Effects of environmental and organizational factors on the health of shiftworkers of a printing company.

This study explored the effects of environmental and organizational stressors on the health of shiftworkers in a printing company (n = 124). A questionnaire was used to gather data on work history, organizational factors, psychosocial characteristics, medical history, present health, occupational and non-occupational exposures, and lifestyle factors. The perception of environmental and organizational conditions was associated (P < 0.05) with chronic back pain (odds ratio [OR], 1.29), varicose veins (OR, 1.35), allergic rhinitis (OR, 1.27), depression (OR, 1.45), and gastritis (OR, 1.15). Anxiety scores were associated with allergic rhinitis (OR, 1.14) and skin allergy (OR, 1.09). Shiftwork was a significantly risk factor for conjunctivitis (OR, 3.68), depression (OR, 0.23), cardiac arrhythmia (OR, 7.13), and gastritis (OR, 4.38). Other associations included tenure and chronic back pain (OR, 4.89), toluene exposure and skin allergy (OR, 3.76), worksite and conjunctivitis (OR, 7.0), and worksite and dermatitis (OR, 1.24 to 4.95). The number of hours of exercise per week was associated with varicose veins (OR, 4.33), and alcohol intake was associated with cardiac arrhythmia (OR, 6.74).

Assessing occupational hearing loss: beyond noise exposures.

In recent years, findings that exposure to industrial chemicals may affect hearing and interact with noise brought to light a risk that had not been given substantial attention previously. The need for research becomes clear when the magnitude of the population of workers exposed to noise and chemicals and the number of potentially hazardous chemicals found in work environments are taken into consideration. The need for research is this area is further heightened by the fact that there are no guidelines or standards for combined exposures of chemical and physical agents. The present paper reviews the effects of combined exposures to chemicals and noise on hearing and examines study designs, hearing assessment alternatives, and strategies for the analysis of combined effects.

Toluene-induced hearing loss among rotogravure printing workers.

OBJECTIVES: This study explored the effects of occupational exposure to solvents and noise on the hearing of rotogravure printing workers from São Paulo, Brazil. METHODS: The study group comprised 124 workers exposed to various levels of noise and an organic solvent mixture of toluene, ethyl acetate, and ethanol. Data on work history, psychosocial aspects of the job, medical history, present health, stress, occupational and nonoccupational exposures to noise or chemicals, and life-style factors were collected through an interview. The participants underwent pure-tone audiometry and immittance audiometry testing. Their exposures to noise and solvents were assessed. RESULTS: Forty-nine percent of the workers had hearing loss. From the numerous variables that were analyzed for their contribution to the development of hearing loss (age, tenure, noise dose, solvent concentrations in air, biological marker for toluene, job category, work and medical history items, smoking, alcohol consumption, work perception scores, nonoccupational exposures), age and hippuric acid (the biologic marker for toluene in urine) were the only variables that met the significance level criterion in the final multiple logistic regression model. The odds ratio estimates for hearing loss were 1.07 times greater for each increment of 1 year of age [95% confidence interval (95% CI) 1.03-1.11] and 1.76 times greater for each gram of hippuric acid per gram of creatinine (95% CI 1.00-2.98). CONCLUSIONS: The findings suggest that exposure to toluene has a toxic effect on the auditory system. Further research is needed on the mechanisms underlying the effects of toluene and on the adequacy of current recommended exposure limits.

Hearing loss from combined exposures among petroleum refinery workers.

Workers from a refinery (n = 438) were interviewed, had their hearing tested and had their exposures to noise and solvents assessed. Measurements suggested that most exposures to noise and solvents were within exposure limits recommended by international agencies; however, the prevalence for hearing loss within the exposed groups ranged from 42 to 50%, significantly exceeding the 15-30% prevalence observed for unexposed groups. The adjusted odds ratio estimates for hearing loss were 2.4 times greater for groups from aromatics and paraffins (95% CI 1.0-5.7), 3 times greater for the maintenance group (95% CI 1.3-6.9) and 1.8 times greater for the group from shipping (95% CI 0.6-4.9), when compared to unexposed workers from the warehouse and health clinic. The results of acoustic reflex decay tests suggest a retrocochlear or central auditory pathway involvement in the losses observed in certain job categories. These findings indicate that factors in addition to noise ought to be considered when investigating and preventing occupational hearing loss.

Auditory and vestibular functions after single or combined exposure to toluene: a review.

Toluene is a widely used organic solvent, heavily employed in many manufacturing industries. Recently, evidence has begun to accumulate on the deleterious effect of toluene exposure has on the auditory and vestibular systems. Although little published information exists regarding these effects, the reported findings indicate a need for further investigation. The results of such investigations may dramatically affect occupational hearing conservation practices and legislation. Both human and animal studies will be summarized in discussing the effects of toluene alone or in combination with noise or other chemicals. Gaps in scientific knowledge are highlighted to assist future research.

Occupational exposure to noise and ototoxic organic solvents.

The objectives of this study were to review the literature on the effects of occupational exposure to organic solvents on the auditory system and to identify work settings in which exposure to these agents and to noise might occur. The criteria for selecting the chemicals were (a) evidence available that indicated that the chemicals may affect the auditory system and enhance noise effects, and (b) the ubiquity of their use. References to ototoxicity were noted for three proven neurotoxicants, i.e., carbon disulfide, toluene, and trichloroethylene, and for two probable human neurotoxicants--styrene and xylene. The percentages of workers (estimated by NIOSH National Occupational Exposure Survey) exposed to these solvents in each economic sector are shown. Work settings are identified where multiple exposures occur to solvents and noise. The need for future research is discussed.

Effects of occupational exposure to organic solvents and noise on hearing.

This study explored the effects of occupational exposure to solvents and noise on hearing. Interviews and hearing tests were conducted for printing and paint manufacturing workers. The experimental groups included unexposed (N = 50) workers and workers exposed to noise (N = 50), noise and toluene (N = 51), or an organic solvent mixture (N = 39). The risk of hearing loss was greater for the exposed groups than for the unexposed group. The adjusted relative risk estimates were four times greater [95% confidence interval (95% CI) 1.4-12.2] for the noise group, 11 times greater (95% CI 4.1-28.9) for the noise and toluene group, and five times greater (95% CI 1.4-17.5) for the solvent-mixture group. The findings suggest that exposure to the studied solvents had a toxic effect on the auditory system and that an interaction between noise and toluene took place. The audiological results of the noise and toluene group suggest a central auditory pathway involvement in the hearing losses observed.

Study of the effects of simultaneous exposure to noise and carbon disulfide on workers' hearing.

The aim of this study was to explore the effects of simultaneous exposure to noise and carbon disulfide on workers' hearing and balance. The study was conducted by interviews and by audiometric and balance tests on workers in a rayon factory in the city of São Paulo, Brazil (n = 258). The workers studied had a history of exposure both to excessive noise levels (86-89 dBA) and to excessive levels of carbon disulfide (89.92 mg/m3). The percentage of hearing loss found was much higher than expected for this occupational activity, which reinforced the possible connection between the exposure to noise and carbon disulfide.