Effect of exposure to low levels of organic solvent mixtures On color vision

Color vision deficiency has a relatively high prevalence in working population and cause difficulties in everyday tasks. Occupational exposure to various neurotoxic chemicals has been shown to be associated with acquired color vision impairment. This study was undertaken to determine the effect of occupational exposure to mixed organic solvents at low levels on color perception. A cross sectional study was conducted in an automobile plant. Workers employed in painting saloon, were considered as cases and workers employed in assembly saloon were considered as controls, as well. We administered a questionnaire, containing age, years of employment, histories of congenital color vision impairment or eye injuries, alcohol consumption and for workers. After considering exclusion criteria, Color vision of 121 case workers compared with 157 controls. The LD-15 test showed that 31.4% of case group had an acquired color vision defect .Most defects were of the blue-yellow type in the case group. Also the prevalence of acquired color vision defect was 3.8% in the control group. The prevalence of acquired color vision defect of exposed employees were statistically significantly higher than those of the control subjects [OR = 11.52, CI = 4.67- 28.38] [P<0.001]. Besides mean of the color-confusion index [CCI] derived from the LD-15 test for exposed employees were statistically significantly higher than those of the control subjects [1.14 and 1.03 respectively and P<0.001].The logistic regression for color confusion index [CCI] showed that it was positively related to exposure to mixed organic solvents [P<0.001]. The results of this study suggest that, chronic occupational exposure to mixed organic solvents even at lower concentrations than permissible levels can cause acquired color vision impairment. Also acquired color vision impairment seems to be a sensitive indicator which can detect solvent-induced neurotoxicity in car painters. Finally we propose that the color confusion index [CCI] may be used as an appropriate indicator of early neurotoxic effects in workers exposed to low concentrations of mixture of organic solvents

Sleepiness among Iranian lorry drivers

Excessive daytime sleepiness [EDS] denotes a propensity to doze off or fall asleep unintentionally during the day, particularly in passive situations. There is cumulative evidence pointing to an association between sleepiness and probability of involvement in motor vehicle crashes. This study was designed to determine the prevalence of sleepiness in a group of Iranian lorry drivers and its association with accidents. A cross-sectional study was carried out in lorry drivers of Tehran goods transportation terminal in 2005. This study used a questionnaire and the Epworth Sleepiness Scale [ESS]. The questionnaire included questions regarding demographic features, professional data, sleep habits and excessive daytime sleepiness. A total of 386 male drivers, aged 43.23 +/- 9.72 years were included in the study. ESS was higher than 10 points in 9.1% of the interviewees; 50.8% never have driven drowsy, although 36% rarely, 7.3% half of the times, 4.9% almost always and 1% always have driven drowsy. Eogistic regression analysis indicated that EDS, age and job satisfaction were associated with an increased risk of accidents. Sleepiness is a prevailing symptom in lorry drivers and is probably related to accidents