Objective Humans are exposed to complex mixtures of environmental chemicals and other factors that can affect their health.Analysis of these mixture exposures presents several key challenges for environmental epidemio...Objective Humans are exposed to complex mixtures of environmental chemicals and other factors that can affect their health.Analysis of these mixture exposures presents several key challenges for environmental epidemiology and risk assessment,including high dimensionality,correlated exposure,and subtle individual effects.Methods We proposed a novel statistical approach,the generalized functional linear model(GFLM),to analyze the health effects of exposure mixtures.GFLM treats the effect of mixture exposures as a smooth function by reordering exposures based on specific mechanisms and capturing internal correlations to provide a meaningful estimation and interpretation.The robustness and efficiency was evaluated under various scenarios through extensive simulation studies.Results We applied the GFLM to two datasets from the National Health and Nutrition Examination Survey(NHANES).In the first application,we examined the effects of 37 nutrients on BMI(2011–2016 cycles).The GFLM identified a significant mixture effect,with fiber and fat emerging as the nutrients with the greatest negative and positive effects on BMI,respectively.For the second application,we investigated the association between four pre-and perfluoroalkyl substances(PFAS)and gout risk(2007–2018 cycles).Unlike traditional methods,the GFLM indicated no significant association,demonstrating its robustness to multicollinearity.Conclusion GFLM framework is a powerful tool for mixture exposure analysis,offering improved handling of correlated exposures and interpretable results.It demonstrates robust performance across various scenarios and real-world applications,advancing our understanding of complex environmental exposures and their health impacts on environmental epidemiology and toxicology.展开更多
The correlation between outdoor exposure and indoor accelerated corrosion test for high polymer materials was investigated according to the variation of the functional group of exposure models aged. Environment aging ...The correlation between outdoor exposure and indoor accelerated corrosion test for high polymer materials was investigated according to the variation of the functional group of exposure models aged. Environment aging intensities at different zones （ Wuhan and Lasa with the same latitude ） and the influences of indoor accelerating factors including water and ultraviolet on weathering performant.e of high polymer materials were also studied by comparing different indoor accelerated corrosion testing results. The experimental results show that ： by testing variations of carbonyl exponent of polythene （ which represented the degradation behavior of high polymer materials due to ultraviolet oxidation of douIole bond） and ultraviolet absorbance of polycarbonate （which represented the degradation behavior of high polymer materials due to abevacuation of branched chain ）, the degradation behavior of high polymer materials could be studied. Carbonyl exponent of polythene exposed in Wuhan and Lasa for 1 year was equal to that exposed in indoor cycle ultraviolet for 128 h anti 170 It, respectively, the ultraviolet absorbance of polycarbonate exposed in Wuhan for 1 year was equal to that exposed in indoor cycle ultraviolet for 240 h. The ratio of environment aging intensity of Lasa to Wuhan was around 1.2. With the prolongation of cycle accelerated ultraviolet exposure time, the variations of carbonyl exponent of polythene and the ultraviolet absorbance of polycarbonate were in the same shape of first order exponential decay curiae. Accompanied with ultraviolet, the effect of water condensated on the sample on weathering performance of polythene was more .significant than that of polycarbonate.展开更多
Objective To develop an individual noise exposure dose estimation model based on spatial distribution of noise in order to provide reference for occupational health management and hearing loss risk assessment caused b...Objective To develop an individual noise exposure dose estimation model based on spatial distribution of noise in order to provide reference for occupational health management and hearing loss risk assessment caused by noise in workplace.Methods From July 2018 to October 2019,10 noise-exposed positions and 48 employees in 3 high-noise workplaces of a manufacturing enterprise in Sichuan Province were selected as the research subjects.Occupational health survey,fixed-point measurement of workplace noise and individual noise measurement were used to obtain noise intensity and employee exposure information.The mean noise intensity and the corresponding exposure time were weighed to estimate the individual noise exposure dose estimation model based on the spatial distribution of workplace noise,and the paired t-test was used to evaluate the accuracy of the individual noise exposure dose estimate(8 h equivalent sound level,Lex,8 h)based on the spatial distribution of workplace,noise and the measured value of individualnoise exposure dose.And the least square regression model was used to correct it.Results The daily noise exposure dose of 44(91.7%)of 48 workers in 10 types of work in 3 sites of the manufacturing enterprise exceeded the standard,and the maximum noise exposure intensity was up to 108.3 dB(A).The measured value of individual noise exposure dose was higher than Lex,s h,and the difference was statistically significant(P<0.001).The noise difference distribution was mostly positive and symmetrical(P=0.958).The measured noise exposure dose of 6 out of 10 work types in 3 sites was higher than Lex,8 h(all P<0.05),and there was a linear correlation between the measured dose and Lex.8 h(r=0.373,P<0.05).Considering the influence of systematic error and the construction,diagnosis and screening of adaptive assessment model,an individual noise exposure dose estimation model based on the spatial distribution of workplace noise was finally obtained:y=0.574x+45.250,where y was the measured value of individual noise exposure dose,x was Lex,s h value.Conclusion The high noise hazard in manufacturing industry is more serious,and the noise exposure assessment of single fixed-point detection is relatively rough.The individual noise exposure dose estimation model based on the spatial distribution of workplace noise has a certain role in the occupational health managementofworkplacenoise hazard in manufacturing industry.展开更多
The assessment of potential health risks posed by formaldehyde in clothing to consumers is of increasing concern worldwide. Because of this, it is necessary to develop an exposure model that can realistically mimic cl...The assessment of potential health risks posed by formaldehyde in clothing to consumers is of increasing concern worldwide. Because of this, it is necessary to develop an exposure model that can realistically mimic clothes wearing conditions. This study aims to preliminarily develop a health risk assessment model for formaldehyde in clothing, and then to assess the potential health risk posed by formaldehyde in textiles to adults and infants in Vietnam using the model. Finally, this study aims to examine the plausibility of the adopted permissible values for formaldehyde in cloth- ing in Vietnam. In the model, two exposure factors for dermal exposure and overall exposure routes, i.e. sweat type and perspiration area, were considered. The margins of exposure (MOE) were calculated to estimate the health risks from worst case and average exposures. The assessment shows that acute exposure via inhalation can pose health risks to Vietnamese consumers in both cases. In regards to chronic exposure, dermal exposure is about four (for infants) and seven (for adults) times higher than exposure via inhalation, but no risks were found for average exposure. If a MOE of 100 is defined as ‘safe’ used, dermal and total chronic exposure to worst case cause potential risks, whereas no health risks were found for exposure to average case. With the model, the adopted Vietnamese permissible values for formaldehyde in clothing were assessed as not posing a health risk to Vietnamese consumers, hence they are accepted.展开更多
This paper investigates a simple step-stress accelerated lifetime test(SSALT)model for the inferential analysis of exponential competing risks data.A generalized type-I hybrid censoring scheme is employed to improve t...This paper investigates a simple step-stress accelerated lifetime test(SSALT)model for the inferential analysis of exponential competing risks data.A generalized type-I hybrid censoring scheme is employed to improve the efficiency and controllability of the test.Firstly,the MLEs for parameters are established based on the cumulative exposure model(CEM).Then the conditional moment generating function(MGF)for unknown parameters is set up using conditional expectation and multiple integral techniques.Thirdly,confidence intervals(CIs)are constructed by the exact MGF-based method,the approximate normality-based method,and the bias-corrected and accelerated(BCa)percentile bootstrap method.Finally,we present simulation studies and an illustrative example to compare the performances of different methods.展开更多
基金supported in part by the Young Scientists Fund of the National Natural Science Foundation of China(Grant Nos.82304253)(and 82273709)the Foundation for Young Talents in Higher Education of Guangdong Province(Grant No.2022KQNCX021)the PhD Starting Project of Guangdong Medical University(Grant No.GDMUB2022054).
文摘Objective Humans are exposed to complex mixtures of environmental chemicals and other factors that can affect their health.Analysis of these mixture exposures presents several key challenges for environmental epidemiology and risk assessment,including high dimensionality,correlated exposure,and subtle individual effects.Methods We proposed a novel statistical approach,the generalized functional linear model(GFLM),to analyze the health effects of exposure mixtures.GFLM treats the effect of mixture exposures as a smooth function by reordering exposures based on specific mechanisms and capturing internal correlations to provide a meaningful estimation and interpretation.The robustness and efficiency was evaluated under various scenarios through extensive simulation studies.Results We applied the GFLM to two datasets from the National Health and Nutrition Examination Survey(NHANES).In the first application,we examined the effects of 37 nutrients on BMI(2011–2016 cycles).The GFLM identified a significant mixture effect,with fiber and fat emerging as the nutrients with the greatest negative and positive effects on BMI,respectively.For the second application,we investigated the association between four pre-and perfluoroalkyl substances(PFAS)and gout risk(2007–2018 cycles).Unlike traditional methods,the GFLM indicated no significant association,demonstrating its robustness to multicollinearity.Conclusion GFLM framework is a powerful tool for mixture exposure analysis,offering improved handling of correlated exposures and interpretable results.It demonstrates robust performance across various scenarios and real-world applications,advancing our understanding of complex environmental exposures and their health impacts on environmental epidemiology and toxicology.
基金Funded by Ministry of Science and Technology of China (No.50499331)
文摘The correlation between outdoor exposure and indoor accelerated corrosion test for high polymer materials was investigated according to the variation of the functional group of exposure models aged. Environment aging intensities at different zones （ Wuhan and Lasa with the same latitude ） and the influences of indoor accelerating factors including water and ultraviolet on weathering performant.e of high polymer materials were also studied by comparing different indoor accelerated corrosion testing results. The experimental results show that ： by testing variations of carbonyl exponent of polythene （ which represented the degradation behavior of high polymer materials due to ultraviolet oxidation of douIole bond） and ultraviolet absorbance of polycarbonate （which represented the degradation behavior of high polymer materials due to abevacuation of branched chain ）, the degradation behavior of high polymer materials could be studied. Carbonyl exponent of polythene exposed in Wuhan and Lasa for 1 year was equal to that exposed in indoor cycle ultraviolet for 128 h anti 170 It, respectively, the ultraviolet absorbance of polycarbonate exposed in Wuhan for 1 year was equal to that exposed in indoor cycle ultraviolet for 240 h. The ratio of environment aging intensity of Lasa to Wuhan was around 1.2. With the prolongation of cycle accelerated ultraviolet exposure time, the variations of carbonyl exponent of polythene and the ultraviolet absorbance of polycarbonate were in the same shape of first order exponential decay curiae. Accompanied with ultraviolet, the effect of water condensated on the sample on weathering performance of polythene was more .significant than that of polycarbonate.
文摘Objective To develop an individual noise exposure dose estimation model based on spatial distribution of noise in order to provide reference for occupational health management and hearing loss risk assessment caused by noise in workplace.Methods From July 2018 to October 2019,10 noise-exposed positions and 48 employees in 3 high-noise workplaces of a manufacturing enterprise in Sichuan Province were selected as the research subjects.Occupational health survey,fixed-point measurement of workplace noise and individual noise measurement were used to obtain noise intensity and employee exposure information.The mean noise intensity and the corresponding exposure time were weighed to estimate the individual noise exposure dose estimation model based on the spatial distribution of workplace noise,and the paired t-test was used to evaluate the accuracy of the individual noise exposure dose estimate(8 h equivalent sound level,Lex,8 h)based on the spatial distribution of workplace,noise and the measured value of individualnoise exposure dose.And the least square regression model was used to correct it.Results The daily noise exposure dose of 44(91.7%)of 48 workers in 10 types of work in 3 sites of the manufacturing enterprise exceeded the standard,and the maximum noise exposure intensity was up to 108.3 dB(A).The measured value of individual noise exposure dose was higher than Lex,s h,and the difference was statistically significant(P<0.001).The noise difference distribution was mostly positive and symmetrical(P=0.958).The measured noise exposure dose of 6 out of 10 work types in 3 sites was higher than Lex,8 h(all P<0.05),and there was a linear correlation between the measured dose and Lex.8 h(r=0.373,P<0.05).Considering the influence of systematic error and the construction,diagnosis and screening of adaptive assessment model,an individual noise exposure dose estimation model based on the spatial distribution of workplace noise was finally obtained:y=0.574x+45.250,where y was the measured value of individual noise exposure dose,x was Lex,s h value.Conclusion The high noise hazard in manufacturing industry is more serious,and the noise exposure assessment of single fixed-point detection is relatively rough.The individual noise exposure dose estimation model based on the spatial distribution of workplace noise has a certain role in the occupational health managementofworkplacenoise hazard in manufacturing industry.
文摘The assessment of potential health risks posed by formaldehyde in clothing to consumers is of increasing concern worldwide. Because of this, it is necessary to develop an exposure model that can realistically mimic clothes wearing conditions. This study aims to preliminarily develop a health risk assessment model for formaldehyde in clothing, and then to assess the potential health risk posed by formaldehyde in textiles to adults and infants in Vietnam using the model. Finally, this study aims to examine the plausibility of the adopted permissible values for formaldehyde in cloth- ing in Vietnam. In the model, two exposure factors for dermal exposure and overall exposure routes, i.e. sweat type and perspiration area, were considered. The margins of exposure (MOE) were calculated to estimate the health risks from worst case and average exposures. The assessment shows that acute exposure via inhalation can pose health risks to Vietnamese consumers in both cases. In regards to chronic exposure, dermal exposure is about four (for infants) and seven (for adults) times higher than exposure via inhalation, but no risks were found for average exposure. If a MOE of 100 is defined as ‘safe’ used, dermal and total chronic exposure to worst case cause potential risks, whereas no health risks were found for exposure to average case. With the model, the adopted Vietnamese permissible values for formaldehyde in clothing were assessed as not posing a health risk to Vietnamese consumers, hence they are accepted.
基金Humanities and Social Sciences Fund in Ministry of Education in China(18YJC910009)the National Natural Science Foundation of China(12061091)Program for the Philosophy and Social Sciences Research of Higher Learning Institutions of Shanxi(201803050)。
文摘This paper investigates a simple step-stress accelerated lifetime test(SSALT)model for the inferential analysis of exponential competing risks data.A generalized type-I hybrid censoring scheme is employed to improve the efficiency and controllability of the test.Firstly,the MLEs for parameters are established based on the cumulative exposure model(CEM).Then the conditional moment generating function(MGF)for unknown parameters is set up using conditional expectation and multiple integral techniques.Thirdly,confidence intervals(CIs)are constructed by the exact MGF-based method,the approximate normality-based method,and the bias-corrected and accelerated(BCa)percentile bootstrap method.Finally,we present simulation studies and an illustrative example to compare the performances of different methods.
