ABSTRACT
Background: the present study was undertaken to ascertain whether [or not] long term occupational exposure to low [sub-TLV levels] atmospheric concentrations of chlorine gas was associated with any significant decrements in the parameters of pulmonary function and/or increased prevalence of respiratory symptoms
Methods: in this retrospective cohort study that was performed in 2012, 54 workers of a local chloralkali unit and 38 non-exposed office staff were enrolled and compared. Atmospheric concentrations of chlorine gas were measured by numerous sampling with gas detector tubes. Data on respiratory symptoms were gathered using a standard questionnaire. Furthermore, spirometry test was performed for subjects both prior to and at the end of shift
Results: mean atmospheric concentration of chlorine gas was 0.27 +/- 0.05 ppm that was lower than the existing TLV value for this toxic irritant gas. Symptoms of respiratory diseases were significantly more frequent among exposed subjects than in referent individuals. Additionally, mean values of most parameters of pulmonary function including FEV1 [P=0.031], FEV1/FVC ratio [P=0.003] and PEF [P=0.005] were significantly lower than their corresponding values for unexposed subjects. Additional cross shift decrements were also noted in some lung functional capacities, although changes were not statistically significant
Conclusions: exposure to sub-TLV levels of chlorine gas is associated with statistically significant decrements in the parameters of pulmonary function as well as increased prevalence of respiratory symptoms
ABSTRACT
Background: Noise is one of the most pervasive hazards in industrial settings. This retrospective study was carried out to assess the effects of noise exposure on hearing status, blood lipids and blood pressure of employees of a local fireclay mine
Methods: Two hundred and forty male workers were studied. Data on audiometric measurements, blood lipids and blood pressure were derived from the workers' medical records and analyzed. Furthermore, area noise measurements were performed. Data were analyzed using SPSS version 16.0
Results: Workers were exposed to a mean noise level of 91 +/- 15 dB. The means of triglyceride [TG], total cholesterol [TC], systolic and diastolic blood pressure [SBP and DBP] were within the normal range for the first three years of the study. However, a slight, non-significant increase in TG level was noted in 2010. Most of the participants [63.6%] suffered from moderate hearing loss [HL]. About 23.6% and 12.7% of the employees had developed severe and mild HL, respectively. A statistically significant difference was noted in the number of workers with high-frequency noise-induced HL. Furthermore, a statistically significant association was found between the mean of highfrequency HL and log-transformed TG values in 2009 and 2010
Conclusions: High frequency HL could be used as a biomarker for identifying workers exposed to excessive noise levels. Highfrequency HL developed over a 4-year exposure to noise was associated with hypertriglyceridemia. Implementing a hearing conservation program seems to be mandatory to prevent further increases in the number of workers who are already in the severe HL group
ABSTRACT
Background/Objective: This study was undertaken to address psychological health effects of dentists' exposure to low ambient levels of mercury
Methods: One hundred and six dentists and 94 general practitioners were randomly selected from clinics in Shiraz city, Iran. Subjects were asked to complete the Persian version of General Health Questionnaire. The data were analyzed using ?2 test, independent sample t-test and Mann-Whitney's U test
Results: Both groups were similar as far as all demographic variables, except age, were concerned. No significant difference was noted between the dentists' mean total score of GHQ-28 [17.9] and that of referent subjects [16.34]. These scores were significantly lower than the cut-off point of 23 [P<0.01]. The mean scores for somatic symptoms, anxiety and insomnia, and depression were significantly higher in dentists than in the referent subjects. The results also showed a significant association between GHQ-28 total scores and length of exposure to mercury [P=0.034]; with increase in the job tenure, GHQ-28 total score also increased, indicating a decrement in psychological health status
Conclusion: The current findings revealed that, in general, the dentists' psychological health status was poorer than the referent subjects. Additionally, in all GHQ subscales, the dentists' scores were significantly different from those of their counterparts. Given the fact that exposure to mercury is the most important differentiating variable between both groups, and that neuropsychological disorders are the most common toxic effect of mercury, the difference between psychological health status of the two groups is likely to be related to exposure to mercury