Influence of FTO (Fat mass and obesity) gene and parental obesity on Brazilian children and adolescents adiposity.

Objectives Evaluate the influence of the genetic variant rs9939609 of the FTO gene on anthropometric characteristics and whether parental obesity is related to children and adolescents being overweight. Methods A total of 2,364 children and adolescents between 6 and 17 years old were genotyped and the lipid profile, plasma glucose level, and anthropometric characteristics were measured to assess adiposity. Results The AA genotype (risk) was associated with higher body mass index (BMI Z-score; p = 0.006), waist circumference (WC; p = 0.001), and triglycerides (p = 0.033). The association of the participants' adiposity characteristics with the parents' BMI and FTO genotypes showed an association of the BMI Z-score when either the mother or father was overweight or obese (p = 0.028 and p = 0.029). In the overweight or obese father/eutrophic mother, we also observe an association of FTO rs9939609 with WC (p = 0.039). The effect of these variables on the risk of obesity was also tested: overweight or obese mother (OR = 1.82, p = 0.041), overweight and obese parents (OR = 3.09, p < 0.0001), and FTO rs9939609 AA genotype (OR = 2.08, p = 0.0004) were associated. With regard to altered WC and high body fat percentage (BF%), either overweight or obese parents (OR = 2.39, p < 0.0001; OR = 1.92, p < 0.002) showed an association. The FTO rs9939609 AA genotype (OR = 1.99, p = 0.0002) was associated with altered WC. Conclusions The results show that parental weight also contributes to obesity and may interact with the FTO genetic make-up.

Genetic risk score based on fat mass and obesity-associated, transmembrane protein 18 and fibronectin type III domain containing 5 polymorphisms is associated with anthropometric characteristics in South Brazilian children and adolescents.

The prevalence of childhood obesity has increased worldwide. Although it is considered a polygenic inheritance disease, little is known about its susceptibility when the additive effect is considered. The aim of this study is to investigate whether the genetic risk score (GRS) based on previously associated obesity polymorphisms (SNP) rs9939609 (fat mass and obesity-associated (FTO)), rs6548238 (transmembrane protein 18 (TMEM18)) and rs16835198 (fibronectin type III domain containing 5 (FNDC5)) could serve as a predictor for anthropometric characteristics in a sample of Brazilian children and adolescents. This is a cross-sectional study with 1471 children and adolescents aged 6-17 years. BMI, waist circumference (WC) and percentage of body fat and metabolic parameters were verified. In all, three SNP were genotyped by TaqMan™ allelic discrimination. The metabolic and anthropometric parameters were compared between the genotypes, and the unweighted and weighted GRS (GRS and wGRS, respectively) were created to test the additive effect of these genetic polymorphisms on anthropometric parameters. The prevalence of overweight plus obesity was 41 %. Significant associations were identified for FTO rs9939609, TMEM18 rs6548238 and FNDC5 rs16835198 and for GRS and wGRS with anthropometric phenotypes. The higher score of wGRS was associated with obesity (OR: 2·65, 95 % CI 1·40, 5·04, P=0·003) and with greater WC (OR: 2·91, 95 % CI 1·57, 5·40, P=0·001). Our results suggest that these genetic variants contribute to obesity susceptibility in children and adolescents and reinforce the idea that the additive effect may be useful to elucidate the genetic component of obesity.

Overweight and Obesity in Schoolchildren: Hierarchical Analysis of Associated Demographic, Behavioral, and Biological Factors.

Studies focused on the mechanisms involved in the development of obesity in children and adolescents have reported associations between this condition and birth weight, sedentary lifestyle, and hereditary conditions. However, few studies have simultaneously evaluated these factors. This cross-sectional study aims to identify demographic, behavioral, and biological factors associated with overweight/obesity in children and adolescents. 381 schoolchildren aged seven to 17 years were included in the study to evaluate the associations between overweight/obesity and biological factors (including family history of obesity, birth weight, and the fat mass and obesity-associated (FTO) rs9939609 polymorphism), demographic variables (including gender and age), and behavioral variables (including physical activity and/or sports participation). The results of this study showed that there was a lower prevalence of obesity in schoolchildren aged 11-17 years (PR: 0.89; p=0.004). Obesity was more prevalent in children whose father (PR: 1.24; p < 0.001) and maternal grandmother (PR: 1.16; p=0.019) were obese. Higher prevalence rates of obesity were also identified in schoolchildren who were overweight at birth (PR: 1.18; p=0.002) and carriers of the obesity risk genotype (PR: 1.13; p=0.016). Biological factors, such as family history of obesity, overweight at birth, and the presence of the fat mass and obesity-associated rs9939609 polymorphism were associated with the prevalence of obesity in children and adolescents.

Genotypic carriers of the obesity-associated FTO polymorphism exhibit different cardiometabolic profiles after an intervention.

BACKGROUND:: Children and adolescents with at-risk genotypes (AA/AT) of the rs9939609 polymorphism in FTO, a fat mass and obesity-associated gene, may exhibit different cardiometabolic profile responses than subjects with the TT genotype after an interdisciplinary intervention. METHODS:: The sample consisted of 36 school children from southern Brazil. We used DNA quantitation and real-time polymerase chain reaction (PCR) for polymorphism genotyping. We measured anthropometric parameters (body mass index (BMI), waist circumference, hip circumference, waist-hip ratio, body fat percentage and skinfold sum), biochemical parameters (glucose, lipid profile, ultra-sensitive C-reactive protein, uric acid, alanine aminotransferase, aspartate aminotransferase, insulin and adiponectin) and blood pressure. The 4-month intervention consisted of physical education classes, nutritional counseling, and postural and oral health counseling. RESULTS:: We observed no significant differences among the groups (AA, AT and TT) after the intervention. However, we observed improvements in three parameters (waist circumference, hip circumference and C-reactive protein) in the AT/AA genotype group and in two parameters (hip circumference and uric acid) in the TT genotype group. CONCLUSIONS:: After an intervention program, carriers of at-risk genotypes for obesity (AA/AT) do not exhibit differences in biochemical parameters, blood pressure and anthropometric parameters compared with carriers of the TT genotype.

Association of IL-6 and CRP gene polymorphisms with obesity and metabolic disorders in children and adolescents.

Activation of adipose tissue inflammation is associated with obesity caused by lipid accumulation in adipocytes. Through this activation, proinflammatory cytokines, such as Interleukin-6 (IL-6) and C-reactive protein (CRP) seem to influence metabolic disorders. The present study evaluated whether polymorphisms in the CRP (rs1205) and IL-6 (rs1800795, rs2069845) genes are associated with the development of metabolic disorders in children and adolescents. A cross-sectional study was performed, consisting of 470 students from the municipality of Santa Cruz do Sul, Brazil, aged 7-17 years. Body mass index (BMI) was classified according to overweight and obesity. Genotyping was performed by real-time Polymerase Chain Reaction (PCR). Anthropometric characteristics, biochemical markers, immunological markers and blood pressure were assessed. Descriptive statistics, chi-square and logistic regression were used for the analyses. No association was detected between the rs1800795 polymorphism and the assessed variables. Individuals with the risk genotype in the rs1205 gene were associated with the risk of developing hypercholesterolemia (OR 2.79; CI 1.40, 5.57; p = 0.003). Carriers of the risk genotype in the rs2069845 gene are associated with the risk of developing obesity (OR 3.07; CI 1.08, 8.72; p = 0.03). The polymorphism rs2069845 was associated with obesity and rs1205 was associated with the risk of developing hypercholesterolemia in Brazilian schoolchildren.