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Objectives To explore the dose-response relationship between low-dose ionizing radiation and thyroid hormone levels of radiation medical workers and provide theoretical basis for occupational health protection to this population. Methods Using a prospective cohort study design, we collected health examination reports on employees that worked on jobs with occupational exposure to radiation at hospital with individually dose monitoring data for 1 237 workers. The effective cumulative radiation dose was divided into three groups: 0～2.586 mSv, 2.586～3.757 mSv, 3.758～31.272 mSv by the interquartile range. The low-dose group was used as a reference to compare the changes in thyroid hormones of medical workers in different cumulative radiation dose groups. The generalized linear models and restricted cubic spline model were used to examine the association and dose-response relationship between the cumulative effective dose and changing thyroid hormones. Results There were statistically significant differences in changing thyroxine (T4) and Free triiodothyronine (FT3) levels among three different dose groups of 1237 subjects (P < 0.05). The results of generalized linear models analysis revealed that 2.586～3.757 mSv was a significant risk factors of changing T4, with β of 3.514 (95% confidence interval [95% CI]: 0.900～6.128) after adjusting for gender, age, working duration, occupation, medical level and smoking, while the association with changing FT3 was not observed (P > 0.05). The restrictive cubic spline (RCS) model analysis indicated a non-linear dose-response correlation between cumulative radiation dose with changing T4 (P = 0.023). Conclusion Long-term exposure to low-dose ionizing radiation could induce the thyroid damage among medical occupational population. And there is a dose-response relationship between cumulative radiation dose and changing thyroxine.
ABSTRACT
BACKGROUND@#Numerous studies have concentrated on high-dose radiation exposed accidentally or through therapy, and few involve low-dose occupational exposure, to investigate the correlation between low-dose ionizing radiation and changing hematological parameters among medical workers.@*METHODS@#Using a prospective cohort study design, we collected health examination reports and personal dose monitoring data from medical workers and used Poisson regression and restricted cubic spline models to assess the correlation between changing hematological parameters and cumulative radiation dose and determine the dose-response relationship.@*RESULTS@#We observed that changing platelet of 1265 medical workers followed up was statistically different among the cumulative dose groups (P = 0.010). Although the linear trend tested was not statistically significant (P@*CONCLUSION@#We concluded that although the exposure dose was below the limit, medical workers exposed to low-dose ionizing radiation for a short period of time might have increased first and then decreased platelets, and there was a dose-response relationship between the cumulative radiation dose and platelets changing.
Subject(s)
Adult , Aged , Female , Humans , Male , Middle Aged , Young Adult , Blood Platelets/radiation effects , Health Personnel/statistics & numerical data , Occupational Exposure/adverse effects , Prospective Studies , Radiation Dosage , Radiation Exposure/adverse effects , Radiation, IonizingABSTRACT
OBJECTIVE: To establish a method for detecting dichloromethane,trichloromethane and 1,2-dichloroethane in blood by gas chromatography-mass spectrometry. METHODS: Using static headspace analysis, three halogenated hydrocarbons in blood samples were separated by DB-5 MS elastic capillary column and detected by gas chromatographymass spectrometry. RESULTS: There was a good linear relationship in the selected range of dichloromethane,trichloromethane and 1,2-dichloroethane in blood. The linear correlation coefficient was greater than 0. 999 8. The detection limit and the lower limit of quantitation was 0. 19-0. 28 and 0. 64-0. 93 μg/L,respectively. The average recovery rate was 95. 1%-106. 6%. The within-run and between-run relative standard deviation was 2. 9%-4. 9% and 5. 0%-7. 0%,respectively. The samples could be preserved at room temperature or 4 ℃ for 3 days and at-8 ℃ or below for7 days. CONCLUSION: With the features of high sensitivity,precision,accuracy,easy operation and less interference,this method is suitable for detecting dichloromethane,trichloromethane and 1,2-dichloroethane in the blood.
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Objective@#To investigate the occupational health survey of 1-brominepropane (1-BP) enterprises and understand the impact of 1-BP on the health of occupational exposure population.@*Methods@#The occupational health data of 15 1-BP workers were collected from 3 time nodes in 0 months, June and December, and the effects of occupational exposure to 1-BP on health were analyzed.@*Results@#In the workplace with pure 1-BP, the mean air concentration in the workplace was 26.8 mg/m3, and the personal contact level was 29.7 to 63.4 mg/m3. The occupational health monitoring data showed that white blood cell count (WBC) , red blood cell count (RBC) , aspartate aminotransferase (AST) and alanine aminotransferase (ALT) were compared in 0 months, June, and 12 months, the difference was statistically significant (P<0.05) .@*Conclusion@#During the 12 months observation period, the occupational exposure to 1-BP caused the number of peripheral blood erythrocyte and leukocyte count and the level of alanine transaminase in the workers, but it did not exceed the normal reference range.
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BACKGROUND: This study was conducted to identify epidemiological characteristics of the first documented CHIK fever outbreak in China and evaluate the effect of the preventive measures taken. METHODOLOGY/PRINCIPAL FINDINGS: From September 1 to October 29, 2010, China's first documented outbreak of CHIK fever occurred in the Xincun community of Wanjiang District of Dongguan city, Guangdong province; 253 case-patients were recorded, of which 129 were laboratory confirmed, with an attack rate of 1%. Before September 18(th) the number of CHIK fever cases remained relatively low in the Xincun community; from September 19(th) onwards, the number of cases increased drastically, with an outbreak peak on October 4(th). Cases were distributed across nine small village groups in the Xincun community, with an attack rate of 0-12% at the village level. The household attack rates ranged between 20% and 100%. No significant difference was found in the attack rate between males and females. There was a significant difference in the attack rate in different age groups (chi-square=18.35, p=0.005); highest in patients aged 60 years or older and the lowest in patients aged under 10. The major clinical characteristics of patients are fever (100%), joint pain (79%) and rash (54%). Phylogenetic analysis of the E1 gene on the five earliest confirmed cases showed that the strains of CHIKV isolated from their sera were highly homologous (up to 99%) with isogeneic strains isolated in Thailand in 2009. After control measures were taken, including killing adult mosquitoes and cleaning breeding habitats of Aedes mosquitoes, the Breteau index and Mosq-ovitrap index decreased rapidly, and the outbreak ended on October 29. CONCLUSION/SIGNIFICANCE: The infection source of the outbreak was imported. Cases showed obvious temporal, spatial, and population aggregation during the outbreak. Comprehensive control measures based on reducing the density of Aedes mosquitoes were effective in controlling the epidemic.
