How Work Organization Affects the Prevalence of WMSDs: A Case-control Study / 生物医学与环境科学（英文）

<p><b>OBJECTIVE</b>In this study, we aimed at exploring the association between work-related musculoskeletal disorders (WMSDs) and work organization based on a case-control study.</p><p><b>METHODS</b>A total of 1938 workers who claimed to suffer from WMSDs were selected from Beijing, Henan, Hubei, and the Guangdong province. The control group consisted of 2009 workers employed in similar industries without severe disease or musculoskeletal discomforts. We used a modified version of the questionnaire developed by the NMQ and the DMQ to investigate individual and work-related factors.</p><p><b>RESULTS</b>A total of 13 variables (P<0.1) were selected by the chi-square test and finally, 7 variables entered into the equation, with 6 variables reaching statistical significance (P<0.05). The odds ratios (OR) of 'work changing with season' and 'sufficient rest time' did not reach 1 (0.749 and 0.441, respectively). In addition, 'sufficient rest time' seemed to be the stronger protective factor according to its higher standardized coefficient. And 'repetitive work every minute', 'constantly repetitive work' (every day), 'shortage of site personnel', and 'often switching shifts with others' seemed to be the risk factors.</p><p><b>CONCLUSION</b>Work organization may have comprehensive effects on the occurrence of WMSDs. This pattern of associations suggests that further investigation into the mechanism of how work organization affects the prevalence of WMSDs is required.</p>

Impact of specimen collection and storage consumable products on trace element quantitative analysis / 中华预防医学杂志

<p><b>OBJECTIVE</b>This study aimed to explore the impact of specimen collection and storage consumable products on trace element quantitative analysis.</p><p><b>METHODS</b>Devices and consumable products of different brands used in specimen collection or storage were selected and treated separately as below:urine collection and storage tubes (Brand A, B, C and D, 2 samples for each brand) were treated with 1% of HNO(3) volume fraction for 2 - 4 h; blood taking device (Brand O, P and Q, 3 samples for each brand) were used for ultra-pure water samples collecting as simulation of blood sampling;dust sampling filters (Brand X, Y and Z, 2 samples for each brand) were cold digested by nitric acid for 12 h, followed by microwave digestion. Then cadmium, cobalt, chromium, copper, iron, manganese, molybdenum, nickel, lead, selenium, stannum, titanium, vanadium and zinc concentrations in the solutions obtained during the course of collect or storage were quantified by inductively coupled plasma mass spectrometer.</p><p><b>RESULTS</b>For the urine collection and storage consumable products, background values of elements were described as mean of parellel samples. The consentration of 14 quantified elements were relatively low for 5 ml cryogenic vials (brand B) with background values range of 0.001 - 0.350 ng/ml. The background values of copper of 50 ml centrifuge tubes (brand A), chromium of 5 ml cryogenic vials (brand C) and zinc of 1.5 ml centrifuge tubes (brand D) were relatively high, which were 1.900, 1.095 and 1.368 ng/ml, respectively. Background values of elements in blood sampling devices were described as x(-) ± s. Background values of chromium for brand O, P and Q were (0.120 ± 0.017), (0.337 ± 0.093) and (0.360 ± 0.035) ng/ml; for copper were (0.050 ± 0.001), (0.017 ± 0.012) and (0.103 ± 0.015) ng/ml; for lead were (0.057 ± 0.072), (0.183 ± 0.118) and (0.347 ± 0.006) ng/ml; for titanium were (7.883 ± 0.145), (8.863 ± 0.190) and (8.613 ± 0.274) ng/ml; zinc were (2.240 ± 0.573), (42.140 ± 22.756) and (8.850 ± 3.670) ng/ml. There were statistically differences of background values for chromium, copper, lead, titanium and zinc among the above three brands of blood sampling devices (all P values < 0.05). For air sampling filters, background values of elements were described as mean of parellel samples. Background values of chromium and nickel of sampling filters (brand X) were lowest, which were 17.000 and 15.400 ng per piece, respectively; while background values for other elements were relatively high, the quantification of cadmium, cobalt, copper, iron, manganese, molybdenum, lead, selenium, stannum, titanium, vanadium and zinc were 0.250, 0.550, 48.500, 690.000, 25.500, 0.900, 6.500, 10.550, 7.950, 10.500, 0.850, 370.000 ng per piece, respectively. Background values of chromium and nickel of sampling filters (brand Z) were highest, which were 171.000 and 29.850 ng per piece.</p><p><b>CONCLUSION</b>Background values of trace elements varied among products of different brands, and the most noticable differences were found in chromium, manganese, nickel, lead, stannum and zinc.</p>