Xiaoyuan Zhao

The common rs9939609 variant of the fat mass and obesity-associated gene is associated with obesity risk in children and adolescents of Beijing, China

BackgroundPrevious genome-wide association studies for type 2 diabetes susceptibility genes have confirmed that a common variant, rs9939609, in the fat mass and obesity associated (FTO) gene region is associated with body mass index (BMI) in European children and adults. A significant association of the same risk allele has been described in Asian adult populations, but the results are conflicting. In addition, no replication studies have been conducted in children and adolescents of Asian ancestry.MethodsA population-based survey was carried out among 3503 children and adolescents (6-18 years of age) in Beijing, China, including 1229 obese and 2274 non-obese subjects. We investigated the association of rs9939609 with BMI and the risk of obesity. In addition, we tested the association of rs9939609 with weight, height, waist circumference, waist-to-height ratio, fat mass percentage, birth weight, blood pressure and related metabolic traits.ResultsWe found significant associations of rs9939609 variant with weight, BMI, BMI standard deviation score (BMI-SDS), waist circumference, waist-to-height ratio, and fat mass percentage in children and adolescents (p for trend = 3.29 × 10-5, 1.39 × 10-6, 3.76 × 10-6, 2.26 × 10-5, 1.94 × 10-5, and 9.75 × 10-5, respectively). No significant associations were detected with height, birth weight, systolic and diastolic blood pressure and related metabolic traits such as total cholesterol, triglycerides, HDL-cholesterol, LDL-cholesterol and fasting plasma glucose (all p > 0.05). Each additional copy of the rs9939609 A allele was associated with a BMI increase of 0.79 [95% Confidence interval (CI) 0.47 to 1.10] kg/m2, equivalent to 0.25 (95%CI 0.14 to 0.35) BMI-SDS units. This rs9939609 variant is significantly associated with the risk of obesity under an additive model [Odds ratio (OR) = 1.29, 95% CI 1.11 to 1.50] after adjusting for age and gender. Moreover, an interaction between the FTO rs9939609 genotype and physical activity (p < 0.001) was detected on BMI levels, the effect of rs9939609-A allele on BMI being (0.95 ± 0.10), (0.77 ± 0.08) and (0.67 ± 0.05) kg/m2, for subjects who performed low, moderate and severe intensity physical activity.ConclusionThe FTO rs9939609 variant is strongly associated with BMI and the risk of obesity in a population of children and adolescents in Beijing, China.

Associations of Six Single Nucleotide Polymorphisms in Obesity-Related Genes With BMI and Risk of Obesity in Chinese Children

OBJECTIVE Childhood obesity strongly predisposes to some adult diseases. Recently, genome-wide association (GWA) studies in Caucasians identified multiple single nucleotide polymorphisms (SNPs) associated with BMI and obesity. The associations of those SNPs with BMI and obesity among other ethnicities are not fully described, especially in children. Among those previously identified SNPs, we selected six (rs7138803, rs1805081, rs6499640, rs17782313, rs6265, and rs10938397, in or near obesity-related genes FAIM2, NPC1, FTO, MC4R, BDNF, and GNPDA2, respectively) because of the relatively high minor allele frequencies in Chinese individuals and tested the associations of the SNPs with BMI and obesity in Chinese children. RESEARCH DESIGN AND METHODS We investigated the associations of these SNPs with BMI and obesity in school-aged children. A total of 3,503 children participated in the study, including 1,229 obese, 655 overweight, and 1,619 normal-weight children (diagnosed by the Chinese age- and sex-specific BMI cutoffs). RESULTS After age and sex adjustment and correction for multiple testing, the SNPs rs17782313, rs6265, and rs10938397 were associated with BMI (P = 1.0 × 10−5, 0.038, and 0.00093, respectively) and also obesity (P = 5.0 × 10−6, 0.043, and 0.00085, respectively) in the Chinese children. The SNPs rs17782313 and rs10938397 were also significantly associated with waist circumference, waist-to-height ratio, and fat mass percentage. CONCLUSIONS Results of this study support obesity-related genes in adults as important genes for BMI variation in children and suggest that some SNPs identified by GWA studies in Caucasians also confer risk for obesity in Chinese children.

Association between Childhood Obesity and Metabolic Syndrome: Evidence from a Large Sample of Chinese Children and Adolescents

Data about metabolic syndrome (MetS) in children is limited in China. We aimed to assess the prevalence of MetS related components, and their association with obesity. Data were collected as part of a representative study on MetS among 19593 children, aged 6–18 years old in Beijing. General obesity was assessed by body mass index (BMI) and central obesity by waist circumference. Finger capillary blood tests were used to assess triglyceride (TG), total cholesterol (TC) and impaired fasting glucose (IFG). Vein blood samples were collected from a subsample of 3814 children aged 10–18 years to classify MetS. MetS was defined according to the International Diabetes Federation 2007 definition. The associations between MetS related components and the degree and type of obesity were tested using logistic regression models. The prevalence of overweight, obesity, high blood pressure, elevated TG, TC and IFG were13.6%, 5.8%, 8.5%, 8.8%, 1.2% and 2.5%, respectively. Compared with normal weight children, overweight and obese children were more likely to have other MetS related components. In the subsample of 3814 children aged 10–18 years, the prevalence of MetS was much higher in obese subjects than in their normal weight counterparts (27.6% vs. 0.2%). Children with both general and central obesity had the highest prevalence of MetS. Compared with normal weight children, overweight and obese children were more likely to have MetS (overweight: OR = 67.33, 95%CI = 21.32–212.61; obesity: OR = 249.99, 95% CI = 79.51–785.98). Prevalence of MetS related components has reached high level among Beijing children who were overweight or obese. The association between metabolic disorders and obesity was strong.

Association of common variants in/near six genes (ATP2B1, CSK, MTHFR, CYP17A1, STK39 and FGF5) with blood pressure/hypertension risk in Chinese children.

Recent genome-wide association studies have identified several single-nucleotide polymorphisms (SNPs) that are associated with blood pressure (BP)/hypertension. In this study, we aimed to examine the established associations amongst Chinese children. We genotyped six SNPs (ATP2B1 rs17249754, CSK rs1378942, MTHFR rs1801133, CYP17A1 rs1004467, STK39 rs3754777 and FGF5 rs16998073) in Chinese children (N=3077, age range, 6–18 years). Based on the Chinese age- and sex-specific BP standards, 619 hypertensive cases and 2458 controls with normal BP were identified. Of the six SNPs, only ATP2B1 rs17249754 SNP was significantly associated with the risk of hypertension (allelic odds ratio (OR)=1.25, 95% confidence interval (CI): 1.08–1.44, P=0.003). Although all other SNPs showed a trend towards increasing the BP values and risk of hypertension, there was no statistically significant association after false discovery rate analysis. We calculated the weighted risk score using six SNPs, for systolic BP (SBP), diastolic BP (DBP) and hypertension. Each additional weighted risk score was associated with SBP by 1.18 mm Hg (95% CI=0.62–1.73, P<0.001), but not with the DBP (β=0.28, 95% CI=(-0.15)-0.74), and overall increased the risk of hypertension by 1.19-fold (95% CI=1.04–1.35, P=0.01). The present study confirmed the significant association of ATP2B1 rs17249754 with risk of hypertension among Chinese children, but failed to replicate the association of CSK rs1378942, MTHFR rs1801133, CYP17A1 rs1004467, STK39 rs3754777 and FGF5 rs16998073 with BP/risk of hypertension.

Adiponectin and Leptin Metabolic Biomarkers in Chinese Children and Adolescents

Objective. To evaluate leptin and adiponectin as biomarkers of metabolic syndrome (MS) risk factors even in nonobese children/adolescents. Methods. Serum leptin, adiponectin, leptin:adiponectin ratio, lipids, glucose, and insulin concentrations as well as body size parameters and pubertal development were evaluated in a large population of Chinese children/adolescents (n = 3505, 6–18 years, 1722 girls and 1783 boys). Results. Leptin concentration increased while adiponectin decreased with obesity, both were influenced by pubertal development. Central obesity had an additive effect on leptin levels (above obesity alone). Leptin/adiponectin increased 8.4-fold and 3.2-fold in overweight/obesity, and 15.8- and 4.5-fold with obesity plus MS, in early and late puberty, respectively. Even in normal weight children/adolescents, higher leptin and lower adiponectin concentrations associated with increased risk profile. Conversely, overweight/obese with lower leptin or higher adiponectin concentrations had a less compromised metabolic profile. Conclusion. Leptin, adiponectin, and leptin:adiponectin ratio are informative biomarkers for obesity, central obesity, MS, and abnormal metabolic profile even in normal weight children/adolescents.

Study of 11 BMI-Associated Loci Identified in GWAS for Associations with Central Obesity in the Chinese Children

Objective Recent genome-wide association studies have identified many single nucleotide polymorphisms (SNPs) associated with body mass index (BMI)/generalized obesity. In this study, we aimed to examine the associations of identified SNPs with risk of central obesity in a child population from China. Methods We genotyped 11 SNPs (FTO rs9939609, MC4R rs17782313, GNPDA2 rs10938397, BDNF rs6265, FAIM2 rs7138803, NPC1 rs1805081, SEC16B rs10913469, SH2B1 rs4788102, PCSK1rs6235, KCTD15 rs29941, BAT2 rs2844479) in the Chinese children (N = 3502, age range 6–18 years) from the Beijing Child and Adolescent Metabolic Syndrome (BCAMS). Based on the age- and sex- specific waist circumference (WC) standards generated in the BCAMS study, 1196 central obese cases and 2306 controls were identified. Results Of 11 studied SNPs, four SNPs and genetic risk score (GRS) based on them were statistically significantly associated with central obesity by WC criteria (FTO rs9939609: OR = 1.29, 95%CI = 1.10–1.50, p = 0.001; MC4R rs17782313: OR = 1.27, 95%CI = 1.12–1.44, p = 1.32×10−4; GNPDA2 rs10938397: OR = 1.22, 95%CI = 1.09–1.37, p = 4.09×10−4; BDNF rs6265: OR = 1.20, 95%CI = 1.08–1.34, p = 8.86×10−4; GRS: OR = 1.25, 95%CI 1.16–1.34, p = 2.58×10−9) after adjustment for sex, age, pubertal stage, physical activity and family history of obesity. Similar observations were made using weight-to-height ratio (WHtR) criterion. However, other SNPs were not associated with central obesity by WC as well as WHtR criterion. Conclusions Our study replicates the statistically significant association of four SNPs (FTO rs9939609, MC4R rs17782313, GNPDA2 rs10938397, BDNF rs6265) with risk of central obesity in the Chinese children.

Change of Body Composition and Adipokines and Their Relationship with Insulin Resistance across Pubertal Development in Obese and Nonobese Chinese Children: The BCAMS Study

A transient increase in insulin resistance (IR) is a component of puberty. We investigated the impact of body composition and adipokines on IR during puberty in Chinese children. This study included 3223 schoolchildren aged 6–18 years. IR was calculated using homeostasis model assessment (HOMA-IR). We revealed that body mass index (BMI) and waist circumference increased gradually during puberty in both genders, while fat-mass percentage (FAT%) increased steadily only in girls. Change of leptin showed striking sexual dimorphisms: in girls leptin increased steadily during puberty, whereas in boys, after a transient rise at the beginning of puberty, leptin declined by Tanner staging even in those overweight or obese. Inversely, adiponectin level decreased significantly during puberty. In both genders, HOMA-IR started to increase at the beginning of puberty, peaked in the middle, and revised at late puberty in overweight/obesity boys while it stayed high till the end of puberty in girls and normal weight boys. Multivariate regression analysis revealed that leptin presented a stronger indicator of HOMA-IR than anthropometric measures during puberty. Our results demonstrated that gender-specific FAT% and leptin changed with pubertal development. Leptin emerged as a stronger predictor of IR than traditional anthropometric indices, suggesting a prominent role in the development of pubertal IR.

Physical activity modifies the associations between genetic variants and hypertension in the Chinese children.

BACKGROUND Childhood hypertension is a complex disease influenced by both genetic and environmental factors. We aimed to examine the effect of interactions of five polymorphisms with physical activity on blood pressure (BP)/hypertension in the Chinese children. METHODS AND RESULTS A population-based case-control study was carried out in Beijing of China in 2004, which included 619 hypertensive cases and 2458 normal BP controls. Physical activity information was collected through the use of a validated questionnaire, and five polymorphisms were genotyped using TaqMan. In active group, there was no significant association of five polymorphisms and genetic risk score with systolic/diastolic BP (SBP/DBP) and risk of hypertension (all p > 0.05). In contrast, in inactive group, two polymorphisms and genetic risk score were significantly associated with SBP (rs17249754: β = 1.26, 95% confidence interval (CI) 0.61-1.90, p < 0.001; rs1004467: β = 0.68, 95%CI 0.03-1.32, p = 0.039; genetic risk score: β = 1.54, 95%CI 0.74-2.33, p < 0.001); three polymorphisms and genetic risk score were significantly associated with hypertension (rs17249754: odds ratio (OR) = 1.27, 95%CI 1.08-1.49, p = 0.004; rs1378942: OR = 1.25, 95%CI 1.00-1.57, p = 0.050 (marginally significant); rs16998073: OR = 1.17, 95%CI 1.01-1.37, p = 0.044; genetic risk score: OR = 1.38, 95%CI 1.13-1.68, p = 0.001). CONCLUSIONS The present study provides evidence that interactions between recently identified variants and physical activity play important roles in the regulation of BP and development of hypertension. Physical activity should be prescribed for hypertensive children, especially for those with high risk genetic alleles.

Acylation stimulating protein but not complement C3 associates with metabolic syndrome components in Chinese children and adolescents

OBJECTIVE Childhood obesity is increasing worldwide and is increasingly associated with metabolic syndrome (MetS). Our aim was to examine acylation stimulating protein (ASP) and its precursor complement C3, in normal, overweight, and obese Chinese children and adolescents, and the relationships with body size, blood parameters, pubertal development, family environment, and MetS. METHODS Children and adolescents (n=1603) from 6 to 18 years, boys (n=873) and girls (n=730), including normal weight (n=603), overweight (n=291) and obese (n=709) were assessed for body size parameters, pubertal development, blood lipids, glucose, insulin, ASP, and C3. RESULTS ASP levels were increased in overweight and obese versus normal weight (P<0.001), while C3 showed little variation. This effect of overweight/obesity remained throughout early stages when boys and girls were separated by pubertal development or age, although age and pubertal status itself had no effect. Separation based on ASP quintiles demonstrated significant associations with blood cholesterol, triglyceride, low-density lipoprotein cholesterol (LDL-Chol), glucose, insulin, and homeostatic model assessment of insulin resistance in boys, and LDL-Chol, high-density lipoprotein cholesterol, and glucose in girls. A positive correlation with mothers body mass index in boys and girls (P=0.002 and P=0.014 respectively) as well as birth weight (P<0.001) was noted. MetS was strongly associated with increased ASP, the presence of a single MetS factor (especially hypertension, central obesity, or hyperglycemia) was associated with increased ASP. CONCLUSION Changes in the plasma adipokine ASP in early obesity are associated with blood lipid and glucose modifications, family environment, and distinct MetS risk factors.

An obesity genetic risk score is associated with metabolic syndrome in Chinese children

Recent genome-wide association studies have identified several single nucleotide polymorphisms (SNPs) associated with body mass index (BMI)/obesity. In this study, we aim to examine the associations of obesity related loci with risk of metabolic syndrome (MetS) in a children population from China. A total of 431 children with MetS and 3046 controls were identified based on the modified ATPIII definition. 11 SNPs (FTO rs9939609, MC4R rs17782313, GNPDA2 rs10938397, BDNF rs6265, FAIM2 rs7138803, NPC1 rs1805081, SEC16B rs10913469, SH2B1 rs4788102, PCSK1rs6235, KCTD15 rs29941, BAT2 rs2844479) were genotyped by TaqMan 7900. Of 11 SNPs, GNPDA2 rs10938397, BDNF rs6265, and FAIM2 rs7138803 were nominally associated with risk of MetS (GNPDA2 rs10938397: odds ratio (OR)=1.21, 95% confidence interval (CI)=1.04-1.40, P=0.016; BDNF rs6265: OR=1.19, 95% CI=1.03-1.39, P=0.021; FAIM2 rs7138803: OR=1.20, 95% CI=1.02-1.40, P=0.025); genetic risk score (GRS) was significantly associated with risk of MetS (OR=1.09, 95% CI=1.04-1.15, P=5.26×10(-4)). After further adjustment for BMI, none of SNPs were associated with risk of MetS (all P>0.05); the association between GRS and risk of MetS remained nominally (OR=1.02, 95%CI=0.96-1.08, P=0.557). However, after correction for multiple testing, only GRS was statistically associated with risk of MetS in the model without adjustment for BMI. The present study demonstrated that there were nominal associations of GNPDA2 rs10938397, BDNF rs6265, and FAIM2 rs7138803 with risk of MetS. The SNPs in combination have a significant effect on risk of MetS among Chinese children. These associations above were mediated by adiposity.