. Working in an office environment is widely known to be associated with work-related musculoskeletal disorders (WMSDs), which are a diverse set of conditions characterized by pain, aching, stiffness, fatigue, discomfort, tingling and/or numbness, generally appearing in the fingers, hand, wrist, elbow, arm, shoulder, neck and/or low back 2) . The literature consistently demonstrates that VDT users are at increased risk for neck and/or shoulder symptoms relative to the risk expected in low-exposure office or industrial tasks 3,4) . WMSDs in the neck (WMSDs-N) are the most common work-related upper extremity disorders (WRUEDs), and a large range of individual, physical and psychosocial risk factors are associated with the development of WMSDs-N. Individual factors include age, gender, education level, smoking habits and so on; work-related physical factors include awkward posture during work, bending, static sedentary posture and task demands; work-related psychosocial factors include overtime and time spent working to meet deadlines [5][6][7] . In addition, several studies have shown that ergonomic factors (e.g., work station design) were possibly linked to WRUEDs Department of Occupational and EnvironmentalHealth, School of Public Health, Peking University, P.R. China-Objectives: Little is known about workrelated musculoskeletal disorders (WMSDs) among computer users mainland China. The aim of this study was to estimate the prevalence of WMSDs in office workers in Beijing, and to determine risk factors for WMSDs in the neck (WMSDs-N). Methods: In a crosssectional study, a self-administered questionnaire was delivered to 720 office workers who use a computer as a main working tool. Odds ratios (ORs) were calculated for risk factors. Results: The prevalence of WMSDs of the neck, shoulder, wrist/hand, upper back and low back amongst office workers were 55.5, 50.7, 31.5, 26.2 and 6.6%, respectively. Both individual risk factor and working condition factors were found to be independently related to WMSDs-N. Conclusions: The WMSDs prevalence rates among office workers in Beijing, China, were high. The most affected area was the neck. Preventive measures for office work should be focused on the neck (e.g., rest breaks). (J Occup Health 2012; 54: 34-43)

The results suggest that interventions aimed at reducing musculoskeletal symptoms in the Chinese working population should take into account multiple risk areas including individual, physical job characteristics and work-related psychosocial factors.

Medical staff in the department of obstetrics and gynecology are a group of professionals reportedly at high risk of work-related musculoskeletal disorders (WMSD), however, little is known about the current status of this problem in China. The aim of this study was to investigate prevalence and risk factors of work-related musculoskeletal disorders among this population in China. A self-developed questionnaire was distributed to 1017 obstetrics and gynecology practitioners to collect information on musculoskeletal symptoms and relevant factors. Prevalence and severity of work-related musculoskeletal disorders in different parts of the body were calculated and the relationship between personal and ergonomic factors and work-related musculoskeletal disorders was analyzed using Chi-square test and unconditional logistic regression models. The results indicated a high prevalence of 85.5% among the subjects, with the shoulder (n = 575, 62.0%), neck (n = 560, 60.3%) and lower back (n = 504, 54.3%) being the three most affected regions. Individual, postural, work-environmental as well as psychosocial factors were recognized to be associated with WMSDs in different body parts. Therefore, attention must be given to the problem of musculoskeletal disorders among Chinese obstetrics and gynecology staff. It is recommended to develop good life habits, improve work environment, adjust work organization as well as train on proper postures in their daily operation.

Although past research has suggested that acute exposure to extremely low-frequency magnetic field (ELF MF) impairs learning and memory function, data on chronic exposure remain scarce. In this study, we examined the changes in spatial learning and memory by the Morris water maze test after 4 weeks of daily exposure of rats to a 50-Hz magnetic field of 2 mT for either 1 or 4 h. We found that chronic exposure to ELF MF reduced the latency to find the hidden platform and improved long-term memory of former location of platform without affecting the short-term memory and motor activity. These findings for the first time indicate that chronic exposure to ELF MF exerts a positive effect on the acquisition and maintenance of spatial memory.