A multicenter study on the audiometric findings of styrene-exposed workers

Abstract

Abstract

Objective: The objective of this study was to evaluate hearing loss among workers exposed to styrene, alone or with noise. Design: This cross-sectional study was conducted as part of NoiseChem, a European Commission 5th Framework Programme research project, by occupational health institutes in Finland, Sweden, and Poland. Study sample: Participants’ ages ranged from 18–72 years (n = 1620 workers). Participants exposed to styrene, alone or with noise, were from reinforced fiberglass products manufacturing plants (n = 862). Comparison groups were comprised of workers noise-exposed (n = 400) or controls (n = 358). Current styrene exposures ranged from 0 to 309 mg/m³, while mean current noise levels ranged from 70–84 dB(A). Hearing thresholds of styrene-exposed participants were compared with Annexes A and B from . Results: The audiometric thresholds of styrene exposed workers were significantly poorer than those in published standards. Age, gender, and styrene exposure met the significance level criterion in the multiple logistic regression for the binary outcome ‘hearing loss’ (P = 0.0000). Exposure to noise (<85 dBA p = 0.0001; ≥85 dB(A) p = 0.0192) interacted significantly with styrene exposure. Conclusions: Occupational exposure to styrene is a risk factor for hearing loss, and styrene-exposed workers should be included in hearing loss prevention programs.

Sumario

Objetivo: El objetivo de este estudio fue evaluar la pérdida auditiva en trabajadores expuestos a estireno, aisladamente o con ruido. Diseño: Se realizó este estudio transversal como parte del NoiseChem, Comisión Europea del 5°. Proyecto Marco de investigación, en institutos de salud ocupacional de Finlandia, Suecia y Polonia. Muestra de estudio: La edad de los participantes fue de 18–72 a os (N = 1,620 trabajadores). Los trabajadores (n = 862) estuvieron expuestos a estireno, solo o con ruido, en plantas de fabricación de productos de fibra de vidrio reforzada. Los grupos de comparación fueron trabajadores expuestos a ruido (n = 400) y los de un grupo control (n = 358). Las exposiciones reales a estireno variaron de 0 a 309 mg/m3, mientras que los niveles reales de ruido, variaron de 80–84 dB(A). Se compararon los niveles de audición de los participantes expuestos a estireno con los de los anexos A y B de . Resultados: Los umbrales audiométricos de los trabajadores expuestos a estireno, fueron significativamente más pobres que los que se han publicado como estándar. La edad, el género y la exposición a estireno, cubrieron los criterios de niveles de significatividad de la regresíón logística múltiple para los resultados binarios de la “perdida auditiva” (P = 0.0000). La exposición a ruido (<85 dB(A) p = 0.0001; ≥85 dB(A) p = 0.0192) interactu significativamente con la exposición a estireno. Conclusiones: La exposición ocupacional a estireno es un factor de riesgo de pérdida auditiva por lo que los trabajadores expuestos a estireno deben ser incluidos en programas de prevención de pérdidas auditivas.

Key Words::

• Pure-tone audiometry
• Otologically unscreened
• Noise
• Hearing loss

Acknowledgements

This paper is dedicated to the memory of Dr. Derek E. Dunn. Ms. Susan Afanuh, Drs. Rickie Davis and Sang Woo Tak from the US National Institute for Occupational Safety and Health, and Dr. Søren Peter Lund from the National Research Centre on the Working Environment, Denmark, provided helpful critiques of the manuscript. The authors wish to thank those who agreed to participate in the study for their time, interest, and cooperation. The study was supported by grants from EU Research project NoiseChem, Contract number QLK4-CT-2000-00293, from the Swedish Council for Working Life and Social Research, Contract number 2006-1526 and from the US National Institute for Occupational Safety and Health, Contract number 0009736801.

Declaration of interest: The authors report no conflicts of interest.

Disclaimer: The findings and conclusions in this report are those of the author(s) and do not necessarily represent the views of the U.S. National Institute for Occupational Safety and Health or the European Commission.