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

Genetic Variants in the Fat Mass and Obesity-Associated Gene and Risk of Obesity/Overweight in Children and Adolescents: A Systematic Review and Meta-Analysis

OBJECTIVE

The variations in the single-nucleotide polymorphisms (SNPs) of the fat mass and obesity (FTO)-associated gene have been linked to being overweight or obese in children. In this research a thorough examination was performed to elucidate the connection between various FTO gene SNPs and overweight or obesity in children and adolescents.

METHOD

We searched PubMed, Google scholar, Web of Science and Scopus until January 2024 to find studies that investigate the association between different SNPs of FTO gene and the risk of overweight/obesity in children and adolescents. After filtering the relevant studies, meta-analysis was used to quantify the association of FTO gene SNPs within different genetic inheritance models.

RESULTS

We have identified 32 eligible studies with 14,930 obese/overweight cases and 24,765 healthy controls. Our recessive model showed a significant association with rs9939609 (OR: 1.56, 95% CI: 1.20; 2.02, p < 0.01) and rs1421085 (OR: 1.77, 95% CI: 1.14; 2.75, p < 0.01). Besides, in the homozygote model, rs1421085 showed the highest association (OR: 2.32, 95% CI: 1.38; 3.89, p < 0.01) with the risk of obesity in a population of children and adolescents. Moreover, there are other SNPs of FTO genes, such as rs9921255, rs9928094 and rs9930333, which showed a positive association with obesity and overweight. However, their effects were evaluated in very few numbers of studies.

CONCLUSION

In this study, we have found that the FTO rs9939609 and rs1421085 are associated to an increased risk of obesity among children and adolescents. Besides, the findings of this study further reaffirmed the established link between rs9939609 and obesity in children and adolescents.

The Impact of Haplotypes of the FTO Gene, Lifestyle, and Dietary Patterns on BMI and Metabolic Syndrome in Polish Young Adult Men

BACKGROUND

Variants in fat mass and the obesity-associated protein (FTO) gene have long been recognized as the most significant genetic predictors of body fat mass and obesity. Nevertheless, despite the overall evidence, there are conflicting reports regarding the correlation between different polymorphisms of the FTO gene and body mass index (BMI). Additionally, it is unclear whether FTO influences metabolic syndrome (MetS) through mechanisms other than BMI's impact. In this work, we aimed to analyze the impact of the following FTO polymorphisms on the BMI as well as MetS components in a population of young adult men.

METHODS

The patient group consisted of 279 Polish young adult men aged 28.92 (4.28) recruited for the MAGNETIC trial. The single-nucleotide polymorphisms (SNPs), located in the first intron of the FTO gene, were genotyped, and the results were used to identify "protective" and "risk" haplotypes and diplotypes based on the literature data. Laboratory, as well as anthropometric measurements regarding MetS, were performed. Measured MetS components included those used in the definition in accordance with the current guidelines. Data regarding dietary patterns were also collected, and principal components of the dietary patterns were identified.

RESULTS

No statistically significant correlations were identified between the analyzed FTO diplotypes and BMI (p = 0.53) or other MetS components (waist circumference p = 0.55; triglycerides p = 0.72; HDL cholesterol p = 0.33; blood glucose p = 0.20; systolic blood pressure p = 0.06; diastolic blood pressure p = 0.21). Stratification by the level of physical activity or adherence to the dietary patterns also did not result in any statistically significant result.

CONCLUSIONS

Some studies have shown that FTO SNPs such as rs1421085, rs1121980, rs8050136, rs9939609, and rs9930506 have an impact on the BMI or other MetS components; nevertheless, this was not replicated in this study of Polish young adult males.

Efficacy of a Comprehensive Weight Reduction Intervention in Male Adolescents With Different FTO Genotypes

BACKGROUND

The FTO gene polymorphisms may influence the effects of lifestyle interventions on obesity. The present study aimed to assess the influence of the rs9930506 FTO gene polymorphism on the success of a comprehensive weight loss intervention in male adolescents with overweight and obesity.

METHODS

This study was carried out on 96 adolescent boys with overweight and obesity who were randomly assigned to the intervention (n = 53) and control (n = 43) groups. The blood samples of the participants were collected, and the FTO gene was genotyped for the rs9930506 polymorphism. A comprehensive lifestyle intervention including changes in diet and physical activity was performed for 8 weeks in the intervention group.

RESULTS

Following the lifestyle intervention, BMI and fat mass decreased significantly in the intervention group compared with the control group (both p < 0.05), while no change was found in weight, height or body muscle percentage between the groups. The participants in the intervention group with the AA/AG genotype and not in carriers of the GG genotype had a significantly higher reduction in BMI (-1.21 vs. 1.87 kg/m2, F = 4.07, p < 0.05) compared with the control group.

CONCLUSION

The intervention in individuals with the AA/AG genotype has been significantly effective in weight loss compared with the control group. The intervention had no association effect on anthropometric indices in adolescents with the GG genotype of the FTO rs9930506 polymorphism.

TRIAL REGISTRATION

Name of the registry: National Nutrition and Food Technology Research Institute; Trial registration number: IRCT2016020925699N2; Date of registration: 24/04/2016; URL of trial registry record: https://www.irct.ir/trial/21447.

Role of rs9939506 polymorphism of FTO gene in resistance to eating in male adolescents

BACKGROUND

Single Nucleotide Polymorphisms (SNPs) of the Fat mass and obesity-associated (FTO) gene may be associated with obesity by regulating appetite. The present study aimed to investigate the relationship between FTO genotype and resistance to eating in male adolescents.

METHODS

The present cross-sectional study included 246 adolescent boys in Tehran, Iran, who were assessed for self-efficacy related to weight control using the Weight Efficacy Lifestyle (WEL), questionnaire, food intake using the Food Frequency Questionnaire (FFQ), physical activity using the International Physical Activity Questionnaire (IPAQ), and anthropometric indices using Bio-Impedance Analyzer (BIA). Moreover, the participants underwent genotyping for the rs9930506 polymorphism of the FTO gene, and the relationship between FTO genotype and resistance to eating was investigated using different models of multiple linear regression.

RESULTS

According to our findings, there was a significant reverse relationship between the FTO rs9930506 genotype and resistance to eating (β: -0.16, P = 0.01). Moreover, the relationship was still significant after adjusting for age, nutritional knowledge, BMI, and mother's BMI, educational level, and occupational status.

CONCLUSION

According to our results, the FTO genotype had a significant effect on resistance to eating and food desires. However, there is a need for further studies to evaluate the underlying mechanisms of the effects of the FTO gene on appetite and obesity.

Unraveling the Complex Interactions between the Fat Mass and Obesity-Associated (FTO) Gene, Lifestyle, and Cancer

Carcinogenesis is a complicated process and originates from genetic, epigenetic, and environmental factors. Recent studies have reported a potential critical role for the fat mass and obesity-associated (FTO) gene in carcinogenesis through different signaling pathways such as mRNA N6-methyladenosine (m6A) demethylation. The most common internal modification in mammalian mRNA is the m6A RNA methylation that has significant biological functioning through regulation of cancer-related cellular processes. Some environmental factors, like physical activity and dietary intake, may influence signaling pathways engaged in carcinogenesis, through regulating FTO gene expression. In addition, people with FTO gene polymorphisms may be differently influenced by cancer risk factors, for example, FTO risk allele carriers may need a higher intake of nutrients to prevent cancer than others. In order to obtain a deeper viewpoint of the FTO, lifestyle, and cancer-related pathway interactions, this review aims to discuss upstream and downstream pathways associated with the FTO gene and cancer. The present study discusses the possible mechanisms of interaction of the FTO gene with various cancers and provides a comprehensive picture of the lifestyle factors affecting the FTO gene as well as the possible downstream pathways that lead to the effect of the FTO gene on cancer.

Association of fat mass and obesity-associated (FTO) gene polymorphisms with non-communicable diseases (NCDs) in the Iranian population: A systematic review of observational studies

Background

Single nucleotide polymorphisms have been implicated in various diseases, most notably non-communicable diseases (NCDs). The aim of this study was to review available evidence regarding associations between FTO polymorphisms and NCDs in the Iranian population.

Methods

A comprehensive search was conducted through PubMed/Medline and Scopus databases up to December 2021, as well as reference lists of pertinent articles and key journals. All observational studies that examined the association between FTO gene polymorphisms and NCDs in the Iranian population were included. There was no limitation on the publication year. The Newcastle-Ottawa Scale (NOS) was used to assess the study's quality.

Results

The initial search yielded 95 studies, of which 30 studies were included in the current systematic review. The underlying disorders were obesity, type 2 diabetes, breast and colorectal cancers, depression, and metabolic syndrome. These studies found an association between FTO gene polymorphisms and obesity in the Iranian population, but the relationship with other NCDs was debatable. Even though, other diseases such as diabetes and metabolic syndrome, which are closely related to obesity, may also be associated with FTO gene polymorphisms.

Conclusion

FTO gene polymorphism appears to play a role in the occurrence of NCDs. Some of the study results may be misleading due to ethnic differences and the effect of other genetic factors on disease onset, which needs to be investigated further. Finally, FTO gene polymorphisms can be studied as a preventive or therapeutic target.

Supplementary Information

The online version contains supplementary material available at 10.1007/s40200-022-01139-4.

The Association between Index of Nutritional Quality (INQ) and Obesity: Baseline Data of Kharameh Cohort

Obesity is an increasing problem that can lead to noncommunicable diseases. The role of dietary factors on one's obesity is confirmed in many studies. One nutritional approach that can be used for assessment of the foods and diets is the Index of Nutritional Quality (INQ). Our study is aimed at exploring the association between INQ and obesity. Our hypothesis is that enriched and high-quality diets reduce the risk of overweight or obesity. This study was carried out on 6248 overweight and obese participants, from whom 4356 (69.7%) and 1892 (30.3%) were overweight and obese, respectively. To assess the dietary intake for the participants, a valid food frequency questionnaire (FFQ) with 130 food items was utilized. The analysis revealed an inverse association between the overweight and the INQ of iron, thiamin, riboflavin, B6, folate, zinc, magnesium, calcium, and vitamin C and E. For the obese group, this inverse association was found for iron, B6, folate, zinc, magnesium, calcium, and vitamin C and E. These results approved our hypothesis that a rich nutrition diet may lead to a lower risk of obesity.

The synergic effects of alpha-lipoic acid supplementation and electrical isotonic contraction on anthropometric measurements and the serum levels of VEGF, NO, sirtuin-1, and PGC1-α in obese people undergoing a weight loss diet

Background: The anti-obesity effects of Alpha-lipoic acid (α-LA) and isotonic contraction has been reported. However, the underlying mechanism is not fully understood. This study aimed to investigate the effect of 1200 mg/day α-LA supplementation and 3 sessions per week of Faradic (an electrical stimulating system) on anthropometric parameters, body composition, VEGF, Sirtuin-1, nitric oxide (NO), and PGC1-α in obese people undergoing a weight loss regime.Methods: This randomised clinical trial was carried out on 100 obese adults. The subjects were randomly assigned to four groups of 25 subjects including Faradic, α-LA, α-LA + Faradic, and control. A Bio Impedance Analyser (BIA) was used to estimate anthropometric measurements including weight, body mass index (BMI), fat mass, and fat free mass. The serum levels of Sirtuin-1, PGC1-α, VEGF, and NO levels were measured. All measurements were done at baseline and after 8 weeks of the intervention.Results: A significant weight reduction was observed in all four groups compared to baseline (p<.01). The placebo group had significantly higher weight, BMI, weight circumstance (WC), and body fat (BF) compared with the other groups. The α-LA + Faradic group had significantly lower weight, BMI, BF, WC than control, faradic, and α-LA groups and higher, Sirtuin and PGC than the control group (all p < .05).Conclusions: The findings indicated that the α-LA and Faradic interventions may have a synergistic effect on weight, BMI, BF, WC, and SLM, possibly through changes in serum level of VEGF, NO, and PGC. Further studies are warranted to clarify the mutual effects of -α-LA and Faradic on obesity and its molecular mechanisms. Name of the registry: Iranian Registry of Clinical TrialsTrial registration number: IRCT20131117015424N2Date of registration: 04/04/2018URL of trial registry record: https://www.irct.ir/search/result?query=IRCT20131117015424N2.

Role of macronutrient intake in the epigenetics of obesity

Obesity is caused by a combination of hereditary and environmental factors. Despite extensive study, contemporary through diet, exercise, education, surgery, and pharmacological treatments, no effective long-term solution has been found to this epidemic. Over the last decade, there has been a tremendous advancement in understanding the science of epigenetics, as well as a rise in public interest in learning more about the influence of diet and lifestyle choices on the health of an individual. Without affecting the underlying DNA sequence, epigenetic alterations impact gene expression. Previous animal studies have shown a link between the type of diet and expression or suppression of obesity genes, but there are very few human studies that demonstrate the relationship between dietary intake and obesity gene expression. This review highlights the effects of carbohydrates, lipids, and protein intake from the diet on obesity-related genes.

Index of Nutritional Quality (INQ) and the Risk of Obesity in Male Adolescents: a Case-Control Study

Dietary factors may play a key role in the etiology of obesity. The Index of Nutritional Quality (INQ) provides a comprehensive overview of the nutrients content of the diet. This study aimed to investigate the association between INQ and obesity in male adolescents. We hypothesize that receiving a high-quality diet reduces the risk of overweight or obese. This study was carried out on 214 obese/overweight as the case group and 321 normal-weight male adolescents as the control group. Dietary intakes of the participants were collected using a food frequency questionnaire (FFQ). The FFQ-derived dietary data were used to calculate the INQ scores. After adjustments for age and height, an inverse association was found between obesity and INQ of iron, vitamin B6, and magnesium, and a positive association was found between obesity and INQ of zinc (all P < 0.05). After further adjustments for nutritional knowledge and calorie intake, an inverse association was observed between obesity and INQ of vitamin C, iron, vitamin B6, pantothenic acid, selenium, and magnesium (all P < 0.05). The positive association of obesity and INQ of zinc remained significant after adjustments. A higher intake of vitamin C, iron, vitamin B6, pantothenic acid, selenium, and magnesium and a lower intake of zinc may be protective against adolescent obesity. More longitudinal studies are required to investigate the relationship between these nutrients and obesity.

Dietary diversity modifies the association between FTO polymorphisms and obesity phenotypes

The current study aimed to evaluate the interaction of the dietary diversity score (DDS) and FTO polymorphisms concerning obesity phenotypes. The 4480 subjects of this cohort study were selected. The polymorphisms rs1121980, rs14211085 and rs8050136 were selected and genotyped. The weighted method was used to calculate the genetic risk score (GRS). Obesity marker changes were calculated. Those with minor allele carriers of rs1121980 had lower body mass index changes (Q1: 1.58 ± 0.60 vs. Q4: 0.13 ± 0.59) and visceral adiposity index (VAI) (Q1: -0.00 ± 0.02 vs. Q4: -0.04 ± 0.02) when they had higher DDS (P interaction = 0.05). Carriers of the minor allele of rs8050136 had significant VAI change across DDS quartiles (Q1: -0.01 ± 0.02 vs. Q4: -0.02 ± 0.02, P interaction = 0.05). No significant interaction was found between the GRS and DDS on general obesity. The pattern of dietary diversity may have a mediatory role in improving obesity markers in subjects with a more genetic predisposition to adiposity.

Association of FTO rs9939609 polymorphism with serum leptin, insulin, adiponectin, and lipid profile in overweight adults

FTO gene polymorphisms are associated with obesity and food intake. This study aimed to investigate the association of FTO rs9939609 polymorphism genotypes with serum glucose, lipid profile and serum hormones level. This cross-sectional study was carried out on 196 randomly selected overweight adults. Anthropometric measurements including weight, height, body mass index (BMI), fat mass, and fat-free mass were assessed. Serum TGs, total cholesterol, HDL cholesterol, LDL cholesterol, glucose and insulin levels were measured. The FTO gene was Genotyped for rs9939609 polymorphism. Dietary intake was assessed by avalid 168-item semi-quantitative food frequency questionnaire (FFQ). The homozygotes for the FTO rs9939609 risk allele (A) had higher serum leptin (p = 0.005, F: 5.131) and lower HDL (p = 0.001, F: 7.687) level than TT genotype. The differences between TT and AT genotypes were not significant. The association remained significant for HDL level after adjustments for age and sex, calorie intake, physical activity, and BMI. The association between rs9939609 polymorphism genotypes and leptin was disappeared after adjustments for calorie intake and physical activity. In conclusion, rs9939609 risk allele was associated with higher serum leptin and lower HDL levels in overweight people. Further studies are warranted.

METTL14 Gene Polymorphisms Confer Neuroblastoma Susceptibility: An Eight-Center Case-Control Study

Neuroblastoma is the primary cause of cancer death in childhood. METTL14 is tightly linked to cancer. However, whether single-nucleotide polymorphisms (SNPs) in the METTL14 gene could predispose to neuroblastoma susceptibility lacks evidence. With an epidemiology case-control study, associations between METTL14 gene SNPs and overall risk for neuroblastoma were estimated in 898 cases and 1,734 controls. Following that, stratified analysis was performed. Among the five analyzed SNPs, rs298982 G>A and rs62328061 A>G exhibited a significant association with decreased susceptibility to neuroblastoma, whereas the associations with increased neuroblastoma susceptibility were observed for rs9884978 G>A and rs4834698 T>C. Moreover, subjects carrying two to five risk genotypes were more inclined to develop neuroblastoma than those with zero to one risk genotypes. The stratified analysis further demonstrated the protective effect of rs298982 G>A and rs62328061 A>G, as well as the predisposing effect of rs4834698 T>C and two to five risk genotypes, in certain subgroups. Haplotype analysis was performed. Moreover, false-positive report probability analysis validated the reliability of the significant results. The expression quantitative trait locus analysis revealed that rs298982 is correlated with the expression levels of its surrounding genes. Our results suggest that some SNPs in the METTL14 gene are associated with predisposition to neuroblastoma.

The effect of rs9930506 FTO gene polymorphism on obesity risk: a meta-analysis

Obesity is associated with polymorphisms of the fat mass and obesity associated gene (FTO). This meta-analysis aimed to investigate the association of the rs9930506 FTO gene polymorphism and obesity. To the best of our knowledge, this study is the first meta-analysis to evaluate the relation between FTO rs9930506 polymorphism and obesity. We searched PubMed, Web of Science, and Embase to identify studies investigating the relations between the rs9930506 FTO gene polymorphism and obesity risk. We pooled adjusted odds ratios (OR) as overall and in continent subgroups. A Fixed-effects model was used to analyze the results of these studies in dominant and recessive models. By examining 3337 obesity cases and 3159 healthy controls, we identified 8 eligible case-control studies. Considering the dominant model of inheritance, there was a relationship between the rs9939506 polymorphism and obesity (OR=1.34 [1.03- 1.74]). The association remained significant in the European subgroup (OR=1.68 [1.2-2.36]), but not in the Asian subgroup. Using the recessive model, we also found a significant relationship when the overall association was investigated (OR=2.47; 95% CI 1.56-3.91). In conclusion, this study identified that the carriers of the risk allele of FTO rs9930506 polymorphism are at higher risk for obesity.

Bidirectional associations between fitness and fatness in youth: A longitudinal study

The aim was to examine the bidirectional association between cardiorespiratory fitness (CRF) and fatness in a 2-year longitudinal study conducted in young people. A total of 1082 children (512 females) and 727 adolescents (342 females) with complete data at baseline and follow-up were included. CRF was determined by the 20-m shuttle run test. Height and weight were measured, and body mass index and fat mass index (kg/m² ) were calculated. Triceps and subscapular skinfolds were assessed to compute body fat percentage. Bidirectionality was tested by including CRF and each fatness index as exposures and outcomes, alternatively, in different regression models. CRF was prospectively associated with fatness index levels (ß from -0.186 to -0.528; P < .001), remaining significant in children after adjusting for baseline fatness indices. Fatness indices were prospectively associated with CRF (ß from -0.207 to -0.479; P < .001), with no substantial changes observed in children and female adolescents when baseline CRF was considered. Changes in CRF were prospectively associated with several fatness indices, regardless of body fatness at baseline (ß from -0.062 to -0.220; P < .05). Body fatness changes were associated with future CRF levels, independently of baseline CRF, especially in children of both sexes and male adolescents (ß from -0.079 to -0.260; P < .05). Overall, a bidirectional association was observed between CRF and fatness in children and adolescents. The attainment of optimal CRF and fatness levels in early ages should be promoted since it could result in favorable future fatness and CRF levels, respectively, which are two key determinants of health status.

Association between FTO gene polymorphisms and breast cancer: the role of estrogen

Introduction: The fat mass and obesity-associated (FTO) gene may be associated with breast cancer risk. This study aimed to systematically investigate the association between FTO gene polymorphisms and breast cancer and the possible role of estrogen in this association.Areas covered: We performed an extensive search of electronic databases such as PubMed, Science Direct, Scopus, and Cochran for published original studies on the association of FTO gene polymorphisms with breast cancer risk. Keywords such as breast cancer and/or FTO gene and/or polymorphism were used in order to identify the related articles. We excluded studies unrelated to the FTO genotype and the outcome of breast cancer.Expert opinion: FTO gene may have a significant association with the risk of breast cancer. The association between FTO gene polymorphisms and breast cancer was influenced by the status of estrogen receptors. Estrogen may promote breast cancer cell proliferation through up-regulation of FTO gene expression and activation of the PI3 K/Akt signaling pathway in estrogen receptor positive patients. Further studies are warranted to identify the underlying mechanisms and signaling pathways involved in the interactions between FTO gene, estrogen, and the risk of breast cancer.

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.

Soy Products Ameliorate Obesity-Related Anthropometric Indicators in Overweight or Obese Asian and Non-Menopausal Women: A Meta-Analysis of Randomized Controlled Trials

Background: The effect of soy products on the weight of overweight or obese people is controversial, so we aimed to conduct a systematic review and a meta-analysis of published randomized controlled trials to analyze whether supplementation with soy products can help them to lose weight. Methods: The relevant data before January 2019 in PubMed, Embase and Cochrane Library were searched. A random-effect model was adopted to calculate the weighted average difference of net changes of body weight, body mass index (BMI), body fat percentage, fat mass, waist circumference, etc. Results: A total of 22 trials (870 overweight or obese participants) were reflected in the present meta-analysis. Analysis showed that soy products significantly reduced body weight, BMI, body fat percent and waist circumference in overweight or obese Asian populations (−0.37 kg, P = 0.010; −0.27 kg/m², P = 0.042; −0.36%, P = 0.032; −0.35 cm, P = 0.049) and more significant effects were observed in non-menopausal women reduced body weight (−0.59 kg, P = 0.041), BMI (−0.59, P = 0.041) and waist circumference (−0.59 cm, P = 0.041) in overweight or obese populations. Conclusion: This meta-analysis showed that soy products have weight loss effects, mainly due to soy protein, isoflavone and soy fiber.

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 (β = 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)

Electronic supplementary material

The online version of this article (10.1186/s12967-019-1921-4) contains supplementary material, which is available to authorized users.

Dietary Carbohydrate Promotes Cell Survival in Cancer Via the Up-Regulation of Fat Mass and Obesity-Associated Gene Expression Level

Cancer cells are mainly dependent on glycolysis for their growth and survival. Dietary carbohydrates play a critical role in the growth and proliferation of cancer and a low-carbohydrate diet may help slow down the growth of tumours. However, the exact mechanisms behind this effect are unclear. This review study aimed to investigate the effect of fat mass and obesity-associated (FTO) gene in the association between dietary carbohydrates and cancer. This study was carried out using keywords such as polymorphism and/or cancer and/or dietary carbohydrate and/or FTO gene. PubMed and Science Direct databases were used to collect all related articles published from 1990 to 2018. Recent studies showed that the level of FTO gene expression in cancer cells is dramatically increased and may play a role in the growth of these cells through the regulation of the cellular metabolic pathways, including the phosphoinositide 3-kinases/protein kinaseB (PI3K/AKT) signaling pathway. Dietary carbohydrate may influence the FTO gene expression by eliminating the inhibitory effect of adenosine monophosphate-activated protein kinase (AMPK) on the FTO gene expression. This review summarised what has been recently discovered about the effects of dietary carbohydrate on cancer cells and tried to determine the mediating role of the FTO gene in these effects.

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 (β = 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.