The Effects of Noise and Heat Strain on the Work Ability Index (WAI) among Rubber Factory Workers.

INTRODUCTION: Assessing the work ability and factors affecting it is essential in developing strategies for preventing damages and managing risks. This study aimed to investigate the simultaneous effect of noise level and physiological strain as well as individual characteristics on the work ability. METHOD: The population in this cross-sectional study included workers of a rubber factory. The TES noise dosimeter was used to examine individual exposure and the electro polar RS100 was used to measure physiological strain index (PSI). Individual characteristics and the work ability index were evaluated using the WAI questionnaire and analyzed using SPSS version 19. chi-square test, pearson correlation coefficient, and one-way and multiple ANOVA were used for data analysis. RESULTS: The final modeling showed that age, exercising period, Equivalent Continuous Sound Pressure Level (Leq), PSI and employment status had significant correlations with the work ability index (p < 0.05). The modified r2 for the obtained model was also calculated to be 0.483. DISCUSSION AND CONCLUSION: Based on the findings, number of exercising hours, employment status, age, Leq, and psi are among the factors affecting the work ability index. Use of management and engineering controls are recommended to balance work environments exposed to noise and heat and improve the work ability index. Further, improving employment status due to creating a sense of stability and reducing stress as well as enhancing lifestyle quality can be effective in increasing the work ability index.

The effect of biological rhythms and personality traits on the incidence of unsafe behaviors among bus drivers in Shiraz, Iran.

BACKGROUND: Unsafe behaviors are main causes of accidents mostly influenced by personal characteristics, social environment and also individual biorhythm cycles. This study was carried out to find out whether personality traits and biorhythm could affect the incidence of unsafe behaviors among city bus drivers. METHODS: This cross-sectional study was conducted on 224 bus drivers in Shiraz, Iran, 2014. The data were collected using NEO personality traits questionnaire. Also, a self-constructed checklist was used to investigate the drivers' unsafe behaviors. Information on drivers' biorhythm was analyzed by Natural Biorhythm software version 3.2. The relationship between demographic characteristics, personality traits and biorhythm were examined by T-Test, One-way ANOVA, correlation coefficient and Chi square tests. Multiple linear regression analysis was used to investigate the factors influencing the incidence of unsafe behaviors. RESULTS: 28.6% of participants have experienced critical days in their biorhythm cycles. Also the mean percentage of unsafe behavior was 54.08 ± 11.91 among the subjects of the study.Significantly negative correlations were observed between each personality factor and the percentage of unsafe behaviors. Also, there was a significant relationship between percentage of derivers' unsafe behaviors and the general cycle of biorhythm (having at least one critical day in each of the cycles). CONCLUSIONS: Taking the measures including selection of low-risk traffic routes in the critical days and considering the personality traits at the time of employment could be effective in reducing the unsafe behaviors and accidents.