Association between gestational diabetes mellitus and preterm birth subtypes / 中华流行病学杂志

Objective: To investigate the association between gestational diabetes mellitus (GDM) and preterm birth subtypes. Methods: Based on the cohort of pregnant women in Anqing Prefectural Hospital, the pregnant women who received prenatal screening in the first or second trimesters were recruited into baseline cohorts; and followed up for them was conducted until delivery, and the information about their pregnancy status and outcomes were obtained through electronic medical record system and questionnaire surveys. The log-binomial regression model was used to explore the association between GDM and preterm birth [iatrogenic preterm birth, spontaneous preterm birth (preterm premature rupture of membranes and preterm labor)]. For multiple confounding factors, the propensity score correction model was used to compute the adjusted association. Results: Among the 2 031 pregnant women with a singleton delivery, the incidence of GDM and preterm birth were 10.0% (204 cases) and 4.4% (90 cases) respectively. The proportions of iatrogenic preterm birth and spontaneous preterm birth in the GDM group (n=204) were 1.5% and 5.9% respectively, while the proportions in non-GDM group (n=1 827) were 0.9% and 3.2% respectively, and the difference in the proportion of spontaneous preterm birth between the two groups was significant (P=0.048). Subtypes of spontaneous preterm were further analyzed, and the results showed that the proportions of preterm premature rupture of membranes and preterm labor in the GDM group were 4.9% and 1.0% respectively, while the proportions in the non-GDM group were 2.1% and 1.1% respectively. It showed that the risk of preterm premature rupture of membranes in GDM pregnant women was 2.34 times (aRR=2.34, 95%CI: 1.16-4.69) higher than that in non-GDM pregnant women. Conclusions: Our results showed that GDM might increase the risk of preterm premature rupture of membranes. No significant increase in the proportion of preterm labor in pregnant women with GDM was found.

The directionality of measurement bias: a directed acyclic graph-based structural perspective / 中华流行病学杂志

Measurement bias (MB) has been described in causal structures but is still not entirely clear. In practice, the correctness of substitution estimate (SE) of effect is a prerequisite for causal inference, usually based on a bidirectionally non-differential misclassification between the measured exposure and the measured outcome. Based on a directed acyclic graph (DAG), this paper proposes a structure for the single-variable measure, where its MB is derived from the choice of an imperfect, "input/output device-like" measurement system. The MB of the SE is influenced both by the measurement system itself and by factors outside the measurement system: while the independence or dependence mechanism of the measurement system still ensures that the MB of the SE is bidirectionally non-differential; however, the misclassification can be bidirectionally non-differential, unidirectionally differential, or bidirectionally differential resulted from the factors outside the measurement system. In addition, reverse causality should be defined at the level of measurement, where measured exposures can influence measured outcomes and vice versa. Combined with temporal relationships, DAGs help elucidate MB's structures, mechanisms, and directionality.

Proportion and rate: connotation and understanding route / 中华流行病学杂志

Proportion and rate have multiple and overlapping meanings, which blur their concepts. Based on the existence of the states and the occurrence of the events and their measuring process, we first put forward the concept of "cumulative number of states in point time". Considering the general meaning of "rate" in mathematics and the units of the elements in indexes, this paper puts forward the concept of "the change of cumulative number of states in point time", which is equal to the commonly acknowledged concept "number of incident event within observation period" or "absolute rate", and further constructs relative rate and proportion. Proportions can be classified into three types: time-point (or rate-type) constitutional proportion, time-period incidence proportion and their synthesis, time-period constitutional proportion. The essential difference between relative rate and time-period proportions is whether the observation period is regarded as a one-unit-length fixed period which would be further moved to the description of the indexes. Furthermore, the sources populations of relative rate and proportions are exclusively those at the beginning of the observation period. Thus, we established a unified identification route about ratios, proportions, and rates, the basic indicators of categorical data in populations. These are applicable to both fixed and dynamic populations. The paper aims to clarify the connotation of the indexes and the feasible understanding route and provide some reference for the population researchers.

Advances in research of application of low-temperature plasma in microbiology / 上海预防医学

Low-temperature plasma has special physicochemical properties that can cause inactivation and mutation of microorganisms through complex biochemical processes.This article reviews the application of low-temperature plasma in microbiology, including sterilization, screening of bacterial strains, and antibacterial treatment.It also discussed the current research status and existing problems to provide ideas for promoting the development of interdisciplinary collaboration in low-temperature plasma reserch.

Detection bias:structural analysis of different study designs / 上海预防医学

Detection bias is an information bias.It was first proposed by Horwitz from the study investigating the association of the administration of estrogen after menopause with the occurrence of endometrial cancer, which still prevails in most epidemiological studies.We use the Directed Acyclic Graph to analyze the effect of a given exposure on a specific outcome with the association estimates between the measured exposure and outcome.Detection bias occurs when there is additional open paths irrelevant to the target path of interest which is originated from measured exposure to measured outcome.We further analyzed how the detection bias was formed under different study designs, including cohort study, randomized clinical trial and case-control study in order to further investigate its potential influence on the effect/association estimation.

Detection bias:structural analysis of different study designs / 上海预防医学

Detection bias is an information bias.It was first proposed by Horwitz from the study investigating the association of the administration of estrogen after menopause with the occurrence of endometrial cancer, which still prevails in most epidemiological studies.We use the Directed Acyclic Graph to analyze the effect of a given exposure on a specific outcome with the association estimates between the measured exposure and outcome.Detection bias occurs when there is additional open paths irrelevant to the target path of interest which is originated from measured exposure to measured outcome.We further analyzed how the detection bias was formed under different study designs, including cohort study, randomized clinical trial and case-control study in order to further investigate its potential influence on the effect/association estimation.

New cases are they incident or newly discovered / 中华疾病控制杂志

@#New case is a basic concept in epidemiology and often serves as the numerator for the indexes of the frequency of disease in a population． However，the exact definition of new case is still un- clear． Based on the natural history of disease combined with the concept of event-state，this article rede- fines case-related concepts and compares them with traditional concepts． The study found that the so- called new cases in traditional epidemiological studies are actually the cases firstly discovered，including newly discovered cases and identifiable newly incident cases ( disease initiation) ． In the real world，new cases are often difficult to measure，and together with the continuous process of disease development and iceberg phenomenon，those may affect the accuracy of disease frequency measurement and causal infer- ence． A correct understanding of the meaning of case-related concepts，the meanings they reflect，and the differences between them help to rationally interpret the results of epidemiological research．

An observation on the long-term efficacy of recombinant hepatitis B vaccines among the newborns / 预防医学

Objective evaluate the long-term efficacy of the recombinant hepatitis B vaccines (HBV) among the newbornswith vaccination at birth. Methods During 1996-1997, 135 newborns were selected from Deqing according to the inclusioncriterion. They were divided into 2 groups: a group of 35 newborns whose mother was HBsAg positive) and a group of 100newbornswhose mother was HBsAg negative. All 135 newborns routinely received 3 doses of yeast -derived hepatitis Bvaccines (i.e. the first dose at birth, the second dose at 1 month old, and the third dose at 6 months old) . Serologicalmarkers to HBV were repeatedly assessed at 3 follow-up stages (i.e. the first follow-up at 12 months, the second follow-upat 2010, the third follow-up at 2012) . Results Participants remained in the study at 3 follow-upstages were 123(91.11%), 95(70.37%) and 46(34.07%) respectively. Participants' serum HBsAg were negative at all 3 follow-upstages. Among participants whose mothers were HBsAg positive, 3 participants were found to be HBcAb positive in 2010,and no new HBcAb positive participants were found in 2012. The rates of HBsAb positive at 3 follow-up stages were 88.89%, 81.48%, and 80.00% respectively. The HBsAb geometric mean concentrations (GMCs) of participants at their 12 monthsold were significantly positively associated with those in 2010 and those in 2012(P<0.05) . Among participants whosemothers were HBsAg negative, no HBcAb positive participants were found. The rates of HBsAb positive at 3 follow-up stageswere 91.18%, 54.41%, and 52.78% respectively. No correlation was found among HBsAb GMCs of participants at 12 monthsold, in 2010 and in 2012. No correlation was found between boost vaccination and the rate of HBsAg positive, afteradjustment of the HBsAg status of their mothers. Conclusion The efficacy of the yeast-derived HBV could sustain for at least13-15 years, and the general population do not need booster immunization. After the 3-dose immunization, the HBsAblevels of the healthy mothers' 12-months-old children were related to those of their adolescence.

The long-term efficacy of recombinant hepatitis B vaccines for children / 预防医学

Objective To observe long-term efficacy of recombinant hepatitis B vaccines for children received fundamental immunization or booster dose. Methods 493 school students from Deqing county with complete information of immunization history were investigated and their serological markers were detected. 430 students received booster dose vaccines at 3-11 years old and were defined as booster group while the remaining 63 students were defined as fundamental group. Results All vaccines the 493 students received for fundamental immunization were recombinant. Compared with fundamental group(57. 14%),booster group had significantly higher Anti-HBs positive rate of 91. 40%(P<0. 01). And the Anti-HBs positive rate had a high level of 94. 99% when 0-5 years after booster immunization while it declined to 64. 71% after 8-15 years and showed no significant difference compared with fundamental group. Conclusion Anti-HBs level and anti -HBs positive rate can significantly increase for short periods after booster immunization,and may decline considerably for long-term. Immunologic amnesia rate is low when 3 -11 years after fundamental immunization among infants.

Epidemiologic and genetic characteristics of hepatitis E virus in Shanghai, 1997-2012 / 中华流行病学杂志

Objective The aim of this study was to systemically analyze the epidemiologic,serological and genetic characteristics of hepatitis E virus (HEV) in Shanghai from 1997 to 2012.Methods We analyzed the data related to the epidemics of hepatitis E from China Information System for Disease Control and Prevention.We implemented serological surveillance program,based on community healthy population with enzyme-linked immunosorbent assay method and estimated the standardized sero-prevalence.We also obtained nucleotide sequences of hepatitis E patients using the nested RT-PCT assays,together with propotype sequences in the GenBank to construct a HEV genetic database in Shanghai.Results In this paper,we found that the distribution of hepatitis E patients was sporadic in the past 16 years in Shanghai.The morbidity kept declining,but with seasonal and periodical fluctuation.Morbidity in males was significantly higher than in females,with the hard hit population between 30 and 65 year-olds.In total,3979 sera samples were collected through the serological surveillance programs in 2001,2004,2007 and 2012.The standardized sero-prevalence rates of the said years were 22.32％,18.56％,10.22％ and 34.43％ which all showing strong relationship with age groups and the regions where the populations were being monitored.73 nucleotide sequences of hepatitis E patients from hospitals were identified,during 2004 and 2008.Results from phylogenetic analysis revealed that all HEV isolates belonged to genotype Ⅳ and including 4 known subtypes 4a,4d,4h and 4i which sharing 83.09％-97.96％,85.87％-97.26％ and 83.80％-95.10％ nucleotide sequence identities with the swine HEV genotype Ⅳ of GU188851,DQ450072 and EF570133.Meanwhile,59 HEV isolates from different districts shared 99％ nucleotide sequence identities with each other.Conclusion Hepatitis E would still be a challenge for long time and the zoonotic questions that related to hepatitis E,need to be explored and explained in the future.

Prevalence of occult hepatitis B virus infection and its phylogenetic features among mother-teenager pairs / 中华流行病学杂志

Objective Prevalence of occult hepatitis B virus (HBV) infection (OBI) was investigated in a paired mother-teenager population and HBV S gene variation including overt and occult HBV,was determined.Methods A follow-up study based on an initial survey of 135 mother-teenager pairs was carried out through collection of questionnaires and blood samples HBsAg were detected by ELISA method,viral load by PCR amplification and HBV S gene by phylogenetic analysis.Results 102 pairs of subjects were followed-up.Blood samples from 94 mothers and 101children were collected.OBI prevalence in mothers was 10.0％ (6/60),significantly higher than 2.0％(2/101) in teenagers.Medians of viral load were 399.9 IU/ml and 247.6 IU/ml in overt and occult HBV strains,but without significant difference.1 occult HBV strain belonged to genotype B with serotype adw while the other 7 were genotype C with serotype adr.15 of the overt HBV strains belonged to genotype B with serotype adw and the other 8 were genotype C with serotype adr.Proportions of genotype-C strains were significantly higher in occult HBV strains than in overt HBV strains.Conclusion OBI was seen in teenage-mother population.

Study on the prevalence and genotype of hepatitis E virus among commercial swine population in Eastern and Southern China / 中华流行病学杂志

Objective To determine the prevalence and genotype of hepatitis E virus (HEV)among commercial swine population in Eastern and Southern China. Methods Six hundred specimens of swine bile collected from 5 slaughterhouses in Eastern and Southern China from 2007 to 2009 were tested for HEV RNA using nested RT-PCR. PCR products were sequenced for phylogenetic analysis. Results Forty-seven out of the 600 samples (7.83%) were positive for HEV RNA. Based on the 150 nt fragment within HEV ORF2, data from phylogenetic analysis revealed that all the 47 HEV isolates were identified to be genotype Ⅳ, sharing 75.0%-83.4%, 75.0%-84.6%, 71.9%-80.7% and 88.1%-91.5% nucleotide identities with prototype Ⅰ,Ⅱ,Ⅲ and Ⅳ HEV strains respectively while majority of the isolates clustered within their respective isolation sites. Conclusion HEV was widespread in commercial swine population in Eastern and Southern China that raised a serious concern about the safety regarding the consumption of pork products.

Phylogenetic analysis of hepatitis E virus strains isolated from both human and swine in Anqing City / 中华预防医学杂志

<p><b>OBJECTIVE</b>To determine the genotype and phylogenetic characteristics of hepatitis E virus (HEV) strains isolated from the human and swine in Anqing City.</p><p><b>METHODS</b>Twenty seven sera from sporadic hepatitis E patients and 400 commercial swine bile samples were collected in Anqing City. According to the collection time, the bile samples were equally divided into 4 groups which were named group A, B, C and D respectively. Nested reverse transcription polymerase chain reaction (RT-PCR) and DNA sequencing technology were performed to obtain the DNA sequences of HEV RNA Open Reading Frame 2 (ORF2) (150 nt) for all the serum and bile samples. The sample sequences and prototype sequences from the GenBank were aligned and their nucleotide sequence identities were calculated. A phylogenetic tree constructed according to the Bayesian inference method was used to analyze the genotype and phylogenetic relationship between the human and swine HEV strains isolated in Anqing City.</p><p><b>RESULTS</b>The male-to-female sex ratio of the patients was 2.86:1 and the average age was 56.78 years old. Sixteen out of 27 serum (59.26%) samples were HEV RNA positive. Human HEV strains isolated in Anqing City shared 74.75% - 82.99%, 75.26% - 83.64%, 72.77% - 80.57% and 88.03%-91.63% nucleotide sequence identities with prototype I, II, III and IV HEV strains respectively. HEV RNA was detected in 22 out of 400 bile samples (5.5%). The swine HEV detection rates for group A, B, C and D were 7.00%, 3.00%, 9.00% and 3.00% respectively, showing no significant difference among these groups (χ(2) = 5.20, P = 0.16). Swine HEV strains isolated in Anqing City shared 75.24% - 83.42%, 75.93% - 84.19%, 72.86% - 80.64% and 88.15% - 91.79% nucleotide sequence identities with prototype I, II, III and IV HEV strains respectively. Phylogenetic analysis revealed that all the HEV strains isolated from both the human and swine belonged to genotype IV and scattered in evolutionary branches without significant species aggregation.</p><p><b>CONCLUSION</b>It's suggested that genotype IV HEV was the dominant genotype among the human and swine in Anqing City and probably transmitted between them in this area.</p>

Seasonal pattern and phylogenetic analysis with human isolates of genotype-IV hepatitis E virus in swine herds, eastern China / 中华预防医学杂志

<p><b>OBJECTIVE</b>To determine the seasonal prevalence of genotype-IV hepatitis E virus (HEV) in swine herds in Eastern China and explore the phylogenetic relationship between swine HEV and human HEV in the situation that zoonotic features of HEV had been confirmed.</p><p><b>METHODS</b>From September 2007 to June 2008, a total of 1200 swine bile specimens were collected from three slaughter houses located in Zhejiang, Anhui and Jiangsu, the Eastern China, and detected for HEV RNA by using nested RT-PCR. The positive PCR products were sequenced. Then the swine HEV were phylogenetically determined with human HEV isolated in Eastern China.</p><p><b>RESULTS</b>The positive rate for HEV RNA in swine herds was 4.5% totally. Significant differences of HEV detection were not observed among seasonal pattern (Sep - Oct: 6%, Dec - Jan: 4.33%, Mar - Apr: 4.33%, May - Jun: 3.33%) but in geographic distribution (Jiangsu: 6%, Anhui: 5%, Zhejiang: 2.5%). Regardless of isolation from different areas,swine and human genotype-IV HEV shared a high similarity. Phylogenetically, there were 80% - 100% and 96% - 100% identities within swine genotype-lV HEV at the nucleotide and amino acid levels respectively. Between swine HEV and human HEV, there were also similarities of 76% -99% and 95% - 100%. It was noted that some human and swine isolates were clustered with bootstrap values of > 90%.</p><p><b>CONCLUSION</b>Genotype-IV HEV is widely prevalent in swine herds in Eastern China and original common ancestor of evolution and transmission was implied. The sustaining prevalence within swine herds should have a probable influence on the epidemic situation of hepatitis E in human beings.</p>

Phylogenetic analysis of sporadic hepatitis E virus in Eastern China / 中华流行病学杂志

<p><b>OBJECTIVE</b>To understand phylogenetic characteristics of sporadic hepatitis E virus (HEV) in eastern China.</p><p><b>METHODS</b>Four hundred and thirteen sera were collected from sporadic hepatitis E cases in 14 second- or first-class hospitals in Eastern China from 2005 to 2008 and detected with a nested RT-PCR assay. Partial nucleotide sequences of the HEV isolates were determined for phylogenetic analysis with prototype sequences in the GenBank.</p><p><b>RESULTS</b>The male-to-female sex ratio of the patients was 1.75:1 with 61.5% of them aged 40 - 69 years old. HEV RNA was detected in 140 out of 413(34%)serum samples. Phylogenetic analysis revealed that all the 140 HEV isolates belonged to genotype IV, sharing 77.9% - 88.3%, 80.8% - 90.6%, 73.4% - 85.2% and 91.0% - 95.4% nucleotide sequence identities with prototype I, II, III and IV HEV isolates respectively.</p><p><b>CONCLUSION</b>It was evident that genotype IV HEV served as the main causative agent of sporadic HEV infection in Eastern China. However the viral origin and evolution needs further clarification.</p>

An investigation on hepatitis E virus infection status among livestock in Xi'an area / 中华流行病学杂志

<p><b>OBJECTIVE</b>To explore the carrier state of hepatitis E virus(HEV) in livestock in Xi'an area.</p><p><b>METHODS</b>Bile samples from swine, canine, sheep and cow were collected from a local slaughtering house. Reverse transcriptase nested polymerase chain reaction (RT-nPCR) was employed to amplify the ORF2 region in HEV RNA genome. All positive samples were sequenced and compared with data from GenBank. Homology analysis was conducted based on the outcome of sequencing.</p><p><b>RESULTS</b>194, 178, 79 and 191 bile samples from swine, canine, cow and sheep were collected. Positive rates with RT-nPCR method in these domestic animals were 4.10%, 0%, 0% and 0% respectively. Genetic distance analysis indicated that strains being identified were close to genotype IV of HEV, then genotype I, II and III in nucleic acid. Same outcome was shown by the same analysis on amino acid.</p><p><b>CONCLUSION</b>Swine was the only reservoir of HEV in livestock and genotype IV was the prevalent genotype.</p>

Isolation of hepatitis E virus from liver of swine at abattoirs in Shandong province / 中华流行病学杂志

<p><b>OBJECTIVE</b>To determine the prevalence and genotype of hepatitis E virus (HEV) in swine liver before on the market and to analyze the phylogenetic relationship between the isolates from swine and human.</p><p><b>METHODS</b>35 swine liver specimens were collected from two slaughtering houses in the countryside of Shandong province, China. Nested reverse transcription-polymerase chain reaction (nested RT-PCR) and subsequent sequencing were used to determine the nucleotide sequences. A phylogenetic tree was constructed with Neighbor-joining method based on the Kimura-2-parameter model.</p><p><b>RESULTS</b>3. (8.57%) of the 35 swine liver specimens being tested were positive for HEV RNA. The three swine HEV strains isolated in the present study from liver samples shared the highest identity to genotype-IV HEV.</p><p><b>CONCLUSION</b>Results from the study confirmed that HEV was detectable among swine before on the market and the genotype was the same as that representing human and swine isolates in China. It also suggested that much more attention should be paid to the safety on the digestion of swine liver.</p>

Sequence analysis on measles viruses isolated in Shanghai in 2005 / 中华流行病学杂志

<p><b>OBJECTIVE</b>To ascertain the genetic characterization and genotype of measles viruses isolated in Shanghai region, in 2005.</p><p><b>METHODS</b>Measles virus was isolated from throat swab specimens collected from suspected measles cases and 450 bp fragment of C terminus of nucleprotein (N) gene was amplified by RT-PCR. Sequence analysis was conducted to ascertain the genotype and to compare the difference of nucleotide with other measles virus strain published in GenBank.</p><p><b>RESULTS</b>4 measles viruses were isolated from 10 throat swab specimens, and the sequence analysis indicated that they belonged to H1 genotype. The homogeneity of 450 nucleotides in the C terminal of the N gene was at 98%-98.2% as compared to H1 genotype (China93-7). They differed from genotype H2 (China94-1) at 6.4%-6.9% and from genotype A (Edmonston) at 6.7%-6.9%, from measles vaccine (Shanghail91) at 7.6%-8.0%. They differed from the other measles viral strain isolated in China in 1993 - 2005 at 0.2%-3.7%. The variation within 4 isolated measles viruses was at 0.7%-1.3%.</p><p><b>CONCLUSION</b>It was H1 genotype measles viruses,which are the native viruses in China that led to the outbreak of measles in Shanghai, in 2005.</p>

Evaluation of two anti-hepatitis E virus IgM kits / 生物医学与环境科学（英文）

<p><b>OBJECTIVE</b>To evaluate two commercial anti-hepatitis E virus (HEV) IgM kits used for differential diagnosis of acute enteric viral hepatitis.</p><p><b>METHODS</b>The kit for IgM capture assay, was produced with a recombinant HEV structural protein protecting primates against experimental infection by different HEV genotypes, while the other kit for indirect ELISA was produced with recombinant structural proteins from different HEV genotypes. The serum specimens were taken from 241 cases with a confirmed or presumptive diagnosis of hepatitis A and 74 cases with a confirmed or presumptive diagnosis of hepatitis E.</p><p><b>RESULTS</b>The sensitivity and specificity of the IgM capture assay kit were 97% and 100%, respectively, and the corresponding values for the other kit were 70% and 78%, respectively.</p><p><b>CONCLUSION</b>The IgM capture assay kit has higher sensitivity and specificity in diagnosing acute enteric viral hepatitis E.</p>

Detection and analysis of partial sequences isolated from human and swine in rural area of southern China / 中华流行病学杂志

<p><b>OBJECTIVE</b>To study the genotype of swines isolated from humans and their relationships with hepatitis E virus (HEV) in the rural areas of southern China.</p><p><b>METHODS</b>Specimens collected from normal people with HEV-IgM positive, acute hepatitis E patients and from swine in the same area were detected for HEV RNA using RT-nPCR with ORF2 primers. The positive PCR products were cloned and sequenced.</p><p><b>RESULTS</b>13 out of the 132 samples from swine stool, 4 of 26 HEV-IgM positive sera of normal people and 1 of 4 acute hepatitis E patients' stool sample and sera were tested positive for HEV RNA. Data from sequence analysis showed that the identity at nucleotide level was 89.3%-100.0% among the 10 isolates which shared 78.7% - 84.7%, 83.3% - 85.3%, 76.0% - 80.0% and 84.7% - 95.3% nucleotide sequence identity with HEV genotype I, II, III and IV respectively in the region (nt6317- 6466).</p><p><b>CONCLUSION</b>HEV circulating in humans and swine in the area belonged to genotype IV.</p>