High-frequency (10-18 kHz) hearing thresholds: reliability, and effects of age and occupational noise exposure.

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.

Occupational noise exposure and hearing loss of workers in two plants in eastern Saudi Arabia.

OBJECTIVE: To determine the prevalence of hearing loss associated with occupational noise exposure and other risk factors. DESIGN: A cross-sectional study involving 269 exposed and 99 non-exposed subjects (non-industrial noise exposed subjects) randomly selected. Current noise exposure was estimated using both sound level meter and noise-dosimeter. Past noise exposure was estimated by interview questionnaire. Otoscopic examination and conventional frequency (0.25-8 kHz) audiometry were used to assess the hearing loss in each subject. RESULTS: 75% (202 subjects) from the exposed group were exposed to a daily Leq above the permissible level of 85 dB(A) and most (61%) of these did not and had never used any form of hearing protection. Hearing loss was found to be bilateral and symmetrical in both groups. Bivariate analysis showed a significant hearing loss in the exposed vs non-exposed subjects with a characteristic dip at 4 kHz. Thirty eight percent of exposed subjects had hearing impairment, which was an 8-fold higher rate than that found for non-exposed subjects. Multivariate analysis indicated exposure to noise was the primary, and age the secondary predictor of hearing loss. Odds of hearing impairment were lower for a small sub-group of exposed workers using hearing protection (N=19) in which logistic regression analysis showed the probability of workers adopting hearing protective devices increased with noise exposure, education, and awareness of noise control. Hearing loss was also greater amongst those who used headphones to listen to recorded cassettes. CONCLUSION: 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.

Pulmonary function of workers exposed to ammonia: a study in the Eastern Province of Saudi Arabia.

To determine the effect of chronic exposure to ammonia on pulmonary function among ammonia workers, 77 workers were randomly selected from an ammonia factory in the Eastern Province of Saudi Arabia and 355 were selected as controls from the administrative staffs of four industrial groups in Eastern Province. Spirometry was carried out and FEV1, FVC, and FEV1/FVC% were calculated. The ammonia level in the working environment was determined spectrophotometrically. 30% of the air samples had ammonia concentrations that exceeded the threshold limit value. Significant reductions in FEV1 % predicted and FVC % predicted were observed in ammonia workers exposed to higher cumulative ammonia levels (above 50 mg/m3-years). FEV1% predicted and FEV1/FVC% were significantly lower in symptomatic than in asymptomatic workers in the exposed group. These findings may raise the possibility that exposure to a high cumulative ammonia level produces a combined restrictive/obstructive ventilatory defect.

Consanguineous marriage in an urban area of Saudi Arabia: rates and adverse health effects on the offspring.

The objective of this cross-sectional study was to determine the pattern and time trend of consanguineous marriage and its adverse health effects on the offspring in Dammam city, Eastern Province, in the Kingdom of Saudi Arabia. This city is known to attract Saudis from different parts of the country because it is in the heart of this industrial region. Five primary health care centers were randomly selected from different sectors of the city in addition to the city's only Maternity and Children's Hospital. For inclusion in the study a wife must have at least one pregnancy that terminated in either full term liveborn baby, still birth, or abortion. A total of 1307 ever-married Saudis completed a pre-structured questionnaire during an interview. The rate of consanguineous marriage was 52.0% with an average inbreeding coefficient of 0.0312. First-cousin marriages were the commonest (39.3%) of all matings. The consanguineous groups had a significantly higher number of pregnancies. The mean birth weight of the offspring of consanguineous couples was not statistically significant being less than that of the non-consanguineous. However, within the consanguineous groups the more closely related couples had smaller babies on average. No significant differences were noted for the rates of inherited diseases and reproductive wastage. The rate of consanguineous marriage in this city was high and so was the inbreeding coefficient. These figures place this nation among the countries with a high rate of consanguineous marriages. A nationwide study to determine accurately the relationship between consanguinity and inherited diseases has much to commend it.

Bronchial asthma in two chemical fertilizer producing factories in eastern Saudi Arabia.

SETTING: Two urea fertilizer producing factories in Saudi Arabia. OBJECTIVE: To determine the prevalence of respiratory symptoms and diseases in employees exposed to ammonia gas. DESIGN: A cross-sectional study involving 161 exposed subjects and 355 controls. All completed a respiratory symptoms questionnaire, with additional questions on present and past occupations. Ammonia concentrations were measured in the different sections of the factories. RESULTS: The ammonia levels in factory B were well below the threshold limit value (TLV) (range 0.02-7.0 mg/m3 of air). In factory A the range was 2.0-130.4 mg/m3. The control and exposed groups were comparable with respect to their smoking habits. The exposed subjects in factory A had significantly higher relative risks (RR) for all respiratory symptoms; the same was true for haemoptysis (RR: 4.1, 95% confidence interval: 1.63-10.28). Bronchial asthma, chronic bronchitis, and a combined diagnosis were significantly higher among those exposed to high cumulative ammonia levels. However, in the logistic regression analysis ammonia concentration was significantly related to cough, phlegm, shortness of breath with wheezing and bronchial asthma. CONCLUSION: Exposure to ammonia gas in the workplace is significantly associated with increase in respiratory symptoms and bronchial asthma. Re-engineering measures to lower the levels of ammonia in factory A are strongly recommended. The affected employees should be removed from further exposure and followed up.

Post-shift changes in pulmonary function in a cement factory in eastern Saudi Arabia.

This cross-sectional study was conducted in 1992 in the oldest of three Portland cement producing factories in Eastern Saudi Arabia. The respirable dust level was in excess of the recommended ACGIH level in all sections. Spirometry was done for 149 cement workers and 348 controls, using a Vitalograph spirometer. FEV1, FVC, FEV1/FVC% and FEF25-75% were calculated and corrected to BTPS. A significantly higher post-shift reduction FEV1, FEV1/FVC% and FEF25-75% was observed in the exposed subjects. Multiple regression analysis showed a significant relationship between post-shift changes and exposure to cement dust but failed to support any relationship with smoking. These findings may indicate an increase in the bronchial muscle tone leading to some degree of bronchoconstriction as a result of an irritant effect induced by the acute exposure to cement dust.

Ocular trauma in an iron forging industry in the eastern province, Saudi Arabia.

Occupational accidents occur in industry worldwide, and the Kingdom of Saudi Arabia (KSA) is no exception. However, accidents are not routinely analyzed in this country and therefore their extent and types remain unknown. The aim of this study was to calculate the rates of ocular injuries in an iron forging factory in the Eastern Province of the KSA. It also aimed at identifying the main causes of injury and the groups at risk. All ocular and non-ocular injuries that occurred during 1991 were reviewed. Data sources were the company's accident report and the employees' medical files. A total of 193 injuries were reported. Seventy-seven (39.9%) of these affected the eyes. The incident rate for ocular injuries was 111.8 per 1,000 men exposed. The age group 33-42 had the highest prevalence rate (55.8%) and 67.5% of the eye injuries involved employees with job experience of 11 months or less. Use of pneumatic chisels was among the most hazardous activities. Projectile foreign bodies were responsible for 76.6% of the incidents. More than a third of the injured were not wearing eye protection. Avoidable factors, such as negligence, were major contributory factors. A training programme concerning safety has much to commend it, and pneumatic chisels should be replaced by other safer means.

International controversies in interpreting the mantoux test with special reference to saudi arabia.

There is a general decline in the incidence of pulmonary tuberculosis (PTB) in developed countries, but infection by HIV has increased the incidence of PTB in affected countries. There are no signs of a similar decline in the incidence of PTB in some developing countries. The Mantoux technique for tuberculin testing continues to be among the effective diagnostic tools. The medical literature and textbooks of medicine show disagreement as to what constitutes a positive (specific) tuberculin reaction. This short review was intended to cite some examples of these differences and suggest a cutting point for use in the Kingdom of Saudi Arabia (KSA) based on the prevalence of environmental mycobacteria (Mycobacteria other than M. tuberculosis, MOTT). From this review different researchers within the KSA used different cut-off points at a time that the prevalence of MOTT was unknown, until 1993 when it was reported to be as low as 3.8/1000 population (based on sputum culture) and that the Kingdom is categorised among the middle PTB prevalent countries. Consequently, it seems appropriate to have 5 mm as a cutting point (positive) in all unvaccinated patients, particularly for those who were in contact with an infectious case, or having symptoms compatible with PTB, and also patients who were immuno-compromised as in HIV infection. This cut-off point can be revised and raised to 8 mm provided that the prevalence of PTB becomes lower than the current reported rate and MOTT prevalence remains low, but the 5 mm cutting point should remain for the aforementioned categories of patients.

Home accidents in Al-Khobar city, eastern province, Saudi Arabia: a case-control socioeconomic study.

A one-month prospective case-control study was conducted in two sectors of Al-Khobar City (Saudi population of 65,070) with the objective of identifying the socioeconomic factors that are related to home accidents among Saudis. All accidents reported to 20 health facilities during the period were recorded and for the home accidents a questionnaire was completed at the Emergency Rooms (ERs) and the subjects were subsequently interviewed at their homes. Of the 1,104 Saudis who reported to the ERs of these health facilities 209 (18.9 percent) had home accidents. 206 were interviewed at home together with 448 families (controls) randomly drawn from the family folders at the primary health care centers in the two sectors. In the event 25 more home accidents were identified and the number of control families was accordingly reduced to 423 while the accidents increased to 231. The overall incidence rate was 355/100,000 Saudis per month, being lower (327.6/100,000) for the first sector (Al-Thougba) with a population of a relatively lower socioeconomic status than the second (Al-Khobar) sector (399.5/100,000). The number of home accidents was related to family size and was also larger in families living in villas and flats compared to single story and portable buildings. Families with home accidents had significantly more members than the controls. It is recommended that extensive community-oriented research be conducted to identify, evaluate, and subsequently control the environmental and human factors that contribute to the incidence and outcome of home accidents in Saudi Arabia.

Respiratory symptoms and occupational bronchitis in chromite ore miners, Sudan.

Prevalence of respiratory symptoms and chronic bronchitis was determined in a group of 122 subjects (77 exposed miners, 18 partially exposed, 27 controls) working at chromite ore mines in Sudan. The mean ages (+/- s.d.) of the three groups were 36.4 (+/- 7.8), 35.2 (+/- 6.8) and 34.6 (+/- 7.5) years respectively. Methods included a respiratory symptoms questionnaire based on the British Medical Research Council (MRC 1976) questionnaire on respiratory symptoms, determination of FEV1, FVC and FEV1/FVC%. The majority (66%) of the exposed subjects were non-smokers (NS) and 20 (77%) of the 'ever-smokers' (current and ex-smokers) were smokers of less than 15 cigarettes day-1. Respiratory symptoms (cough, phlegm, dyspnoea) were more frequent among the miners and so was chronic bronchitis. The prevalence of the latter was 26% among the miners compared to 11% and 7% among the partially exposed and the controls respectively. These differences could not be accounted for by cigarette smoking. Sixty-five per cent of the miners diagnosed as having asthma, chronic bronchitis or both were non-smokers. Although the values for the FEV1/FVC% remained normal or near the lower limits of the normal range, the mean value was significantly lower among the miners. It was concluded that the mine dust was the prime cause of the respiratory symptoms and chronic bronchitis among the miners.