longitudinal study.

Lipid profiles are influenced by both noise and genetic variants. However, little is known about the associations of occupational noise and genetic variants with age-related changes in blood lipids, a crucial event in the initiation and evolution of atherosclerotic cardiovascular diseases. We aimed to evaluate the associations of blood lipid change rates with occupational noise and genetic variants in stress hormone biosynthesis-based genes. This cohort was established in 2012 and 2013 and was followed up until 2017. A total of 952 participants were included in the final analysis and all of them were categorized to two groups, the exposed group and control group, according to the exposed noise levels in their working area. Single nucleotide polymorphisms (SNPs) in stress hormone biosynthesis-based genes were genotyped. Five physical examinations were conducted from 2012 to 2017 and lipid measurements were repeated five times. The estimated annual changes (EACs) of blood lipid were calculated as the difference in blood lipid levels between any 2 adjacent examinations divided by their time interval (year). The generalized estimating equations for repeated measures analyses with exchangeable correlation structures were used to evaluate the influence of exposing to noise (versus being a control) and the SNPs mentioned above on the EACs of blood lipids. We found that the participants experienced accelerated age-related decline in high-density lipoprotein cholesterol (HDL-C) levels as they were exposed to noise (ß = -0.38, 95% confidence interval (CI), -0.66 to -0.10, P = 0.007), after adjusting for work duration, gender, smoking, alcohol consumption, and pack-years. This trend was only found in participants with COMT-rs165815 TT genotype (ß = -1.19, 95% CI, -1.80 to -0.58, P < 0.001), but not in those with the CC or CT genotypes. The interaction of noise exposure and rs165815 was marginally significant (Pinteraction = 0.010) after multiple adjustments. Compared with DDC-rs11978267 AA genotype carriers, participants carrying rs11978267 GG genotype had decreased EAC of triglycerides (TG) (ß = -5.06, 95% CI, -9.07 to -1.05, P = 0.013). Participants carrying DBH-rs4740203 CC genotype had increased EAC of total cholesterol (TC) (ß = 1.19, 95% CI, 0.06 to 2.33, P = 0.039). However, these findings were not statistically significant after multiple adjustments. These results indicated that Occupational noise exposure was associated with accelerated age-related decreases in HDL-C levels, and the COMT-rs165815 genotype appeared to modify the effect of noise exposure on HDL-C changes among the occupational population.

Association of occupational noise exposure, bilateral hearing loss with hypertension among Chinese workers.

OBJECTIVE: To evaluate the relationship of occupational noise, bilateral hearing loss with blood pressure and hypertension among a Chinese population. METHODS: We included 15 422 individuals from a cross-sectional survey of the key occupational diseases in 2017 in Wuhan, Hubei Province, China. Occupational noise exposure was evaluated through workplace noise level and/or the job titles. Hearing loss was defined as a pure-tone average of 25 dB or higher at speech frequency (0.5, 1, 2 kHz) or high frequency (3, 4, 6 kHz) in both ears. Hypertension was defined as blood pressure at least 140/90 mmHg or self-reported current use of antihypertensive medication. RESULTS: Compared with participants without occupational noise exposure, the prevalence of hypertension was significantly higher for noise exposure duration of 5 to less than 10 years [odds ratio (OR) = 1.13, 95% confidence interval (CI) = 1.04-1.27] and at least 10 years (OR = 1.17, 95% CI = 1.09-1.30). In the sex-specific analysis, the association was significantly pronounced in male (OR = 1.18, 95% CI = 1.06-1.32 for duration of 5 to <10 years; OR = 1.25, 95% CI = 1.12-1.38 for duration ≥10 years), but not in female (OR = 1.01, 95% CI = 0.80-1.11 for duration of 5 to <10 years; OR = 1.06, 95% CI = 0.90-1.20 for duration ≥10 years). In the subsample analyses, bilateral hearing loss was associated with a higher prevalence of hypertension, no matter for speech frequency hearing loss (OR = 1.12, 95% CI = 1.02-1.30 for mild; OR = 1.35, 95% CI = 1.20-1.50 for severe) or for high-frequency hearing loss (OR = 1.24, 95% CI = 1.03-1.50 for mild; OR = 2.40, 95% CI = 1.80-3.17 for severe). The sex-subgroup analysis of hearing loss with hypertension was similar as occupational noise and hypertension. CONCLUSION: Our study has suggested occupational noise exposure is a potential risk factor for hypertension.

[Comparative field study on high flow rate samplers for respirable fraction-A solution to smaller collected masses].

OBJECTIVE: Dust sample mass gain is too smaller to satisfy the limit of detection (LOD) even in most cases during dust sampling at workplaces nowdays, especially for respirable fraction. Therefore, it is aimed to solve the problem by increasing sample load with high flow rate samplers. METHODS: In A and B two shipyards respirable welding fume was sampled by high flow rate cyclone samplers of FSP-10 (10 L/min) for 2-2.5 hours and normal flow rate FSP-2 (2 L/min) for 3-4 hours with a stratigy of parallele sampling at the same workpalce, in order to compare their mass gain, coincidence rate with LOD, and airborn dust concentration. RESULTS: Sample mass gain of 0.97±0.40 mg and 1.61±0.86 mg respectively in the two factories by FSP-10 was significantly higher than that of 0.29±0.12 mg and 0.51±0.27 mg by FSP-2 (t-test, P<0.05 in both cases) , increasing herewith the coincidence rate with LOD from 26.8% (when sampling with FSP-2, calculated together with samples of the two factories) to 89.7%. However there was no significant difference in dust concentrations by the two different samplers, 0.53±1.88 vs 0.73±1.61 mg/m(3) by FSP-2 and FSP-10 in the shipyard A and 1.14±1.78 vs 1.01±1.63 mg/m(3) in the factory B (t-test, P>0.05 in every case) . In addtion, sample loading by FSP-2 was found to be correlated to sampling time (R(2)=0.7906, y=0.002 6x) , therefore, it has to sample for ≥192.3 min to meet the LOD (0.5 mg) in case of normal flow rate. CONCLUSION: By using of high flow rate cyclone FSP-10 the problem of LOD could be solved, along with increased sample mass and similar respirable dust concentration by the two samplers. Some techincal improvements of FSP-10 and increasing of LOD coincidence rate by other methods was also disscussed.

Re-characterization of some factors influencing aerosol sampling in the workplace: results from field studies.

OBJECTIVE: Workplace aerosol sampling is challenged by its influencing factors and methodological limitations. Some factors, including blank setting, electrostatic effect, sample mass gain, and limit of detection (LOD), were studied to characterize them further and thereby to improve the sampling method. METHODS: Through a field sampling in two shipyards and by an analysis of a large amount of dust data from different industries, the influencing factors were comparatively studied with emphasis on their effect on the final result. RESULTS: After calibration with field blanks, the concentrations of most sample types in the shipyards decreased significantly, varying by as much as -24.3% of the final measurements. After laboratory blank calibration, dust concentrations increased or decreased without a definite change trend. With a variation of -1.8%, only the measurements of Chinese "total dust" sampled with polypropylene filters were significantly influenced by the electrostatic effect. The LOD coincidence rate was only 17.3% for American respirable dust in different industries and 12.2% for respirable particles collected by normal flow rate samplers (FSP2) in the shipyards. The latter increased to 73.9% when high flow samplers (FSP10) were used. CONCLUSIONS: It was suggested that field blank calibration was the predominant influencing factor in comparison with electrostatic effect and laboratory blank adjustment. The LOD coincidence rate was too low for reliable sampling, and this might be improved by use of high flow samplers.

[Effects of p,p'-DDE on intracellular MAPK pathway of rat Sertoli cells in vitro].

OBJECTIVE: To study effects of p,p'-DDE on intracellular p-ERK of rat Sertoli cells in vitro. METHODS: We cultured Sertoli cells separated from testicular tissue of rats and examined the changes of intracellular p-ERK, using immunohistochemical SABC method. RESULTS: It was showed that intracellular p-ERK increased with the dose of p,p'-DDE and had a dose-dependent trend. CONCLUSION: The results suggested that p,p'-DDE could result in the phosphorylation of ERK and induce the activation of the downstream road and the transcription and expression of genes.