Effects of high occupational physical activity, aging, and exercise on heart rate variability among male workers

OBJECTIVES: Effects of aging and leisure time physical activity (LPA) might influence the effect of occupational physical activity (OPA) on risk for cardiovascular disease (CVD). This study was conducted to determine whether OPA affects CVD after controlling the effects of LPA and other risk factors for CVD such as job stress. METHODS: Participants were 131 male Korean manual workers. Tests for heart rate variability (HRV) were conducted for five minutes in the morning at work. We defined OPA as the combined concept of relative heart rate ratio (RHR), evaluated using a heart rate monitor. RESULTS: Whereas high OPA was not related to any HRV items in the younger age group, high OPA was associated with an increased number of low-value cases among all HRV items in older workers. Exercise had beneficial effects only in the younger group. After controlling for exercise and other risk factors, the odds ratios of the root-mean square of the difference of successive normal R-R intervals (rMSSD) and high frequency band power (HF) among the older age and high OPA group compared with the younger age and low OPA group were 64.0 and 18.5, respectively. Social support and shift work were independent risk factors in HRV. CONCLUSIONS: OPA in aging workers increases CVD risks. This study provides support for the need for protection of aging workers from physical work overload, and indicates the need for further study of optimal limits of OPA.

Respiratory Symptoms, Pulmonary Function Tests, and Asbestos Related Chest Radiograph Abnormalities of Former Asbestos Textile Factory Workers / 대한산업의학회지

OBJECTIVES: The objective of this study was to examine the prevalence of respiratory symptoms, asbestos-related chest radiograph abnormalities and abnormal pulmonary function tests among former asbestos textile factory workers and to reveal the related factors of these abnormal findings. METHODS: There were 119 persons former asbestos textile industry workers registered in the health management pocketbook. Of 97 retired asbestos workers living in Busan, Yangsan and Gimhae, 63(64.9%) retired asbestos workers were enrolled into this study. The researchers administered questionnaires, and performed chest radiographys, and pulmonary function tests (PFT) on participants. The survey was conducted during July, 2009. RESULTS: Among former workers the number of lung fibrosis, pleural plaque, pleural calcification, and pleural thickening was 13(20.6%), 6(9.5%), 3(4.8%), and 1(1.6%) in chest radiography, respectively. Asbestos-related disorders and abnormal pulmonary function test groups had higher prevalence of respiratory symptoms. Participants with crocidolite exposure or long latency period had higher asbestos-related x-ray findings or abnormal PFT findings. CONCLUSIONS: Former asbestos textile workers had a high rate of asbestos-related disorders. Workers with crocidolite exposure or having had a longer latency period had more asbestos-related disorders. Because gradual increase of asbestos related disorders among high asbestos exposure group is expected, sustained, and intensive management is needed for these former workers.

The Relationship between Work Ability and Job Stress Factors in Manufacturing Industries / 대한산업의학회지

OBJECTIVE: This study was performed to investigate the association between work ability and job stress factors in three manufacturing industries. METHODS: The data were gathered from 705 workers of 3 manufacturing industries, from August 2007 to January 2008. A structured, self-reported questionnaire was used to access the demographic, socioeconomic and work related characteristics. Work ability and job stress factors were determined using two questionnaires: the work ability index (WAI) of the Finnish Institute of Occupational Health and the Korean Occupational Stress Scale (KOSS), respectively. RESULTS: According to the logistic regression analysis results, WAI was related to job stress factors after adjustment for age, shift work, employment type and exercise. Of the eight subscales, job demand, interpersonal conflict, lack of reward, occupational climate and total score were significantly associated with WAI. In the analysis of each factory, interpersonal conflict, job insecurity and lack of reward were significantly associated with WAI in factory II, and organizational system, lack of reward and total score in factory III, but there was no significant association in factory I. CONCLUSIONS: Job stress factors were significantly associated with WAI in two of the three manufacturing industries. Further and more detailed study needs to be conducted to reduce the job stress and improve the work ability.

A Case of Chronic Renal Failure and Renal Cancer in a Worker Exposed to Lead / 대한산업의학회지

INTRODUCTION: Studies evaluating rats and mice have provided convincing evidence that renal adenoma and carcinoma are induced by oral doses of lead acetate and lead subacetate, as well as by parenteral doses of lead phosphate. In addition, at least 2 cases of kidney cancer associated with heavy exposure to lead have been reported. However, there is still not enough information to confirm or rule out an association between kidney cancer and exposure to lead. CASE REPORT: In this study, we describe a case of kidney cancer in 54-year-old male worker that was exposed to lead-stearate while employed in the polyvinyl chloride processing industry for 17 years. The patient presented with gout and hypertension. Further examination revealed proteinuria, glucose in the urine and elevated blood urea nitrogen/creatinine levels. Renal ultrasonography, renal computed tomography and renal biopsy revealed chronic renal failure and renal cell cancer. CONCLUSION: We concluded that the gout and chronic renal failure in this case was caused by chronic lead exposure. However, further study is required to determine if the renal cancer was induced by lead exposure.

Reliability and Validity of Questionnaire for Assessing Physical Workloads / 대한산업의학회지

OBJECTIVES: The aims of the study were to make a questionnaire for assessing physical workloads and to evaluate its reliability and validity. METHODS: A total of 220 workers (foundry workers 30, large vehicle assemblers 30, shipyard workers 75, and automobile manufacturers 80) completed a self-administered questionnaire and took examinations for physical work capacity and working heart rate. We excluded data with insufficient responses or incorrect physical work capacity and working heart rate. Finally, the data of 154 workers (70.0%) were used for our study. In order to evaluate the reliability and validity of the questionnaire, we used statistical analyses including the scaling assumption test and a comparison with the objective tool for physical workload which was evaluated by working energy expenditure. RESULTS: The items of the questionnaire in the same categories had close distribution in the evaluation of the scaling assumption. The item internal consistency was 0.41-0.73 for posture factor, and 0.62-0.79 for non-posture factor. The item discriminate validity was 100%. Cronbach's alphacoefficient of the total items was 0.73 (0.58 for posture factor and 0.74 for nonposture factor). In the correlation between working energy expenditure and questions, general physical activity (p=0.008), proportion of the workday with hands above shoulder (p=0.002), proportion of the workday with trunk bent (p=0.028), proportion of the workday with awkward posture (p=0.048), sweating after work (p=0.006), total scales (p=0.003) and Borg scale (p=0.011) all had statistical significance. CONCLUSIONS: Our questionnaire for assessing physical workloads demonstrated statistically significant reliability and validity. But the questions for the proportions of the workday with sitting work posture and with static posture should be modified via a larger study.