Objective: To study the prevalence of occupational musculoskeletal disorders (OMSD) of male steelworkers and explore its occupational and individual risk factors.
Methods: 1620 male workers from a steel mill were selected as subjects through random cluster sampling in 2010. A revised Nordic Musculoskeletal disorder standard questionnaire and a questionnaire from National Institute for Occupational and Health of the Netherlands were used to ask and record the OMSD and its risk factors. The questionnaires were filled in by the workers. Annual prevalence of OMSD in different parts of the body were counted according to different age, working years and educational level, logistic regression was used to analyze its influence factors.
Results: OMSD in these workers primarily located in waist, neck and shoulders, annual prevalence were 51.0% (825), 48.5% (785) and 37.7% (610) respectively. Annual prevalence of other body parts were 28.0% (454) for back, 23.6% (383) for knee, 21.0% (341) for wrist, 17.9% (290) for ankle/foot, 14.1% (229) for elbow and 12.7% (205) for coxa. The annual prevalence of OMSD for each part tended to increase with age, mainly in waist and neck. Of the different age groups ≤ 24, 25 - 29, 30 - 34, 35 - 39, 40 - 44, 45 - 49, ≥ 50, the annual prevalence in waist was 26.4% (43/163), 37.8% (71/188), 52.8% (162/307), 55.6% (160/288), 53.8% (99/184), 55.9% (80/143), 61.6% (204/331) respectively (χ(2) = 72.5, P < 0.05); correspondingly, the annual prevalence in neck was 22.7% (37/163), 40.4% (76/188), 50.2% (154/307), 48.6% (140/288), 56.0% (103/184), 53.1% (76/143), 57.7% (191/331) respectively (χ(2) = 65.3, P < 0.05). The annual prevalence of OMSD increased with the working years. Of the different working years groups ≤ 4, 5 - 9, 10 - 14, 15 - 19, 20 - 24, 25 - 29, ≥ 30, the annual prevalence in waist was 30.2% (85/281), 46.2% (66/143), 56.4% (162/287), 56.8% (137/241), 50.6% (78/154), 59.2% (90/152), 60.7% (173/285) respectively (χ(2) = 71.3, P < 0.05);correspondingly, the annual prevalence in neck was 28.8% (81/281), 49.0% (70/143), 52.6% (151/287), 50.2% (121/241), 51.9% (80/154), 53.9% (82/152), 59.3% (169/285) respectively (χ(2) = 61.5, P < 0.05). The annual prevalence of OMSD decreased with education level. Of the different groups of education level (junior high school level and below, senior high school level, university level or above), the OMSD prevalence in waist was 61.5% (176/286), 61.9% (359/692), 44.2% (272/615) respectively (χ(2) = 26.0, P < 0.05);correspondingly, the annual prevalence in neck was 56.3% (161/286), 50.0% (346/692), 42.3% (260/615)respectively (χ(2) = 21.2, P < 0.05). Univariate logistic regression showed that the work load factors such as the working years ≥ 30 (OR = 3.562, 95%CI: 2.514 - 5.046), maintain substantial stoop for a long time (OR = 2.003, 95%CI: 1.612 - 2.488), often stooping with vast scale (OR = 1.897, 95%CI: 1.557 - 2.312), and torso repeating same action many times per minute (OR = 1.870, 95%CI: 1.529 - 2.288) could increase the annual prevalence of OMSD in waist most likely (P < 0.05). The working years ≥ 30 (OR = 3.597, 95%CI: 2.535 - 5.105), neck leaning forward (OR = 2.455, 95%CI: 2.010-2.99), neck leaning back (OR = 1.999, 95%CI: 1.569 - 2.546), and neck rotation (OR = 2.381, 95%CI: 1.907 - 2.972) were main risk factors causing OMSD in neck (P < 0.05).
Conclusion: The most serious musculoskeletal disorders of male steelworkers were waist and neck pain. Personal factors such as age, working years, work load factors such as harmful working postures, manual heavy lifting, and labour organizational factors such as work overtime were the main risk factors of musculoskeletal disorders to the male steelworkers.