A descriptive analysis of hyperlipidemia in adult twins in China / 中华流行病学杂志

Objective: To describe the distribution characteristics of hyperlipidemia in adult twins in the Chinese National Twin Registry (CNTR) and explore the effect of genetic and environmental factors on hyperlipidemia. Methods: Twins recruited from the CNTR in 11 project areas across China were included in the study. A total of 69 130 (34 565 pairs) of adult twins with complete information on hyperlipidemia were selected for analysis. The random effect model was used to characterize the population and regional distribution of hyperlipidemia among twins. The concordance rates of hyperlipidemia were calculated in monozygotic twins (MZ) and dizygotic twins (DZ), respectively, to estimate the heritability. Results: The age of all participants was (34.2±12.4) years. This study's prevalence of hyperlipidemia was 1.3% (895/69 130). Twin pairs who were men, older, living in urban areas, married,had junior college degree or above, overweight, obese, insufficient physical activity, current smokers, ex-smokers, current drinkers, and ex-drinkers had a higher prevalence of hyperlipidemia (P<0.05). In within-pair analysis, the concordance rate of hyperlipidemia was 29.1% (118/405) in MZ and 18.1% (57/315) in DZ, and the difference was statistically significant (P<0.05). Stratified by gender, age, and region, the concordance rate of hyperlipidemia in MZ was still higher than that in DZ. Further, in within-same-sex twin pair analyses, the heritability of hyperlipidemia was 13.04% (95%CI: 2.61%-23.47%) in the northern group and 18.59% (95%CI: 4.43%-32.74%) in the female group, respectively. Conclusions: Adult twins were included in this study and were found to have a lower prevalence of hyperlipidemia than in the general population study, with population and regional differences. Genetic factors influence hyperlipidemia, but the genetic effect may vary with gender and area.

A descriptive analysis on hypertension in adult twins in China / 中华流行病学杂志

Objective: To describe the distribution characteristics of hypertension among adult twins in the Chinese National Twin Registry (CNTR) and to provide clues for exploring the role of genetic and environmental factors on hypertension. Methods: A total of 69 220 (34 610 pairs) of twins aged 18 and above with hypertension information were selected from CNTR registered from 2010 to 2018. Random effect models were used to describe the population and regional distribution of hypertension in twins. To estimate the heritability, the concordance rates of hypertension were calculated and compared between monozygotic twins (MZ) and dizygotic twins (DZ). Results: The age of all participants was (34.1±12.4) years. The overall self-reported prevalence of hypertension was 3.8%(2 610/69 220). Twin pairs who were older, living in urban areas, married, overweight or obese, current smokers or ex-smokers, and current drinkers or abstainers had a higher self-reported prevalence of hypertension (P<0.05). Analysis within the same-sex twin pairs found that the concordance rate of hypertension was 43.2% in MZ and 27.0% in DZ, and the difference was statistically significant (P<0.001). The heritability of hypertension was 22.1% (95%CI: 16.3%- 28.0%). Stratified by gender, age, and region, the concordance rate of hypertension in MZ was still higher than that in DZ. The heritability of hypertension was higher in female participants. Conclusions: There were differences in the distribution of hypertension among twins with different demographic and regional characteristics. It is indicated that genetic factors play a crucial role in hypertension in different genders, ages, and regions, while the magnitude of genetic effects may vary.

Gene-lifestyle interaction on coronary heart disease in adult twins of China / 中华流行病学杂志

Objective: To explore the gene-lifestyle interaction on coronary heart disease (CHD) in adult twins of China. Methods: Participants were selected from twin pairs registered in the Chinese National Twin Registry (CNTR). Univariate interaction model was used to estimate the interaction, via exploring the moderation effect of lifestyle on the genetic variance of CHD. Results: A total of 20 477 same-sex twin pairs aged ≥25 years were recruited, including 395 CHD cases, and 66 twin pairs both had CHD. After adjustment for age and sex, no moderation effects of lifestyles, including current smoking, current drinking, physical activity, intake of vegetable and fruit, on the genetic variance of CHD were found (P>0.05), suggesting no significant interactions. Conclusion: There was no evidence suggesting statistically significant gene-lifestyle interaction on CHD in adult twins of China.

A descriptive analysis on coronary heart disease in adult twins in China / 中华流行病学杂志

Objective: To describe the distribution characteristics of coronary heart disease in adult twins recruited from Chinese Twin Registry (CNTR), and provide clues and evidence for the effect of genetic and environmental influences on coronary heart disease. Methods: By using the data of CNTR during 2010-2018, a total of 34 583 twin pairs aged ≥18 years who completed questionnaire survey and had related information were included in the current study to analyze the population and area distribution characteristics of coronary heart disease. Random effect models were used to compare the differences between groups. The concordane rate of coronary heart disease were calculated respectively in monozygotic (MZ) twin pairs and dizygotic (DZ) twin pairs to estimate the heritability. Results: The twin pairs included in this analysis were aged (34.2±12.4) years. The overall prevalence rate of coronary heart disease in twin pairs was 0.7%. Twin pairs who were women, older, obese and lived in northern China had higher prevalence of coronary heart disease (P<0.05). Intra-pair analysis in the same-sex twin pairs found that the concordane rate of coronary heart disease was higher in MZ twin pairs (25.3%) than in DZ twins (7.4%), and the difference was statistically significant (P<0.001). The overall heritability of coronary heart disease was 19.3% (95%CI: 11.8%-26.8%). Stratified by gender, age and area, the concordane rate was still higher in MZ twin pairs than in DZ pairs. Participants who were women, aged 18-30 years or ≥60 years and lived in northern China had a higher heritability of coronary heart disease. Conclusion: The distribution of coronary heart disease in twin pairs differed in populations and areas. The prevalence of coronary heart disease was affected by genetic factors, but the effect varied with age, gender and area.

A descriptive analysis on type 2 diabetes in twins in China / 中华流行病学杂志

Objective: To describe the distribution characteristics of type 2 diabetes in twins in Chinese National Twin Registry (CNTR), provide clues and evidence for revealing the influence of genetic and environmental factors for type 2 diabetes. Methods: Of all twins registered in the CNTR during 2010-2018, a total 18 855 twin pairs aged ≥30 years with complete registration information were included in the analysis. The random effect model was used to describe the population and area distribution characteristics and concordance of type 2 diabetes in twin pairs. Results: The mean age of the subjects was (42.8±10.2) years, the study subjects included 10 339 monozygotic (MZ) twin pairs and 8 516 dizygotic (DZ) twin pairs. The self-reported prevalence rate of type 2 diabetes was 2.2% in total population and there was no sighificant difference between MZ and DZ. Intra-twin pairs analysis showed that the concordance rate of type 2 diabetes was 38.2% in MZ twin pairs, and 16.0% in DZ twin pairs, the difference was statistically significant (P<0.001). The concordance rate of type 2 diabetes in MZ twin parts was higher than that in DZ twin pairs in both men and women, in different age groups and in different areas (P<0.05). Further stratified analysis showed that in northern China, only MZ twin pairs less than 60 years old were found to have a higher concordance rate of type 2 diabetes compared with DZ twin pairs (P<0.05). In southern China, the co-prevalence rate in male MZ twin pairs aged ≥60 years was still higher than that in DZ twin pairs (P<0.05). Conclusion: The twin pairs in this study had a lower self-reported prevalence of type 2 diabetes than the general population. The study results suggested that genetic factors play a role in type 2 diabetes prevalence in both men and women, in different age groups and in different areas, however, the effect might vary.

Correlation between fasting plasma glucose, HbA1c and DNA methylation in adult twins / 北京大学学报(医学版)

OBJECTIVE@#To explore the cytidine-phosphate-guanosine (CPG) sites associated with fas-ting plasma glucose (FPG) and glycated haemoglobin (HbA1c) in twins.@*METHODS@#In the study, 169 pairs of monozygotic twins were recruited in Qingdao, Zhejiang, Jiangsu, Sichuan and Heilongjiang in June to December of 2013 and June 2017 to October 2018. The methylation was detected by Illumina Infinium HumanMethylation450 BeadChip and Illumina Infinium MethylationEPIC BeadChip. According to the Linear Mixed Effect model (LME model), fasting plasma glucose and HbA1c were taken as the main effects, the methylation level (β value) was taken as the dependent variable, continuous variables, such as age, body mass index (BMI), blood pressure, components of blood cells, surrogate variables generated by SVA, and categorical variables, such as gender, smoking and drinking status, hypoglycemic drugs taking, were included in the fixed effect model as covariates, and the identity numbers (ID) of the twins was included in the random effect model. The intercept was set as a random. Regression analysis was carried out to find out the CpG sites related to fasting blood glucose or HbA1c, respectively.@*RESULTS@#In this study, 338 monozygotic twins (169 pairs) were included, with 412 459 CpG loci. Among them, 114 pairs were male, and 55 pairs were female, with an average age of (48.2±11.9) years. After adjustment of age, gender, BMI, blood pressure, smoking, drinking, blood cell composition, and other covariates, and multiple comparison test, 7 CpG sites (cg19693031, cg01538969, cg08501915, cg04816311, ch.8.1820050F, cg06721411, cg26608667) were found related to fasting blood glucose, 3 of which (cg08501915, ch.8.1820050f, cg26608667) were the newly found sites in this study; whereas 10 CpG sites (cg19693031, cg04816311, cg01538969, cg01339781, cg01676795, cg24667115, cg09029192, cg20697417, ch.4.1528651F, cg16097041) were found related to HbA1c, and 4 of which(cg01339781, cg24667115, cg20697417, and ch.4.1528651f) were new. We found that cg19693031 in TXNIP gene was the lowest P-value site in the association analysis between DNA methylation and fas-ting plasma glucose and HbA1c (PFPG=2.42×10-19, FDRFPG<0.001; PHbA1c=1.72×10-19, FDRHbA1c<0.001).@*CONCLUSION@#In this twin study, we found new CpG sites related to fasting blood glucose and HbA1c, and provided some clues that partly revealed the potential mechanism of blood glucose metabolism in terms of DNA methylation, but it needed further verification in external larger samples.

Correlation between blood pressure and DNA methylation in adult twins / 北京大学学报(医学版)

OBJECTIVE@#To explore the DNA methylation sites correlated with blood pressure (systolic blood pressure, diastolic blood pressure, mean arterial pressure, pulse pressure) in adult twin population.@*METHODS@#A total of 476 twins from the Chinese National Twin Registry were selected as the research population. Questionnaires were used to collect demographic characteristics, lifestyle, disease status and other information, and blood pressure, height, weight and other anthropometric indicators were measured. The genome-wide DNA methylation of whole blood samples was detected by using Infinium HumanMethylation450 BeadChip. The DNA methylation sites correlated with blood pressure were analyzed by constructing mixed effect model with adjusting potential confounding factors, and the significant level was false discovery rate <0.05.@*RESULTS@#After data quality control, 465 twins (122 pairs of monozygotic twins, 104 pairs of dizygotic twins, 13 individuals from 13 pairs of twins) aged (44.8±13.2) years were finally enrolled. There were more males and more monozygotic twins, and the current smokers and current regular drinkers both accounted for more than 30%. No significant CpG site was found after multiple testing in the correlation study between genome-wide DNA methylation and blood pressure by using the collected twins. However, the cg07761116 located on chromosome 10 had low P value in the correlation analysis of 3 blood pressure indices (systolic blood pressure, diastolic blood pressure, mean arterial pressure), suggesting that this site might be correlated with blood pressure. The other 7 sites had low P value in the correlation analysis of the two blood pressure indices, respectively, which pointed to genes involved in neurological development, protein homeostasis, inflammatory reaction and other pathways.@*CONCLUSION@#There is no sufficient evidence to support any DNA methylation site correlated with blood pressure, which may be caused by insufficient sample size and other reasons. This study could provide a reference for subsequent similar twin studies, and subsequent studies can focus on the cg07761116 located on chromosome 10 and other sites with low P values.

Genetic and environmental effects on the bone development of the hand and wrist in Chinese young twins / 生物医学与环境科学（英文）

We assessed genetic and environmental effects on bone development of the hand and wrist, and on key anthropometric measures in Chinese young twins. In total, 139 monozygotic and 95 dizygotic twin pairs aged from 5 to 18 years were recruited. The twin correlations of total hand and wrist scores for monozygotic (MZ) and dizygotic (DZ) twins were 0.71 and 0.36, respectively. Bivariate model analysis showed moderate genetic correlations only for total skeletal maturity vs. weight and total skeletal maturity vs. waist circumference (r, 0.51 and 0.46, respectively). Our findings demonstrated that genetic factors played important roles in bone development of the hand and wrist in Chinese young twins, and that these genetic effects might be distinct from those influencing anthropometric measures.

Association Between Serum Uric Acid and Prevalence of Type 2 Diabetes Diagnosed using HbA1c Criteria Among Chinese Adults in Qingdao, China / 生物医学与环境科学（英文）

<p><b>OBJECTIVE</b>To determine whether elevated serum uric acid (UA) levels are associated with type 2 diabetes diagnosed using HbA1c levels among Chinese adults.</p><p><b>METHODS</b>We conducted two population-based cross-sectional studies in Qingdao in China in 2006 and 2009. A total of 6894 (39.4% men) subjects aged 35-74 years were included in the data analysis. Newly diagnosed diabetes was defined as HbA1c level of ⋝6.5%, and prediabetes was classified as HbA1c level between 5.7% and 6.4% according to the International Diabetes Federation criteria. Multivariate logistic regression was employed to assess the association between UA and prevalence of type 2 diabetes defined using Glycated hemoglobin A1c (HbA1c) levels.</p><p><b>RESULTS</b>Subjects with prediabetes had higher UA levels than those with normal glucose tolerance, newly diagnosed diabetes, and known diabetes, with corresponding values of 325.1 (82.5) µmol/L, 310.9 (84.2) µmol/L, 291.3 (81.7) µmol/L, 305.2 (83.6) µmol/L, respectively (P<0.001 for all comparisons). Binary logistic regression analysis showed that UA was a possible predictor for the prevalence of type 2 diabetes diagnosed using HbA1c levels, and the second quartile of UA levels had a higher odds ratio (OR: 4.088; 95% CI: 2.900-5.765) for HbA1c than the other quartiles after adjusting for age, body mass index, sex, marital status, education, income, alcohol consumption, smoking, and cardiometabolic parameters.</p><p><b>CONCLUSION</b>Serum UA is significantly associated with type 2 diabetes diagnosed using HbA1c levels, independent of other cardiometabolic parameters.</p>

Heritability of serum uric acid in adult twins / 中华流行病学杂志

Objective To assess the heritability of serum uric acid in adult,using the classic twin design.Methods Adult Twins were recruited from the Qingdao Twin Registry.Uric acid,height,weight were measured.Zygosity in all the same-sex twin pairs was determined by 16 polymorphic markers.Heritability was assessed by structural equation models,with age,gender and body mass index(BMI) included as covariates.Results In total,687 twin pairs were available for data analyses,including 420 pairs of monozygotic and 267 pairs of dizygotic twins.After logarithm transformed,uric acid in males ( 17.47±1.91 ) was significantly higher than in females ( 15.22±1.70,P＜0.0001 ).After adjustment on age,sex and BMI,intraclass correlations for uric acid were 0.70 for monozygotic twins and 0.40 for dizygotic twins.The sex-limitation AE model,combining additive genetic and unique environmental factors,could produce the best fit for the data.Heritability estimate for uric acid was 70.5% (95% CI:65.9-74.6),with the proportion of unique environmental effects as 29.5%(95%CI:25.4-34.2).Conclusion Additive genetic effects appeared to be the major contributor to the variation of uric acid in this twins sample being studied.

Genotyping of Epstein-Barr virus in Epstein-Barr virus associated gastric carcinoma / 病毒学报

Tumor samples from 236 gastric carcinoma patients and throat washings (TWs) from 135 healthy adults were collected and screened for EBV genome. 17 Epstein-Barr virus associated gastric carcinoma (EBVaGC) and 33 EBV positive TWs were further examined for type 1/2 EBV and polymorphism at Bam HI F, Bam HI W1/I1 boundary regions and Xho I restriction site in LMP1 gene. No type f of Bam HI F polymorphism was found in all the cases, nor type 2 in EBVaGC. 25 of 33 TWs (75.8%) analyzed detected type 1 virus, while 8 TWs (24.2%) detected type 2 virus. Type I and i of Bam HI W1/I1 polymorphism accounted for 1(5.9%) and 16 (94.1%) in EBVaGC and 11 (33.3%) and 19 (57.6%) in TWs, respectively. LMP1 Xho I(+) and (-) polymorphism accounted for 0(0) and 15 (88.2%) in EBVaGCs and 12 (36.4%) and 18 (54.5%) in TWs, respectively. Among those specimens with determinable genotypes through all the polymorphism, the distribution rate of type 1/i/Xho I(-) in EBVaGC (15/15, 100%) was significantly higher than that in TWs (4/28, 14.3%) (chi2 = 29.098, P < 0.0001), suggesting that the distinctive EBV strain (1/i/Xho I(-)) could be associated with Chinese EBVaGC.

A twin study of personality disorder heritability / 中华流行病学杂志

<p><b>OBJECTIVE</b>To calculate heritabilities of personality disorders (PDs) in twin population.</p><p><b>METHODS</b>Based on informed consent, we used Personality Diagnostic Questionnaire (fourth-version) as our screening tool to study the adult twins (aged 20 - 70 years) in Qingdao city. There were 324 twin pairs whose zygosity had been determined. Structural equation modeling was used to estimate the heritabilities by 242 same-sex twin pairs.</p><p><b>RESULTS</b>The best-fitting models yielded a heritability of 68.26% (60.26 - 74.78) of overall PDs, 59.00% (49.22 - 67.17) of cluster A, 64.99% (56.24 - 72.16) of cluster B, and 63.66% (54.72 - 71.02) of cluster C. There were significant genetic effects for schizotypal, narcissistic and dependent, explaining 49.96% (37.94 - 60.14), 52.89% (41.85 - 62.24) and 68.87% (60.80 - 75.40) of the variance respectively. No genetic effects were found on Histrionic, but common environmental effect accounted for 54.08% (44.50 - 62.43) of the total variances.</p><p><b>CONCLUSION</b>PD was mainly determined by genetic factor. These findings may provide evidence for future research on PD.</p>

Study on the relative risk factors of adult measles in a case-control study in Qingdao city / 中华流行病学杂志

<p><b>OBJECTIVE</b>To explore the relative risk factors of adult measles in Qingdao city.</p><p><b>METHODS</b>Case-control study was used to collect the information from 70 adult measles cases and 140 controls. Information would include general social and demographic characteristics, history and times regarding measles vaccination, demography of the study of population etc.</p><p><b>RESULTS</b>The case group had lower proportion of measles vaccination (chi2 = 26.88, P < 0.05, OR = 5.12, 95% CI: 2.69 - 9.73) than the control group with statistical significance. The vaccination frequencies were stratified as three ranks: 0, 1, > or = 2 times for analysis. When having 0 and 1 time measles vaccination, no statistical significance was found in these two groups (chi2 = 1.86, P = 0.173), but there were statistical significance between 0 and > or = 2 times (chi2 = 45.24, P = 0.000, OR = 13.35, 95% CI: 5.80 - 30.71), 1 and > or = 2 times (chi2 = 26.23, P = 0.000, OR = 7.91, 95% CI: 3.37 - 18.59) in the two groups. It was also found that the proportion of floating population was higher in case group than that of the control group (chi2 = 21.60, P < 0.01, OR = 4.06, 95% CI: 2.21 - 7.45). At the same time, statistically significant correlation was found between adult measles and average family incomes (chi2 = 2.23, P < 0.05, OR = 2.08, 95% CI: 1.15 - 3.76) by single-factor statistical analysis.</p><p><b>CONCLUSION</b>Results showed that 'without history of measles vaccination' was key relative risk factor for the adult measles while being a part of 'floating population' and those having lower incomes were among vulnerable groups.</p>

Design and rapid evaluation of a TaqMan assay for the detection of influenza A viruses / 中华实验和临床病毒学杂志

<p><b>OBJECTIVE</b>To design and rapidly evaluate a TaqMan assay for detecting influenza A viruses.</p><p><b>METHODS</b>The probe and the primers of the assay were designed with the software packages of DNA Star and Primer Premier 5.0. Their specificity and conservation were verified through Blast in GenBank and electronic hybridization. The assay's sensitivity was compared with the standard RT-PCR.</p><p><b>RESULTS</b>The designed primers and probe were confirmed to be very specific and conserved. The assay was 3-27 folds more sensitive than the standard RT-PCR. The RT and PCR steps could be simplified into one step.</p><p><b>CONCLUSION</b>The TaqMan Real-time PCR assay is specific, sensitive and easy to perform.</p>

Heritability of serum lipids and lipoproteins and its related factors in twins aged 5 to 19 years of China / 中华预防医学杂志

<p><b>OBJECTIVES</b>To study the contribution of the genes and environment to variation of serum levels of lipids and lipoprotein.</p><p><b>METHODS</b>One hundred and forty-three healthy monozygotic (MZ) twin pairs and 93 dizygotic (DZ) ones aged 5 to 19 [with a mean of (11.2 +/- 3.4) years]. Microsatellite polymorphism (STR) was used to diagnose zygosity of twins, and intraclass correlation coefficient method and Falconer formula were performed to investigate heritability of serum lipids and lipoproteins unadjusted or adjusted for age and sex. Logarithmic transformation was used for data with skewed distribution. Influence of relevant physical and biochemical indicators on serum lipids and other components was analyzed with partial coefficients of correlation adjusted for age and sex.</p><p><b>RESULTS</b>In the twin samples, difference in serum level of triglycerides (TG) between MZ and DZ was not statistically significant with intraclass variation and intraclass correlation. There was significant difference in serum levels of total cholesterol (TC), high-density lipoprotein-cholesterol (HDL-C), low-density lipoprotein-cholesterol (LDL-C), and lipoprotein [Lp(a)] between MZ and DZ, with their heritability estimates of 0.56, 0.55, 0.49 and 0.58 unadjusted, respectively, and 0.63, 0.63, 0.55 and 0.64 adjusted for age and sex, respectively. Serum levels of TC, HDL-C, LDL-C and Lp(a) correlated reversely with age. Serum levels of TC, HDL-C and LDL-C in girls were slightly higher than those in boys. Most indicators for serum levels of lipids and lipoprotein, except for serum level of Lp(a) correlated with body mass index (BMI), body fat ratio, Pelidisi index, and other indexes such as blood pressure, blood sugar, serum level of calcium, adjusted for age and sex.</p><p><b>CONCLUSIONS</b>Serum levels of TC, HDL-C and Lp(a) were influenced more greatly by genetic factors, and serum level of TG was mainly influenced by environmental ones. Levels of blood lipids in children were influenced by age and sex, and correlated with indicators that reflect their body fat and nutritional status.</p>