Noise-induced Hearing Loss: Continuous versus Impact/impulse Noise.

Background: Impact/impulse and continuous noise are two main causes of noise-induced hearing loss (NIHL) in workplaces. The aim of this study was to compare the effects of impulse/impact noise and continuous noise on hearing status. Methods: In this study, 259 workers referred to the occupational medicine clinic of Shahid Rahnemoun hospital, Yazd, Iran, entered the study and were divided into two groups: with exposure to impact/impulse noise and with exposure to continuous noise. Hearing thresholds were measured and compared between the two groups by pure-tone audiometry (PTA). The frequency of hearing loss and audiometric notch according to the results of PTA was compared between the two groups. Data were analyzed by SPSS (ver. 16) using Student's t-test, Chi-square test, and Mann-Whitney U test. Results: Hearing thresholds were significantly higher at all frequencies in the impact noise group. The hearing threshold at 6000 Hz was higher than other frequencies in both groups. The frequency of hearing loss at high frequencies was higher in the impact group. The frequency of audiometric notch was not significantly different between the two groups. Conclusions: The results of this study showed that hearing loss after exposure to impact/impulse noise is probably more frequent and more severe than exposure to continuous noise, but the pattern of hearing loss is similar in both types of noise exposure.

Spirometric Parameters in Waterpipe Smokers, Cigarette Smokers, and Non-smokers of Shahedieh Cohort Study.

Background: Different kinds of smoking tobacco may affect pulmonary function and reduce some spirometric parameters. This study aimed to assess the relationship between smoking cigarettes and waterpipe and spirometric parameters. Methods: This was a cross-sectional study on 1543 middle-aged individuals, as a sub-study of the Shahedieh cohort study in Yazd. The participants were randomly selected from the Shahedieh cohort population and were divided into 6 groups according to their smoking habits: non-smokers (n=455), cigarette smokers (n=139), waterpipe smokers (n=287), ex-cigarette smokers (n=131), concurrent waterpipe and cigarette smokers (n=121), and cigarette or waterpipe passive smokers (n=410). Spirometry was performed on all participants and spirometric parameters were compared between different groups. The data were analyzed by SPSS (version 20) using Kolmogorov-Smirnov, Kruskal-Wallis, and Mann-Whitney U tests. Findings: FEV1 %, FEV1/FVC, and PEF25-75% were significantly lower in cigarette smokers, compared to waterpipe smokers and non-smokers. The measures were not significantly lower in waterpipe smokers in comparison to non-smokers. The frequency of obstructive pattern and small airway diseases was significantly higher in cigarette smokers compared to waterpipe smokers and non-smokers. Conclusion: The results of this study showed that in the middle-aged population, spirometric parameters related to airway obstruction (FEV1, FEV1/FVC, and FEF25-75%) were significantly lower in cigarette smokers than in non-smokers and waterpipe smokers, but these parameters were not significantly different between waterpipe smokers and non-smokers.

Association between different patterns of shift work and liver function tests: A cross-sectional analysis of Shahedieh PERSIAN cohort data, Iran, 2020.

BACKGROUND: Recent studies suggest that shift work may cause liver dysfunction. OBJECTIVE: This study aimed to examine the relationship between different patterns of shift work and elevated level of liver enzymes. METHODS: In this cross-sectional study, 1910 workers aged 35 to 70 years were selected with simple random sampling from 9978 participants of the recruitment phase of Shahedieh PERSIAN cohort study. Level of serum liver enzymes (ALT, AST, ALP, and GGT) and ALT/AST ratio was compared between shift workers and non-shift workers, and among employees working in different patterns of shift work. Data were analyzed by SPSS (version 21.0) using Student's T test, Mann-Whitney U test, chi-square test, Kruskal Wallis test, and logistic regression. RESULTS: Among 1347 males (71%) and 563 females (29%) with a mean age of 40.4±7.4 years, 469 were shift workers. Fixed evening type shift was the most common (30.3%) and fixed night-shift was the least common (0.9%) type of shift work. The mean blood levels of liver enzymes was not significantly different between shift workers and non-shift workers. In comparison between different patterns of shift work, the mean serum level of GGT was significantly higher in individuals with slow rotating shifts than those with fixed evening shifts, rapid rotating, split and fixed 24 hour shifts (p≤0.001). After adjusting for confounding factors only elevated AST was significantly higher in shift workers. CONCLUSION: There was only a significant association between shift work and elevated AST, and no relationship was found with ALT, ALP, GGT, and ALT/AST ratio.

The Effect of Water-Pipe and Cigarette Smoking on Exhaled Nitric Oxide.

Context: Fractional exhaled nitric oxide can be used as a biomarker of some respiratory diseases. Aims: This study was conducted to compare exhaled nitric oxide in cigarette and water-pipe smokers with nonsmokers. Methods: This cross-sectional study was conducted on 549 adult subjects as a sub-study of Shahedieh cohort in Yazd. Participants were divided into 5 groups according to their smoking habits: non-smokers (n = 202), cigarette smokers (n = 121), water-pipe smokers (n = 129), cigarette ex-smokers (n = 58), water-pipe and cigarette smokers (n = 39). The smokers were also categorized into heavy and light smokers. Fractional exhaled nitric oxide was compared between the groups. Statistical Analysis Used: The data were analyzed by SPSS (ver. 20) using Kolmogorov-Smirnov, Kruskal-Wallis, and Mann-Whitney U tests. Results: Fractional exhaled NO was lower in all smokers than nonsmokers, but cigarette smokers showed the least level of NO than other groups. Fractional exhaled NO was not significantly lower in water-pipe smokers than nonsmokers. Conclusions: Cigarette smoking significantly affect fractional exhaled NO, but water-pipe smoking did not significantly affect exhaled NO level.

The Comparison of The Efficacy of Photobiomodulation and Ultrasound in the Treatment of Chronic Non-specific Neck Pain: A Randomized Single-Blind Controlled Trial.

Introduction: Chronic neck pain is a common complaint among office workers. The aim of the present study was to compare the efficacy of a high-intensity laser and physiotherapy in office workers who were diagnosed with chronic non-specific neck pain. Methods: This study was a single-blind randomized controlled trial, with parallel allocation. Sixty office workers with chronic neck pain, aged between 25 and 55 years, participated in the study. The participants were randomly divided into two groups: photobiomodulation (by a high-level laser) and physiotherapy. Visual analogue scale (VAS), Neck Disability Index (NDI), Neck Pain and Disability Scale (NPDS) and Bournemouth Questionnaire (BQN) were completed on three occasions (before, immediately and 2 weeks after the intervention) to assess and compare the efficacy of the high-intensity laser and physiotherapy in neck pain. Data were analyzed by SPSS 23 software using the chi-square test, Student's t test, multivariate tests, and Fisher's exact test. Results: The mean age of the participants was 37.53±9.52 and 41.16±7.85 years in physiotherapy and laser therapy respectively. The VAS score and NDI scores decreased after both kinds of interventions, and the effect of photobiomodulation was significantly higher than physiotherapy (P < 0.001). Both treatment modalities significantly affect different aspects of chronic neck pain assessed by NDPS and BQN questionnaires and the effect of photobiomodulation was more prominent than physiotherapy. Conclusion: The findings of this study showed that photobiomodulation and physiotherapy can reduce chronic neck pain and its different aspects and the effect of laser therapy was significantly higher than physiotherapy.

Hearing Thresholds Changes after MRI 1.5T of Head and Neck.

INTRODUCTION: Exposure to high intensity noise produced by MRI is a cause for concern. This study was conducted to determine the temporary and permanent effects of exposure to noise created by performing MRI on the hearing threshold of the subjects using conventional and extended high frequency audiometry. METHODS: This semiexperimental study was performed on 35 patients referred to Shahid Rahnemoun Hospital for head and neck MRI due to different clinical conditions. The hearing threshold of patients was measured before, immediately after, and 24 hours after performing 1.5 Tesla MRI using conventional and extended high frequency audiometry. SPSS version 18 was used to compare the mean hearing thresholds before and after MRI using paired T test and repeated measures analysis. RESULTS: Comparison of auditory thresholds in conventional and extended high frequencies before and immediately after MRI showed a significant shift at 4 KHz (P = 0.008 and P = 0.08 for right and left ears), 6 KHz (P = 0.03 and P = 0.01 for right and left ears), and 14 KHz (P =0.03 and P = 0.31 for right and left ears). However, there was no significant difference between audiometric thresholds before and 24 hours after MRI. CONCLUSION: Noise due to 1.5 Tesla MRI can only cause transient threshold shift.

The effect of industrial noise exposure on attention, reaction time, and memory.

PURPOSE: Noise, a common physical hazard in many workplaces, may affect different aspects of human cognitive function. In this study, the effect of exposure to noise on some aspects of cognitive function was assessed in industrial workers. MATERIALS AND METHODS: This was a cross-sectional study on 84 individuals exposed to noise level higher than 85 dBA in a metal industry (noise group), comparing a group of workers from the same industry (n = 80) with exposure to noise level lower than 80 dBA (control group). The individuals in the noise group were classified as well according to noise intensity into: high exposure (90 dBA and higher) and low exposure (between 85 and 90 dBA). Selective attention score, divided attention score, selective response time, divided response time, and memory scale were measured before and after work shift. Data were analyzed by SPSS (Ver. 16) using Kolmogorov-Smirnov test, paired t test, Student's t test and Mann-Whitney U test were used to compare mean difference of the variables between two groups. p < 0.05 was considered as significant. RESULTS: All measured cognitive functions were significantly changed after work shift in the noise group and the difference was statistically significant between noise and control group. Exposure to higher noise intensity caused more change in cognitive function. CONCLUSION: Exposure to noise higher than 85 dBA affects some aspects of cognitive function (reaction time, attention and memory).

Shift Work Effects and Pregnancy Outcome: A Historical Cohort Study.

Objective: Employed mothers face considerable amount of hazards. Especially shift work can impact pregnant women by affecting some hormones. This study was conducted to assess the adverse effects of shift work on pregnancy outcomes. Materials and methods: This historical cohort study was conducted in 2017 in order to assess the effect of shift work on pregnancy outcomes. The subjects were consecutively selected from pregnant women, which referred to Al Zahra and Shahid Beheshti hospitals, Isfahan, Iran for their pregnancy care. The effect of shift work on pregnancy and labor complications (low birth weight, small for gestational age, pre-eclampsia and eclampsia, intra-uterine growth retardation, spontaneous abortion, preterm delivery, excessive bleeding during labor, and type of labor) was assessed. The effect was adjusted for occupation and number of children as well. Data were analyzed by SPSS (ver. 17) usingT-test, chi-Square test and logistic regression analysis. Results: Totally, 429 pregnant women entered the study. There was not a statistically significant difference between morning and shift workers regarding age. It was found that shift work probably increases the incidence of small for gestational age, pre-eclampsia and eclampsia, intra-uterine growth retardation, spontaneous abortion, and preterm delivery, but after adjustment for job and number of children the effect was observed only on preterm delivery. Conclusion: Working in a rapid cycling schedule of shift work may cause an increase in the incidence of preterm delivery in pregnant mothers.

Anthropometric hand dimensions in a population of Iranian male workers in 2012.

BACKGROUND: The mismatch between the hand size of workers and the size of industrial instruments is a growing concern; it can lead to various musculoskeletal complications. Currently, there are few reliable studies available to address this concern in Iran. This study was conducted to measure 30 upper-extremity parameters in a group of Iranian industrial workers. METHODS: This study is a cross-sectional study on 529 workers. The study population was randomly selected from male Iranian industrial workers who were referred to the Yazd hospital occupational medicine clinic for surveillance evaluations. RESULTS: The M (SD) age of the participants was 30.13 (8.29) years. Statistical analysis was performed using the mean, standard deviation and 5th, 50th and 90th percentiles for each measured hand dimension. A considerable number of dimensions were significantly different between the measurements of right and left hands in each examinee. The results showed significant differences between Iranian hand size and that of other populations. CONCLUSION: This study provided a valuable databank of hand dimensions in a population of Iranian male workers. These data can be used by manufacturers in designing high-quality hand-tools and industrial gloves, taking into consideration Iranian worker characteristics.

Anthropometry of Iranian Guidance School Students with Different Ethnicities: A Comparative Study.

Objective. We measured some anthropometric dimensions of Iranian guidance school students selected from different ethnicities. Background. Anthropometric dimensions are used for design of equipment, furniture, and clothing. Furniture with inappropriate design not fulfilling the users' anthropometric dimensions may have a negative effect on health. Method. A total of 7400 Iranian guidance school students aged 12-14 years entered the study and their static anthropometric dimensions were measured. Descriptive statistics such as mean, standard deviation, and key percentiles were calculated. All dimensions were compared among different ethnicities and different genders. Results. This study showed significant differences in a set of 22 anthropometric dimensions regarding gender, age, and ethnicity. Conclusion. According to the results of this study, difference between genders and among different ethnicities should be taken into account by designers and manufacturers of guidance school furniture. Application. This study has prepared a data bank of anthropometric dimensions of 12-14-year-old students which can be used as basic information to find appropriate dimensions of school furniture.

Static anthropometric dimensions in a population of Iranian high school students: considering ethnic differences.

BACKGROUND: Anthropometric dimensions of the end users should be measured in order to create a basis for manufacturing of different products. This study was designed to measure some static anthropometric dimensions in Iranian high school students, considering ethnic differences. METHOD: Nineteen static anthropometric dimensions of high school students were measured and compared among different Iranian ethnicities (Fars, Turk, Kurd, Lor, Baluch, and Arab) and different genders. RESULTS: In this study, 9,476 subjects (4,703 boys and 4,773 girls) ages 15 to 18 years in six ethnicities were assessed. The difference among ethnicities was statistically significant for all dimensions (p values < .001 for each dimension). CONCLUSION: This study showed statistically significant differences in 19 static anthropometric dimensions among high school students regarding gender, age, and ethnicity.

Occupational stress and cardiovascular risk factors in high-ranking government officials and office workers.

BACKGROUND: Cardiovascular diseases are among the most important sources of mortality and morbidity, and have a high disease burden. There are some major well-known risk factors, which contribute to the development of these diseases. Occupational stress is caused due to imbalance between job demands and individual's ability, and it has been implicated as an etiology for cardiovascular diseases. OBJECTIVES: This study was conducted to evaluate the cardiovascular risk factors and different dimensions of occupational stress in high-ranking government officials, comparing an age and sex-matched group of office workers with them. PATIENTS AND METHODS: We invited 90 high-ranking officials who managed the main governmental offices in a city, and 90 age and sex-matched office workers. The subjects were required to fill the occupational role questionnaire (Osipow) which evaluated their personal and medical history as well as occupational stress. Then, we performed physical examination and laboratory tests to check for cardiovascular risk factors. Finally, the frequency of cardiovascular risk factors and occupational stress of two groups were compared. RESULTS: High-ranking officials in our study had less work experience in their current jobs and smoked fewer pack-years of cigarette, but they had higher waist and hip circumference, higher triglyceride level, more stress from role overload and responsibility, and higher total stress score. Our group of office workers had more occupational stress because of role ambiguity and insufficiency, but their overall job stress was less than officials. CONCLUSIONS: The officials have higher scores in some dimensions of occupational stress and higher overall stress score. Some cardiovascular risk factors were also more frequent in managers.

Ergonomic intervention, workplace exercises and musculoskeletal complaints: a comparative study.

BACKGROUND: Musculoskeletal disorders are among the most prevalent occupational disorders in different jobs such as office work. Some interventions such as ergonomic modifications and workplace exercises are introduced as the methods for alleviating these disorders. In this study we compared the effect of ergonomic modifications and workplace exercises on musculoskeletal pain and discomfort in a group of office workers. METHODS: In an interventional study on office workers, the effect of two interventions was compared. Ergonomic modification consisted of correcting the arrangement of workstation and changing some equipment; workplace exercises included stretching exercises focusing on neck, shoulders, low back, and hand and wrist. Musculoskeletal complaints were assessed and compared before and after 1 month interventions. RESULTS: The frequency of musculoskeletal complaints was high before the study. Both interventions significantly reduced complaints in a similar manner except for low back pain which was reduced in exercise group more than the other group. CONCLUSION: In this study we found a beneficial short-term effect for both ergonomic modifications and stretching work-place exercises on reducing musculoskeletal pain in office workers.

Evaluation of the return to work and its duration after myocardial infarction.

BACKGROUND: The evaluation of the ability for return to work among patients after myocardial infarction (MI) is subject to controversy. Understanding various factors, which may affect return to work process, will help in promoting effective communication between physicians and patients. Return to work is dependent on such factors as patients' functional capacity, MI expansion, cardiac muscle function, some psychiatric variables, job satisfaction, economic status, and age. In this study, we aimed to assess the frequency of return to work after first MI attack, and factors affecting it. METHODS: This was a follow-up study performed in Yazd, Iran from September 2007 until September 2010 on 200 patients suffering from their first MI attack. Patients were assessed 6 months and 1-year after MI regarding their cardiac function. Job satisfaction was evaluated by Direct Support Professional job satisfaction questionnaire. RESULTS: Seventy-seven percent of MI patients returned to work after 1-year. Mean time for return to work was 46.00 ± 4.12 days. Sixty percent of patients returned to work during the first 50 days after MI and 50% of them during 40 days after MI. The most common reason for not returning to work was patient's decision. CONCLUSION: This study showed that a considerable numbers of patients returned to work after 1-year. The only factors which affected the rate of return to work were left ventricular function after MI and job satisfaction.

Conventional Audiometry, Extended High-Frequency Audiometry, and DPOAE for Early Diagnosis of NIHL.

BACKGROUND: Noise most frequently affects hearing system, as it may typically cause a bilateral, progressive sensorineural hearing loss at high frequencies. OBJECTIVES: This study was designed to compare three different methods to evaluate noise-induced hearing loss (conventional audiometry, high-frequency audiometry, and distortion product otoacoustic emission). MATERIAL AND METHODS: This was a cross-sectional study. Data was analyzed by SPSS (ver. 19) using chi square, T test and repeated measures analysis. Study samples were workers from tile and ceramic industry. RESULTS: We found that conventional audiometry, extended high-frequency audiometry, low-tone distortion product otoacoustic emission and high-tone distortion product otoacoustic emission had abnormal findings in 29 %, 69 %, 22 %, and 52 % of participants. Most frequently affected frequencies were 4000 and 6000Hz in conventional audiometry, and 14000 and 16000 in extended high-frequency audiometry. CONCLUSIONS: Extended high-frequency audiometry was the most sensitive test for detection of hearing loss in workers exposed to hazardous noise compared with conventional audiometry and distortion product otoacoustic.

Efficacy of low-level laser therapy in the management of tinnitus due to noise-induced hearing loss: a double-blind randomized clinical trial.

Background. Several remedial modalities for the treatment of tinnitus have been proposed, but an effective standard treatment is still to be confirmed. In the present study, we aimed to evaluate the effect of low-level laser therapy on tinnitus accompanied by noise-induced hearing loss. Methods. This was a double-blind randomized clinical trial on subjects suffering from tinnitus accompanied by noise-induced hearing loss. The study intervention was 20 sessions of low-level laser therapy every other day, 20 minutes each session. Tinnitus was assessed by three methods (visual analog scale, tinnitus handicap inventory, and tinnitus loudness) at baseline, immediately and 3 months after the intervention. Results. All subjects were male workers with age range of 30-51 years. The mean tinnitus duration was 1.85 ± 0.78 years. All three measurement methods have shown improved values after laser therapy compared with the placebo both immediately and 3 months after treatment. Laser therapy revealed a U-shaped efficacy throughout the course of follow-up. Nonresponse rate of the intervention was 57% and 70% in the two assessment time points, respectively. Conclusion. This study found low-level laser therapy to be effective in alleviating tinnitus in patients with noise-induced hearing loss, although this effect has faded after 3 months of follow-up. This trial is registered with the Australian New Zealand clinical trials registry with identifier ACTRN12612000455864).

Epidemiologic characteristics of occupational burns in yazd, iran.

OBJECTIVE: Occupational burns are among the important causes of work-related fatalities and absenteeism. Epidemiologic assessment of these injuries is important to define high-risk jobs. We designed this study to evaluate the epidemiology of occupational burns in Yazd, an industrial province in Iran. METHODS: This is a prospective study on work-related burns in a 1-year period (2008-2009). A questionnaire was completed for them about the characteristics of the burn injury. RESULTS: Three Hundred and Thirty Eight patients with occupational burns were identified. Their mean age was 29.64 years. Most burn victims were male workers in the metal industry. The most common job was smelting. Most burns were happened in the morning. Thermal burns were observed more than chemical and electrical burns. Mean total body surface area burned was 6.5%. The most common cause of burn was hot fluid, followed by hot object and flame. There was no any significant relationship between burn type, and burn degree or burned body surface. CONCLUSIONS: The highest incidence of occupational burns was in 21-30 year-old workers. There was a male preponderance in work-related burns. Metal industry had the most injured workers and among them, smelters were more frequently injured.

Effect of workplace noise on hearing ability in tile and ceramic industry workers in Iran: a 2-year follow-up study.

INTRODUCTION: Noise as a common physical hazard may lead to noise-induced hearing loss, an irreversible but preventable disorder. Annual audiometric evaluations help detect changes in hearing status before clinically significant hearing loss develops. This study was designed to track hearing threshold changes during 2-year follow-up among tile and ceramic workers. METHODS: This follow-up study was conducted on 555 workers (totally 1110 ears). Subjects were divided into four groups according to the level of noise exposure. Hearing threshold in conventional audiometric frequencies was measured and standard threshold shift was calculated for each ear. RESULTS: Hearing threshold was increased during 2 years of follow-up. Increased hearing threshold was most frequently observed at 4000, 6000, and 3000 Hz. Standard threshold shift was observed in 13 (2.34%), 49 (8.83%), 22 (3.96%), and 63 (11.35%) subjects in the first and second years of follow-up in the right and left ears, respectively. CONCLUSIONS: This study has documented a high incidence of noise-induced hearing loss in tile and ceramic workers that would put stress on the importance of using hearing protection devices.

Prevalence of Cardiovascular Risk Factors among Tile and Ceramic Workers in Yazd, Iran.

Introduction. Cardiovascular disorders (CVDs) are among the most important diseases in the world and determination of their risk factors is essential for primary and secondary prevention. This study aimed to evaluate these risk factors in workers of tile and ceramic industry, a main industry in Yazd. Materials and Methods. In a cross-sectional study, 1075 tile and ceramic workers were selected by simple sampling method. BMI, blood pressure, FBS, and lipid profile were measured and compared to international standards. Results. 731 individuals (68%) had at least one risk factor, and 52%, 12%, 3%, and 0.7% had one, two, three, and four risk factors, respectively. The most common risk factor was abnormal BMI (49.6%); low HDL (48.4%) and high TG (14.1%) were in the second and third orders. Conclusion. This study showed a relatively high prevalence for CVD risk factors among tile and ceramic workers. Low HDL, high TG, and overweight were the most frequent risk factors in this population.

An epidemiologic study on anthropometric dimensions of 7-11-year-old Iranian children: considering ethnic differences.

Anthropometric data can be used to identify the physical dimensions of equipment, furniture, clothing and workstations. The use of poorly designed furniture that fails to fulfil the users' anthropometric dimensions, has a negative impact on human health. In this study, we measured some anthropometric dimensions of Iranian children from different ethnicities. A total of 12,731 Iranian primary school children aged 7-11 years were included in the study and their static anthropometric dimensions were measured. Descriptive statistics such as mean, standard deviation and key percentiles were calculated. All dimensions were compared among different ethnicities and different genders. This study showed significant differences in a set of 22 anthropometric dimensions with regard to gender, age and ethnicity. Turk boys and Arab girls were larger than their contemporaries in different ages. According to the results of this study, difference between genders and among different ethnicities should be taken into account by designers and manufacturers of school furniture. PRACTITIONER SUMMARY: In this study, we measured 22 static anthropometric dimensions of 12,731 Iranian primary school children aged 7-11 years from different ethnicities. Descriptive statistics such as mean, standard deviation and key percentiles were measured for each dimension. This study showed significant differences in a set of 22 anthropometric dimensions in different genders, ages and ethnicities.