Iranian Journal of

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Background and Objectives: Noise-induced hearing loss is a prevalent work-related morbidity in the country. We determined the strength of association between hearing loss and occupational noise exposure as the first step in prevention programs.
Material and Methods: A historical cohort study involving 100 exposed and 31 non-exposed subjects was conducted. Noise exposure was estimated using sound level meter BSEN 60651, Type 2. Past noise exposure was estimated using the existing data on the place and type of work. Audiometry was used to assess hearing loss in each subject in 3- year intervals on an occupational cohort from 1993-2004.

Results: Noise-induced hearing loss was found in 49% (49 subjects) of the exposed group and 9.7 %( 3 subjects) of non-exposed group (p<.0001). Nobody used any form of hearing protection routinely in either group. Relative risk for noise-induced hearing loss was 5.1(CI95%: 1.7- 15.1).Time at risk was estimated 24.9 years (22.7-27.1) in exposed and 22.2 years (20.7-23.7) in unexposed group by survival analysis.
Conclusion: More legislation, hearing conservation programs, and surveillance and biological monitoring of work sites and workers are required to prevent occupational hearing loss. Planning strategies for noise assessment and control can help improve the work environment. Gross occupational exposure to noise has been demonstrated to cause hearing loss and the authors believe that occupational hearing loss in the country is a widespread problem.

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Background & Objectives: Cholera is always being considered as a public health threat in poor and developing countries. However outbreaks of cholera are not very common in central area of Iran in 2008 district health authority reported a cluster of diarrhea cases. We investigated this cluster to identify the etiological agent, source of transmission and propose control measures.
Methods: We analyzed the data of total of 1219 patients with colorectal cancer who registered between 1 January 2002 to 1 October 2007. Data were analyzed using univariate and multivariate Accelerated Failure Time (AFT) parametric survival model with frailty, utilizing STATA statistical software.
Results: In the univariate analysis for age at diagnosis, gender, marital status, race and education level, the survival of patients with colon cancer were approximately between half to one fourth and for BMI, alcohol history, Inflammatory Bowel Disease (IBD), familial history of cancer and the pathologic stage of tumor, the survival of patients with colon cancer were significantly (between 0.12 to 0.56 times) shorter than those patients with rectal cancer. In the multivariate analysis, for age at diagnosis (45-65 years), there was significant difference between colon and rectum cancer. But for BMI, alcohol history, IBD and pathologic stage there were not significant differences. The adjusted survival and 1, 2, 3, 4 and 5 year survival of patients with rectal cancer were better than those with colon cancer.
Conclusions: Site-specific evaluation of colon and rectum could give a better perspective of factors affecting these cancers. It may help to design of clinical trials, better diagnosis of diseases and optimal administration of specific treatments.

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Background and Objectives: This study assessed the validity and reliability of the Persian version of the standard "Problematic Internet Use" questionnaire to be used in epidemiological studies.
Methods: This cross-sectional study was performed in 2016. This questionnaire comprises five domains, including preference for online social interaction, mood regulation, cognitive preoccupation, compulsive Internet use, and negative outcomes. The questionnaire has 15 questions with a total score ranges from 15 to 105. A score of 15-45 indicates a normal state, a score of 46-65 shows a mild disorder, a score of 66-85 suggests a moderate disorder, and a score of 86-105 reveals a severe disorder.
Results: Three hundred and seven students (31.1%) had a normal score, 445 (45.1%) had a mild disorder, 191 (19.4%) had a moderate disorder, and 43 (4.4%) had a severe disorder. Based on CVR, 10 questions had a validity of 100%, 3 questions had a validity of 80%, 1 question had a validity of 40%, and 1 question had a validity of zero. The overall validity of the questionnaire was 85.3%. Based on alpha coefficient, the reliability of the domain of preference for online social interaction, mood regulation, cognitive preoccupation, compulsive Internet use, and negative outcomes was 87.6%, 91.1%, 89.8%, 90.8%, and 86.2%, respectively. The overall reliability of the questionnaire was 92.5%.
Conclusion: The validity and reliability of the questionnaire were high; thus, it can be used as a standard tool in epidemiological studies to explore the pathology of injuries related to the Internet and social networks.

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Background and Objectives: The aim of this study was to determine the predictability of the PLS-SEM model for injuries resulting in hospitalization in motorcyclists using a mediator variable in a case-control study.
 
Methods: In this case-control study, 300 cases and 156 controls were randomly selected from 150 clusters using random cluster sampling. The data were collected using the motorcycle riding behavior (MRB) questionnaire, adult attention deficit hyperactivity disorder (ADHD) questionnaire (subscales) and a checklist containing motorcycle related variables.
 
Results: The motorcycle riding behavior, adult ADHD, motorcycling related variables and some demographic variables were found to be the predictors of injury. There were significant positive relationships between injury and motorcycling related variables (B=0.20, P=0.001) and ADHD (B=0.33, P=0.001), between MRB and motorcycling related variables (B=0.51, P=0.001) and ADHD (B=0.52, P=0.001), and between ADHD and motorcycling related variables (B=0.39, P=0.001).
 
Conclusion: Considering the more accurate results of PLS-SEM, the intervention programs should especially address those who have hyperactive children, those who use the cellphone while riding, and those who ride in dark hours of the night.

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Background and Objectives: Progressive muscle relaxation (PMR) training as part of an educational program for patients involved in pathologic and physiological events (PPE) can have important physiological and psychological benefits for the patients, and can affect various dimensions of their lives including the quality of life. This systematic review and meta-analysis was conducted to determine the effect of PMR on the quality of life of patients involved in PPE.
 
Methods: Through searching the words “PMR” and “quality of life (QOL)” in Persian databases including SID, MagIran, IranMedex, and IranDoc and international databases including Google Scholar, Scopus, PubMed, Web of Science, ProQuest, and ScienceDirect, all studies published on the effect of PMR on the QOL were extracted. The methodological quality of the papers was examined using Cochrane risk of bias. Data analysis was carried out using a random-effects model and heterogeneity was assessed by I2. The data were analyzed using the STATA software version 14.0.
 
Results: Of 495 studies, only 10 explored the effect of PMR on the QOL of patients. The pooled mean of the QOL and all dimensions were statistically significant, including physical functioning (0.339), physical role limitation (0.378), bodily pain (0.341), general health (0.598), social functioning (0.873), mental health (0.736), emotional role limitation (0.791), vitality (0.706), total physical dimensions (0.652), total mental dimensions (1.316), and total QOF score (0.480). Only one study had a low risk of bias.
 
Conclusion: Implementation of PMR has a significant effect on the quality of life of patients involved in PPE. PMR is recommended to improve the QOL of the patients.