BackgroundThe most common risks for street sweepers are respiratory symptom and airway obstruction increases as a result of dust inhalation. The aim of this study was to compare the respiratory symptoms and pulmonary functions of dust-exposed street sweepers with those of unexposed individuals.MethodsThis was a retrospective cohort study of 84 street sweepers with occupational dust exposure (exposed group) and 80 office workers (control group) working for the municipality of Zahedan in Iran. Each of the participants completed the American Thoracic Society respiratory questionnaire, and their lung functions were measured using a calibrated spirometer.ResultsThe respiratory symptom frequencies were significantly higher in the exposed group than in the reference group (P < 0.05). Specifically, coughing was the most common complaint of the street sweepers (81%) when compared to the controls (16.3%). The means of the peak expiratory flow and forced expiratory flow at 25%–75% of the pulmonary volume were significantly less in the exposed group than in the control group.ConclusionOccupational exposure and unhealthy working conditions are the most likely causes of mild obstructive disease and pulmonary function parameter changes. Providing street sweepers with the appropriate respiratory protection equipment, as well as periodic spirometry for the early diagnosis of pulmonary dysfunction, could be effective for preventing many types of pulmonary damage.

Background: Seatbelts are a relatively low-cost safety device that provides easy basic protection for occupants of 4-wheeled vehicles. Objectives: This study investigates frequency of seatbelt use and its related factors among drivers involved in a vehicle crash. Materials and Methods:In this cross-sectional study, all crash profiles recorded in a province from March 2010 to March 2011 were reviewed. Necessary information was extracted from crash reports in which at least one 4-wheeled vehicle was involved. Data were analyzed using binary and multinomial logistic regression. Results: Of a total of 1427 motor vehicle crashes, a seatbelt was used by 58.2% of drivers. In the univariate analysis, the following were significantly associated with seatbelt use: driver age, education, and occupation along with front seat passenger's sex and seatbelt use, type and make of vehicle, speed, road surface condition, and type of road. In the multivariate model, the following remained significant: driver education, seatbelt use by front seat passenger, and type of road. Furthermore, a restraining seatbelt protected drivers from severe injury and death. Unbelted drivers were 7 and 17.4 times more likely to experience injury and death respectively than belted drivers. Conclusions: The seatbelt wearing rate among the study participants was much lower than the 90% rate reported among Iranian drivers in 2010. Mandating seatbelt use, as in most countries, will be more effective if a combination of factors such as changes in vehicle design, road safety, and driver and passenger behavior are taken into account.

Cigarette smoking is a possible risk factor for hearing loss. However, the impact of simultaneous exposure to noise and smoke on hearing has remained controversial. This study investigated the combined effect of exposure to cigarette smoking and noise on hearing loss. Three groups of male Wistar rats (275 + 25 g) were subjected to white noise (102 + 0.5 dB), cigarette smoking (20 cigarettes), and both cigarette smoking and noise for 8 h and 10 days inside the exposure chamber. The control group was exposed to neither noise nor smoke. Distortion product otoacoustic emissions (DPOAE) were measured before any intervention, and it was repeated 1, 7, and 21 days after the last exposure. One-day postexposure to noise, cigarette smoking, and both cigarette smoking and noise, the mean of DPOAE amplitudes decreased significantly (p < 0.05) between, respectively, 5.7-30.7, 1.5-7.5, and 5.2-32.6 dB within the frequency range of 4620-9960. Temporal DPOAE change in rats exposed to noise or both cigarette smoking and noise was not significantly different (p > 0.05). DPOAE amplitudes returned to the baseline values in the group subjected to smoking 21 days postexposure. The most permanent change was observed in rats exposed to both cigarette smoking and noise. Accordingly, simultaneous subacute exposure to noise and cigarette smoking increases the effect of noise on permanent hearing loss. Therefore, smoking workers exposed to noise might be at a greater risk of developing hearing loss, and it is recommended that authorities in charge take note of this evidence.

BackgroundNoise exposure causes loss of cochlea hair cells, leading to permanent sensorineural hearing loss, and initiates pathological changes to the bipolar primary auditory neurons (ANs). This study focuses on the effects of N-acetyl-l-cysteine (NAC) in protecting the density of spiral ganglion cells and in histological changes induced by continuous noise exposure in rats.MethodsTwenty-four male Wistar rats were randomly allocated into four experimental groups to receive NAC, saline, noise, or both noise and NAC. Noise exposure continued for ten days. Saline and NAC were injected daily during the noise exposure, and 2 days before and after the noise exposure. Evaluation of cochlear histopathology and the density of spiral ganglion cells was performed 21 days after exposure.ResultsIn the animals exposed to noise, a reduction in the density of spiral ganglion cells was evident in both the basal and middle turns of the cochlea. This improved on receiving NAC treatment (P = 0.046). In the histopathology evaluation, some histological changes, such as disorganised architecture of the outer hair and supporting cells and a slightly thickened basilar membrane, were found in the basal turns in the noise group.ConclusionNAC offered partial protection against noise exposure by improving the density of spiral ganglion cells and reducing morphological changes.

Background: Different types of direct and passive smoking have been reported to be associated with conductive and sensorineural hearing loss. In this study, we aimed to investigate the relationship between cigarette smoke exposure and cochlear dysfunction.