Journal of School of Public Health and

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This study has been carried out in two shoe-making factories in Tehran with the aim ofevaluating the cobined effects of noise and toluene on the workers' hearing. Sixty four workers were assigned to three groups according to their exposure to noise andtoluene. 33 were exposed to noise (group 0), 5 to toluene (group 1) and 26 to noise andtoluene (group 2).The concentration were measured in the workers' breathing zone as well as A-weightedsound Pressure level, LPA and equivalent continuous A-weighted sound pressure levelover 30 minuets , leq (30") A in head position of workers. Then noise level was calculatedand hearing thresholds measured in 500 - 400 Hz frequencey range.The amounts of air and bone hearing los were caluculated. Results indicate that therelationship between hearing loss caused by noise (group 0) and noise and toluene (group2) was statistically significant, P<0.05. Hearing loss due to toluene in mid frequency washigher than in higher frequencies.

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Background and Aim: Logistic regression is an analytic tool widely used in medical and epidemiologic research. In many studies, we face data sets in which some of the data are not recorded. A simple way to deal with such "missing data" is to simply ignore the subjects with missing observations, and perform the analysis on cases for which complete data are available.
Materials and Methods: We consider methods for analyzing logistic regression models with complete data recorded for some covariates (Z) but missing data for other covariates (X). When data on X are Missing At Random (MAR), we present a likelihood approach for the observed data that allows the analysis as if the data were complete.
Results: By this approach, estimation of parameters is done using both Maximum Likelihood and Bayesian methods through the Markov Chain Monte Carlo numerical computation scheme and the results are compared. The illustrative example considered in this article involves data from lung auscultations as part of a Health Survey in Tehran.
Conclusion: In comparing different methods, Bayesian estimates using the model described in this study are much closer to those generated by analysis of the full data by the standard model.

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Background and Aim: Infectious complications after renal transplantation are associated with significant morbidity and mortality. We evaluated post-transplant complications due to infections and their relationship with graft function, immunosuppressive drugs and mortality.
Materials and Methods: Over a 2-year period (2002-2004), 179 renal transplantations were performed in our center. Of these, 142 cases were followed for a period of one year. The immunosuppressive regimen included cyclosporin A, mycophenolate mofetil and prednisolone. Each patient was assessed through regular visits and according to the ward protocol. Results of the investigations (infections and their relationship with age, sex, donor type, creatinine level, acute rejection, immunosuppressive drugs, graft and patient survival) were recorded and analyzed.
Results: The overall incidence of infection was 54%. The most common sites were lower urinary tract (42%) and respiratory tract (6%). The most frequent causes were Klebsiella (24%) and Cytomegalovirus (18%). Wound infection occurred in 5% of the patients. The overall mortality was 7.7%, and almost half of the death cases (3.5%) involved sepsis development. Graft loss occurred in 16 (11%) of the cases: 2 developed Cytomegalovirus infection, 2 experienced urinary tract infection (UTI) and 5 developed sepsis (and expired). Mycobacterial and hepatitis C infections were noticeably low compared to other studies. The hazard rate in occurrence of UTI, CMV, acute rejection and mortality were higher in cadaveric transplant recipients than in others.
Conclusion: This study identifies infections as a major cause of morbidity and mortality in the post-transplant period. Patients having higher creatinine levels and those receiving high doses of drugs at discharge are considered to be at high risk and should be evaluated thoroughly.

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Background and aim: The chromium mist generator is an essential tool for research and for making evidence-based recommendations in evaluating air pollution and its control systems. The purpose of this study was to design and construct a homogeneous chromium mist generator and to look at the effects of factors such as sampling height and distance between samplers in side-by-side sampling on the chromium mist sampling method.
Material and Methods: First we developed a mist generator, using a chromium electroplating bath in pilot scale. Concentrations of CrO3 and sulfuric acid in plating solution were 125 g L-1 and 1.25 g L-1, respectively. To set up permanent air sampling locations, a Plexiglas cylindrical chamber (75 cm height, 55 cm i.d) was installed as the bath overhead. Sixty holes were made on the chamber in 3 rows (20 in each row). The distance between rows and holes was 15 and 7.5 cm, respectively. Homogeneity and the related factors were studied using a side-by-side air sampling method. Forty-eight clusters of samples were collected on polyvinyl chloride (PVC) filters contained in sampling closed-face cassettes. Cassettes were located 35, 50, and 65 cm above the solution surface with < 7.5 and/or 7.5-15 cm distance between heads. All samples were analyzed by the NIOSH method 7600.
Results: ANOVA tests showed no significant differences between locations in side-by-side sampling (P=0.82) or between different sampling heights or sampler distances (P=0.86 and 0.86, respectively). However, there were notable differences between means of coefficients of variation (CV) in various heights and distances.
Conclusion: We conclude that the most chromium mist homogeneity could be obtained at a height of 50 cm from the bath solution surface and with a distance of < 7.5 cm between samplers.

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Background and Aim: Hexavalent chromium (Cr⁶⁺) is a known occupational carcinogen. Over the recent years, the increasing number of exposed workers and the emergence of serious health effects have led to considerable lowering of permissible exposure levels for Cr⁶⁺. Moreover, a number of methods have been developed for rapid and precise measurement of Cr⁶⁺concentrations. Given the importance of accurate measurements, this study was carried out to compare the performance of different samplers in relation to factors such as sampling height, sampling duration, and electroplating solution concentration.

Material and Methods: We used a hexavalent chromium generator fitted with a special sampling chamber and with proven ability to produce homogenous atmospheric concentrations. The performances of 4 samplers including IOM and CIS (as inhalable particle samplers) and Open and Closed-face cassettes (as total particle samplers) were examined through a simultaneous sampling technique. Sampling was done using the NIOSH 7600 method (samples were collected on PVC membrane filters with a pore size of 5.0 µm, at an air flow rate of 2.0 ± 0.1 l/min). Variables investigated with regard to their effects on sampler performance were sampling height (heights from bath solution: 35 and 50 cm), duration (30 and 180 min) and solution concentration (125 and 250 g/l).

Results: The measured concentrations ranged from 2 to 2725 µg.m^-3. Analysis of the results in a completely randomized block design showed significant differences in performance between different samplers (P< 0.001). There were also differences between samplers at different heights and electroplating concentrations (P=0.0007). Multiple comparisons by Scheffe's method showed that the difference detected was due to the superior precision of the IOM (P<0.05).

Conclusion: Overally, there were statistically significant differences between the performances of the studied samplers Cr⁶⁺ concentrations at the studied heights (4.09, 8.68 µg.m^-3), sampling duration (5.90, 6.88 µg.m^-3), and bath concentration (2.73, 11.88 µg.m^-3) had no significant effects on sampler performance. The CIS sampler underwent corrosion during acidic mist collection and thus can not be recommended for Cr⁶⁺ mist collection.

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Background and Aim: Environmental health impact assessment of industrial estates will help greatly in better planning for sustainable development and reducing disease risk in a community. The objective of this study was to assess the positive and negative effects of establishing an industrial estate in Jovein, Sabzevar, Iran in 2006-7 and suggest managerial strategies to reduce undesirable environmental health impacts.

Methods and Materials: A modified Leopold Matrix and Scaling checklist method was used. The existing environmental situation was investigated and then environmental impact assessment alternatives were determined, bearing in mind the amounts and kinds of predicted pollutants in the construction and operational phases . The assessment was made considering the immediate, direct, and indirect impacts in the short and long terms. It was attempted to use a wide range of values of different factors (-5, +5) in order to estimate the impact of all activities on the environmental status.

Results: The results of the study are presented with two alternatives, i.e., "No" (conducting the project with no concern for environmental issues), and "Yes" (performance of the project with application of methods to reduce the environmental harmful impacts), when establishing the industrial estate, in the construction and operation phases. The impact assessment with the "No" alternative scored -791, meaning that execution of the project had to be rejected. However, after reducing the harmful impacts the score rose to +252, indicating that the project would be accepted.

Conclusion: The method of reducing harmful environmental impacts along with environmental management programs introduced are accepted in this study. It is recommended that the Ministry of Health and Medical Education and The Iranian Environmental Protection Agency collaborate closely in the area of environmental health impact assessment of industries and industrial estates.

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Background and Aim: The aims of this study was to explore the feasibility of improving efficiency of the wastewater treatment system of the Fars Pegah Dairy Industries (FPDI) and propose ways to upgrade it in 2006-2007. The FPDI wastewater treatment system was of a successive anaerobic-aerobic type using anaerobic stabilization ponds and conventional and extended aeration activated sludge. Due to improper design and operation, it did not meet the required standards with regard to disposal to the surrounding cultivated land.
Materials and Methods: To overcome the problem and eliminate the bad smell, modifications were made, such as changing the entries and exits of the ponds, adjustment of the activated sludge process, and converting the conventional activated sludge F/M to a step-feed activated sludge shift. The efficiency of the system was assessed before and after these modifications
Results: The efficiency of the system to eliminate biochemical oxygen demand (BOD5), chemical oxygen demand (COD), total dissolved solids (TDS), total suspended solids (TSS), total coliform, and fecal coliform increased from 82.42%, 86.87%, 64.18%, 20.23%, 54.56% and 50.87% to 97.34%, 98.61%, 90.4%, 28.44%, 90.09% and 89.95%, respectively.
Conclusion: The findings show improvements in the efficiency of the wastewater treatment system due to the changes made in it. It was also observed that efficiencies of the feed-step aeration and the extended aeration are similar. This means that application of the extended aeration in the treatment system of the plant would result in waste of money and energy.

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Background and Aim: This paper reports on the predictors of high school students' oral health behaviors (OHBs) based on the Pender's Health Promotion Model (HPM) in an attempt to identify effective factors that may be addressed through intervention efforts.

Materials and Methods: A multistage cluster sample of 403 high school students were recruited from 8 high schools in Marivan County, Iran. The study was conducted between April and July, 2010. Appropriate instruments were used to measure the relevant variables. The statistical analysis of the data included bivariate correlations, t-test, one-way ANOVA and linear regression.

Results: All HPM variables (perceived self-efficacy, perceived benefits and barriers, activity-related affects, interpersonal and situational influences and commitment to a plan of OHBs) were significantly related to OHBs among the respondents (p < 0.01), and a negative association was found between OHBs and perceived barriers (p < 0.01). All HPM variables were statistically significant predictors of OHBs and accounted for 42.2% of the variance.

Conclusion: Promotion of interpersonal influences and the students' perceived self-efficacy and also commitment to a plan of action should be priorities of any program aimed at promoting OHBs among students. School health care providers should suggest strategies to overcome the barriers of performing OHBs, rather than noting the benefits of these behaviors.

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Background and Aim: The most important single determinant of the quality of life of the elderly is health. Studies have shown that health declines with age. Because of high vulnerablity of the elderly due to many problems, they need particular attention and self-care programs for their health promotion. The objective of this study was to assess the quality of life of elderly clients under coverage of the Southern Tehran Health Center and determine the effects of a self-care program on it.

Materials and Methods: This was a controlled interventional study conducted in 2010-2011. A total of 132 elderly clients (52 in the intervention, and 80 in the control, group) were selected by randomised cluster sampling from 5 Health Care Centers in Southern Tehran. A 3-month educational program was prepared with contents based on books published by the Ministry of Health and Medical Education and implemented. The quality of life was assessed in both groups at the beginning and 2 months after the intervention using a short questionnaire (sf36). Data were collected through a structured interview (demographic characterstics) and analyzed using descriptive and analytical statistical tests.

Results: The mean quality-of-life score of the experimental group increased after education the mean score of physical domain of the quality of life increased from 52.75 in 66.11 and that of the emotional domain from 53.61 to 70.85. The scores of different domains of quality of life of the control subjects did not change significantly.

Conclusion: The findings show that a self-care educational program can have a positive affect on quality of life of the elderly.

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Background and Aim: This study aimed to investigate the association of Internet addiction and self-control with mental health among students of the University of Applied Sciences and Technology (UAST) in Ilam city, Iran.

Materials and Methods: Data collection tools included the Mental Health Goldenberg scale, Tanji Self-control Inventory and Young Internet Addiction questionnaires. The sample consisted of 101 UAST students in Ilam City, Iran.

Results: Analysis of the data showed a statistically significant negative relationship between internet addiction and mental health and a positive association between self-control and mental health in male- and female-students.

Conclusion: It can be concluded that he more a student uses the Internet, the more likely he/she is to be less healthy mentally, while if a student has more self-control, he/she is more likely to be healthier mentally.The use of the Internet among the new generation in the society is spreading, becoming an important part of life. It has been said that teenagers are at a high risk. Hence the responsible authorities should consider mental health as a factor preventing extreme behavior of young people.

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Background and Aim: The incidence of breast cancer in women is expected to rise sharply over the coming decades in Iran. The aim of this study was to determine risk factors for breast cancer in under-50-year-old women during the period 2013-2015 in Kermanshah, Iran.

Materials and Methods: This case-control study was carried out in Imam Reza Hospital and private clinics of oncologists (three clinics) in Kermanshah, Iran. The participants were 202 patients with breast cancer and 398 without breast cancer. Subjects of the experiment group were selected from among patients in the Departments of Oncology, Radiation Therapy, and Chemotherapy of the hospital, while the control group subjects were selected from among outpatients referred to specialty and subspecialty departments and private clinics of the hospital (outpatient, oncology, gynecology, ophthalmology, sonography, ENT, infertility). The two groups were matched for age. Data were collected by interviewing the subjects, the Gill standard questionnaire and the patients’ files and analyzed using the STATA software (version 12) ─ Odds Ratio (OR), 95% Confidence Interval (CI) and the Conditional logistic regression model.

Result: The following variables were found to be the most important risk factors for breast cancer among under-50-Year-old women: a family history of breast cancer in second degree relatives, an age of 18-35 years at the first childbirth, and a history of a benign breast lump.  

Conclusion: It is recommended to conduct further studies on the subject with due consideration of other risk factors for breast cancer, as well as education of women about breast self-examination  and importance of periodic clinical examinations.

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Background and Aim: Despite the increasing prevalence of infection with some blood-borne viruses, no standard precautions have been developed so far based on the Health Belief Model (HBM). This study aimed to assess, based on the HBM, the predictors of adherence to standard precautions in preventing needle stick injuries among the Personnel of Sanandaj Teaching Hospitals, Sanandaj City, Iran in 2020.
Materials and Methods: This cross-sectional study included 444 medical and non-medical staff members of the Sanandaj teaching hospitals in Sanandaj City, Iran, using a researcher-developed questionnaire. Descriptive and analytical data analysis was performed using Mann-Whitney U and Kruskal-Wallis tests, Pearson correlation coefficient, one-way analysis of variance, multivariate regression and the chi-square test, the software being SPSS version 22.
Results: The results of multivariate regression analysis showed that from among the HBM constructs, three constructs, namely perceived sensitivity (p=0.033), perceived benefits (p=0.032) and self-efficacy (p=0.001), were the predictors of staff duty performance (implementation of  standard precautions) in preventing needle stick injuries. As regards the implementation of standard precautions, 22%, 75.3% and 2.7% of the staff members had a low, medium and high performance level, respectively.
Conclusion: The constructs of perceived sensitivity, perceived benefits and self-efficacy are the strongest predictors in adherence to standard precautions.

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Background and Aim: Family female heads are one of the most vulnerable groups in the society and empowering them is essential. This research was a systematic study to design and develop a model of educational needs of female heads in the female-headed households.
Materials and Methods: This study was a qualitative applied research of a research synthetic type conducted using content-analysis and meta-analysis. The statistical population included all the relevant works published in Persian or English between 2012 and 2021 available in four reliable databases, namely, ERIC, Science Direct, PubMed and Google Scholar. Using the keywords "education of women-headed households, women's empowerment, women-headed households, and skills of women-headed households" and based on the inclusion criteria, initially 140 scientific articles were identified and finally, based on the exclusion criteria, 47 articles were selected for the final analysis. The Software MAXQDA 18 was used for the qualitative analysis of the articles.
Results: Analysis of the data obtained showed the educational needs of women-headed households as the main theme to consist of four subthemes including "knowledge and skills of desirable sexual orientation", "knowledge and skills of raising children", "knowledge and skills of occupation" and "individual and social development and empowerment”. Based on meta-analysis out of the four main themes 22 themes were extracted and a model was designed for educating female-headed households.  
Conclusion: Considering that the educational needs of female-headed households have been identified, it is recommended that educational courses be designed in accordance with their educational needs.