Macarena Valladares

Melanocortin-4 receptor gene variants in Chilean families: association with childhood obesity and eating behavior

Abstract Objective: To screen for mutations in the coding region of the melanocortin-4 receptor (MC4R) gene and to assess the association between the rs17782313 variant near MC4R with childhood obesity and eating behavior. Subjects and methods: A cross-sectional sample of 221 obese Chilean children and 268 parents were incorporated in the study to assemble 134 case–parent trios. We performed direct sequencing of the MC4R coding region while the rs17782313 variant was genotyped by a Taqman assay. Eating behavior scores were calculated using the Child Eating Behavior and Three Factor Eating Questionnaires adapted for Chilean families. Results: A low frequency of genetic variation in the coding region of MC4R was found in Chilean obese children (Thr150Ile mutation and polymorphisms Ile251Leu and Val103Ile). The rs17782313 variant is possibly associated with satiety responsiveness (P = 0.01) and enjoyment of food scores (P = 0.03). Conclusion: The rs17782313 variant may influence eating behavior in obese children.

Melanocortin-3 receptor gene variants: Association with childhood obesity and eating behavior in Chilean families

OBJECTIVE To evaluate the association between melanocortin-3 receptor common genetic polymorphisms with childhood obesity and eating behavior in Chilean families. METHODS Two hundred twenty-nine obese children (6-12 y old, body mass index >95th percentile of Centers for Disease Control and Prevention/National Center for Health Statistics, 2000) and 270 parents were selected. Genotypes for MC3R genetic markers -239A>G, 17C>A (Thr6Lys), 241G>A (Val81Ile), +2138InsCAGACC, and microsatellite D20s32e were determined. Eating behavior scores were computed using the Child Eating Behavior Questionnaire and a shorter version of the Three Factor Eating Questionnaire adapted for evaluating eating inclinations in children. Genotype-obesity associations were assessed by the Transmission Disequilibrium Test. Non-parametric tests were used to compare eating behavior scores across study groups. RESULTS Allelic frequencies of -239G, 17A, 241A, and +2138InsCAGACC were estimated as 4.5%, 5.9%, 5.6%, and 17.6%, respectively, in obese children. The Transmission Disequilibrium Test in case-parent trios revealed no significant associations between childhood obesity and genetic markers, including the microsatellite D20s32e. In girls, we found significantly higher scores of the emotional eating subscale in carriers of the +2138InsCAGACC compared with non-carriers (P=0.04). In boys, carriers of 17A and 241A showed lower scores for the emotional eating subscale (P=0.01), whereas carriers of +2138InsCAGACC showed significantly lower scores for the enjoyment of food subscale compared with non-carriers (P=0.04). CONCLUSIONS There is not sufficient evidence to support the contribution for common melanocortin-3 receptor variants in childhood obesity. However, our results are concordant for a role of melanocortin-3 receptor variants in some dimensions of eating behavior such as emotional eating and enjoyment of food.

Association between genetic variants of the clock gene and obesity and sleep duration

Obesity is a multifactorial disease caused by the interaction of genetic and environmental factors related to lifestyle aspects. It has been shown that reduced sleep is associated with increased body mass index (BMI). Circadian Locomotor Output Cycles Kaput (CLOCK) gene variants have also been associated with obesity. The objective of this mini-review was to discuss the available literature related to CLOCK gene variants associated with adiposity and sleep duration in humans. In total, 16 articles complied with the terms of the search that reported CLOCK variants associated with sleep duration, energy intake, and BMI. Overall, six CLOCK single nucleotide polymorphisms (SNPs) have been associated with sleep duration, and three variants have been associated with energy intake variables. Overall, the most studied area has been the association of CLOCK gene with obesity; close to eight common variants have been associated with obesity. The most studied CLOCK SNP in different populations is rs1801260, and most of these populations correspond to European populations. Collectively, identifying at risk CLOCK genotypes is a new area of research that may help identify individuals who are more susceptible to overeating and gaining weight when exposed to short sleep durations.

Melanocortin-4 Receptor Gene Variation Is Associated with Eating Behavior in Chilean Adults

Background/Aims: To evaluate the association between allelic variants of melanocortin receptors -3 and -4 (MC3R and MC4R, respectively) and leptin receptor (LEPR) genes with body mass index (BMI) and eating behavior. Methods: We selected 344 Chilean adults (57.8% women; age 39.1 ± 6.6 years) with a wide variation in BMI (30.3 ± 6.3 kg/m2). The Three-Factor Eating Questionnaire-R18 that measures uncontrolled eating (UE), emotional eating (EE) and cognitive restraint scores was adapted, validated and assessed for association with BMI. Genotypes were determined by polymerase chain reaction followed by restriction fragment length polymorphism techniques and Taqman assays. Results: Higher EE scores were found in obese vs. non-obese in both men (p = 0.01) and women (p < 0.001). UE scores were significantly associated with BMI only in women (p = 0.002). No significant differences in eating behavior scores or BMI were found by LEPR (rs1137101, rs8179183 and rs1137100 polymorphisms) or MC3R (rs3746619 and rs3827103). Carriers of the C allele for MC4R rs17782313 showed significantly higher scores of UE compared to non-carriers (2.3 ± 0.8 vs. 2.0 ± 0.7; p = 0.02). Additionally, we also report a monogenic case of obesity carrying the pathogenic mutation 449C>T (Thr150Ile) in MC4R gene with no apparent alterations in eating behavior scores. Conclusions: UE scores were higher in C-allele carriers of MC4R-rs17782313 compared to non-carriers.

Prevalence of metabolic syndrome in obese Chilean children and association with gene variants of the leptin-melanocortin system.

Abstract Metabolic syndrome (MS) related to adult type 2 diabetes mellitus and cardiovascular disease is prevalent among obese children/adolescents. Genetic variants of the leptin-melanocortin system have been associated with components of MS. The aim of our study is to estimate the prevalence of MS (according to Cook’s criteria) in a Chilean cross-sectional sample of 259 obese children (47.1% girls, aged 6–12 years), and to assess the association between common genetic variants of leptin-melanocortin pathway genes (LEP, LEPR, POMC, MC3R and MC4R) with components of the MS using logistic regression. We observed an overall MS prevalence of 26.3% (32.2% in girls and 21.1% in boys) in obese Chilean children. No associations were detected between genetic variants of leptin-melanocortin genes and MS components. MS prevalence among our obese children sample is similar to those previously described in Chile, demonstrating the increased risk of diseases in adulthood that obese children carry.

Obesity and eating behaviour in a three-generation chilean family with carriers of the Thr150Ile mutation in the melanocortin-4 receptor gene

It has been proposed that functional mutations in the melanocortin 4 receptor (MC4R) gene have an important impact in body mass index, being considered as a major susceptibility gene for obesity. A number of mutations have been reported in the MC4R gene in subjects from different countries and ethnic groups. However, no reports of MC4R mutations are have been published for South American populations. In this study, DNA samples of thirty-two unrelated obese women of Chilean origin were examined to search for genetic variants in the single exon of the gene through the use of single strand conformational polymorphism techniques and direct sequencing, leading to the identification of a Thr150Ile mutation in heterozygous status. The evaluation of family relatives of the index case for this mutation using PCR-RFLP analysis, identified two additional carriers in a three-generation family. Obesity, eating behavior and body composition phenotypes in this family revealed a possible relation of this variant with obesity in the presence of reduced penetrance. According to our knowledge, this is the first report of MC4R mutations in South American populations.ResumenLas mutaciones funcionales del receptor 4 de melanocortina (MC4R) tienen un impacto muy relevante sobre el índice de masa corporal, siendo considerado MC4R como un gen may or de susceptibilidad frente a la obesidad. Se han descrito mutaciones en este gen en diferentes grupos étnicos, aunque aún no existen publicaciones sobre variantes de MC4R en poblaciones de Sudamérica. En este estudio, se analizaron 32 mujeres obesas de Chile en la búsqueda de variantes genéticas en MC4R mediante uso de la técnica de polimorfismo conformacional de hebra simple, seguida de secuenciación bidireccional, encontrándose una portadora de la mutación Thr150Ile en heterocigosis. Se buscaron los familiares de este caso índice a través de tres generaciones, lo que llevó a la identificación de otras dos personas portadoras de esta mutación mediante técnicas de PCR-RFLP. La evaluación de fenotipos de obesidad, composición corporal y conducta alimentaria reveló la posible existencia de asociación de esta mutación con obesidad en presencia de penetrancia reducida. Hasta donde sabemos, este estudio representa la primera publicación sobre mutaciones en MC4R en poblaciones de Sudamérica.

Association between Eating Behavior and Academic Performance in University Students

Objective: To determine the association between academic performance and eating behavior in university students in Chile. Methods: A total of 680 college students, 409 (60%) women and 271 (40%) men, were randomly recruited and the mean age of the entire sample was 26. The Three-Factor Eating Questionnaire (TFEQ), which evaluates 3 dimensions of eating behavior—cognitive restriction (limiting own intake), uncontrolled eating (inclination to eat), and emotional eating (control of food intake in the context of negative emotions)—was used. Academic performance was measured by the grade point average (GPA) and was associated with eating behavior. Results: Women had significantly higher scores in the “emotional eating” dimension than men (p = 0.002). The eating behavior analysis showed that female students with higher GPAs (above 5.5) had statistically significantly lower uncontrolled eating scores (p = 0.03) and higher cognitive restriction scores (p = 0.05) than women with lower academic performance (below 5.5). There were no significant associations between eating behavior and academic performance in men. Conclusions: A positive association between eating behavior and academic performance was observed in female university students in Chile. Further studies are needed to explore the causes of this association and determine how to improve the nutritional habits of this population.

Association of the FTO fat mass and obesity–associated gene rs9939609 polymorphism with rewarding value of food and eating behavior in Chilean children

OBJECTIVES The aim of this study was to assess the association between the single-nucleotide polymorphism rs9939609 in the FTO gene and homeostatic/non-homeostatic eating behavior patterns in Chilean children. METHODS A cross-sectional study was conducted in 258 children (44% female; 8-14 y of age). Anthropometric measurements (weight, height, Z-score of height, body mass index, and waist circumference) were performed. Eating behavior was assessed using the Eating in Absence of Hunger Questionnaire; the Child Eating Behavior Questionnaire; the Three Factor Eating Questionnaire, and the Food Reinforcement Value Questionnaire. Genotype of rs9939609 was determined by a Taqman assay. Association of rs9939609 with eating behavior was assessed using non-parametric tests. RESULTS Allelic frequencies of rs9939609 were estimated as 77% for the A allele and 23% for the T allele. We found that normal-weight girl A carriers had higher scores of Satiety Responsiveness and Slowness on the Eating subscale. Normal-weight boy A carriers showed significantly higher scores on the Negative Affect and lower scores of the Desire to Drink subscale. In overweight children, A carriers showed higher scores on the Food Responsiveness, Emotional Overeating, Enjoyment of Food, and Food Choice subscales and lower scores on the Satiety- Responsiveness and Slowness in Eating subscales. In obese children, we found higher scores on the Cognitive Restrained subscale and lower Food Choice. CONCLUSION The rs9939609 A allele of the FTO gene is associated with eating behavior traits and may predispose to obesity.

Effect of healthy and unhealthy habits on obesity: a multicentric study

OBJECTIVE Our aim was to characterize and compare eating patterns of university students in Chile, by sex and body weight, body mass index, and nutritional status. METHODS This was a cross-sectional study. University students (n = 1454) of Chile were evaluated. A self-assessment survey was used to evaluate healthy eating habits using a questionnaire with values between 1 (do not consume) and 5 (consume) for a total of 9 to 45 points (higher values represent better eating habits). Unhealthy habits were assessed with six questions, including consumption of sugary soft drinks, alcohol, fried foods, fast food, and snacks and adding salt to foods without tasting first. RESULTS Obese students had a lower consumption of healthy foods (P <0.05) compared with normal weight participants. Underweight male participants had higher unhealthy food consumption (P <0.05) and obese women had the lowest score (P <0.05). Protective factors for being overweight/obese were included (odds ratio [OR]  = 0.5; 95% confidence interval [CI] 0.3-0.8), consumption of ≥2 servings of vegetables (OR = 0.5; 95% CI 0.4-0.7). Risk factors included consumption (more than 1 cup a day) of sugary soft drinks (OR = 1.5; 95% CI 1.0-2.1) and male sex (OR = 1.8; 95% CI 1.3-2.4). CONCLUSION The consumption of vegetables and belonging to an undergraduate program in health sciences at a university contributed to protection against for obesity. On the other hand, male sex and consumption of sugary drinks were found to be risk factors for obesity.

Individual differences in chronotypes associated with academic performance among Chilean University students

ABSTRACT A chronotype is an individual trait that determines circadian rhythm (dark/light cycle) characteristics, associated with bedtime, waking, and other daily activities. A chronotype is classified as morning, intermediate, and evening. The objective is to associate chronotypes with academic performance in university students. A cross-sectional study was performed to evaluate the chronotype of university students (n = 703) by Horne-Ostberg questionnaire and associated with academic performance. The group with higher GPAs had higher chronotype scores (p = 0.002). Morning and intermediate chronotypes exhibited better academic performance; however, more studies are necessary to determine the underlying causes, which could influence cognitive aspects.