Genetic and environmental effects on the bone development of the hand and wrist in Chinese young twins.

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.

OBJECTIVE: To determine whether elevated serum uric acid (UA) levels are associated with type 2 diabetes diagnosed using HbA1c levels among Chinese adults. METHODS: 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. RESULTS: 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. CONCLUSION: Serum UA is significantly associated with type 2 diabetes diagnosed using HbA1c levels, independent of other cardiometabolic parameters.

[Effects of functional connectivity between anterior cingulate cortex and dorsolateral prefrontal cortex on executive control of attention in healthy individuals].

OBJECTIVE: To explore the presence of functional connectivity between anterior cingulate cortex (ACC) and dorsolateral prefrontal cortex (DLPFC) during the manipulation of attentional network test (ANT) and its relationship with behavioral performance. METHODS: Functional magnetic resonance imaging was performed on 25 healthy subjects aged 17 - 20 years. And ANT was used as a paradigm. Functional connectivity between ACC-DLPFC was tested and correlation analysis conducted between functional connectivity coefficients and behavioral scores of ANT. RESULTS: Significant functional connectivity between the dorsal ACC (dACC) with bilateral DLPFC was found. Furthermore, event-related functional connectivity coefficients between left dACC and left DLPFC were negatively associated with the behavioral scores of executive control (r = -0.63; P < 0.01). CONCLUSION: Our findings provide new evidence that ACC and DLPFC are functionally connected and such functional connectivity has advantageous influence on executive control function of attention so as to contribute to our understanding of the integrated role of these brain regions in attentional network.

[A comparative study on blood pressure, obesity, smoking and alcohol drinking behavior in Chinese twins reared apart and together].

OBJECTIVE: To test the potential feasibility for studies conducted in twins reared apart and together from the Chinese National Twin Registry (CNTR) and to answer the question whether the rearing environment affects chronic disease risk factors. METHODS: The samples were composed of twins from two sub-registries, which included 503 twin pairs in Lishui and 505 twin pairs in Qingdao. RESULTS: There was a big difference in the rates of twins reared apart in different areas (from 0.6% in Qingdao to 5.4% in Lishui). Only nine pairs of dizygotic twins reared apart in Lishui were recruited. The intraclass correlation coefficients for many indices were not significant. Rearing environment might affect diastolic blood pressure and smoking behavior, but it was hard to interpret its impacts in systolic blood pressure, body mass index, waist-hip ratio and drinking behavior. CONCLUSION: The design of twins reared apart is a valuable study and can be conducted in the CNTR, but the current sample size is still a big issue which requires the registry to recruit more twins to support it.

[Heritability of serum uric acid in adult twins].

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.

[Study of twin-birth on genetic or environmental determinants of male Chinese smoking initiation].

OBJECTIVE: To determine the role of genetic and environmental factors in the onset of smoking in Chinese male twins. METHODS: Retrospective data on initiation and age at onset of smoking, reported by 1,006 adult twin pairs [aged 18 year-old or more, 638 pairs of monozygotic (MZ) twins and 368 pairs of dizygotic (DZ) twins] were analyzed to calculate the heritability of smoking behavior and smoking initiation. RESULTS: Different from western culture, 66.8% of males in this Chinese sample are smokers or have the experience of smoking, but only 0.2% of females do so. In the MZ twins, 88.7% (566/638 pairs) of them are both smokers or have smoking experience or both non-smokers, while the number is 63.6% (234/368 pairs) in the DZ twins. The heritability of smoking in this Chinese twin sample is 69.0%+/-4.1%. The smokers usually started their smoking at the age of 20.4+/-5.3 years old. The correlation coefficient for age at onset of smoking in male MZ twin smokers is 0.393, compared to correlation coefficient 0.860 in male DZ twin smokers. CONCLUSION: The moderate level of heritability shows that genetic factors have influence on smoking choice; when the smokers start their smoking, however, this depends more on individual environmental variation in our Chinese twin sample.

[Genotyping of Epstein-Barr virus in Epstein-Barr virus associated gastric carcinoma].

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].

OBJECTIVE: To calculate heritabilities of personality disorders (PDs) in twin population. METHODS: 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. RESULTS: 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. CONCLUSION: PD was mainly determined by genetic factor. These findings may provide evidence for future research on PD.

[Study on the relative risk factors of adult measles in a case-control study in Qingdao city].

OBJECTIVE: To explore the relative risk factors of adult measles in Qingdao city. METHODS: 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. RESULTS: 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. CONCLUSION: 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.

[Design and rapid evaluation of a TaqMan assay for the detection of influenza A viruses].

OBJECTIVE: To design and rapidly evaluate a TaqMan assay for detecting influenza A viruses. METHODS: 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. RESULTS: 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. CONCLUSION: The TaqMan Real-time PCR assay is specific, sensitive and easy to perform.

[Heritability analysis of insulin sensitivity and the effect of age and sex: a twin study in Chinese aged 5-18].

OBJECTIVE: To study the contribution of genes and environment to the variation of insulin sensitivity, and the effect of body mass index (BMI), age and sex. METHODS: A total of 296 healthy same-sex twin pairs were studied, including 223 monozygotic (MZ) and 73 dizygotic (DZ) twin pairs aged 5-18(mean age, 12+/-4 years). Microsatellite polymorphism (STR) was used to diagnose zygosity of twins. Model-fitting method using Mx package was performed to analyze the genetic and environmental variance of homeostasis model assessment insulin resistance index (HOMA IR) and HOMA beta cell function index (HBCI), before and after adjusting BMI. The effect of age and sex on the model was tested. RESULTS: HOMA IR was correlated with age, sex and BMI, while HBCI was correlated with age. Genetic analysis showed in ACE model, heritability of HOMA IR in boys and girls was different before and after BMI adjustment; heritability of HBCI was not different significantly. Heritability of HOMA IR and HBCI were 0.25, 0.24, respectively, after adjusting BMI. CONCLUSION: Gene and environment influence insulin sensitivity of children and adolescents together, whereas environment seems to play a more important role. The effect of BMI on estimating heritability of insulin sensitivity is considerable, differing from sex or age.

[Heritability of serum lipids and lipoproteins and its related factors in twins aged 5 to 19 years of China].

OBJECTIVES: To study the contribution of the genes and environment to variation of serum levels of lipids and lipoprotein. METHODS: 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. RESULTS: 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. CONCLUSIONS: 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.