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Background The optimal model method for estimation of benchmark dose (BMD) does not consider the uncertainty of model selection. There is a lack of studies on using Bayesian model averaging (BMA) to estimate BMD. Objective To apply BMA to the exposure assessment of cadmium pollution in China, discuss the role of BMA in estimating BMD based on dose-response models, and to provide methodological support for health risk assessment of hazardous substances. Methods The parameters of five dose-response models (Gamma, Log-logistic, Log-probit, Two-stage, and Weibull models) estimated from the data from a cadmium-contaminated area in Baiyin City of Gansu Province and the urinary cadmium ranges in five cadmium-contaminated areas in China were used to simulate the data of varied correct models with different numbers of dosage groups (5 and 8) and different sample sizes (50, 100, and 200), then the performance of BMA and traditional optimal model were compared. The case analysis used the cadmium exposure data in Baiyin, Gansu Province. All analyses set urinary cadmium as the indicator of cadmium exposure, the abnormal rate of β2-microglobulin as the effect indicator, and the benchmark response to 10%. The correct model (the model used when simulating data), optimal model [the model with smallest Akaike information criterion (AIC)], and BMA were used to estimate BMD and lower confidence limit of benchmark dose (BMDL); the BMDs, BMDLs, and relative deviations from different methods were compared. Results In the simulation study, with increasing sample size or the number of dosage groups, the intervals of the 5th percentile and the 90th percentile of BMD tended to be narrower; when the correct model was a single model, the relative deviation of BMD estimation by BMA was greater than that of the traditional optimal model; when the correct model was an equal weight mixed model, the relative deviation of BMD estimation by BMA was less than that by the traditional optimal model. For the data of cadmium-contaminated areas, the optimal model was a Log-probit model (AIC=1814.46), followed by a Log-logistic model (AIC=1814.57); the BMDs (BMDLs) estimated by the Log-probit model, the Log-logistic model, and BMA were 3.46 (2.68), 3.16 (2.33), and 2.92 (2.07) μg·g−1, respectively. Conclusion The traditional optimal model is still recommended when the correct model is known. However, when the dose-response relationship of a hazardous substance is uncertain or with different sources or exposure grouping, compared with the traditional optimal model, BMA theoretically provides more stable estimation of BMD and BMDL by considering multiple possible alternative models.
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Objective:To investigate the iodine content distribution of drinking water in Jiangsu Province.Methods:In 2017, the iodine content in drinking water of residents in townships (streets, hereinafter referred to as townships) of Jiangsu Province was investigated. Administrative villages (neighborhood committees, hereinafter referred to as administrative villages) of Jiangsu Province were selected as units for the investigation of townships with the median water iodine greater than 10 μg/L. Delimitation criteria: the median iodine content of water < 40 μg/L was iodine deficiency area, 40-100 μg/L was suitable iodine area, and > 100 μg/L was high iodine area.Results:A total of 1 285 townships were surveyed in 101 counties (cities, districts) in 13 cities, and the median water iodine in townships was 7.28 μg/L. Among them, there were 875 townships with median water iodine < 10 μg/L, accounting for 68.09%; 315 townships 10-< 40 μg/L, accounting for 24.51%; 56 townships 40-100 μg/L, accounting for 4.36%; 39 townships > 100 μg/L, accounting for 3.04%. The water iodine survey at the administrative village level was conducted in 5 864 administrative villages in 410 townships in 6 cities. Among them, 769 administrative villages with median water iodine < 10 μg/L, accounting for 13.11%; 3 558 administrative villages 10 - < 40 μg/L, accounting for 60.68%; 613 administrative villages 40 - 100 μg/L, accounting for 10.45%; and 924 administrative villages > 100 μg/L, accounting for 15.76%.Conclusion:According to the water iodine, there are iodine deficiency, suitable iodine and high iodine areas in Jiangsu Province, mainly in iodine deficiency areas.
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Objective To estimate the dose-response relationship between sedentary behavior with mortality in patients with type 2 diabetes. Methods A total of 17786 type 2 diabetic patients were recruited as participants, who were included in National Basic Public Health Service in Changshu County of Suzhou City, Qinghe District and Huai'an District in Huai'an City of Jiangsu Province. Cox proportional hazards regression model and restricted cubic spline model were employed to estimate the dose-response relationship between sedentary behavior with all-cause and cause specific mortality in patients with type 2 diabetes. Results Among 78114.34 person-years of the fo1low-up, the median of follow-up time was 4 years, and 1285 deaths occurred during that period. Compared to patients with sedentary behavior≤2 h/d, the multivariate adjusted hazard ratios of all-cause death associated with sedentary behavior levels of 3-4 h/d, 5-6 h/d, and≥7 h/d were 1.05(95％CI 0.92-1.20), 1.20(95％CI 1.03-1.42), and 1.39 (95％CI 1.16-1.65), respectively. Eevry increase of 1 h/d in sedentary behavior was associated with an increased hazard of death from cardiovascular disease(CVD) of 4％(HR=1.04, 95％CI 1.01-1.07) and from other causes of 6％( HR=1.06, 95％CI 1.03-1.09) . However, no significant association between sedentary behavior and malignant tumor death was found. The multivariable restrictive cubic spline regression indicated that the linear dose-response relationships were found between sedentary time with the all-cause, CVD cause, and other cause of mortality ( Non-linear test, P>0.05) . Conclusion Longer sedentary behavior could increase the risk of mortality in patients with type 2 diabetes.
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Objective@#To investigate the relationship between duration of sleep and all-cause mortality in patients with type 2 diabetes.@*Methods@#A total of 17 452 type 2 diabetic patients who were under the National Basic Public Health Service Project, in Changshu county, Qinghe district and Huai’an district in Huai’an city of Jiangsu province, were recruited as participants. Cox proportional hazards regression models were used to estimate the associations between different levels on the duration of sleep and all-cause mortality. Stratified analysis was performed according to factors as gender, age, and lifestyle.@*Results@#Among the 67 912 person-years of observation, from the fo1low- up program, the median time of follow-up was 4 years, with 1 057 deaths occurred during the follow-up period. Taking patients with duration of sleep as 7 h/d for reference, the multivariate adjusted hazard ratios (95%CI) of all-cause mortality appeared as ≤6, 8, 9 and ≥10 h/d were 1.14 (0.94-1.37), 1.10 (0.91-1.32), 1.33 (1.05-1.70), and 1.52 (1.24-1.87), respectively which were associated with the duration of sleep. Data from the subgroup analysis showed that this was consistent with the whole population. Longer duration of sleep was associated with the all-cause mortality but no significant association was found between shorter duration of sleep and the all-cause mortality.@*Conclusion@#Longer duration of sleep seemed to have increased the risk of all-cause mortality in type 2 diabetic patients.
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Objective: To observe the effect of ethanol extract of Crataegus Pinnatifida Bge. Var. major N. E. Br. from Hei-longjiang province on hemodynamics of acute myocardial ischemia caused by ligation and platelet aggregation induced by isoproterenol. Methods:After the model establishment of acute myocardial ischemia by ligation in rats, the systolic blood pressure ( SBP) ,diastolic blood pressure ( DBP ) , heart rate ( HR ) , left ventricular systolic pressure ( LVSP ) , left ventricular end-diastolic pressure ( LV-EDP) , left ventricular peak systolic ( +) and diastolic ( -) rate ( ± dp ·dt max-1 ) were recorded. Meanwhile, the acute myocar-dial ischemia model induced by isoproterenol was established. The platelet aggregation was measured by a platelet aggregation instru-ment. Results:The ethanol extract of Crataegus Pinnatifida Bge. Var. major N. E. Br. from Heilongjiang province could significantly increase the SBP, DBP, LVSP, +dp · dtmax-1 and HR, and reduce LVEDP,-dp·dtmax-1 in high dose group with statistical sig-nificance (P<0. 05). The medium dose group had small impact on the DBP, while showed statistically significant effect on the other hemodynamic indices. The low dose group had statistically significant effect on the SBP, LVSP and ± dp·dtmax-1 (P<0. 05), while showed no notable effects on the other indices. The results of aggregation rate in 1 min and 5 min after the determination and the maxi-mum one in the high and medium dose groups showed that the ethanol extract could significantly inhibit the platelet aggregation with sta-tistical significance (P<0. 05). Conclusion:The ethanol extract of Crataegus Pinnatifida Bge. Var. major N. E. Br. can improve the blood flow of acute myocardial ischemia in rats and reduce platelet aggregation after ischemia.
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Dexmedetomidine,a highly effective and selective adrenergic α2 receptor agonist,is applied in the sedation of adult ICU,and it is widely used in clinical anesthesia in recent years.Dexmedetomidine is still in the exploratory stage in clinical application of children.However,there are more evidence suggesting that dexmedetomidine has presented good effects in the anxiolytic,pediatric sedation,analgesic,anti-sympathetic,and stablizing hemodynamic.This review presents the clinical application of dexmedetomidine in pediatric clinical anesthesia.