Hipoacusia sensorioneural por ruidos: resultados de un estudio longitudinal en trabajadores siderúrgicos / Neurosensorial hearing loss due to noise: results of a longitudinal study in siderurgical workers

ABSTRACT

One thousands two hundred thirty two workers exposed to low, moderate and high noise levels were studied. All had a normal admission audiogram and at least one further audiogram. Four hundred forty five subjects, aged 40.4+-8.2 years old, were exposed to low environmental noise, 341 subject aged 39+-7.8 years old were exposed to moderate noise and 446, aged 39.2+-7.3 years old were exposed to high noise for 16.7+-8.1, 14.8+-7.7 and 15.2+-7.6 years old respectively. The prevalence of hearing lost was 7.2, 11.7 and 13.2 per cent among those exposed to low, moderate or high environmental noise. According to our legislation 0.4, 1.5 and 2.5 per cent of those workers had a hearing impairment entitled to compensation. The regretion slope for hearing loss was 0.5, 0.7 and 0.8 dB/year of age in workers exposed to low, moderate and high noise levels respectively. A significant effect of noise was observed after the age of exposed to moderate levels. According to our safe noise exposure criteria, we are accepting that 18.2 per cent of workers will suffer a disabling hearing loss at the end of their job life and that 0.4 per cent will not attain an economic compensation in spite of their impairment