Ana María Obregón

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.

Childhood obesity and eating behaviour.

Abstract The prevalence of childhood obesity has increased substantially in the recent decade as a result of the reduction in physical activity and the availability of high-fat and high-energy-density foods which the paediatric population faces daily. Although children are highly exposed to these foods, there is a wide variation in body weight, suggesting the presence of different patterns of response to an “obesogenic” environment. This wide variability from the point of view of eating behaviour involves a number of social issues (e.g., food availability, cost) as well as genuine behavioural traits such as the response to satiety, energy compensation, eating rate, responsiveness to food, food reward and dietary preferences. This article reviews the main physiological variables related to energy intake affecting eating behaviour in the paediatric population.

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.

Effect of the melanocortin-3 receptor Thr6Lys and Val81Ile genetic variants on body composition and substrate oxidation in Chilean obese children

Mice genetically deficient in the melanocortin-3 receptor gene are characterized by normal body weight, increased body fat, mild hypophagia, reduced locomotor activity, and increased respiratory quotient compared with wild-type mice. In humans, the 6Lys–81Ile haplotype of melanocortin-3 receptor (MC3R) gene has been associated with childhood obesity, higher body fat percentage, and reduced fat oxidation compared to non-carriers. The aim of this study was to evaluate the association between MC3R 6Lys–81Ile haplotype with body composition and substrate oxidation in response to moderate exercise in obese children. Eight Chilean obese children (aged 8–12) carriers of MC3R 6Lys–81Ile haplotype were compared with eight age–gender-matched obese non-carriers. Children were identified through a previous cross-sectional study on genetic determinants of childhood obesity (n = 229). Genotypes for MC3R Thr6Lys and Val81Ile were determined by polymerase chain reaction–restriction fragment length polymorphism. Body composition was assessed by the four-compartment model (dual-energy X-ray absorptiometry, total body water by the deuterium dilution technique, and total fat mass by air-displacement plethysmography). Substrate oxidation was assessed by indirect calorimetry in response to moderate exercise (60% VO2 max). Wilcoxon matched-pairs test was used to compare quantitative variables. No significant differences among carriers and non-carriers were found in anthropometrical and body composition measurements. The Carriers of the 6Lys–81Ile haplotype showed higher respiratory quotient (p = 0.06) and a significantly higher glucose oxidation (p = 0.01) compared with non-carriers after standardization for fat-free mass. Our results are consistent with a possible participation of MC3R 6Lys–81Ile variants in glucose oxidation in response to moderate exercise.

Asociación entre adicción a la comida y estado nutricional en universitarios chilenos

BACKGROUND High calorie foods, especially high in sugar and sodium may have an addictive potential. Experimental rats are able to develop symptoms and neurochemical changes, comparable to those observed in drug abuse, when they are exposed intermittently to sucrose. AIM To evaluate the association between nutritional status and the prevalence of food addiction in Chilean college students. MATERIAL AND METHODS Food addiction was assessed using the Yale Food Addiction Scale in 292 Chilean students aged 18-39 years (35% males). Height and weight were measured and body mass index (weight/height²) was calculated. RESULTS Eleven percent of participants met the criteria for food addiction. Women had a higher prevalence than men (14.4% and 4.8%, respectively). Thirty percent of individuals with a body mass index over 30 kg/m² met the criteria for food addiction. CONCLUSIONS In these Chilean students, food addiction was more prevalent in women and a higher prevalence was observed in obese individuals.Background: High calorie foods, especially high in sugar and sodium may have an addictive potential. Experimental rats are able to develop symptoms and neurochemical changes, comparable to those observed in drug abuse, when they are exposed intermittently to sucrose. Aim: To evaluate the association between nutritional status and the prevalence of food addiction in Chilean college students. Material and Methods: Food addiction was assessed using the Yale Food Addiction Scale in 292 Chilean students aged 18-39 years (35% males). Height and weight were measured and body mass index (weight/height2) was calculated. Results: Eleven percent of participants met the criteria for food addiction. Women had a higher prevalence than men (14.4% and 4.8%, respectively). Thirty percent of individuals with a body mass index over 30 kg/m2 met the criteria for food addiction. Conclusions: In these Chilean students, food addiction was more prevalent in women and a higher prevalence was observed in obese individuals.

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.

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.