Associations between maternal occupational exposures and pregnancy outcomes among Chinese nurses: a nationwide study.

BACKGROUND: Several studies have provided evidence about adverse pregnancy outcomes of nurses involved in occupational exposure. However, the pregnancy outcomes among nurses in middle-income countries are not well demonstrated. The main aim of this study is to present the prevalence and influencing factors of pregnancy outcomes among female nurses in China. METHODS: We included 2243 non-nurse health care workers, and 4230 nurses in this national cross-sectional study in China. Information on occupational exposures and pregnancy outcomes was collected using a face-to-face investigation. Odds ratios (ORs) were estimated through logistic regression. RESULTS: The proportion of threatened abortion, spontaneous abortion, and stillbirth of female nurses was 2.6%, 7%, and 2.1%, respectively. We found an increased risk of threatened abortion among nurses with overtime work (OR = 1.719, 95% CI 1.158-2.550). The risk of threatened abortion and spontaneous abortion was elevated among nurses handling disinfectant (OR = 2.293 and 1.63, respectively). We found a nearly twofold increased risk of premature birth (OR = 2.169, 95% CI 1.36-3.459) among nurses handling anti-cancer drugs. CONCLUSIONS: Our findings suggested that maternal occupational exposures might be associated with the risk of adverse pregnancy outcomes among female nurses in China. We recommend that policy-markers and hospital managers work together to reduce exposure to occupational hazards and improve pregnancy outcomes among female nurses.

Exposure to copper induces endoplasmic reticulum (ER) stress-mediated apoptosis in chicken (Gallus gallus) myocardium.

Copper (Cu), an omnipresent environmental pollutant, can cause potential harm to the public and ecosystems. In order to study the cardiotoxicity caused by Cu, molecular biology techniques were used to analyze the effect of Cu on ER stress-mediated cardiac apoptosis. In vivo investigation, 240 1-day-old chickens were fed with Cu (11, 110, 220, and 330 mg/kg) diet for 7 weeks. The consequence showed that high-Cu can induce ER stress and apoptosis in heart tissue. The vitro experiments, the Cu treatment for 24 h could provoke ultrastructural damage and upregulate the apoptosis rate. Meanwhile, GRP78, GRP94, eIF2α, ATF6, XBP1, CHOP, Bax, Bak1, Bcl2, Caspase-12 and Caspase-3 genes levels, and GRP78, GRP94 and Caspase-3 proteins levels were increased, which indicated that ER stress and apoptosis in cardiomyocytes. But the mRNA level of Bcl2 were decreased after Cu exposure. Conversely, Cu-induced ER stress-mediated apoptosis can be alleviated by treatment with 4-PBA. These findings generally showed that Cu exposure can contribute to ER stress-mediated apoptosis in chicken myocardium, which clarifies the important mechanism link between ER stress and apoptosis, and provides a new perspective for Cu toxicology.

Mitochondrial miR-1285 regulates copper-induced mitochondrial dysfunction and mitophagy by impairing IDH2 in pig jejunal epithelial cells.

Copper (Cu), a hazardous heavy metal, can lead to toxic effects on host physiology. Recently, specific mitochondria-localized miRNAs (mitomiRs) were shown to modulate mitochondrial function, but the underlying mechanisms remain undefined. Here, we identified mitomiR-1285 as an important molecule regulating mitochondrial dysfunction and mitophagy in jejunal epithelial cells under Cu exposure. Mitochondrial dysfunction and mitophagy were the important mechanisms of Cu-induced pathological damage in jejunal epithelial cells, which were accompanied by significant increase of mitomiR-1285 in vivo and in vitro. Knockdown of mitomiR-1285 significantly attenuated Cu-induced mitochondrial respiratory dysfunction, ATP deficiency, mitochondrial membrane potential reduction, mitochondrial reactive oxygen species accumulation, and mitophagy. Subsequently, bioinformatics analysis and luciferase reporter assay demonstrated that IDH2 was a direct target of mitomiR-1285. RNA interference of IDH2 dramatically reversed the effect that mitomiR-1285 knockdown relieved mitochondrial dysfunction and mitophagy induced by Cu, and the opposite effect was shown by overexpression of IDH2. Therefore, our results suggested that mitomiR-1285 aggravated Cu-induced mitochondrial dysfunction and mitophagy via suppressing IDH2 expression. These findings identified the important mechanistic connection between mitomiRs and mitochondrial metabolism under Cu exposure, providing a new insight into Cu toxicology.

Associations of age at natural menopause and occupations in Chinese female workers: A cross-sectional study.

AIMS: To investigate the impact of occupation types on age at natural menopause. METHODS: This is a nation-wide cross-sectional study based on 17,948 female workers aged over 40, who come from different industries or organizations. A face-to-face standardized questionnaire was conducted in all participants with the help of occupational hygienists. Occupational titles were coded according to the International Standard Classification of Occupations (2008) (ISCO08). Cox regression model was used to assess the association between each independent occupation and menopausal timing. Models were adjusted for marriage, education, average annual family income, parity, cigarette smoking, alcohol consumption. RESULTS: Higher risks of earlier age at natural menopause was found among legislators and senior officials (ISCO Minor group:111, HR = 2.328, P < 0.001), among other health associated professionals (ISCO Minor group: 325, HR = 1.477, P = 0.003), the workers involved in mining and mineral processing (ISCO Minor group: 811, HR = 1.515, P = 0.048) and metal processing and finishing (ISCO Minor group: 812, HR = 1.722, P < 0.001). Reduced risks of earlier age at natural menopause, including: finance professionals (ISCO Minor group: 241, HR = 0.751, P = 0.021), manufacturing and construction supervisors (ISCO Minor group: 312, HR = 0.477, P = 0.002), administrative and specialized secretaries (ISCO Minor group: 334, HR = 0.788, P = 0.045), cleaners and helpers (ISCO Minor group: 911, HR = 0.633, P = 0.01). CONCLUSIONS: This is the first study to address the influence of occupation types on reproductive aging, showing some specific occupations could be associated with age at natural menopause. Further investigations are necessary to clarify whether it is chance finding or a true association.

Copper induces energy metabolic dysfunction and AMPK-mTOR pathway-mediated autophagy in kidney of broiler chickens.

To explore the effects of copper (Cu) on energy metabolism and AMPK-mTOR pathway-mediated autophagy in kidney, a total of 240 one-day-old broiler chickens were randomized into four equal groups and fed on the diets with different levels of Cu (11, 110, 220, and 330 mg/kg) for 49 d. Results showed that excess Cu could induce vacuolar degeneration and increase the number of autophagosomes in kidney, and the adenosine triphosphate (ATP) level and mRNA levels of energy metabolism-related genes were decreased with the increasing dietary Cu level. Moreover, immunohistochemistry and immunofluorescence showed that the positive expressions of Beclin1 and LC3-II were mainly located in cytoplasm of renal tubular epithelial cells and increased significantly with the increasing levels of Cu. The mRNA levels of Beclin1, Atg5, LC3-I, LC3-II, Dynein and the protein levels of Beclin1, Atg5, LC3-II/LC3-I and p-AMPKα1/AMPKα1 were markedly elevated in treated groups compared with control group (11 mg/kg Cu). However, the mRNA and protein levels of p62 and p-mTOR/mTOR were significantly decreased with the increasing levels of Cu. These results suggest that impaired energy metabolism induced by Cu may lead to autophagy via AMPK-mTOR pathway in kidney of broiler chickens.

Menstrual disorders and occupational exposures among female nurses: A nationwide cross-sectional study.

BACKGROUND: The regularity of menstrual cycles is one of the important indicators of female reproductive health. However, the current evidence on the association of occupational exposures and menstrual disorders is scarce. OBJECTIVES: This study aims to elucidate the relationship between occupational hazards and menstrual characteristics in female nurses and non-nurse health care workers in China. DESIGN: We conducted a national cross-sectional study on the reproductive health of female nurses in China. SETTINGS: A total of 1, 300 medical institutions in 15 provincial administrative regions in China participated in the study. PARTICIPANTS: There were 8, 904 nurses and 3, 977 non-nurse health care workers who were selected using simple random sampling method. METHODS: All participants were administered a face-to-face standardized questionnaire, including personal socio-demographic information, occupational activities, and self-reported menstrual characteristics. Univariate and multivariate logistic regressions were used for statistical analyses. RESULTS: The results demonstrated that 41% of nurses experienced menstrual disorders. We found handling disinfectants was the most significant risk factor for menstrual disorders (OR = 1.53, 95% CI: 1.39-1.68), followed by abnormal workload (OR = 1.28, 95% CI: 1.19-1.39), and occupation as a nurse (OR = 1.28, 95% CI: 1.18-1.40). Noise, prolonged standing or frequent heavy lifting, night work, anti-cancer drug exposure, and overtime work were moderately associated with the occurrence of menstrual disorder (OR > 1). CONCLUSIONS: This national-wide cross-sectional study has revealed the significant association between menstrual disorders and occupational hazards among female nurses in China.

Copper induces oxidative stress and apoptosis through mitochondria-mediated pathway in chicken hepatocytes.

The aim of this study was to investigate the effects of excessive copper (Cu)-induced cytotoxicity on oxidative stress and mitochondrial apoptosis in chicken hepatocytes. Chicken hepatocytes were cultured in medium in the absence and presence of copper sulfate (CuSO4) (10, 50, 100 µM), in N-acetyl-L-cysteine (NAC) (1 mM), and the combination of CuSO4 and NAC for 24 h. Morphologic observation and function, reactive oxygen species (ROS) level, antioxidant indices, nitric oxide (NO) content, mitochondrial membrane potential (MMP), and apoptosis-related mRNA and protein levels were determined. These results indicated that excessive Cu could induce release of intracellular lactate dehydrogenase (LDH), aspartate aminotransferase (AST), and alanine aminotransferase (ALT); increase levels of ROS, superoxide dismutase (SOD), malondialdehyde (MDA), catalase (CAT), lipid peroxidation (LPO), and NO; decrease glutathione (GSH) content and MMP; upregulated Bak1, Bax, CytC, and Caspase3 mRNA and protein expression, inhibited Bcl2 mRNA and protein expression, and induced cell apoptosis in a dose effect. The Cu-caused changes of all above factors were alleviated by treatment with NAC. These results suggested that excessive Cu could induce oxidative stress and apoptosis via mitochondrial pathway in chicken hepatocytes.

Autophagy attenuates copper-induced mitochondrial dysfunction by regulating oxidative stress in chicken hepatocytes.

Copper (Cu) is an essential trace element that is required for the catalysis of several cellular enzymes. Excessive Cu could induce hepatotoxicity in humans and multiple animals. The purpose of this study was to investigate the effects of autophagy machinery on Cu-induced hepatotoxicity. Chicken hepatocytes were cultured in medium in the absence and presence of Cu sulfate (CuSO4) (0, 10, 50, and 100 µM) for 0, 6, 12, and 24 h, and in the combination of CuSO4 and N-acetyl-l-cysteine (NAC) (1 mM), rapamycin (10 nM), and 3-methyladenine (3-MA) (5 mM) for 24 h. Results showed that Cu could markedly increase the number of autophagosomes and LC3 puncta, induce autophagy-related genes (Beclin1, ATG5, LC3Ⅰ, LC3Ⅱ, mTOR, and Dynein) mRNA expression and proteins (BECN1, LC3Ⅱ/LC3Ⅰ) expression. NAC could relieve Cu-induced the changes of above genes and proteins. Additionally, rapamycin attenuated Cu-induced the increased lactic dehydrogenase (LDH), aspartate amino transferase (AST), and alanine aminotransferase (ALT) activities, and SOD-1 mRNA expression as well as the decreased cell viability, reactive oxygen species (ROS), hydrogen peroxide, total superoxide dismutase (T-SOD), malonaldehyde (MDA), catalase (CAT), HO-1 mRNA expression, adenosine triphosphate (ATP) levels, mitochondrial mass, and mitochondria membrane potential (MMP). But 3-MA had the opposite effects on above factors. Collectively, these findings provide strong evidence that Cu could induce autophagy by generating excessive ROS in hepatocytes, and autophagy might attenuate Cu-induced mitochondrial dysfunction by regulating oxidative stress.

[An investigation of prevalence of malignant tumors in 1204 nurses].

OBJECTIVE: To investigate the prevalence of malignant tumors in nurses and its influencing factors and to provide a reference for protecting the health of nurses. METHODS: Cluster sampling was used to randomly survey 1204 married nurses working in one tumor hospital and two tertiary general hospital in Beijing, China, from June to August in 2014. Using the homemade health questionnaire and medical examination reports, the prevalence of malignant tumors in nurses was analyzed. RESULTS: The prevalence of malignant tumors in nurses was 18.3‰, and the prevalence of malignant tumors in the tumor hospital was the highest, reaching 40.1‰. The prevalence of malignant tumors varied significantly between nurses in different hospitals (P<0.05) and in different departments (P<0.05). The malignant tumors in nurses mainly included breast cancer, thyroid cancer, and cervical cancer. The mean age of nurses suffering from malignant tumors was 41 years, and the mean length of service was 20 years. The hospital and department where nurses worked, as well as their age and length of service, were significantly associated with malignant tumors (P<0.05). CONCLUSION: The prevalence of breast cancer, thyroid cancer, and cervical cancer is high in nurses surveyed, particularly those working in the tumor hospital. Further in-depth analysis of the reasons is needed to take preventive interventions for protecting the health of nurses.

[Analysis on reproductive health status and influencing factors of female workers of pharmaceutical industry in Gansu province].

OBJECTIVE: To understand the reproductive health status of female workers in pharmaceutical industry of Gansu Province, to explore influencing factors, and to propose some reference basis of intervening measures. METHODS: The cluster sampling method was used to study 1801 female workers from 16 pharmaceutical industries in 6 cities (Pingliang, Qingyang, Lanzhou, Dingxi, Zhangye and Jiuquan cities) of Gansu Province. The investigation was performed by interviewing and adopting questionnaires. RESULTS: There were the problems of labor and organization, which included the overtime work, continuous work, standing for long periods, rapid monotonous action assignments, the loading work and a variety of harmful factors in the working environment of the pharmaceutical industry in Gansu Province. There were many problems in the reproductive health status of female workers. The morbidities of abnormal menstruation and breast diseases in female workers were 43.25% and 20.43%. The order of high morbidities was hyperplasia of mammary glands (91.30%), breast adenofibroma (5.43%) and mastitis (2.99%). The order of morbidities for three reproductive system disease was adnexitis (21.57%), cervical erosion (20.06%) and vaginitis (11.09%). The rates of abnormal menstrual cycle, abnormal menstrual amount and cervical erosion increased with the length of service (P < 0.01). The taking breaks, long standing, loading work, exposure to harmful factors were related to abnormal menstruation (P < 0.05). The rapid repeat monotonous action was an important influencing factor for female reproductive system disease (OR = 1.255, 95%CI = 1.031 ∼ 1.528). CONCLUSION: There are relatively serious occupational hazards in the pharmaceutical industry of Gansu Province. The reproductive health status of female workers is not improved. Social public should pay attention to the protection for female workers.