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Ergonomics Publication details, including instructions for authors and subscription information: http://www.tandfonline.com/loi/terg20
An epidemiological study of low-back pain in crane operators a
ALEX BURDORF & HARRY ZONDERVAN
a
a
Institute of Occupational Health, Medical Faculty , Erasmus University, PO Box 1738 3000, DR Rotterdam, The Netherlands Published online: 24 Oct 2007.
To cite this article: ALEX BURDORF & HARRY ZONDERVAN (1990) An epidemiological study of low-back pain in crane operators, Ergonomics, 33:8, 981-987, DOI: 10.1080/00140139008925307 To link to this article: http://dx.doi.org/10.1080/00140139008925307
PLEASE SCROLL DOWN FOR ARTICLE Taylor & Francis makes every effort to ensure the accuracy of all the information (the “Content”) contained in the publications on our platform. However, Taylor & Francis, our agents, and our licensors make no representations or warranties whatsoever as to the accuracy, completeness, or suitability for any purpose of the Content. Any opinions and views expressed in this publication are the opinions and views of the authors, and are not the views of or endorsed by Taylor & Francis. The accuracy of the Content should not be relied upon and should be independently verified with primary sources of information. Taylor and Francis shall not be liable for any losses, actions, claims, proceedings, demands, costs, expenses, damages, and other liabilities whatsoever or howsoever caused arising directly or indirectly in connection with, in relation to or arising out of the use of the Content. This article may be used for research, teaching, and private study purposes. Any substantial or systematic reproduction, redistribution, reselling, loan, sub-licensing, systematic supply, or distribution in any form to anyone is expressly forbidden. Terms & Conditions of access and use can be found at http:// www.tandfonline.com/page/terms-and-conditions
ERGONOMITCS, 1990, YOLo 33, NO. 8,981-987
An epidemiological study of low-back pain in crane operators ALEX BURDORF and HARRY ZONDERYAN Institute of Occupational Health, Medical Faculty, Erasmus University, PO Box 1738, 3000 DR Rotterdam, The Netherlands
Downloaded by [New York University] at 23:20 26 October 2014
Keywords: Crane operators; Low-back pain; Prevalence; Occupational risk factors.
A survey among workers in a steel factory was conducted to determine the risk for low-back pain (LBP) among male crane operators. Crane operators (n = 33) were matched for age with male control workers (n = 30)and examined for frequency and nature of LBP by the on-site medicalservice. Comparison betweencrane operators and controls showed a statistically significant odds ratio for LBP of 3·6.Although crane operators had been exposed more often to backstraining factors in previous occupations, in the employed logistic analysis only their current job explained the elevated occurrence of LBP. It is suggested that workers in sedentary position with exposure to whole-body vibration are at special risk for LBP. The results of this study provide evidence to strongly recommend persons with a history of back complaints not to seek employment as crane operators.
I. Introduction The relationship between occupation and the risk of developing low-back pain (LBP) is not well understood, although several risk factors are known. There is evidence that workers in heavy manual jobs have a higher prevalence of LBP than light manual workers. Heavy lifting, frequent bending, static work posture, and whole-body vibration have been identified as important factors for the onset of LBP (Troup 1984, Yu et al. 1984). Because of the multifactorial nature of the etiology of LBP, the importance of individual risk factors remains still unclear (Riihirnaki et al. 1989). In the working conditions of operators on overhead travelling cranes, several strenuous work postures occur which can be assumed to increase the risk for LBP. In order to maintain a good view of the lifting device and the transported goods, several trunk movements are required. Frequent twisting, deep sideways bendings, and stooping positions occur frequently. Operating a crane demands a static sedentary position with hands held steady on the operating handles. While driving, the crane operators are exposed to whole-body vibration. On the basis of these known risk factors for LBP in the occupational environment of crane operators, a study was conducted to determine the frequency and nature of LBP and its occupational origin.
2. Materials and methods The survey population was restricted to subjects with a minimal duration of employment of one year, in order to avoid disturbances due to high labour turnover in the first months of employment. A total of 49 male operators working on overhead travelling cranes in a steel factory were invited by letter to take part in the study. They were asked to visit the occupational physician for a medical examination. For each crane operator entering the study, in the same week a control worker was asked to participate in the study. The control group worked as crane helpers, general operators or maintenance workers (n = 281 in the factory) and were matched for age by a 5 year OOI4-{)139/90 5300
© 1990 Taylor & Francis Ltd.
Downloaded by [New York University] at 23:20 26 October 2014
982
A. Burdorf and H. Zondervan
range. The workload between crane operators and controls was not comparable for all risk factors of LBP. The control workers carried out moderate or heavy physical work with more standing, walking and lifting, and less sitting, than crane operators. All subjects were examined by the on-site medical service. Each person had to answer 15 questions from a medical and occupational questionnaire, administered by an occupational physician. The medical questionnaire, derived from the standardized Nordic questionnaire (Kuorinka et al. 1987), concerned frequency, duration, nature and medical treatment of LBP. The prevalence of LBP was estimated by using the standardized question: 'Have you had pain in your lower back within the last twelve months?' (Biering-Sorensen and Hilden 1984). The presence of sciatica was derived from reported complaints on pain radiating to one or both legs. The occupational questionnaire was designed to obtain information of the earlier employment history and details of the present risk factors in the occupational environment in previous jobs, both inside and outside the steel company. In the statistical analysis the comparisons between cases and controls were based on the x2-test and the Fisher's exact test for categorical variables, and the r-test for continuous variables. Univariate logistic analyses were carried out in order to determine the importance of different variables for the occurrence of LBP. The regression coefficients in the logistic models were used to calculate odds ratios (Schlesselman 1982). Finally, a multivariate logistic regression was performed with all variables that in previous steps of the logistic regression analyses showed statistical significance at p < 0·1O. 3. Results Thirty-three out ofthe 49 (67%)crane operators invited participated in this study. The selection of matched controls was easy because none of the controls approached personally refused to participate. During the analyses three control workers were excluded because they worked on a crane for more than 10% of their daily working time, or they were exposed to whole-body vibration for more than one year in the past. Therefore, the final control group consisted of 30 subjects. Table I summarizes personal characteristics and employment history of crane operators and controls. The mean height and weight differ significantly between the groups, the controls being shorter and lighter. Table I.
Comparison of individual characteristics and working experience for crane operators and controls. Crane operators (n = 33) SO mean Individual characteristics age (yr) height (em) weight (kg) Work history total working experience (yr) work at the steel company (yr) years on a crane (yr)
• p
Ergonomics Publication details, including instructions for authors and subscription information: http://www.tandfonline.com/loi/terg20
An epidemiological study of low-back pain in crane operators a
ALEX BURDORF & HARRY ZONDERVAN
a
a
Institute of Occupational Health, Medical Faculty , Erasmus University, PO Box 1738 3000, DR Rotterdam, The Netherlands Published online: 24 Oct 2007.
To cite this article: ALEX BURDORF & HARRY ZONDERVAN (1990) An epidemiological study of low-back pain in crane operators, Ergonomics, 33:8, 981-987, DOI: 10.1080/00140139008925307 To link to this article: http://dx.doi.org/10.1080/00140139008925307
PLEASE SCROLL DOWN FOR ARTICLE Taylor & Francis makes every effort to ensure the accuracy of all the information (the “Content”) contained in the publications on our platform. However, Taylor & Francis, our agents, and our licensors make no representations or warranties whatsoever as to the accuracy, completeness, or suitability for any purpose of the Content. Any opinions and views expressed in this publication are the opinions and views of the authors, and are not the views of or endorsed by Taylor & Francis. The accuracy of the Content should not be relied upon and should be independently verified with primary sources of information. Taylor and Francis shall not be liable for any losses, actions, claims, proceedings, demands, costs, expenses, damages, and other liabilities whatsoever or howsoever caused arising directly or indirectly in connection with, in relation to or arising out of the use of the Content. This article may be used for research, teaching, and private study purposes. Any substantial or systematic reproduction, redistribution, reselling, loan, sub-licensing, systematic supply, or distribution in any form to anyone is expressly forbidden. Terms & Conditions of access and use can be found at http:// www.tandfonline.com/page/terms-and-conditions
ERGONOMITCS, 1990, YOLo 33, NO. 8,981-987
An epidemiological study of low-back pain in crane operators ALEX BURDORF and HARRY ZONDERYAN Institute of Occupational Health, Medical Faculty, Erasmus University, PO Box 1738, 3000 DR Rotterdam, The Netherlands
Downloaded by [New York University] at 23:20 26 October 2014
Keywords: Crane operators; Low-back pain; Prevalence; Occupational risk factors.
A survey among workers in a steel factory was conducted to determine the risk for low-back pain (LBP) among male crane operators. Crane operators (n = 33) were matched for age with male control workers (n = 30)and examined for frequency and nature of LBP by the on-site medicalservice. Comparison betweencrane operators and controls showed a statistically significant odds ratio for LBP of 3·6.Although crane operators had been exposed more often to backstraining factors in previous occupations, in the employed logistic analysis only their current job explained the elevated occurrence of LBP. It is suggested that workers in sedentary position with exposure to whole-body vibration are at special risk for LBP. The results of this study provide evidence to strongly recommend persons with a history of back complaints not to seek employment as crane operators.
I. Introduction The relationship between occupation and the risk of developing low-back pain (LBP) is not well understood, although several risk factors are known. There is evidence that workers in heavy manual jobs have a higher prevalence of LBP than light manual workers. Heavy lifting, frequent bending, static work posture, and whole-body vibration have been identified as important factors for the onset of LBP (Troup 1984, Yu et al. 1984). Because of the multifactorial nature of the etiology of LBP, the importance of individual risk factors remains still unclear (Riihirnaki et al. 1989). In the working conditions of operators on overhead travelling cranes, several strenuous work postures occur which can be assumed to increase the risk for LBP. In order to maintain a good view of the lifting device and the transported goods, several trunk movements are required. Frequent twisting, deep sideways bendings, and stooping positions occur frequently. Operating a crane demands a static sedentary position with hands held steady on the operating handles. While driving, the crane operators are exposed to whole-body vibration. On the basis of these known risk factors for LBP in the occupational environment of crane operators, a study was conducted to determine the frequency and nature of LBP and its occupational origin.
2. Materials and methods The survey population was restricted to subjects with a minimal duration of employment of one year, in order to avoid disturbances due to high labour turnover in the first months of employment. A total of 49 male operators working on overhead travelling cranes in a steel factory were invited by letter to take part in the study. They were asked to visit the occupational physician for a medical examination. For each crane operator entering the study, in the same week a control worker was asked to participate in the study. The control group worked as crane helpers, general operators or maintenance workers (n = 281 in the factory) and were matched for age by a 5 year OOI4-{)139/90 5300
© 1990 Taylor & Francis Ltd.
Downloaded by [New York University] at 23:20 26 October 2014
982
A. Burdorf and H. Zondervan
range. The workload between crane operators and controls was not comparable for all risk factors of LBP. The control workers carried out moderate or heavy physical work with more standing, walking and lifting, and less sitting, than crane operators. All subjects were examined by the on-site medical service. Each person had to answer 15 questions from a medical and occupational questionnaire, administered by an occupational physician. The medical questionnaire, derived from the standardized Nordic questionnaire (Kuorinka et al. 1987), concerned frequency, duration, nature and medical treatment of LBP. The prevalence of LBP was estimated by using the standardized question: 'Have you had pain in your lower back within the last twelve months?' (Biering-Sorensen and Hilden 1984). The presence of sciatica was derived from reported complaints on pain radiating to one or both legs. The occupational questionnaire was designed to obtain information of the earlier employment history and details of the present risk factors in the occupational environment in previous jobs, both inside and outside the steel company. In the statistical analysis the comparisons between cases and controls were based on the x2-test and the Fisher's exact test for categorical variables, and the r-test for continuous variables. Univariate logistic analyses were carried out in order to determine the importance of different variables for the occurrence of LBP. The regression coefficients in the logistic models were used to calculate odds ratios (Schlesselman 1982). Finally, a multivariate logistic regression was performed with all variables that in previous steps of the logistic regression analyses showed statistical significance at p < 0·1O. 3. Results Thirty-three out ofthe 49 (67%)crane operators invited participated in this study. The selection of matched controls was easy because none of the controls approached personally refused to participate. During the analyses three control workers were excluded because they worked on a crane for more than 10% of their daily working time, or they were exposed to whole-body vibration for more than one year in the past. Therefore, the final control group consisted of 30 subjects. Table I summarizes personal characteristics and employment history of crane operators and controls. The mean height and weight differ significantly between the groups, the controls being shorter and lighter. Table I.
Comparison of individual characteristics and working experience for crane operators and controls. Crane operators (n = 33) SO mean Individual characteristics age (yr) height (em) weight (kg) Work history total working experience (yr) work at the steel company (yr) years on a crane (yr)
• p
