evaluation of hearing loss and changes in blood pressure of welders in a 4 year period

improvements in science and technology and the use of modern machinery in manufacture have led to increase in the number of workers exposed to hazardous agents including noise. this study evaluated the effects of occupational noise on hearing loss and blood pressure in welders after 4 years.in this cohort study, all of the welders working at one of neyshabur's water heater producing factories were studied. a questionnaire including demographic data, history of diseases and certain drug use was completed for each worker. moreover the workers audiometry results and blood pressure measurements from 4 years ago were compared with recent results. data analysis was performed using spss18software.the average age of the welders was of 35.6 ± 6.25 and the mean years of employment was 7.66 ± 2.18 years. the equivalent noise exposure of workers on one business day was 97.8 db and varied between 90-110 db. after 4 years, there was a significant increase in hearing loss (6.04 db) in the right ear of workers at 8000 hz ( p =0.0001) and in the left ear at 1000 (1.77 db)( p =0.04), 4000 (2.29 db)( p =0.02)and 8000 hz (4.89 db)( p =0.0001). during this time blood pressure also increased but was not significant. there was no significant relation between age, years of employment, smoking and education with individual hearing loss during these four years. many neglected job groups such as welders are prone to hearing loss and possibly chronic increases in blood pressure due to noise exposure in their workplace and should use protective hearing equipment.