Interactions between macro-nutrients' intake, FTO and IRX3 gene expression, and FTO genotype in obese and overweight male adolescents.

This study is the first to identify the effects of FTO genotype on the interactions between the level of macro-nutrients intake and the expression level of fat mass and obesity associated (FTO) and homeobox transcription factor iriquois-3 (IRX3) genes This longitudinal study was carried out on 84 overweight and obese adolescent boys in Tehran, Iran. The rs9930506 SNP in FTO was genotyped at baseline and the level of FTO and IRX3 expression in PBMCs and macro-nutrients' intake were assessed at baseline and after 18 weeks of the intervention. The results identified that the higher carbohydrates intake significantly up-regulated the FTO gene (P = 0.001) and down-regulated the IRX3 gene (P = 0.01). Protein intake up-regulated the FTO gene (P = 0.001). In carriers of GG genotype of FTO gene, the amount of dietary carbohydrate had a positive association with FTO gene expression (p = 0.001, and p = 0.04, respectively). In AA/AG carriers, dietary protein was positively associated with FTO gene expression (p = 0.001) and dietary carbohydrate was negatively associated with IRX3 gene expression (P = 0.04). Therefore, dietary carbohydrateseems to be associated with FTO and IRX3 genes expression. These associations are influenced by FTO genotype.

Up-regulation of FTO gene expression was associated with increase in skeletal muscle mass in overweight male adolescents.

INTRODUCTION: The modifying effect of FTO gene expression level on change in body mass index and body composition has not been studied before. This study aimed to investigate the association between change in the expression level of the FTO gene and changes in anthropometric measurements in obese and overweight adolescent boys. MATERIAL AND METHODS: Eighty-four boys aged 12 to 16 years participated in this longitudinal study. A Bio Impedance Analyzer (BIA) was used to estimate percentage of body fat (%BF) and percentage of skeletal muscle (%SM). The FTO gene expression level in peripheral blood mononuclear cells was assessed using quantitative real-time PCR (qPCR). All measurements were performed at baseline and after 18 weeks. RESULTS: After 18 weeks, mean weight was reduced by 2.39 kg, body mass index by 0.09 kg/m2, %BF by 0.82% and %SM increased by 0.44%. Moreover, the level of FTO gene expression increased 0.42-fold higher than baseline. The change in expression level of the FTO gene was positively associated with change in %SM (ß = 0.31, p = 0.02). CONCLUSIONS: FTO gene expression change was associated with change in %SM in male adolescents. Future studies are required to assess the interactions between FTO gene expression in different tissues and body composition.

Changes in FTO and IRX3 gene expression in obese and overweight male adolescents undergoing an intensive lifestyle intervention and the role of FTO genotype in this interaction.

BACKGROUND: Lifestyle intervention may have a critical effect on the association between genetics and obesity. This study aimed to investigate changes in FTO and IRX3 gene expression in obese and overweight male adolescents undergoing a lifestyle intervention and the role of FTO genotype in this interaction. METHODS: This study was a field trial of 62 adolescents from boys' high schools in Tehran, Iran. Two schools were randomly allocated as the intervention (n = 30) and control (n = 32) schools. The rs9930506 SNP in FTO was genotyped at baseline and the level of FTO and IRX3 expression in peripheral blood mononuclear cells (PBMCs). Anthropometric measurements were assessed at baseline and after 18 weeks of intensive lifestyle intervention. RESULTS: Our results showed that IRX3 expression in the intervention group was significantly up-regulated compared to baseline (P = 0.007) and compared to the control group (P = 0.011).The intervention group had significantly up-regulated transcripts of IRX3 only in rs9930506 risk allele carriers of the intervention group compared to risk allele carriers of the control group (P = 0.017). Moreover, our data showed that the FTO expression was up-regulated in AA genotype carriers and down-regulated in AG/GG genotype carriers (P = 0.017). CONCLUSION: Lifestyle modification may exert its effects on obesity through changes in the expression level of the FTO and IRX3 genes. However, FTO genotype plays a role in the extent of the effect of lifestyle changes on gene expression. Further studies are crucial to have a better understanding of the interaction between lifestyle, genetics and anthropometric measurements. Trial registration This paper reports a comprehensive intervention study (Interactions of Genetics, Lifestyle and Anthropometrics study or IGLA study), which is retrospectively registered in the Iranian Registry of Clinical Trials as IRCT2016020925699N2. Date registered: April 24, 2016. ( https://www.irct.ir/searchresult.php?id=25699&number=2 ).

The Role of FTO Genotype in the Association Between FTO Gene Expression and Anthropometric Measures in Obese and Overweight Adolescent Boys.

The role of FTO genotype in the effect of FTO gene expression level on change in body mass index and body composition has not been studied. This study aimed to investigate the role of FTO genotype in the association between change in the expression level of the FTO gene with changes in anthropometric measurements in obese and overweight adolescent boys. Eighty-four boys aged 12 to 16 years participated in this longitudinal study. A bioimpedance analyzer (BIA) was used to estimate percentage of body fat (%body fat) and percentage of skeletal muscle (%skeletal muscle). The FTO gene expression level in peripheral blood mononuclear cells (PBMCs) was assessed using quantitative Real Time PCR (qPCR). The DNA samples were genotyped for the FTO gene polymorphisms by DNA sequencing. All measurements were performed at baseline and after intervention. A significant association was observed between the level of gene expression and %skeletal muscle. The gene expression fold change was significantly associated with change in %skeletal muscle in AA or AG genotype carriers (ß = 0.34, p = .02). No significant association was detected between the change in FTO gene expression with change in anthropometric indices in GG genotype carriers. In conclusion, the association between FTO gene expression and body composition can be influenced by FTO genotype. Future studies are required to assess the interactions between FTO genotype, FTO gene expression in different tissues, and body composition.

A complete linkage disequilibrium in a haplotype of three SNPs in Fat Mass and Obesity associated (FTO) gene was strongly associated with anthropometric indices after controlling for calorie intake and physical activity.

BACKGROUND: The underlying mechanism of the effect of FTO genotype on body mass index (BMI) and body composition is unknown. The objective of the study was to investigate the association of FTO gene polymorphisms with anthropometric indices in adolescent boys after adjustments for dietary intake and physical activity. METHODS: In this school-based study, we enrolled 123 male adolescents without extra weight and 110 male adolescents with body mass index (BMI) higher than + 1 Z-score. The DNA samples were genotyped for the FTO gene polymorphisms by DNA Sequencing. BMI and body composition were assessed using bioelectrical impedance analyzer scale. Association of the FTO polymorphisms with Weight, height, BMI, body fat percent and skeletal muscle percent were investigated. Data on potential confounders (calorie intake and physical activity) were collected through the use of pre-tested questionnaires. RESULTS: Adolescents with higher BMI and body fat percent and lower skeletal muscle percent were more likely to have a newly found haplotype of rs9930506, rs9930501 & rs9932754 (GGT) in the first intron of the FTO with complete linkage disequilibrium (LD) compared with those with the lower BMI (6.15;2.28-16.63), body fat percent (9.54;0.92-47.44) and higher skeletal muscle percent (9.26;1.85-46.38). This association was not changed after controlling for age. Additional adjustments for calorie intake and physical activity did not alter the association. CONCLUSIONS: A haplotype in the first intron of the FTO gene had a strong association with obesity indices in adolescent boys after adjustments for calorie intake and physical activity. It's suggested that the FTO genotype exert its effects on adolescents' anthropometric indices as haplotype and through mechanisms other than changes in calorie intake and expenditure. TRIAL REGISTRATION: This paper reports the first phase of a comprehensive interventional study (Interactions of Genetics, lifestyle and anthropometrics study or IGLA study) and is retrospectively registered in the Iranian Registry of Clinical Trials as IRCT2016020925699N2. Date registered: April 24, 2016. ( http://www.irct.ir/searchresult.php?id=25699&number=2 ).

A haplotype of three SNPs in FTO had a strong association with body composition and BMI in Iranian male adolescents.

BACKGROUND: Single-nucleotide polymorphisms (SNPs), which are located in the first intron of the FTO gene, are reported to be associated with body weight and the body mass index (BMI). However, their effects on anthropometric measurements in adolescents are poorly understood. OBJECTIVE: This study aimed to investigate the association of three adjacent polymorphisms (rs9930506, rs9930501, & rs9932754) in the FTO gene with anthropometric indices in Iranian adolescent males. DESIGN: The participants comprised a total of 237 adolescent males who were recruited randomly from two high schools in Tehran, Iran. The DNA samples were genotyped for the FTO gene polymorphisms by DNA sequencing. BMI, body fat percentage (BF%), and body muscle percentage (BM%) were determined using a validated bioelectrical impedance analysis scale. The association of the FTO polymorphisms with weight, height, BMI, BF%, and BM% was investigated. RESULTS: A haplotype of rs9930506, rs9930501, and rs9932754 (GGT) in the first intron of the FTO with complete linkage disequilibrium (LD) was found to be significantly associated with higher weight (OR = 1.32), BMI (OR = 5.36) and BF% (OR = 1.46), and lower BM% (OR = 3.59) (all P<0.001). None of the students with GGC genotypes were underweight, while all of the students with AAT genotypes had high muscle mass. CONCLUSIONS: A haplotype in the first intron of the FTO gene had a strong association with obesity indices in Iranian adolescent males. The FTO gene polymorphisms might have greater effects on anthropometric indices than what was previously imagined. Moreover, we suggested that the FTO gene exerted their effects on anthropometric measurements through haplotypes (and not single SNPs).

Indicator for Success of Obesity Reduction Programs in Adolescents: Body Composition or Body Mass Index? Evaluating a School-based Health Promotion Project after 12 Weeks of Intervention.

BACKGROUND: Obesity in adolescence is the strongest risk factor for obesity in adulthood. This study aimed to evaluate the effects of a comprehensive lifestyle intervention on different anthropometric indices in 12-16-year-old boy adolescents after 12 Weeks of Intervention. METHODS: A total of 96 male adolescents from two schools participated in this study. The schools were randomly assigned to intervention (53 students) and control school (43 students). Height and weight of students were measured and their body mass index (BMI) was calculated. Body fat percent (BF) and body muscle percent (BM) was assessed using a bioimpedance analyzer considering the age, gender, and height of students at baseline and after intervention. The obesity reduction intervention was implemented in the intervention school based on the Ottawa charter for health promotion. RESULTS: Twelve weeks of intervention decreased BF percent in the intervention group in comparison with the control group (decreased by 1.81% in the intervention group and increased by 0.39% in the control group, P < 0.01). However, weight, BMI, and BM did not change significantly. CONCLUSIONS: The result of this study showed that a comprehensive lifestyle intervention decreased the body fat percent in obese adolescents, although these changes was not reflected in the BMI. It is possible that BMI is not a good indicator in assessment of the success of obesity management intervention.

Strategies and Opportunities Ahead to Reduce Salt Intake.

In Iran, as in most countries, cardiovascular diseases are the leading cause of death (highest mortality rate), but rank third in terms of disease burden. On the other hand, the relationship between high salt intake, hypertension, and cardiovascular disease has been proven. Food consumption pattern in Iran shows that consumption of salt, pickled foods and salty snacks is common. Regarding the World Health Organization (WHO) target for salt intake (about 5 g per day), the evidence indicates that Iranian people consume 2-3 times more than the recommended amount of salt. Fortunately, serious attention has been paid to this matter since 2009 and along with arrangements for it, support of all relevant sectors (public and private) has been included in the agenda. At present, reduction of salt intake is among the major priorities of planners, policy makers, and experts of the Iranian health services system. On the other hand, many studies in EMRO have shown high levels of daily salt intake in these countries. In this review, the solutions used in the Islamic Republic of Iran at various levels were considered, including determination of salt intake measurement methods, revision in the amount of salt in processed food products, food labeling, promoting awareness of various social groups, gathering support from all relevant sectors, designing a regular public awareness campaign for reducing salt intake, and lessons learned in this regard, that can be helpful to countries in the region.