Ferroptosis defense mechanisms: The future and hope for treating osteosarcoma.

Currently, challenges such as chemotherapy resistance, resulting from preoperative and postoperative chemotherapy, postoperative recurrence, and poor bone regeneration quality, are becoming increasingly prominent in osteosarcoma (OS) treatment. There is an urgent need to find more effective ways to address these issues. Ferroptosis is a novel form of iron-dependent programmed cell death, distinct from other forms of cell death. In this paper, we summarize how, through the three major defense systems of ferroptosis, not only can substances from traditional Chinese medicine, antitumor drugs, and nano-drug carriers induce ferroptosis in OS cells, but they can also be combined with immunotherapy, differentiation therapy, and other treatment modalities to significantly enhance chemotherapy sensitivity and inhibit tumor growth. Thus, ferroptosis holds great potential in treating OS, offering more choices and possibilities for future clinical interventions.

Exploring the Genetic Association between Obesity and Serum Lipid Levels Using Bivariate Methods.

It is crucial to understand the genetic mechanisms and biological pathways underlying the relationship between obesity and serum lipid levels. Structural equation models (SEMs) were constructed to calculate heritability for body mass index (BMI), total cholesterol (TC), triglyceride (TG), high-density lipoprotein cholesterol (HDL-C), low-density lipoprotein cholesterol (LDL-C), and the genetic connections between BMI and the four classes of lipids using 1197 pairs of twins from the Chinese National Twin Registry (CNTR). Bivariate genomewide association studies (GWAS) were performed to identify genetic variants associated with BMI and lipids using the records of 457 individuals, and the results were further validated in 289 individuals. The genetic background affecting BMI may differ by gender, and the heritability of males and females was 71% (95% CI [.66, .75]) and 39% (95% CI [.15, .71]) respectively. BMI was positively correlated with TC, TG and LDL-C in phenotypic and genetic correlation, while negatively correlated with HDL-C. There were gender differences in the correlation between BMI and lipids. Bivariate GWAS analysis and validation stage found 7 genes (LOC105378740, LINC02506, CSMD1, MELK, FAM81A, ERAL1 and MIR144) that were possibly related to BMI and lipid levels. The significant biological pathways were the regulation of cholesterol reverse transport and the regulation of high-density lipoprotein particle clearance (p < .001). BMI and blood lipid levels were affected by genetic factors, and they were genetically correlated. There might be gender differences in their genetic correlation. Bivariate GWAS analysis found MIR144 gene and its related biological pathways may influence obesity and lipid levels.

Blood DNA methylation markers associated with type 2 diabetes, fasting glucose, and HbA1c levels: An epigenome-wide association study in 316 adult twin pairs.

DNA methylation plays an important role in the development and etiology of type 2 diabetes; however, few epigenomic studies have been conducted on twins. Herein, a two-stage study was performed to explore the associations between DNA methylation and type 2 diabetes, fasting plasma glucose, and HbA1c. DNA methylation in 316 twin pairs from the Chinese National Twin Registry (CNTR) was measured using Illumina Infinium BeadChips. In the discovery sample, the results revealed that 63 CpG sites and 6 CpG sites were significantly associated with fasting plasma glucose and HbA1c, respectively. In the replication sample, cg19690313 in TXNIP was associated with both fasting plasma glucose (P = 1.23 × 10-17, FDR < 0.001) and HbA1c (P = 2.29 × 10-18, FDR < 0.001). Furthermore, cg04816311, cg08309687, and cg09249494 may provide new insight in the metabolic mechanism of HbA1c. Our study provides solid evidence that cg19690313 on TXNIP correlates with HbA1c and fasting plasma glucose levels.

Associations of Obesity Measurements with Serum Metabolomic Profile: A Chinese Twin Study.

The objective of this study was to investigate how different obesity measures link to circulating metabolites, and whether the connections are due to genetic or environmental factors. A cross-sectional analysis was performed on follow-up survey data at the Chinese National Twin Registry (CNTR), which was conducted in four areas of China (Shandong, Jiangsu, Zhejiang and Sichuan) in 2013. The survey collected detailed questionnaire information and conducted physical examinations, fasting blood sampling and untargeted metabolomic measurements among 439 adult twins. Linear regression models and bioinformatics analysis were used to examine the relation of obesity measures, including body mass index (BMI), waist circumference (WC) and waist-to-hip ratio (WHR) with serum metabolite levels and related pathways. A co-twin control study was additionally conducted among 15 obesity-discordant monozygotic (MZ) pairs (intrapair BMI difference >3 kg/m2) to examine any differences in metabolites controlling for genetic factors. Eleven metabolites were associated with BMI, WC and WHR after controlling for genetic and shared environmental factors. Pathway analysis identified pathways such as phenylalanine metabolism, purine metabolism, valine, leucine and isoleucine biosynthesis that were associated with obesity. A wide range of unfavorable alterations in the serum metabolome was associated with obesity. Obesity-discordant twin analysis suggests that these associations are independent of genetic liability.

Association of Educational Level and Marital Status With Obesity: A Study of Chinese Twins.

The prevalence of overweight and obesity is growing rapidly in many countries. Socioeconomic inequalities might be important for this increase. The aim of this study was to determine associations of body mass index (BMI), overweight and obesity with educational level and marital status in Chinese twins. Participants were adult twins recruited through the Chinese National Twin Registry (CNTR), aged 18 to 79 years, and the sample comprised 10,448 same-sex twin pairs. Current height, weight, educational attainment, and marital status were self-reported. Regression analyses and structural equation models were conducted to evaluate BMI, overweight, and obesity associated with educational level and marital status in both sexes. At an individual level, both educational level and marital status were associated with higher BMI and higher risk of being overweight and obesity in men, while in women the effects of educational level on BMI were in the opposite direction. In within-Monozygotic (MZ) twin-pair analyses, the effects of educational level on BMI disappeared in females. Bivariate structural equation models showed that genetic factors and shared environmental confounded the relationship between education and BMI in females, whereas marital status was associated with BMI on account of significant positive unique environmental correlation apart in both sexes. The present data suggested that marital status and BMI were associated, independent of familiar factors, for both sexes of this study population, while common genetic and shared environmental factors contributed to education-associated disparities in BMI in females.

Associations Between Obesity Indicators and Blood Pressure in Chinese Adult Twins.

Obesity is associated with blood pressure (BP), but the associations between different obesity indicators and BP have not reached agreement. Besides, both obesity and BP are influenced by genetic and environmental factors. Whether they share the same genetic or environmental etiology has not been fully understood. We therefore analyzed the relationship between different obesity indicators and BP components as well as the genetic and environmental contributions to these relationships in a Chinese adult twin sample. Twins aged 18-79 years (n = 941) were included in this study. Body mass index (BMI) was used as the index of general obesity, whereas waist circumference (WC), waist-to-height ratio (WHtR), and waist-to-hip ratio (WHR) were used as the indicators of central obesity. BP components included systolic blood pressure (SBP) and diastolic blood pressure (DBP). Linear regression models and bivariate structural equation models were used to examine the relation of various obesity indicators with BP components, and genetic or environmental influences on these associations, respectively. A strong association of BP components with BMI-and a somewhat weaker association with WC, WHtR, and WHR-was found in both sexes, independent of familial factors. Of these phenotypic correlations between obesity indicators and BP components, 60-76% were attributed to genetic factors, whereas 24-40% were attributed to unique environmental factors. General obesity was most strongly associated with high BP in Chinese adult twins. There were common genetic backgrounds for obesity and BP, and unique environmental factors also played a role.

The association of cigarette smoking and alcohol drinking with body mass index: a cross-sectional, population-based study among Chinese adult male twins.

BACKGROUND: Obesity is a multifactorial abnormality which has an underlying genetic control but requires environmental influences to trigger. Numerous epidemiological studies have examined the roles of physical inactivity and dietary factors in obesity development. Interactions between obesity-related genes and these lifestyles have also been confirmed. However, less attention has been paid to these complex relationship between cigarette smoking, alcohol drinking and obesity. The purpose of this study was to assess whether cigarette smoking and alcohol drinking were associated with body mass index (BMI), and whether these lifestyle factors modified the genetic variance of BMI. METHODS: Subjects were twins recruited through the Chinese National Twin Registry, aged 18 to 79 years, and the sample comprised 6121 complete male twin pairs. Information on height, weight, cigarette smoking and alcohol drinking status were assessed with self-report questionnaires. The associations of cigarette smoking and alcohol drinking with BMI were evaluated by linear regression models. Further, structure equation models were conducted to estimate whether cigarette smoking and alcohol drinking status modified the degree of genetic variance of BMI. RESULTS: After adjustment for a variety of socio-demographic and lifestyle factors, former smokers had higher BMI (ß = 0.475; 95 % CI, 0.196 to 0.754) whereas moderate to heavy smokers had lower BMI (ß = -0.115; 95 % CI, -0.223 to -0.007) when compared with nonsmokers. BMI decreased with increased cigarette pack-years (ß = -0.008; 95 % CI, -0.013 to -0.003). These effects still existed substantially in within-MZ twin pair analyses. By contrast, current alcohol drinking had no significant influence on BMI when additionally controlled for shared factors in within-pair analyses. Genetic modification by alcohol drinking was statistically significant for BMI (ß = -0.137; 95 % CI, -0.215 to -0.058), with the intake of alcohol decreasing the additive genetic component of BMI. CONCLUSIONS: Cigarette smoking was negatively associated with BMI independent of genetic influences. The influence of genes on BMI was moderated by alcohol drinking, such that for individuals who were regular drinkers, genetic factors became less influential. Our findings highlight gene-alcohol interaction in finding candidate genes of BMI and elucidating the etiological factors of obesity.

Genetic and Environmental Influences on Obesity-Related Phenotypes in Chinese Twins Reared Apart and Together.

The relative importance of genetic and environmental influences on obesity-related phenotypes remains unclear, and few studies have targeted the Chinese population. Here, we used Chinese twins reared apart and together to explore genetic and environmental influences on body mass index (BMI), waist circumference (WC) and waist-height ratio (WHtR), further to differentiate phenotype heritability between different age groups and genders separately and to differentiate influences of rearing environment and correlated environment. Phenotype heritability was calculated using the structural equation model in 11,401 twin pairs aged 25-85 years. BMI (0.70, 95 % confidence interval (CI) 0.66-0.74) of the total population was highly heritable, while WC (0.53, 95 %CI 0.50-0.57) and WHtR (0.48, 95 %CI 0.45-0.51) were moderately heritable. Age and gender stratified analyses found higher heritability in the younger group and males than the older group and females. The correlated environment had a greater influence on the phenotypes than the rearing environment, especially on WC and WHtR, indicating that more correlated environment actions should be taken to prevent the rising trend of abdominal obesity.

Genetic and Environmental Effects on Weight, Height, and BMI Under 18 Years in a Chinese Population-Based Twin Sample.

This study examined the genetic and environmental effects on variances in weight, height, and body mass index (BMI) under 18 years in a population-based sample from China. We selected 6,644 monozygotic and 5,969 dizygotic twin pairs from the Chinese National Twin Registry (CNTR) aged under 18 years (n = 12,613). Classic twin analyses with sex limitation were used to estimate the genetic and environmental components of weight, height, and BMI in six age groups. Sex-limitation of genetic and shared environmental effects was observed, especially when puberty begins. Heritability for weight, height, and BMI was low at 0-2 years old (less than 20% for both sexes) but increased over time, accounting for half or more of the variance in the 15-17 year age group for boys. For girls, heritabilities for weight, height and BMI was maintained at approximately 30% after puberty. Common environmental effects on all body measures were high for girls (59-87%) and presented a small peak during puberty. Genetics appear to play an increasingly important role in explaining the variation in weight, height, and BMI from early childhood to late adolescence, particularly in boys. Common environmental factors exert their strongest and most independent influence specifically in the pre-adolescent period and more significantly in girls. These findings emphasize the need to target family and social environmental interventions in early childhood years, especially for females. Further studies about puberty-related genes and social environment are needed to clarify the mechanism of sex differences.

Utilizing the resource of twins reared apart: their distribution across nine provinces or cities of China.

Twins reared apart provide a fascinating experiment to distinguish genetic from environmental influences. However, there is as yet no broad report on distribution of twins reared apart, especially in the Chinese population. In this study, information on 18,295 volunteer twin pairs of all age groups was compiled in nine provinces or cities of China, and questionnaires were used for zygosity determination. It was discovered that twins reared apart from 0 to 10 years of age accounted for 2.2% of all twin interviewees, with the proportion of this 0-10 group separated before 1, 2, and 5 years old, accounting for 65.3%, 76.1%, and 91.3%, respectively. The proportion of twins reared apart is not significantly related to zygosity or gender, but it is related to region and twin age. As the age of twins lowers, the proportion of those reared apart gradually decreases. Twins reared apart will become rarer in the future and therefore should be cherished as a resource.

Association between socioeconomic status and obesity in a Chinese adult population.

BACKGROUND: Existing studies which regarding to the association between individual socioeconomic status (SES) and obesity are still scarce in developing countries. The major aim of this study is to estimate such association in an adult population which was drawn from an economically prosperous province of China. METHODS: Study population was determined by multilevel randomized sampling. Education and income were chosen as indicators of individual SES, general obesity and abdominal obesity were measured by body mass index (BMI) and waist circumference (WC). Descriptive statistical methods were used to depict overall and factor-specific distributions of general and abdominal obesity among 16,013 respondents. Two-step logistic regression models were fitted on gender basis. RESULTS: The age-and-sex adjusted rates of general overweight, general obesity, abdominal overweight and abdominal obesity in study population were 28.9% (95%CI: 27.9%-29.9%), 7.5% (95%CI: 7.0%-8.1%), 32.2% (95%CI: 31.2%-33.3%) and 12.3% (95%CI: 11.6%-13.1%), respectively. Based on model fitting results, a significant inverse association between education and obesity only existed in women, while in men, income rather than education was positively related to obesity. CONCLUSIONS: The atypical SES-obesity relationship we found reflected the on-going social economy transformation in affluent regions of China. High-income men and poorly-educated women were at higher risk of obesity in Zhejiang province, thus merit intense focuses.

[Association between dyslipidemia and different subtypes of hypertension among Zhejiang population in 2010].

OBJECTIVE: To explore the association between dyslipidemia and different subtypes of hypertension among Zhejiang population. METHODS: From June to October in 2010, 19 113 local residents aged ≥ 18 years old were selected among 7571 families from fifteen counties in Zhejiang by four stage stratified-random sampling method. A self-designed questionnaire was adopted to collect information on demographic characteristics, physical activity and life style. At the same time, physical examinations including height, weight, blood pressure and blood lipids were carried out. RESULTS: A total of 19 113 participants completed the interviews, physical examinations and collected the blood samples.Excluding those who did not meet the criteria, 14 731 were finally enrolled in the study. The prevalence rates of isolated systolic hypertension (ISH), isolated diastolic hypertension (IDH), systolic and diastolic hypertension (SDH) were 7.16% (1055/14 731, standardized rate:5.46%), 4.60% (677/14 731, standardized rate:4.41%), 7.09% (1045/14 731, standardized rate:5.75%), respectively. Among normal blood pressure group, subjects with normal TC, high TC and abnormal TC were separately 10 571 (88.43%), 1173 (9.81%) and 210 (1.76%); subjects with normal HDL-C and low HDL-C were separately 6885 (57.60%) and 5069 (42.40%); subjects with normal TG, high TG, abnormal TG were separately 9952 (79.91%), 1213 (10.15%) and 1189(9.95%).In ISH group, subjects with normal TC, high TC and abnormal TC were separately 826 (78.29%), 188 (17.82%) and 41 (3.89%); subjects with normal HDL-C and low HDL-C were separately 666(63.13%) and 389 (36.87%); subjects with normal TG, high TG and abnormal TG were separately 737 (69.86%), 150 (14.22%) and 168 (15.92%). Multi factor analysis showed that high TG and abnormal TG were associated with ISH (OR (95%CI):1.43 (1.16-1.76), 1.65 (1.34-2.03) respectively). Among IDH group, subjects with normal TC, high TC, abnormal TC were separately 556(82.13%), 99(14.62%) and 22 (3.25%); subjects with normal HDL-C, low HDL-C were separately 335 (49.48%) and 342 (50.52%); subjects with normal TG, high TG, and abnormal TG separately were 402 (59.38%), 107 (15.81%) and 168 (24.82%). The multi factor analysis showed that high TG and abnormal TG could increase the risk of IDH (OR(95%CI):1.57 (1.24-1.98), 2.18 (1.76-2.70) respectively). Among SDH group, subjects with normal TC, high TC and abnormal TC were 817 (78.18%), 193 (18.47%) and 35 (3.35%); subjects with normal HDL-C and abnormal HDL-C were separately 599 (57.32%) and 446 (42.68%); subjects with normal TG, high TG, abnormal TG were separately 675 (64.59%), 164 (15.69%) and 206 (19.71%). The multi factor analysis showed that high TC, high TG and abnormal TG were also associated with the increased risk of SDH (OR (95%CI):1.38 (1.14-1.67), 1.43(1.18-1.75), 1.73 (1.43-2.10) respectively). CONCLUSION: Dyslipidemia is an important factor of different subtypes of hypertension among Zhejiang population, especially triglycerides. Dyslipidemia screening should be strengthened to reduce the risk of cardiovascular diseases.

Longitudinal Association of DNA Methylation With Type 2 Diabetes and Glycemic Traits: A 5-Year Cross-Lagged Twin Study.

Investigators of previous cross-sectional epigenome-wide association studies (EWAS) in adults have reported hundreds of 5'-cytosine-phosphate-guanine-3' (CpG) sites associated with type 2 diabetes mellitus (T2DM) and glycemic traits. However, the results from EWAS have been inconsistent, and longitudinal observations of these associations are scarce. Furthermore, few studies have investigated whether DNA methylation (DNAm) could be modified by smoking, drinking, and glycemic traits, which have broad impacts on genome-wide DNAm and result in altering the risk of T2DM. Twin studies provide a valuable tool for epigenetic studies, as twins are naturally matched for genetic information. In this study, we conducted a systematic literature search in PubMed and Embase for EWAS, and 214, 33, and 117 candidate CpG sites were selected for T2DM, HbA1c, and fasting blood glucose (FBG). Based on 1,070 twins from the Chinese National Twin Registry, 67, 17, and 16 CpG sites from previous studies were validated for T2DM, HbA1c, and FBG. Longitudinal review and blood sampling for phenotypic information and DNAm were conducted twice in 2013 and 2018 for 308 twins. A cross-lagged analysis was performed to examine the temporal relationship between DNAm and T2DM or glycemic traits in the longitudinal data. A total of 11 significant paths from T2DM to subsequent DNAm and 15 paths from DNAm to subsequent T2DM were detected, suggesting both directions of associations. For glycemic traits, we detected 17 cross-lagged associations from baseline glycemic traits to subsequent DNAm, and none were from the other cross-lagged direction, indicating that CpG sites may be the consequences, not the causes, of glycemic traits. Finally, a longitudinal mediation analysis was performed to explore the mediation effects of DNAm on the associations of smoking, drinking, and glycemic traits with T2DM. No significant mediations of DNAm in the associations linking smoking and drinking with T2DM were found. In contrast, our study suggested a potential role of DNAm of cg19693031, cg00574958, and cg04816311 in mediating the effect of altered glycemic traits on T2DM.

Cardiometabolic Traits in Adult Twins: Heritability and BMI Impact with Age.

Background: The prevalence of obesity and cardiometabolic diseases continues to rise globally and obesity is a significant risk factor for cardiometabolic diseases. However, to our knowledge, evidence of the relative roles of genes and the environment underlying obesity and cardiometabolic disease traits and the correlations between them are still lacking, as is how they change with age. Method: Data were obtained from the Chinese National Twin Registry (CNTR). A total of 1421 twin pairs were included. Univariate structural equation models (SEMs) were performed to evaluate the heritability of BMI and cardiometabolic traits, which included blood hemoglobin A1c (HbA1c), fasting blood glucose (FBG), systolic blood pressure (SBP), diastolic blood pressure (DBP), total cholesterol (TC), triglycerides (TGs), low-density lipoprotein cholesterol (LDL-C) and high-density lipoprotein cholesterol (HDL-C). Bivariate SEMs were used to assess the genetic/environmental correlations between them. The study population was divided into three groups for analysis: ≤50, 51−60, and >60 years old to assess the changes in heritability and genetic/environmental correlations with ageing. Results: Univariate SEMs showed a high heritability of BMI (72%) and cardiometabolic traits, which ranged from 30% (HbA1c) to 69% (HDL-C). With age increasing, the heritability of all phenotypes has different degrees of declining trends. Among these, BMI, SBP, and DBP presented significant monotonous declining trends. The bivariate SEMs indicated that BMI correlated with all cardiometabolic traits. The genetic correlations were estimated to range from 0.14 (BMI and LDL-C) to 0.39 (BMI and DBP), while the environmental correlations ranged from 0.13 (BMI and TC/LDL-C) to 0.31 (BMI and TG). The genetic contributions underlying the correlations between BMI and SBP and DBP, TC, TG, and HDL-C showed a progressive decrease as age groups increased. In contrast, environmental correlations displayed a significant increasing trend for HbA1c, SBP, and DBP. Conclusions: The findings suggest that genetic and environmental factors have essential effects on BMI and all cardiometabolic traits. However, as age groups increased, genetic influences presented varying degrees of decrement for BMI and most cardiometabolic traits, suggesting the increasing importance of environments. Genetic factors played a consistently larger role than environmental factors in the phenotypic correlations between BMI and cardiometabolic traits. Nevertheless, the relative magnitudes of genetic and environmental factors may change over time.

Temporal associations between leukocytes DNA methylation and blood lipids: a longitudinal study.

BACKGROUND: The associations between blood lipids and DNA methylation have been investigated in epigenome-wide association studies mainly among European ancestry populations. Several studies have explored the direction of the association using cross-sectional data, while evidence of longitudinal data is still lacking. RESULTS: We tested the associations between peripheral blood leukocytes DNA methylation and four lipid measures from Illumina 450 K or EPIC arrays in 1084 participants from the Chinese National Twin Registry and replicated the result in 988 participants from the China Kadoorie Biobank. A total of 23 associations of 19 CpG sites were identified, with 4 CpG sites located in or adjacent to 3 genes (TMEM49, SNX5/SNORD17 and CCDC7) being novel. Among the validated associations, we conducted a cross-lagged analysis to explore the temporal sequence and found temporal associations of methylation levels of 2 CpG sites with triglyceride and 2 CpG sites with high-density lipoprotein-cholesterol (HDL-C) in all twins. In addition, methylation levels of cg11024682 located in SREBF1 at baseline were temporally associated with triglyceride at follow-up in only monozygotic twins. We then performed a mediation analysis with the longitudinal data and the result showed that the association between body mass index and HDL-C was partially mediated by the methylation level of cg06500161 (ABCG1), with a mediation proportion of 10.1%. CONCLUSIONS: Our study indicated that the DNA methylation levels of ABCG1, AKAP1 and SREBF1 may be involved in lipid metabolism and provided evidence for elucidating the regulatory mechanism of lipid homeostasis.

Associations of Metabolic/Obesity Phenotypes with Insulin Resistance and C-Reactive Protein: Results from the CNTR Study.

BACKGROUND: Obesity is a heterogeneous condition in terms of metabolic status. Different obesity phenotypes have various health risks. The aim of this work was to define different subtypes of obesity and investigate their relationship with inflammatory-cardiometabolic abnormalities among Chinese adult twins. METHODS: The analyses used data from 1113 adult twins in 4 provinces (Shandong, Zhejiang, Jiangsu and Sichuan) from Chinese National Twin Registry (CNTR) which collected detailed information. We defined those with 0 or 1 metabolic syndrome (MetS) components excluding waist circumference as metabolically healthy, and those with waist circumference ≥90 cm (for men) and ≥85 cm (for women) as obese. The two-category obesity status and metabolic states are combined to generate four metabolic/obesity phenotypes. High sensitivity C reactive protein (hsCRP) was measured to assess underlying inflammation and homeostasis model assessment of insulin resistance (HOMA-IR) was calculated as surrogate measure of insulin resistance. Mixed-effect linear regression models and fixed-effect linear regression models were used to analyse the correlation between HOMA-IR, hsCRP and different metabolic/obesity phenotypes. RESULTS: In cross-sectional analyses of 1113 individuals (mean [SD] age, 46.6 [12.9] years; 463 obese [41.6%]), 20.3% obese twins were metabolic healthy and 64.2% non-obese twins were metabolic unhealthy. Serum HOMA-IR level was higher in metabolically unhealthy non-obesity (MUNO) (ß=0.42, 95% CI: 0.21-0.64), metabolically healthy obesity (MHO) (ß=0.68, 95% CI: 0.36-1.00) and metabolically unhealthy obesity (MUO) (ß=0.69, 95% CI: 0.46-0.91) twins, compared with their metabolically healthy non-obesity (MHNO) counterparts. HsCRP was similar between MHO and MUO, which differed significantly to metabolic healthy non-obesity (MHNO). CONCLUSION: MHO and MUNO phenotypes were common in Chinese twin population. Both phenotypes were associated with elevated IR and hsCRP which may not be benign and need to be concerned.

Behavioral and psychosocial predictors of condom use among university students in Eastern China.

In China the HIV epidemic has started to infiltrate into a broader population through heterosexual contact and particularly to impact young people. The purpose of this study was to identify behavioral and psychosocial correlates of condom use among Chinese university students. A self-administered questionnaire survey with cross-sectional design was conducted among all classes of undergraduate students at two universities in one municipality of Eastern China, 2003. Data obtained from 1850 sexually active students who answered the question on condom use during the previous year were used for analysis. Frequent (always/often) condom use during the previous year was reported by only about 40% of both men and women. Multivariate analysis revealed that condom use during the first sexual experience, oral contraceptive use in the previous year and higher condom self-efficacy score in both genders were potent predictors of frequent condom use, while frequent condom use was less likely practiced by men who ever had non-vaginal sex, by those with higher risk-awareness for pregnancy/HIV/sexually transmitted diseases and by women with lower scores for perceived condom benefits. Safe sex education for Chinese students should be urgently introduced and should not be limited to knowledge provision but should also address psychosocial factors, such as condom self-efficacy and gender differences adequately to effectively encourage safer behavior.

Early initiation of sexual activity: a risk factor for sexually transmitted diseases, HIV infection, and unwanted pregnancy among university students in China.

BACKGROUND: To explore any association between the timing of the initiation of sexual activity and sexual behaviors and risks among university students in China. METHODS: Data were derived from a cross-sectional study on sexual behavior among university students conducted in Ningbo municipality, China, at the end of 2003. Students completed a self-administered, structured questionnaire. Of 1981 sexually active male students, 1908 (96.3%) completed the item for timing of the initiation of sexual activity and were included in bivariate trend analyses and multiple logistic regression analyses to compare the association between this timing and sexual behavior and risks. RESULTS: Male early sexual initiators had a significantly higher risk profile, including a significantly higher proportion reporting non-regular partners (i.e., casual or commercial partners), multiple partners, diagnosis with a sexually transmitted disease (STD), partner history of pregnancy, partner history of induced abortion, and less condom and oral contraceptive use, compared with late initiators. Multivariate analyses confirmed the increased likelihood of these risks in early initiators versus late initiators, other than partner type during the last year. CONCLUSION: Our results showed that, compared to late initiators, people who initiated sexual activity early engaged in more risky behaviors that could lead to elevated risks of unwanted pregnancies and STDs or human immunodeficiency virus infection. Sex-education strategies should be focused on an earlier age, should include advice on delaying the age of first sexual activity, and should target young people who continue to take sexual risks.

Unintended pregnancy and its risk factors among university students in eastern China.

BACKGROUND: The study was conducted to determine the prevalence of unintended pregnancy, induced abortion and contraceptive use, and factors associated with unintended pregnancy among Chinese university students. STUDY DESIGN: A self-administered questionnaire survey with cross-sectional design was administered among students in two universities in Ningbo, China, in November-December 2003. Sociodemographic and behavioral factors associated with unintended pregnancy were identified in both genders using univariate and multivariate analyses. RESULTS: Of sexually active students, 10.6% of male and 11.6% of female students reported their partner or they had a history of pregnancy; 10.0% of male and 11.3% of female students reported their partner or they had a history of induced abortion. The risk factors for unintended pregnancy identified among males by multivariate analysis were older age [odds ratio (OR), 2.12; 95% confidence interval (CI), 1.15-3.88], initiation of sexual activity before high school (OR, 2.45; 95% CI, 1.36-4.44), reported lack of condom use in first sexual activity (OR, 1.71; 95% CI, 1.10-2.64), multiple sexual partners (OR, 1.54; 95% CI, 1.06-2.23), and often used condoms during their lifetime (OR, 1.97; 95% CI, 1.01-3.81). The identified risk factors among females were initiation of sexual activity before high school (OR, 5.12; 95% CI, 1.49-17.68), non-consensual sexual intercourse as first sex (OR, 1.77; 95% CI, 1.08-2.90), multiple partners (OR, 2.75; 95% CI, 1.61-4.71), and sometimes/never (OR, 3.02; 95% CI, 1.16-7.87) or often (OR, 3.92; 95% CI, 1.43-10.73) used condoms during their lifetime. CONCLUSION: The high prevalence of unintended pregnancies and induced abortions in this population indicates a need for better and targeted sex education and family planning services.

The characterisation of sexual behaviour in Chinese male university students who have sex with other men: a cross-sectional study.

BACKGROUND: The risks for Chinese male university students who have sex with other men (MSM) have not been compared with those for non-MSM students. This information is important for the development of targeted HIV prevention programmes for this population. METHODS: Sexually active MSM and non-MSM students were compared for demographic characteristics, sexual behaviour, and related psychosocial variables using bivariate analyses. The data were a subset drawn from a large-scale cross-sectional questionnaire survey of sexually active male students conducted at two universities in a large city in Zhejiang Province, China, in 2003. RESULTS: Of 1824 sexually active male students, 68 (3.7%) reported having had sex with a man at least once; 33.8% of these 68 men had also had female partners. Compared with non-MSM students, MSM students were 3-6.5 times more likely to have had sexual encounters with casual or commercial sex partners and were three times less likely to have protected sex in the past year or during their lifetime. They were three to five times more likely to have had multiple partners and 15 times more likely to have had a sexually transmitted disease (STD). In addition, the MSM students knew half as much about HIV and had less condom-decision than did non-MSM students and were two times more accepting of commercial sex. However, the MSM students were twice as aware of the risks for HIV infection. CONCLUSION: MSM composed 3-4% of the male sexually active university student population studied and was found to be at greater risk than non-MSM students for STD/HIV infection. There is an urgent need for STD/HIV programmes in university health services that take into consideration the sexuality and psychosocial issues of MSM students.