This paper discusses the nested case-control analysis under a class of general additive-multiplicative hazard models which includes the Cox model and the additive hazard model as special cases.A pseudo-score is constr...This paper discusses the nested case-control analysis under a class of general additive-multiplicative hazard models which includes the Cox model and the additive hazard model as special cases.A pseudo-score is constructed to estimate the regression parameters.The resulting estimator is shown to be consistent and asymptotically normally distributed.The limiting variance-covariance matrix can be consistently estimated by the nested case-control data.A simulation study is conducted to assess the finite sample performance of the proposed estimator and a real example is provided for illustration.展开更多
AIM:To examine the determinants of maternal-neonatal transmission of hepatitis B virus(HBV) METHODS:A nested case-control study was conducted in Changsha,Hunan,People's Republic of China from January 1,2005 to Sep...AIM:To examine the determinants of maternal-neonatal transmission of hepatitis B virus(HBV) METHODS:A nested case-control study was conducted in Changsha,Hunan,People's Republic of China from January 1,2005 to September 31,2006 To avoid potential maternal blood contamination,we collected vein blood of newborns immediately after birth and before initial hepatitis B vaccination to determine the HBV infection status of the newborn For each HBsAg-positive infant,one HBsAg-negative infant born to an HBsAg-positive mother was matched by hospital at birth(same),gender(same),and date of birth(within 1 mo) A faceto-face interview was conducted to collect clinical and epidemiological data Conditional logistic regression analysis was used to estimate the independent effects of various determinants on maternal-neonatal transmission of HBV RESULTS:A total of 141 HBsAg-positive infants and 141 individually matched HBsAg-negative infants were included in the final analysis Maternal first-degree family history of HBV infection,intrahepatic cholestasis,and premature rupture of membranes were risk factors for perinatal transmission of HBV,whereas systematic treatment and HBV immunoglobulin injections for mothers with HBV infection were protective factors for maternal-neonatal transmission of HBV,after adjustment for potential confounding factors CONCLUSION:For HBsAg-positive mothers,systematic treatment,HBV immunoglobulin administration,and controlling intrahepatic cholestasis and pregnancy complications may reduce the incidence of perinatal transmission of HBV.展开更多
BACKGROUND When opportunistic infections occur, patients with inflammatory bowel disease(IBD) commonly display a significantly increased rate of morbidity and mortality.With increasing use of immunosuppressive agents ...BACKGROUND When opportunistic infections occur, patients with inflammatory bowel disease(IBD) commonly display a significantly increased rate of morbidity and mortality.With increasing use of immunosuppressive agents and biological agents,opportunistic infections are becoming a hot topic in the perspective of drug safety in IBD patients. Despite the well-established role of opportunistic infections in the prognosis of IBD patients, there are few epidemiological data investigating the incidence of opportunis-tic infections in IBD patients in China. Besides, the risk factors for opportunistic infection in Chinese IBD patients remain unclear.AIM To predict the incidence of opportunistic infections related to IBD in China, and explore the risk factors for opportunistic infections.METHODS A single-center, prospective study of IBD patients was conducted. The patients were followed for up to 12 mo to calculate the incidence of infections. For each infected IBD patient, two non-infected IBD patients were selected as controls. A conditional logistic regression analysis was used to assess associations between putative risk factors and opportunistic infections, which are represented as odds ratios(OR) and 95% confidence intervals(CIs).RESULTS Seventy(28.11%) out of 249 IBD patients developed opportunistic infections.Clostridium difficile infections and respiratory syncytial virus infections were found in 24 and 16 patients, respectively. In a univariate analysis, factors such as the severity of IBD, use of an immunosuppressant or immunosuppressants, high levels of fecal calprotectin, and C-reactive protein or erythrocyte sedimentation rate were individually related to a significantly increased risk of opportunistic infection. Multivariate analysis indicated that the use of any immunosuppressant yielded an OR of 3.247(95%CI: 1.128-9.341), whereas the use of any two immunosuppressants yielded an OR of 6.457(95%CI: 1.726-24.152) for opportunistic infection. Interestingly, when immunosuppressants were used in combination with infliximab(IFX) or 5-aminosalicylic acid, a significantly increased risk of opportunistic infection was also observed. The relative risk of opportunistic infection was greatest in IBD patients with severe disease activity(OR = 9.090; 95%CI: 1.532-53.941, relative to the remission stage). However, the use of IFX alone did not increase the risk of opportunistic infection.CONCLUSION Factors such as severe IBD, elevated levels of fecal calprotectin, and the use of immunosuppressive medications, especially when used in combination, are major risk factors for opportunistic infections in IBD patients. The use of IFX alone does not increase the risk of opportunistic infection.展开更多
To assess the relationship between serum levels of insulin-like growth factor-1(IGF1)/IGF-binding protein-3(IGFBP3)and the risk of esophageal carcinoma.METHODSWe assessed the relationship between the serum levels of t...To assess the relationship between serum levels of insulin-like growth factor-1(IGF1)/IGF-binding protein-3(IGFBP3)and the risk of esophageal carcinoma.METHODSWe assessed the relationship between the serum levels of these molecules and the risk of esophageal cancer in a prospective,nested case-control study of participants from the Japan Collaborative Cohort Study.A baseline survey was conducted from 1988 to 1990.Of the 110585 enrolled participants,35%donated blood samples.Those who had been diagnosed with esophageal cancer were considered cases for nested case-control studies.A conditional logistic model was used to estimate odds ratios for the incidence of esophageal cancer associated with serum IGF1 and IGFBP3 levels.RESULTSThirty-one cases and 86 controls were eligible for the present assessment.The molar ratio of IGF1/IGFBP3,which represents the free and active form of IGF1,was not correlated with the risk of esophageal carcinoma.A higher molar difference between IGFBP3 and IGF1,which estimates the free form of IGFBP3,was associated with a decreased risk of esophageal carcinoma(P=0.0146),and people in the highest tertile had the lowest risk(OR=0.107,95%CI:0.017-0.669).After adjustment for body mass index,tobacco use,and alcohol intake,the molar difference of IGFBP3-IGF1 was inversely correlated with the risk of esophageal carcinoma(P=0.0150).CONCLUSIONThe free form of IGFBP3,which is estimated by this molar difference,may be inversely associated with esophageal cancer incidence.展开更多
Objective This study prospectively investigates the association between immunoglobulin G(IgG)N-glycan traits and ischemic stroke(IS) risk.Methods A nested case-control study was conducted in the China suboptimal healt...Objective This study prospectively investigates the association between immunoglobulin G(IgG)N-glycan traits and ischemic stroke(IS) risk.Methods A nested case-control study was conducted in the China suboptimal health cohort study,which recruited 4,313 individuals in 2013–2014. Cases were identified as patients diagnosed with IS, and controls were 1:1 matched by age and sex with cases. Ig G N-glycans in baseline plasma samples were analyzed.Results A total of 99 IS cases and 99 controls were included, and 24 directly measured glycan peaks(GPs) were separated from Ig G N-glycans. In directly measured GPs, GP4, GP9, GP21, GP22, GP23, and GP24 were associated with the risk of IS in men after adjusting for age, waist and hip circumference,obesity, diabetes, hypertension, and dyslipidemia. Derived glycan traits representing decreased galactosylation and sialylation were associated with IS in men(FBG2S2/(FBG2 + FBG2S1 + FBG2S2): odds ratio(OR) = 0.92, 95% confidence interval(CI): 0.87–0.97;G1n: OR = 0.74, 95% CI: 0.63–0.87;G0n: OR =1.12, 95% CI: 1.03–1.22). However, these associations were not found among women.Conclusion This study validated that altered Ig G N-glycan traits were associated with incident IS in men, suggesting that sex discrepancies might exist in these associations.展开更多
BACKGROUND Type 1 diabetes(T1D)is a severe and prevalent metabolic disease.Due to its high heredity,an increasing number of genome-wide association studies have been performed,most of which were from hospital-based ca...BACKGROUND Type 1 diabetes(T1D)is a severe and prevalent metabolic disease.Due to its high heredity,an increasing number of genome-wide association studies have been performed,most of which were from hospital-based case-control studies with a relatively small sample size.The association of single nucleotide polymorphisms(SNPs)and T1D has been less studied and is less understood in natural cohorts.AIM To investigate the significant variants of T1D,which could be potential biomarkers for T1D prediction or even therapy.METHODS A genome-wide association study(GWAS)of adult T1D was performed in a nested case-control study(785 cases vs 804 controls)from a larger 5-year cohort study in Suzhou,China.Potential harmful or protective SNPs were evaluated for T1D.Subsequent expression and splicing quantitative trait loci(eQTL and sQTL)analyses were carried out to identify target genes modulated by these SNPs.RESULTS A harmful SNP for T1D,rs3117017[odds ratio(OR)=3.202,95%confidence interval(CI):2.296-4.466,P=9.33×10-4]and three protective SNPs rs55846421(0.113,0.081-0.156,1.76×10-9),rs75836320(0.283,0.205-0.392,1.07×10-4),rs362071(0.568,0.495-0.651,1.66×10-4)were identified.Twenty-two genes were further identified as potential candidates for T1D onset.CONCLUSION We identified a potential genetic basis of T1D,both protective and harmful,using a GWAS in a larger nested case-control study of a Chinese population.展开更多
BACKGROUND Dementia is a prevalent condition in type 2 diabetes mellitus(T2DM)patients.While Chinese herbal medicine(CHM)is often employed as complementary therapy for glycemic control,its effect in controlling likeli...BACKGROUND Dementia is a prevalent condition in type 2 diabetes mellitus(T2DM)patients.While Chinese herbal medicine(CHM)is often employed as complementary therapy for glycemic control,its effect in controlling likelihood of dementia has not yet been fully elucidated.AIM To compare the risk of dementia between T2DM patients with and without CHM treatment.METHODS We undertook a nested case-control study and obtained data on patients 20-70 years of age who received medical care for T2DM between 2001 and 2010 from the National Health Insurance Research database in Taiwan.Cases,defined as those with dementia that occurred at least one year after the diagnosis of T2DM,were randomly matched to controls without dementia from the study cohort at a 1:1 ratio.We applied conditional logistic regression to explore the associations between CHM treatment and dementia.RESULTS A total of 11699 dementia cases were matched to 11699 non-dementia controls.We found that adding CHM to conventional care was related to a lower risk of dementia[adjusted odds ratio(OR)=0.51],and high-intensity CHM treatment was associated with an adjusted OR of 0.22.CONCLUSION This study shows that the cumulative CHM exposure was inversely associated with dementia risk in an exposureresponse manner,implying that CHM treatment may be embraced as a disease management approach for diabetic patients to prevent dementia.展开更多
Preeclampsia is a pregnancy complication;early identification with increased risk is one of the key goals in obstetrics. In a nested case control study, serum uric acid and calcium measured in first and second trimest...Preeclampsia is a pregnancy complication;early identification with increased risk is one of the key goals in obstetrics. In a nested case control study, serum uric acid and calcium measured in first and second trimesters of pregnancy were correlated with Xanthine oxidase (XO) activity, mean arterial pressure (MAP) and fetal birth weight. The mean ± SD of uric acid (2.01 ± 0.85, 4.8 ± 1.93), calcium (10.88 ± 1.97, 9.72 ± 2.04), MAP (84.32 ± 6.71, 78.40 ± 8.53) and XO activity (11.96 ± 1.91, 14.05 ± 3.09) of the study group (n=86) were observed in the first and second trimesters respectively. First trimester normotensive group (n=79) and preeclampsia cases (n = 7), showed a mean ± SD of uric acid (1.93 ± 0.80, 2.9 ± 0.88), Calcium (10.92 ± 1.9, 10.6 ± 1.72), MAP (84.19 ± 6.75, 85.71 ± 6.58) XO activity (11.82 ± 1.83, 13.57 ± 2.21). In the second trimester, normotensive group and preeclampsia cases showed a mean ± SD uric acid (4.6 ± 1.75, 7.3 ± 2.19), Calcium (9.4 ± 1.85, 12.9 ± 1.04), MAP (76.41 ± 5.41, 100.95 ± 2.52) and XO activity (13.37 ± 1.93, 21.70 ± 3.50). Statistical analysis revealed a non-significant positive correlation in first trimester between uric acid and MAP (r = +0.116, p = 0.288), negative correlations between uric acid and fetal birth weight (r = -0.118, 0.279) and between calcium and MAP (r =?-0.288, p = 0.007). In the second trimester, significant positive correlations were observed between uric acid (r = +0.246, p = 0.022), calcium (r = +0.326, p = 0.007) with MAP along with a significant negative correlation between uric acid (r = -0.641, p = 0.000), calcium (r = -0.316, p = 0.003), Proteinuria (r = -0.514, p = 0.000) with fetal birth weight. The screening of first and second trimesters XO activity, uric acid, calcium and MAP during pregnancy is beneficial in identifying women likely to develop preeclampsia with poor fetal outcome.展开更多
Background: Binary as well as polytomous logistic models are widely used for estimating odds ratios when the exposure of prime interest assumes unordered multiple levels under matched pairs case-control design. In our...Background: Binary as well as polytomous logistic models are widely used for estimating odds ratios when the exposure of prime interest assumes unordered multiple levels under matched pairs case-control design. In our previous studies, we have shown that the use of a polytomous logistic model for estimating cumulative odds ratios when the outcome (response) variable is ordinal (in addition to being polytomous) under matched pairs case-control design. The cumulative odds ratios were estimated based on separate fitting of the model at each of the cutpoint level as compared to less than equal to that level. In this paper we propose an alternative method of estimating the cumulative odds ratios and reanalyze the Los Angeles Endometrial Cancer data in the context of dose levels of conjugated oestrogen exposure and development of endometrial cancer under the matched pair case-control design. Methods: In the present study, the cumulative logit model is fitted using a single multinomial logit model for the data. For this, the full maximum likelihood estimation procedure is adopted. A test for equality of the cumulative odds ratios across the exposure levels is proposed. Results: The analysis revealed that there is a strong evidence of risk for developing endometrial cancer due to oestrogen exposure above each of the three dose level as compared to less than equal to that level. The estimated values at the three cutpoint levels were found to be 6.17, 3.60 and 5.16 respectively. Conclusions: The odds of developing endometrial cancer are very high for the users of any amount of oestrogen, even if it is the least dose, as compared to the non-users.展开更多
Methods of constructing the optimum chemical balance weighing designs from symmetric balanced incomplete block designs are proposed with illustration. As a by-product pairwise efficiency and variance balanced designs ...Methods of constructing the optimum chemical balance weighing designs from symmetric balanced incomplete block designs are proposed with illustration. As a by-product pairwise efficiency and variance balanced designs are also obtained.展开更多
Introducing basic design methodology for developing backstepping nonlinear controller for vibration control system. With a simplified second-order system model of nonlinear vibration system （Duffing＇s equation）, wh...Introducing basic design methodology for developing backstepping nonlinear controller for vibration control system. With a simplified second-order system model of nonlinear vibration system （Duffing＇s equation）, where, the process has illustrated the backstepping design step-by-step. Backstepping is a novel nonlinear design tool, which is based on constructing the Lyapunov function for the closed-loop systems and guarantees the stability and tracking performance through energy dissipation. In general, this nonlinear control design approach generates aggressive control effort to reduce the tracking error presented in this control system and significantly improve the system bandwidth. The effectiveness of the design scheme is shown through the computer simulation.展开更多
为系统解决硬度自动化检测系统的测量系统分析(Measurement System Analysis, MSA)应用难题,阐述了其MSA的特殊性,指出传统重复性与再现性(Gage Repeatability and Reproducibility, GR&R)方法在变异源识别与实验设计上的局限性。...为系统解决硬度自动化检测系统的测量系统分析(Measurement System Analysis, MSA)应用难题,阐述了其MSA的特殊性,指出传统重复性与再现性(Gage Repeatability and Reproducibility, GR&R)方法在变异源识别与实验设计上的局限性。在此基础上,提出一种“过程解耦-混合GR&R”实验策略,将硬度检测流程解耦为压痕生成(破坏性)与压痕测量(非破坏性)2个子过程,分别采用嵌套设计与交叉设计进行变异源分离与量化。通过构建双检测单元自动化平台,开展系统的MSA实验,运用方差分析法评估设备重复性、再现性及交互作用的影响。研究结果表明:所提出的方法能有效识别主导变异源,为硬度自动化检测系统的性能评估与优化提供了可行的分析框架,具有较强的工程适用性与推广价值。展开更多
基金Supported by the National Natural Science Foundation of China(10971033,11101091)
文摘This paper discusses the nested case-control analysis under a class of general additive-multiplicative hazard models which includes the Cox model and the additive hazard model as special cases.A pseudo-score is constructed to estimate the regression parameters.The resulting estimator is shown to be consistent and asymptotically normally distributed.The limiting variance-covariance matrix can be consistently estimated by the nested case-control data.A simulation study is conducted to assess the finite sample performance of the proposed estimator and a real example is provided for illustration.
基金Supported by Hunan Ministry of Science and Technology,No.06FJ3177,China
文摘AIM:To examine the determinants of maternal-neonatal transmission of hepatitis B virus(HBV) METHODS:A nested case-control study was conducted in Changsha,Hunan,People's Republic of China from January 1,2005 to September 31,2006 To avoid potential maternal blood contamination,we collected vein blood of newborns immediately after birth and before initial hepatitis B vaccination to determine the HBV infection status of the newborn For each HBsAg-positive infant,one HBsAg-negative infant born to an HBsAg-positive mother was matched by hospital at birth(same),gender(same),and date of birth(within 1 mo) A faceto-face interview was conducted to collect clinical and epidemiological data Conditional logistic regression analysis was used to estimate the independent effects of various determinants on maternal-neonatal transmission of HBV RESULTS:A total of 141 HBsAg-positive infants and 141 individually matched HBsAg-negative infants were included in the final analysis Maternal first-degree family history of HBV infection,intrahepatic cholestasis,and premature rupture of membranes were risk factors for perinatal transmission of HBV,whereas systematic treatment and HBV immunoglobulin injections for mothers with HBV infection were protective factors for maternal-neonatal transmission of HBV,after adjustment for potential confounding factors CONCLUSION:For HBsAg-positive mothers,systematic treatment,HBV immunoglobulin administration,and controlling intrahepatic cholestasis and pregnancy complications may reduce the incidence of perinatal transmission of HBV.
基金National Natural Science Foundation of China,No.81473506Natural Science Foundation of Zhejiang Province,No.LY16H290001 and No.LY17H290009+1 种基金Project of Department of Construction of Zhejiang Province,No.WKJ-ZJ-1531Zhejiang TCM Science and Technology Project,No.2016ZB047 and No.2017ZA056
文摘BACKGROUND When opportunistic infections occur, patients with inflammatory bowel disease(IBD) commonly display a significantly increased rate of morbidity and mortality.With increasing use of immunosuppressive agents and biological agents,opportunistic infections are becoming a hot topic in the perspective of drug safety in IBD patients. Despite the well-established role of opportunistic infections in the prognosis of IBD patients, there are few epidemiological data investigating the incidence of opportunis-tic infections in IBD patients in China. Besides, the risk factors for opportunistic infection in Chinese IBD patients remain unclear.AIM To predict the incidence of opportunistic infections related to IBD in China, and explore the risk factors for opportunistic infections.METHODS A single-center, prospective study of IBD patients was conducted. The patients were followed for up to 12 mo to calculate the incidence of infections. For each infected IBD patient, two non-infected IBD patients were selected as controls. A conditional logistic regression analysis was used to assess associations between putative risk factors and opportunistic infections, which are represented as odds ratios(OR) and 95% confidence intervals(CIs).RESULTS Seventy(28.11%) out of 249 IBD patients developed opportunistic infections.Clostridium difficile infections and respiratory syncytial virus infections were found in 24 and 16 patients, respectively. In a univariate analysis, factors such as the severity of IBD, use of an immunosuppressant or immunosuppressants, high levels of fecal calprotectin, and C-reactive protein or erythrocyte sedimentation rate were individually related to a significantly increased risk of opportunistic infection. Multivariate analysis indicated that the use of any immunosuppressant yielded an OR of 3.247(95%CI: 1.128-9.341), whereas the use of any two immunosuppressants yielded an OR of 6.457(95%CI: 1.726-24.152) for opportunistic infection. Interestingly, when immunosuppressants were used in combination with infliximab(IFX) or 5-aminosalicylic acid, a significantly increased risk of opportunistic infection was also observed. The relative risk of opportunistic infection was greatest in IBD patients with severe disease activity(OR = 9.090; 95%CI: 1.532-53.941, relative to the remission stage). However, the use of IFX alone did not increase the risk of opportunistic infection.CONCLUSION Factors such as severe IBD, elevated levels of fecal calprotectin, and the use of immunosuppressive medications, especially when used in combination, are major risk factors for opportunistic infections in IBD patients. The use of IFX alone does not increase the risk of opportunistic infection.
基金Supported by the Ministry of Education,Culture,Sports,Science,and Technology and from the Ministry of Health,Labour and Welfare,Japan
文摘To assess the relationship between serum levels of insulin-like growth factor-1(IGF1)/IGF-binding protein-3(IGFBP3)and the risk of esophageal carcinoma.METHODSWe assessed the relationship between the serum levels of these molecules and the risk of esophageal cancer in a prospective,nested case-control study of participants from the Japan Collaborative Cohort Study.A baseline survey was conducted from 1988 to 1990.Of the 110585 enrolled participants,35%donated blood samples.Those who had been diagnosed with esophageal cancer were considered cases for nested case-control studies.A conditional logistic model was used to estimate odds ratios for the incidence of esophageal cancer associated with serum IGF1 and IGFBP3 levels.RESULTSThirty-one cases and 86 controls were eligible for the present assessment.The molar ratio of IGF1/IGFBP3,which represents the free and active form of IGF1,was not correlated with the risk of esophageal carcinoma.A higher molar difference between IGFBP3 and IGF1,which estimates the free form of IGFBP3,was associated with a decreased risk of esophageal carcinoma(P=0.0146),and people in the highest tertile had the lowest risk(OR=0.107,95%CI:0.017-0.669).After adjustment for body mass index,tobacco use,and alcohol intake,the molar difference of IGFBP3-IGF1 was inversely correlated with the risk of esophageal carcinoma(P=0.0150).CONCLUSIONThe free form of IGFBP3,which is estimated by this molar difference,may be inversely associated with esophageal cancer incidence.
基金supported by grants from the National Natural Science Foundation of China [No.81673247, 8187268281903401]。
文摘Objective This study prospectively investigates the association between immunoglobulin G(IgG)N-glycan traits and ischemic stroke(IS) risk.Methods A nested case-control study was conducted in the China suboptimal health cohort study,which recruited 4,313 individuals in 2013–2014. Cases were identified as patients diagnosed with IS, and controls were 1:1 matched by age and sex with cases. Ig G N-glycans in baseline plasma samples were analyzed.Results A total of 99 IS cases and 99 controls were included, and 24 directly measured glycan peaks(GPs) were separated from Ig G N-glycans. In directly measured GPs, GP4, GP9, GP21, GP22, GP23, and GP24 were associated with the risk of IS in men after adjusting for age, waist and hip circumference,obesity, diabetes, hypertension, and dyslipidemia. Derived glycan traits representing decreased galactosylation and sialylation were associated with IS in men(FBG2S2/(FBG2 + FBG2S1 + FBG2S2): odds ratio(OR) = 0.92, 95% confidence interval(CI): 0.87–0.97;G1n: OR = 0.74, 95% CI: 0.63–0.87;G0n: OR =1.12, 95% CI: 1.03–1.22). However, these associations were not found among women.Conclusion This study validated that altered Ig G N-glycan traits were associated with incident IS in men, suggesting that sex discrepancies might exist in these associations.
基金the National Science Foundation for Young Scientists of China(No.81602919)the National Science Foundation for Young Scientists of China(No.82070814)+1 种基金the Suzhou Science and Technology Development Plan(No.SYS2018099)and the 5th Suzhou Health Talent Program(No.GSWS2019071).
文摘BACKGROUND Type 1 diabetes(T1D)is a severe and prevalent metabolic disease.Due to its high heredity,an increasing number of genome-wide association studies have been performed,most of which were from hospital-based case-control studies with a relatively small sample size.The association of single nucleotide polymorphisms(SNPs)and T1D has been less studied and is less understood in natural cohorts.AIM To investigate the significant variants of T1D,which could be potential biomarkers for T1D prediction or even therapy.METHODS A genome-wide association study(GWAS)of adult T1D was performed in a nested case-control study(785 cases vs 804 controls)from a larger 5-year cohort study in Suzhou,China.Potential harmful or protective SNPs were evaluated for T1D.Subsequent expression and splicing quantitative trait loci(eQTL and sQTL)analyses were carried out to identify target genes modulated by these SNPs.RESULTS A harmful SNP for T1D,rs3117017[odds ratio(OR)=3.202,95%confidence interval(CI):2.296-4.466,P=9.33×10-4]and three protective SNPs rs55846421(0.113,0.081-0.156,1.76×10-9),rs75836320(0.283,0.205-0.392,1.07×10-4),rs362071(0.568,0.495-0.651,1.66×10-4)were identified.Twenty-two genes were further identified as potential candidates for T1D onset.CONCLUSION We identified a potential genetic basis of T1D,both protective and harmful,using a GWAS in a larger nested case-control study of a Chinese population.
文摘BACKGROUND Dementia is a prevalent condition in type 2 diabetes mellitus(T2DM)patients.While Chinese herbal medicine(CHM)is often employed as complementary therapy for glycemic control,its effect in controlling likelihood of dementia has not yet been fully elucidated.AIM To compare the risk of dementia between T2DM patients with and without CHM treatment.METHODS We undertook a nested case-control study and obtained data on patients 20-70 years of age who received medical care for T2DM between 2001 and 2010 from the National Health Insurance Research database in Taiwan.Cases,defined as those with dementia that occurred at least one year after the diagnosis of T2DM,were randomly matched to controls without dementia from the study cohort at a 1:1 ratio.We applied conditional logistic regression to explore the associations between CHM treatment and dementia.RESULTS A total of 11699 dementia cases were matched to 11699 non-dementia controls.We found that adding CHM to conventional care was related to a lower risk of dementia[adjusted odds ratio(OR)=0.51],and high-intensity CHM treatment was associated with an adjusted OR of 0.22.CONCLUSION This study shows that the cumulative CHM exposure was inversely associated with dementia risk in an exposureresponse manner,implying that CHM treatment may be embraced as a disease management approach for diabetic patients to prevent dementia.
文摘Preeclampsia is a pregnancy complication;early identification with increased risk is one of the key goals in obstetrics. In a nested case control study, serum uric acid and calcium measured in first and second trimesters of pregnancy were correlated with Xanthine oxidase (XO) activity, mean arterial pressure (MAP) and fetal birth weight. The mean ± SD of uric acid (2.01 ± 0.85, 4.8 ± 1.93), calcium (10.88 ± 1.97, 9.72 ± 2.04), MAP (84.32 ± 6.71, 78.40 ± 8.53) and XO activity (11.96 ± 1.91, 14.05 ± 3.09) of the study group (n=86) were observed in the first and second trimesters respectively. First trimester normotensive group (n=79) and preeclampsia cases (n = 7), showed a mean ± SD of uric acid (1.93 ± 0.80, 2.9 ± 0.88), Calcium (10.92 ± 1.9, 10.6 ± 1.72), MAP (84.19 ± 6.75, 85.71 ± 6.58) XO activity (11.82 ± 1.83, 13.57 ± 2.21). In the second trimester, normotensive group and preeclampsia cases showed a mean ± SD uric acid (4.6 ± 1.75, 7.3 ± 2.19), Calcium (9.4 ± 1.85, 12.9 ± 1.04), MAP (76.41 ± 5.41, 100.95 ± 2.52) and XO activity (13.37 ± 1.93, 21.70 ± 3.50). Statistical analysis revealed a non-significant positive correlation in first trimester between uric acid and MAP (r = +0.116, p = 0.288), negative correlations between uric acid and fetal birth weight (r = -0.118, 0.279) and between calcium and MAP (r =?-0.288, p = 0.007). In the second trimester, significant positive correlations were observed between uric acid (r = +0.246, p = 0.022), calcium (r = +0.326, p = 0.007) with MAP along with a significant negative correlation between uric acid (r = -0.641, p = 0.000), calcium (r = -0.316, p = 0.003), Proteinuria (r = -0.514, p = 0.000) with fetal birth weight. The screening of first and second trimesters XO activity, uric acid, calcium and MAP during pregnancy is beneficial in identifying women likely to develop preeclampsia with poor fetal outcome.
文摘Background: Binary as well as polytomous logistic models are widely used for estimating odds ratios when the exposure of prime interest assumes unordered multiple levels under matched pairs case-control design. In our previous studies, we have shown that the use of a polytomous logistic model for estimating cumulative odds ratios when the outcome (response) variable is ordinal (in addition to being polytomous) under matched pairs case-control design. The cumulative odds ratios were estimated based on separate fitting of the model at each of the cutpoint level as compared to less than equal to that level. In this paper we propose an alternative method of estimating the cumulative odds ratios and reanalyze the Los Angeles Endometrial Cancer data in the context of dose levels of conjugated oestrogen exposure and development of endometrial cancer under the matched pair case-control design. Methods: In the present study, the cumulative logit model is fitted using a single multinomial logit model for the data. For this, the full maximum likelihood estimation procedure is adopted. A test for equality of the cumulative odds ratios across the exposure levels is proposed. Results: The analysis revealed that there is a strong evidence of risk for developing endometrial cancer due to oestrogen exposure above each of the three dose level as compared to less than equal to that level. The estimated values at the three cutpoint levels were found to be 6.17, 3.60 and 5.16 respectively. Conclusions: The odds of developing endometrial cancer are very high for the users of any amount of oestrogen, even if it is the least dose, as compared to the non-users.
文摘Methods of constructing the optimum chemical balance weighing designs from symmetric balanced incomplete block designs are proposed with illustration. As a by-product pairwise efficiency and variance balanced designs are also obtained.
文摘Introducing basic design methodology for developing backstepping nonlinear controller for vibration control system. With a simplified second-order system model of nonlinear vibration system （Duffing＇s equation）, where, the process has illustrated the backstepping design step-by-step. Backstepping is a novel nonlinear design tool, which is based on constructing the Lyapunov function for the closed-loop systems and guarantees the stability and tracking performance through energy dissipation. In general, this nonlinear control design approach generates aggressive control effort to reduce the tracking error presented in this control system and significantly improve the system bandwidth. The effectiveness of the design scheme is shown through the computer simulation.
文摘为系统解决硬度自动化检测系统的测量系统分析(Measurement System Analysis, MSA)应用难题,阐述了其MSA的特殊性,指出传统重复性与再现性(Gage Repeatability and Reproducibility, GR&R)方法在变异源识别与实验设计上的局限性。在此基础上,提出一种“过程解耦-混合GR&R”实验策略,将硬度检测流程解耦为压痕生成(破坏性)与压痕测量(非破坏性)2个子过程,分别采用嵌套设计与交叉设计进行变异源分离与量化。通过构建双检测单元自动化平台,开展系统的MSA实验,运用方差分析法评估设备重复性、再现性及交互作用的影响。研究结果表明:所提出的方法能有效识别主导变异源,为硬度自动化检测系统的性能评估与优化提供了可行的分析框架,具有较强的工程适用性与推广价值。
