Factors That Predict Early Return to Work After Myocardial Infarction: Importance of Coworker Support

Aim    Myocardial infarction (MI) affects the working-age group and cause many absences and lost days of work. Some occupational factors effect in the prognosis of MI patients. The objective of this study was to determine predictors of early, late and no return to work (RTW) after MI.Material and methods    In this cohort study, 240 pre-employed, male patients with MI from April 2020 through February 2022 provided data about their demographic, occupational, psychosocial, and medical information. Data was also collected about the treatment they received as patients, their feelings about socioeconomic support, and RTW time. RTW within two weeks after MI was defined as early RTW. The relationships of these variables and with early RTW and with late or no RTW were analyzed.Results    Ninety-four patients (39.6 %) returned to work within two weeks after MI, whereas 207 patients (87.3 %) returned to work by the end of six months. Many variables, including coworker support, were associated with early RTW in a univariate analysis. Regression analysis revealed that age, coworker support, marital status, the patient's own estimated RTW time, the number of the vessels with occlusion, and comorbidity were predictors of early RTW. Of these factors, only coworker support would be subject to modification.Conclusions    This study indicates that improving support from coworkers can increase early RTW after MI.

Disparities in the prevalence of metabolic syndrome between Iranian industrial workers and university staff

Background

Is there a difference in the prevalence of metabolic syndrome between employee service jobs and industrial jobs in Iran? In this study, we tried to answer this question. For this purpose, we compared the two populations of employees and workers. We compared the staff of the University of Medical Sciences as a service employees population (clinical and office work) to the industrial workers of a large automotive company (often with industrial occupations).

Method

In this cross-sectional study conducted in Tehran in 2020, the prevalence of metabolic syndrome among 4,372 people employed by the university and 3,899 automotive industry employees was examined and compared. The prevalence of metabolic syndrome was assessed based on two criteria, National Cholesterol Education Program Adult Treatment Panel III (ATP III) and International Diabetes Federation (IDF).

Results

The results showed that the prevalence of metabolic syndrome among university staff was higher than the automotive industrial workers. According to ATP III criteria, the former and latter showed the prevalence of metabolic syndrome of 13.1% among and 6.1%, respectively among. Also, based on IDF criteria, the prevalence of metabolic syndrome was 23.3% and 12.6% in two groups mentioned.

Conclusion

Based on the findings of this study, the prevalence of metabolic syndrome in university staff was almost double that in industry workers. At first glance, the physical activity of most automotive, industrial workers seems to be the main reason for this difference; however, a prevalence of about twice implies further factors. According to the authors, the legal implementation of monitoring, promotion, and surveillance programs of occupational health, in industrial environments can be a factor accounting for a significant difference in the prevalence of metabolic syndrome between the two populations observed. The authors suggest implementing similar programs for Iranian public sector employees to enhance their health status.

Violence Against Medical Assistants by Colleagues at Educational Hospitals and Its Effects on the Quality of Education

Background: Violence against medical assistants (residents) by colleagues is a serious problem at educational hospitals that has not been sufficiently examined. The present study was conducted to determine the prevalence, risk factors, and types of violence perpetrated by colleagues against medical assistants. Methods: In a cross-sectional study conducted at two large tertiary referral educational hospitals, the study questionnaires were distributed among 480 healthcare professionals to investigate their experiences of violence. Results: Of 280 responders, 162 residents (57.9%) reported a history of violence or aggression. Of these, nearly 50% had experienced pure psychological violence, and 16.7% had been physically abused. The prevalence of victimization was high among the residents of the neurosurgery, orthopedic, and obstetric departments (90%, 88%, and 85%, respectively). Conclusion: Harassment experience was more common among the surgical residents than the internal medicine residents because of the former’s high level of work stress. Senior residents or fellowship residents were the main abusers. Losing professional selfesteem, decreasing job satisfaction, and dropping out of school were the main adverse outcomes of violence experienced by the victims.

Association between Red blood cell distribution width and pulmonary function among Iranian employees

Background:

RDW has been proposed as a routine test and is available as a prognosis for many diseases and disorders, especially respiratory disorders. In this study, we intend to see if the association between pulmonary function and RDW also applies to non-patients.

Methods:

This study was performed on 800 people including 466 women and 344 men. Participants in the study were staff enrolled in the Tehran University of Medical Sciences cohort [TEC] study. In this study, RDW levels and pulmonary function were assessed. Elderly populations were not included in this study

Results:

The results of the univariate analysis showed that normal values versus abnormal values of RDW were significantly associated with pulmonary function index FEV1, FVC, FEV1/FVC in non-patient individuals. On the other hand, a significant correlation was observed between RDW values and FEV1 index and FEV1/FVC ratio. Based on linear regression, there was an association between RDW and FVC [R2=0.721].

Conclusion:

In this study, we found an association between RDW and FVC so we suggest that abnormal RDW may consider as a sign of pulmonary dysfunction.

Needlestick Injury and Psychomotor Performance as Measured by Pursuit-Aiming Test in Health-Care Professionals

Background

Several factors play a role in Needlestick Injury (NSI). We aimed to determine the association of NSI with psychomotor performance in health-care workers.

Materials and Methods

In this cross-sectional study, demographic, occupational characteristics, and needlestick history were completed for 357 health personnel of a university hospital of Tehran in 2019 through a checklist. Psychomotor performance was measured using a pursuit-aiming test.

Results

Most of the NSI occurred in nurses. The mean age of the workers with a positive history of NSI was significantly lower compared to their peers with a negative history, and similarly, they had lower work experience. After adjustment for the confounding variables, the correct pursuit-aiming test had a borderline association with the occurrence of the NSI.

Conclusions

Psychomotor performance had a borderline association with the history of NSI.

Body impedance analyzer and anthropometric indicators; predictors of metabolic syndrome

Aim

Metabolic syndrome is one of the outcomes of a sedentary lifestyle in the modern world. In this study, we want to introduce the predictors of metabolic syndrome using anthropometric indices and Bio-Electrical Impedance Analysis (BIA) test values.

Method

This cross-sectional study was performed on 2284 employees of Tehran University of Medical Sciences in different job categories. Metabolic syndrome was determined according to IDF criteria. Anthropometric dimensions, para-clinical tests, basic information were collected from the participants. Also, the body analysis of the participants was performed using a BIA method.

Result

The prevalence of metabolic syndrome in this study was 23.2% based on IDF criteria, which was 21% and 26.6% in men and women, respectively. The most important factor among the components of IDF criteria was HDL deficiency. In this study, neck circumference, fat mass, visceral fat, muscle mass percentage and waist to height ratio were observed as predictors of metabolic syndrome.

Conclusion

This study realized that there is association between fat mass, fat-free mass, visceral fat and muscle mass which all are some elements of body composition analysis and metabolic syndrome as a major health issue.

Association Between Body Composition and Pulmonary Function Tests Among Health Care Workers in Iran

Background:

Why is bodyweight not a predictor of lung function, while height, sex, race, and age are predictors of lung capacity and function? In this study, we want to investigate the association between body composition and pulmonary function. And, as much as possible, answer the question of why bodyweight is not predictive of lung function.

Methods:

This cross-sectional study was performed among 2967 employees of Tehran University of Medical Sciences (TUMS) who participated in the TUMS Employees Cohort (TEC) study. The body composition of the participants was measured using the Bioelectrical Impedance Analysis (BIA) method. Anthropometric variables were also measured as a confounder. The pulmonary function of participants was assessed by a forced spirometry test.

Results:

The correlation of BIA values including fat-free mass and total body water with a pulmonary function such as FEV1, FVC, and FEF25-75is higher than most anthropometric values such as weight, wrist circumference, and the waist to hip ratio. Also, in regression analysis, age and sex had an association with pulmonary function, but the weight did not show a significant relationship. On the other hand, fat-free mass and visceral fat were significantly associated with pulmonary function. One is direct and the other is inverse.

Conclusion:

We observed a negative association between visceral fat and pulmonary function tests and a direct association between Fat-free mass pulmonary function tests (FEV1 and FVC) adjusted for age, sex, and anthropometric indices.

Effects of Simultaneous Exposure to Smoking and Welding Fume on Pulmonary Function Tests in Spot Welders

BACKGROUND

The respiratory effects of fume exposure during spot welding may aggravate some environmental risk factors such as tobacco smoking. Fume exposure and smoking have negative effects on pulmonary function tests (PFTs). This study assessed the simultaneous effects of smoking and welding fume on spirometry tests in spot welders.

MATERIALS AND METHODS

This cross-sectional study was conducted on 667 spot welders and 1000 assemblers in an automotive manufacturing plant. Spirometry was carried out on all the participants under standard conditions and according to the American Thoracic Society Clinical Practice Guidelines and indices including FEV1, FVC, FEV1/FVC, FEF 25-75, and PEF were measured and compared between two groups of the study population including workers of spot welding and assembling.

RESULTS

It was found that the effect of simultaneous exposure to smoking and welding fume was aggravated on the PFT indices including the FEV1 percent, FEV1/FVC, the FEV1/FVC percent, the PEF percent, FEF25-75, and the FEF25-75 percent, but not on indices such as FVC, the FVC percent, and PEF.

CONCLUSION

Simultaneous exposure to smoking and welding fume resulted in a reduction in some spirometry indices, causing respiratory airway obstruction in the spot welders. Occupational safety and regular medical examinations with shorter intervals in smoking spot welders can prevent acute respiratory effects of exposure to smoking and welding fume.

Manual material handling in the Tehran Grand Bazaar, a type of traditional heavy work with musculoskeletal effects

BACKGROUND

Manual Material Handling (MMH) is a type of heavy work that causes a wide variety of musculoskeletal disorders (MSDs). Porters constitute a poor socioeconomic group of workers who are faced with these risk factors. This study focuses on porters who push and pull loads of goods on handcarts inside and outside the Tehran Grand Bazaar.

OBJECTIVES

This study was conducted to investigate the prevalence of MSDs in porters of the Tehran Grand Bazaar.

METHODS

Based on official registries, more than 5000 porters work in the Tehran Grand Bazaar. In total, 398 porters were selected using the simple random sampling method. The prevalence of MSDs was assessed using the Standardized Nordic Questionnaire for the Analysis of Musculoskeletal Symptoms. The tasks of the porters were analyzed during walk-through surveys in the Tehran Grand Bazaar.

RESULTS

The prevalence of MSDs in at least one body part was 53.8% in the last 12 months and 45.2% in the last 7 days. The most prevalent symptoms in the last 12 months were low-back pain (29.6%) and knee pain (19.6%). Symptoms were associated with age, height, weight, waist circumference, work duration, number of children, and manually handling goods heavier than 20 kg.

CONCLUSIONS

The prevalence of MSDs is high in the porters of the Tehran Grand Bazaar, likely due to heavy MMH.

Effects of Car Painting Vapors on Spirometric Parameters in Automobile Painting Workers

BACKGROUND

Automobile spray painting is considered a high-risk occupation for respiratory diseases. The present survey aimed to assess the effects of automobile paint vapors on spirometric parameters among workers of a painting workshop in a large automobile manufacturing plant in Iran.

MATERIALS AND METHODS

This cross-sectional study was conducted on 820 workers of an automobile manufacturing plant, including 431 spray painters (case group) and 389 assembly line workers (control group). Spirometry was conducted for all participants under standard conditions, according to the American Thoracic Society (ATS) Clinical Practice Guidelines. The forced expiratory volume in one second (FEV1), forced vital capacity (FVC), FEV1/FVC, and forced expiratory flow at 25% and 75% of the pulmonary volume (FEF25-75) were reported.

RESULTS

Painters with more than ten years of work experience had significantly lower predicted values of FEV1/FVC (P= 0.005), FEV1 (P=0.008), and FEF25-75 (P=0.003), compared to the control group. Also, painters who were exposed to solvent-based paints were not significantly different from those exposed to water-based paints in terms of spirometric parameters (P>0.05).

CONCLUSION

The results indicated the impact of automobile spray painting on the spirometric parameters. A slight decrease in the mean values of these parameters calls for attention to occupational safety, regular medical examinations, and effective measures.

A Burden Assessment of Occupational Exposures in Iran, 1990-2010: Findings from the Global Burden of Disease Study 2010

Background

The present study describes the burden of occupational diseases in Iran based on the results of the Global Burden of Disease study conducted in 2010 (GBD 2010). This study aimed to determine the burden of occupational diseases in Iran based on the results of GBD 2010. It is a cross-sectional study.

Methods

Disability-adjusted life years (DALYs) of occupational diseases were calculated based on the prevalence rates obtained through model estimation, as well as GBD 2010 disability weights and mortality rates obtained from different data registry systems of Iran. Causal association criteria application to select risk outcome pairs, estimation of exposure to each risk factor in the population, estimation of etiological effect size, selection of a counterfactual exposure distribution, risk assessment, and identification of burden attributable to each risk factor were the main conducted statistical steps.

Results

There was an increasing trend of DALYs (710.08/100,000 people in 1990 and 833.00/100,000 people in 2005) followed by a slight decrease (833.00/100,000 in 2005-784.55/100,000 people in 2010). A total of 50.4% and 36% of total DALYs per 100,000 people were due to the adverse effects of musculoskeletal disorders and work-related injuries, respectively.

Conclusions

Musculoskeletal disorders and work-related injuries are the most important adverse consequences of work-related risks that require urgent interventions to be controlled. Male workers (15-25 years and over 60) with the highest DALYs and mortality rates need more training programs, safety regulations, and higher level of protection support. In spite the decreasing trend of occupational disease related DALYs and death rates in Iran in recent years, a long-term effort is required to maintain the currently decreasing trend.

Association between Metabolic Syndrome and Job Rank

Background:

The occupation of the people can influence the development of metabolic syndrome.

Objective:

To determine the association between metabolic syndrome and its determinants with the job rank in workers of a large car factory in Iran.

Methods:

3989 male workers at a large car manufacturing company were invited to participate in this cross-sectional study. Demographic and anthropometric data of the participants, including age, height, weight, and abdominal circumference were measured. Blood samples were taken to measure lipid profile and blood glucose level. Metabolic syndrome was diagnosed in each participant based on ATPIII 2001 criteria. The workers were categorized based on their job rank into 3 groups of (1) office workers, (2) workers with physical exertion, and (3) workers with chemical exposure. The study characteristics, particularly the frequency of metabolic syndrome and its determinants were compared among the study groups.

Results:

The prevalence of metabolic syndrome in our study was 7.7% (95% CI 6.9 to 8.5). HDL levels were significantly lower in those who had chemical exposure (p=0.045). Diastolic blood pressure was significantly higher in those who had mechanical exertion (p=0.026). The frequency of metabolic syndrome in the office workers, workers with physical exertion, and workers with chemical exposure was 7.3%, 7.9%, and 7.8%, respectively (p=0.836).

Conclusion:

Seemingly, there is no association between metabolic syndrome and job rank.

Noise-Induced hearing loss among professional musicians

OBJECTIVES

After presbycusis, noise exposure is considered the second cause of sensorineural hearing loss. Due to exposure to high-intensity sounds, musicians may be at risk of noise-induced hearing loss (NIHL). Given the importance of good hearing in music career, this study aimed to investigate the frequency of hearing loss and use of protective measures among Iranian musicians.

METHODS

In this cross-sectional study, 125 musicians, including 21 women (16.8%) and 104 men (83.2%), with at least five years of work experience were recruited. All participants underwent clinical and audiometric examinations. Demographic data, complaints about hearing loss, and information about the use of protective devices were collected through interviews.

RESULTS

Audiometric notch in either one or both ears and bilateral hearing loss were present in respectively 42.4% and 19.2% of the participants. The history of tinnitus after performance and ear pain during performance was reported by 64 (51%) and 35 (28%) individuals, respectively. Less than 2% of the participants used hearing protection devices.

CONCLUSIONS

Long-term exposure to loud sounds puts musicians at risk of hearing loss. However, due to their inadequate knowledge, most musicians never use protective devices to prevent damage to their auditory system.

Effect of Acute Noise Exposure on Salivary Cortisol: A Randomized Controlled Trial

Cardiovascular adverse effects are interesting aspects of occupational noise exposure. One possible mechanism of these effects is an alternation in hypothalamic-pituitary-adrenal axis. Our aim was to measure salivary cortisol response to relatively high-intensity noise exposure in a controlled randomized trial study. We exposed 50 male volunteers to 90 dBA noise for 20 minutes and compared their level of salivary cortisol with 50 non-exposed controls. Salivary samples obtained before and after exposure. Before intervention means (SD) salivary cortisol level were 3.24 (0.47)ng/ml and 3.25 (0.41)ng/ml for exposed and non-exposed groups respectively. Mean salivary cortisol level increased to 4.17 ng/mlafter intervention in exposure group. This increment was statistically significant (P=0.00). Mean salivary cortisol level of the non-exposed group had statistically non-significant decrement after this period (0.2 ng/ml). The difference between salivary cortisol level of non-exposed and exposed groups after the intervention was statistically significant. Noise exposure may affect the hypothalamic-pituitary-adrenal axis activity, and this may be one of the mechanisms of noise exposure cardiovascular effects.

Micronucleus, Nucleoplasmic Bridge, and Nuclear Budding in Peripheral Blood Cells of Workers Exposed to Low Level Benzene

BACKGROUND

Benzene is one of the important occupational pollutants. There are some reports about the leukemogenic effects related to low-level exposure to benzene.

OBJECTIVE

To study the frequency of micronucleus (MN), nucleoplasmic bridge (NB), and nuclear budding (NBUD) in the peripheral blood lymphocytes of petrochemical workers with low level exposure to benzene.

METHODS

We enrolled 50 workers exposed to low-level benzene and 31 unexposed workers of a petrochemical industry. After exclusion of 3 samples, peripheral blood lymphocytes of the remaining 47 exposed and 31 unexposed workers were analyzed for the frequency of MN, NB, and NBUD by cytochalasin-blocked MN technique.

RESULTS

MN was present in 28 (60%) exposed and 18 (58%) unexposed workers. NB was observed in 6 (13%), and 2 (7%) exposed and unexposed workers, respectively; the frequency for NBUD was 20 (43%), and 13 (42%), respectively. No significant difference was found in the observed frequencies of MN, NB, and NBUD in the peripheral blood lymphocytes between the exposed and unexposed group workers.

CONCLUSION

Occupational exposure to low-level benzene does not increase the frequency of MN, NB, and NBUD in the peripheral blood lymphocytes, biomarkers for DNA damage.

Work Predictors of Lapse in Patients under Treatment of Methadone Maintenance Therapy

BACKGROUND

Addiction to narcotics ‎can cause serious problems and ‎monetary losses. Therapeutic ‎success can be predicted ‎through identifying lapse risk ‎factors.‎

OBJECTIVE

Determining Job Risk ‎Factor of Lapse.‎

METHODS

This was a cross ‎sectional study on 351 addicts ‎visiting five methadone clinics. A ‎Data collection sheet consisting ‎of questions on demographic ‎and job information was filled up ‎through direct interviews. ‎Information relating to lapse in ‎the first month was analyzed.‎

RESULTS

The mean (SD) age of ‎the participants was 40(12) ‎years; of them, 74% were ‎employed, of whom 34% had ‎lapsed. A relationship was ‎noticed between education ‎qualification (secondary school ‎compared with higher and lower ‎education) and lapse (p = .04), ‎and also between type of drug ‎abuse (amphetamine) and lapse ‎‎(p = .001).‎

CONCLUSION

‎ ‏ ‏‎ Lapse was more ‎dependent on type of drug abused, ‎and employment had a protective role, ‎with no correlation with the type of ‎job and other job conditions. Non-‎work factors mediated/suppressed the ‎role of occupational conditions.‎.

Urinary 8-hydroxy-deoxyguanosine as a biomarker of oxidative DNA damage in employees of subway system

Exposure to air pollutants, steel dust or other occupational and environmental hazards as oxidative stress have adverse effects on subway workers' health. Oxidative stress generates an excessive amount of reactive oxygen species (ROS) and Oxygen Free Radicals during their work time in the tunnels. Once DNA is repaired, Urinary 8-hydroxy-deoxyguanosine (8-OHdG) is excreted in the urine. Therefore, urinary level of 8-OHdG can reflect the extent of oxidative DNA damage. The aim of this study was to document the oxidative stress caused by exposure to these hazards by measuring 8-OHdG in workers urine. We collected urine samples of 81 male subway workers after their working shift. The concentration of urinary 8-OHdG was measured by ELISA method. We used linear regression analysis to compare the level of urinary 8-OHdG as a biomarker of oxidative stress between workers in tunnels and other staff. The mean concentration of urinary 8-OHdG for workers in the tunnel was 58.05 (SD=28.83) ng/mg creatinine and for another staff was 54.16 (SD =26.98) ng/mg creatinine.  After adjustment for age, smoking, driving and a second job in a linear regression model, the concentration of 8-OHdG for the exposed group was significantly higher than unexposed group (P=0.038). These findings confirm that the concentration of urinary 8-OHdG for workers who work in tunnels was significantly higher than the other staff. Additional investigations should be performed to understand that which ones of occupational exposures are more important to cause oxidative stress.

Psychosocial factors at work and blood-borne exposure among nurses

BACKGROUND

Exposure to human blood and body fluids is a common risk for nurses. Many factors can affect the prevalence and incidence of this occupational hazard. Psychosocial factors at work may be a risk factor for the exposure.

OBJECTIVE

To assess needle stick, sharp injury and mucus exposure to blood-borne pathogens among nurses in Iran and to determine the association between these exposures and psychosocial factors at work.

METHODS

A cross-sectional study was conducted on nurses in a public hospital, Tehran, Iran. 364 nurses received and 339 completed and returned a self-reported questionnaire containing demographic data, history of exposure to blood-borne pathogens at work during previous year and the General Nordic questionnaire for psychological and social factors at work (QPS Nordic 34+ Questionnaire).

RESULTS

Of 339 participants, 197 (58.1%) reported needle-stick injury, 186 (54.6%) reported another type of sharp injury, and 112 (33%) reported a mucous membrane exposure during the previous year. More than half of the participants who had history of exposure, had not reported it. Those with middle or high level of stress had higher crude and adjusted odds than those with lower stress for all kinds of exposure. Adjusted odds ratios for high stress group (ranging from 2.8 to 4.4) were statistically different from 1.

CONCLUSION

There is a high prevalence of needle-stick and sharp injury and mucous membrane exposure to patients' blood or body fluids among studied nurses. There is a significant association between increasing psychosocial factors at work and exposure to blood-borne pathogens among this group of nurses.

Restless Legs Syndrome in shift workers: A cross sectional study on male assembly workers

Background

Restless Legs Syndrome (RLS) is a common neurological movement disorder characterized by symptoms that follow a circadian pattern. Night and rotating shift work schedules exert adverse effects on functions of the human body by disturbing circadian rhythms, and they are known to cause sleep disturbances and insomnia. In this paper, we investigate the possible association between shift work and RLS.

Methods

This cross sectional study was conducted in an automobile manufacturing factory in Tehran, Iran. A total of 780 male assembly workers were recruited in three groups, each with 260 workers: workers on a permanent morning shift (A) and two different rotating shift schedules (B and C) with morning, afternoon and night shifts. We used the international RLS study group criteria for diagnosis of RLS, and the severity scale for severity assessment in subjects with RLS. Self administered questionnaires were used to gather information on age, smoking, work history, medical condition, and existence and severity of RLS symptoms.

Results

The prevalence of RLS was significantly higher in rotational shift workers (15%) than workers with permanent morning work schedule (8.5%). In workers suffering from RLS, we found greater mean values of age and work experience, higher percentages of drug consumption, smoking, and co-morbid illnesses compared with subjects who did not have RLS, although these differences were statistically significant only for age, work experience and drug consumption.

Conclusion

Rotational shift work acts as a risk or exacerbating factor for Restless Legs Syndrome.

Efficacy and hypnotic effects of melatonin in shift-work nurses: double-blind, placebo-controlled crossover trial

Background

Night work is associated with disturbed sleep and wakefulness, particularly in relation to the night shift. Circadian rhythm sleep disorders are characterized by complaints of insomnia and excessive daytime sleepiness that are primarily due to alterations in the internal circadian timing system or a misalignment between the timing of sleep and the 24-h social and physical environment.

Methods

We evaluated the effect of oral intake of 5 mg melatonin taken 30 minutes before night time sleep on insomnia parameters as well as subjective sleep onset latency, number of awakenings, and duration of sleep. A double-blind, randomized, placebo-controlled crossover study with periods of 1 night and washouts of 4 days comparing melatonin with placebo tablets was conducted. We tried to improve night-time sleep during recovery from night work. Participants were 86 shift-worker nurses aged 24 to 46 years. Each participant completed a questionnaire immediately after awakening.

Results

Sleep onset latency was significantly reduced while subjects were taking melatonin as compared with both placebo and baseline. There was no evidence that melatonin altered total sleep time (as compared with baseline total sleep time). No adverse effects of melatonin were noted during the treatment period.

Conclusion

Melatonin may be an effective treatment for shift workers with difficulty falling asleep.

Interaction of smoking and occupational noise exposure on hearing loss: a cross-sectional study

BACKGROUND

Noise is the most common hazardous agent at workplaces. Noise induced hearing loss (NIHL) has been known since the industrial revolution. Although NIHL is permanent, irreversible and frequent, it is preventable. The economic costs of NIHL have been estimated to be about billions of dollars. Besides, cigarette smoking is a common habit worldwide, and according to some recent studies smoking and noise may act in common causal pathways for hearing loss.

METHODS

A cross-sectional study was designed to study the effect of smoking on NIHL in 206 male smoker workers and 206 male non-smoker workers in a large food-producing factory, in which workers were exposed to noise levels exceeding 85 dBA. To determine noise exposure level, we used sound level measurements reported by industrial hygienists.A qualified audiologist assessed hearing acuity by using standardized audiometric procedures assuring at least 14 h of noise avoidance.

RESULTS

We observed that the percentage of workers with hearing threshold differences of greater than or equal to 30 dB between 4000 Hz and 1000 Hz in both ears were 49.5% and 11.2% in smoker and non smoker groups, respectively (Odds ratio = 7.8, 95% CI = 4.7-13), and the percentage of workers with a hearing threshold of greater than 25 dB at 4000 Hz in the better ear were 63.6% and 18.4% in smoker and non smoker groups, respectively. This difference was statistically significant after adjustment for age and exposure duration.

CONCLUSION

It can be concluded that smoking can accelerate noise induced hearing loss, but more research is needed to understand the underlying mechanisms. Accurate follow up of smoker workers who are exposed to noise levels exceeding 85 dBA is suggested. Smokers should periodically attend educational courses on "smoking cessation", especially in noisy workplaces.

In chronic low back pain, low level laser therapy combined with exercise is more beneficial than exercise alone in the long term: a randomised trial

QUESTION

Is low level laser therapy an effective adjuvant intervention for chronic low back pain?

DESIGN

Randomised trial with concealed allocation, blinded assessors and intention-to-treat analysis.

PARTICIPANTS

Sixty-one patients who had low back pain for at least 12 weeks.

INTERVENTION

One group received laser therapy alone, one received laser therapy and exercise, and the third group received placebo laser therapy and exercise. Laser therapy was performed twice a week for 6 weeks.

OUTCOME MEASURES

Outcomes were pain severity measured using a 10-cm visual analogue scale, lumbar range of motion measured by the Schober Test and maximum active flexion, extension and lateral flexion, and disability measured with the Oswestry Disability Index on admission to the study, after 6 weeks of intervention, and after another 6 weeks of no intervention.

RESULTS

There was no greater effect of laser therapy compared with exercise for any outcome, at either 6 or 12 weeks. There was also no greater effect of laser therapy plus exercise compared with exercise for any outcome at 6 weeks. However, in the laser therapy plus exercise group pain had reduced by 1.8 cm (95% CI 0.1 to 3.3, p = 0.03), lumbar range of movement increased by 0.9 cm (95% CI 0.2 to 1.8, p < 0.01) on the Schober Test and by 15 deg (95% CI 5 to 25, p < 0.01) of active flexion, and disability reduced by 9.4 points (95% CI 2.7 to 16.0, p = 0.03) more than in the exercise group at 12 weeks.

CONCLUSION

In chronic low back pain low level laser therapy combined with exercise is more beneficial than exercise alone in the long term.