The objective was to investigate the reliability and effects of age and noise on high-frequency hearing thresholds. A cross-sectional study was used involving 187 exposed and 52 non-industrial noise-exposed subjects selected randomly from noise-exposed and non-industrial noise-exposed subjects, respectively. Each subject was tested with both conventional-frequency (0.25-8 kHz) and high-frequency (10-18 kHz) audiometry. Test-retest results showed that high-frequency audiometry (HFA) was as reliable as the conventional procedure. Although the inter-subject variation was large, the intra-subject variation was small, indicating that HFA can be used more reliably than the conventional procedure to monitor individual cases over time. Both the hearing threshold at high frequencies and the upper frequency limit deteriorated as a function of age and frequency. The exposed subjects had significantly higher hearing thresholds than the non-exposed subjects at all the high frequencies tested, the difference between the two groups being greatest at 14 kHz. Multivariate analysis indicated that age was the primary predictor and noise exposure the secondary predictor of hearing thresholds in a high frequency range (10-18 kHz). In contrast, multivariate analysis indicated the reverse order-noise exposure as the primary predictor, then age-for a conventional frequency range (0.25-8 kHz). The results of this study suggest that HFA might be used as an early indicator for noise-induced hearing loss and acoustic trauma rather than audiometry at a conventional frequency (4 kHz), particularly for younger groups.

Henna is very popular in the United Arab Emirates (UAE); it is part of the culture and traditions. Allergy to natural henna is not usual; however the addition of para-phenylenediamine (PPD) to the natural henna increases the risk of allergic contact dermatitis. The objectives of the study were to identify the presence and concentration of PPD in henna available in UAE. Fifteen henna salons were selected randomly from three cities in UAE. Twenty five henna samples were acquired from these selected salons. The presence of PPD in henna samples was determined qualitatively and quantitatively using High Performance Liquid Chromatography (HPLC). The study showed that PPD was present in all of the black henna samples at concentrations ranging between 0.4% and 29.5% and higher than that recommended for hair dyes in most of the black henna samples. The presence of PPD in the black henna increases the risk of allergic contact dermatitis among users of black henna and a number of cases have already been reported in UAE.

A cross-sectional study was conducted in a randomly selected factory producing Portland cement in eastern Saudi Arabia to determine the prevalence of respiratory symptoms and diseases and chest x-ray changes consistent with pneumoconiosis in the employees. A sample of 150 exposed and 355 unexposed employees was selected. A questionnaire about respiratory symptoms was completed during an interview. Chest x-rays were read according to the ILO criteria for pneumoconiosis. Dust level was determined by the gravimetric method. Concentrations of personal respirable dust ranged from 2.13 mg/m3 in the kilns to 59.52 mg/m3 in the quarry area. Cough and phlegm were found to be related to cigarette smoking, while wheezing, shortness of breath, and bronchial asthma were related to dust levels. It is recommended that engineering measures be adopted to reduce the dust level in this company, together with health monitoring of exposed employees.

Through a cross-sectional survey and integrated sound level meter, this research examined noise exposure and auditory- and nonauditory-related problems experienced by students of a dentistry college located in the United Arab Emirates (UAE). A structured interview questionnaire was used to examine hearing-related problems, noise annoyance, and awareness of 114 students toward noise. The results showed that maximum noise levels were between 65 and 79 dB(A) with peak levels (high and low frequencies) ranging between 89 and 93 dB(A). Around 80% of the students experienced a certain degree of noise annoyance; 54% reported one of the hearing-related problems; and about 10% claimed to have hearing loss to a certain extent. It is recommended that sound-absorbent materials be used during the construction of dental clinics and laboratories to reduce the noise levels.

This study was conducted in a cement factory in the United Arab Emirates to assess cement dust exposure and its relationship to respiratory symptoms among workers. A total of 149 exposed and 78 unexposed workers participated in this cross-sectional study. Information on demographic and respiratory symptoms was collected by questionnaire. Personal total dust levels were determined by the gravimetric method. Concentration of the total dust ranged between 4.20 mg/ m 3 in the crushers and 15.20 mg/m 3 in the packaging areas, and exceeded the exposure limit in the packaging and raw mill areas. The prevalence of respiratory symptoms was higher among the exposed workers, but the difference from that of unexposed workers was statistically significant only for cough (19.5%; OR=4.5; 95%CI=1.5-13.2), and phlegm (14.8%; OR=13.3; 95%CI=1.8-100.9). Cough and phlegm were found to be related to exposure to dust, cumulative dust and smoking habit, while chronic bronchitis was related to smoking habit. The few factory workers (19.5%) who used masks all the time had a lower prevalence rate of respiratory symptoms than those not using them. High dust level was the only variable that influenced the workers to use the mask all the time. It is recommended that control measures be adopted to reduce the dust and workers should be encouraged to use respiratory protection devices during their working time.

Gross occupational exposure to noise has been demonstrated to cause hearing loss and the authors believe that occupational hearing loss in Saudi Arabia is a widespread problem. Strategies of noise assessment and control are introduced which may help improve the work environment.

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ObjectivesLaboratory technicians, students, and instructors are at high risk, because they deal with chemicals including formaldehyde. Thus, this preliminary study was conducted to measure the concentration of formaldehyde in the laboratories of the University of Sharjah in UAE.Materials and Methods:Thirty-two air samples were collected and analyzed for formaldehyde using National Institute for Occupational Safety and Health (NIOSH) method 3500. In this method, formaldehyde reacts with chromotropic acid in the presence of sulfuric acid to form a colored solution. The absorbance of the colored solution is read in spectrophotometer at wavelength 580 nm and is proportional to the quantity of the formaldehyde in the solution.Results:For the anatomy laboratory and in the presence of the covered cadaver, the mean concentration of formaldehyde was found to be 0.100 ppm with a range of 0.095–0.105 ppm. Whereas for the other laboratories, the highest mean concentration of formaldehyde was 0.024 ppm in the general microbiology laboratory and the lowest mean concentration of formaldehyde was 0.001 ppm in the environmental health laboratory. The 8-hour (time-weighted average) concentration of formaldehyde was found to be ranging between 0.0003 ppm in environmental health laboratory and 0.026 ppm in the anatomy laboratory.Conclusions:The highest level of concentration of formaldehyde in the presence of the covered cadaver in anatomy laboratory exceeded the recommended ceiling standard established by USA-NIOSH which is 0.1 ppm, but below the ceiling standard established by American Conference of Governmental Industrial Hygienists which is 0.3 ppm. Thus, it is recommended that formaldehyde levels should be measured periodically specially during the dissection in the anatomy laboratory, and local exhaust ventilation system should be installed and personal protective equipment such as safety glass and gloves should be available and be used to prevent direct skin or eye contact.