A Cross-Sectional And Mechanism Study On Work-Related Musculoskeletal Disorders In Female Sewing Workers

[Objective]To collect the epidemical data on work-related musculoskeletal disorders, analyze the affecting factors on low back pain in femal sewing workers and to explore the mechanism of muscle injury caused by static load.[Methods]A cross-sectional investigation was carried out and self-answered questionnaires performed by 300 female sewing workers and 300 female free posture workers.The annual prevalence of work-related musculoskeletal disorders and its influence on normal life and work in the last one year were collected in the questionnaires.The questionnaires were made out by informant themselves.A logistic regression analysis was used to analyze the affecting factors on low back pain,including individual factors,occupational factors,psychological factors and organizational factors.The contents of maleic dialdehyde in rabbit serum,the activity of glutathione peroxidasep,creatine kinase and superoxide dismutase in rabbit serum and the activity of Ca²⁺-Mg²⁺-ATP enzyme in rabbit psoas muscle chondriosome was measured with constructing a static load animal model.[Results]The total annual prevalence of WMSDs in femal sewing workers is 82.0%and the sort order by annual prevalence(high to low)is shoulder,neck,low back, hand/wrist,upper back,buttocks/upper leg,elbow,ankle/foot,knee.The variance between control and study group has a statistical significance in all parts of the musculoskeletal systems(P＜0.05).The increasing tendency of the prevalence of WMSDs following with age and length of service is clear and linear.On the four higher prevalence parts,serious influences were caused by WMSDs among 33.3% patients,such as lossing work capacity,asking for leave,baffling living,and there are 70%patients with a duration of symptoms for half a year,50%patients with symptoms everyday and 50%patients considered that WMSDs were completely caused by working.On the four higher prevalence parts,there are only 17.6%patients visited in hospital because of pain.The single factor analysis shows that the variances between control and study group in the fators of age,exercise,marriage,length of service,the degree of satisfaction of job,work environment,the degree of fatigue,interpersonal relationship, support from managers and colleagues have statistical significances(P＜0.05).Age,work environment,the degree of fatigue were selected in the logistic regression model.The degree of fatigue and work environment have medial correlate with low back pain,and age has a weak correlate with low back pain.One week later,the content of MDA in rabbit serum in the study group increased obviously(P＜0.01)and is highter than the control group statistically(P＜0.05).The activity of GSH-PX in rabbit serum increased obviously(P＜0.01)and is highter than the control group statistically(P＜0.01).The activity of SOD in rabbit serum increased obviously(P＜0.05),and is not highter than the control group statistically(P＞0.05). The activity of CK in rabbit serum increased obviously(P＜0.01),and is highter than the control group statistically(P＜0.05).Two weeks later,the content of MDA in rabbit serum in the study group increased obviously(P＜0.01)and is highter than the control group statistically(P＜0.01).The activity of GSH-PX in rabbit serum reduced than itself after the first week,but is still higher than itself before the experiment and is highter than the control group statistically(P＜0.01).The activity of SOD in rabbit serum increased obviously(P＜0.01),and is highter than the control group statistically(P＜0.01).The activity of CK in rabbit serum increased obviously(P＜0.01),and is highter than the control group statistically(P＜0.01).Two weeks later,the activity of Ca²⁺-Mg²⁺-ATP enzyme in rabbit psoas muscle chondriosome in the study group statistically lower than the control group(P＜0.05).[Conclusions]The annual prevalence of WMSDs in femal sewing workers was up to 82.0%. The annual prevalence of shoulder,neck and low back were ranked first,second and third in the musculoskeletal systems.WMSDs did serious influences on workers'work and life,but it was not paid much attention.Low back pain may be caused by many different factors,and in order to mitigate the influence of low back pain,much attention must be paid to work posture,work load,organization management,work environment,individual protection,and health education.Muscle injury may be caused by the increase of the permeability of cellular membrane and the disorder of energy supply of myocyte which were caused by the great quantity of free radicle in the body induced by sustained static load.CK,MDA, SOD,GSH-PX and Ca²⁺-Mg²⁺-ATP enzyme may be the biomarkers of muscle injury caused by static load and a further study on the association between these indexes needed.