Occupational noise as a cardiovascular risk factor.

The results from routine medical screening of 806 workers in a very wide range of different occupational activities were analysed in order to assess the relationship between blood pressure and occupational exposure to noise. Blood pressure was measured for each worker by conventional methods. Noise exposure was estimated according to the main company activity and each worker's specific job, computing three categories of noise exposure: low, medium and high. Preliminary analysis of the data did not reveal any relationship between noise exposure and blood pressure. Nevertheless, when comparing two groups of workers with noise induced hearing loss (NIHL) at 4000 Hz higher and lower than 65 dB, the group with the highest NIHL also shows the highest mean blood pressure value and the highest proportion of hypertensive workers (however, these results are statistically not significant). The limitations and problems posed by the methods used to assess the effects of occupational noise exposure as a cardiovascular risk factor are discussed.