Plasma lipid metabolites as potential biomarkers for identifying individuals at risk of obesity-induced metabolic complications.

Lipidomics studies have indicated an association between obesity and lipid metabolism dysfunction. This study aimed to evaluate and compare cardiometabolic risk factors, and the lipidomic profile in adults and older people. A cross-sectional study was conducted with 72 individuals, divided into two sex and age-matched groups: obese (body mass index-BMI ≥ 30 kg/m2; n = 36) and non-obese (BMI < 30 kg/m2; n = 36). The lipidomic profiles were evaluated in plasma using 1H nuclear magnetic resonance (1H-NMR) spectroscopy. Obese individuals had higher waist circumference (p < 0.001), visceral adiposity index (p = 0.029), homeostatic model assessment insulin resistance (HOMA-IR) (p = 0.010), and triacylglycerols (TAG) levels (p = 0.018). 1H-NMR analysis identified higher amounts of saturated lipid metabolite fragments, lower levels of unsaturated lipids, and some phosphatidylcholine species in the obese group. Two powerful machine learning (ML) models-k-nearest neighbors (kNN) and XGBoost (XGB) were employed to characterize the lipidomic profile of obese individuals. The results revealed metabolic alterations associated with obesity in the NMR signals. The models achieved high accuracy of 86% and 81%, respectively. The feature importance analysis identified signal at 1.50-1.60 ppm (-CO-CH2-CH2-, Cholesterol and fatty acid in TAG, Phospholipids) to have the highest importance in the two models.

Instruments for evaluation of motivations for weight loss in individuals with overweight and obesity: A systematic review and narrative synthesis.

This systematic review aims to identify instruments used to assess motivations for weight loss in individuals with overweight and obesity from different age groups, such as children, adolescents, adults, and older adults. The virtual search was carried out using the PubMed, Scopus, LILACS, and ADOLEC databases, and by manual search. The following descriptors were used: questionnaire, scale, instrument, evaluation, motivation, motive, reason, "lose weight," "losing weight," "weight loss," and slimming. Methodological quality was assessed according to the criteria of the COSMIN checklist. The search yielded 3,524 results, seven of which were included in the review. Six questionnaires assessing motivations for weight loss, which could be applied to various age groups, were identified. All the questionnaires presented items related to appearance and health as the main motivation for weight loss. In addition to these motivations, the questionnaires also included items related to improved sports performance, self-confidence, participation in important social events, family and social pressure, and fitting into different clothes. The most evaluated measurement properties in the studies were internal consistency, reliability, content validity, and construct validity. Regarding internal consistency, one was rated as excellent, one as fair, and three as poor. For reliability, two were rated as being of fair quality, and one as of poor quality. Two studies analyzed the content validity and the questionnaires were rated as being of poor methodological quality. Regarding structural validity, one was rated as excellent, another as fair, and another as poor quality. Only the Weight Loss Motivation Questionnaire presented excellent methodological quality for most of the analyzed criteria. There is a need to develop questionnaires that are of better methodological quality to assess motivations for weight loss. Instruments targeting the adolescent population should also be developed.

Motivations for weight loss in adolescents with overweight and obesity: a systematic review.

BACKGROUND: Adolescents with overweight and obesity report various motivations for weight loss other than the desire for better health. However, there is little evidence regarding the main motivations for weight loss in adolescents. The present systematic review aimed to identify the motivations for weight loss in adolescents with overweight and obesity. METHODS: A systematic search for original articles published up to December 2016 was carried out in the PubMed, Scopus, LILACS, and ADOLEC databases. The terms used in the search were: motivation, motive, reason, "weight loss," "lose weight," and adolescent. RESULTS: Six studies (all cross-sectional) met the selection criteria and were included in the review. The instruments used to assess the participants' motivations for weight loss were interviews and questionnaires with open questions. Seventeen motivations for weight loss were identified, the main ones being better health, esthetic/cosmetic reasons, improvements in self-esteem, and avoidance of provocation/bullying. CONCLUSIONS: The results of the present review show the need for validated instruments to assess the motivations for weight loss in adolescents with overweight and obesity. Moreover, the high frequency of motivations for weight loss related to appearance and social acceptance evidences the need for multidisciplinary weight loss interventions that consider not only the biological factors, but also the psychological and social aspects.

Variance sources and ratios to estimate energy and nutrient intakes in a sample of adolescents from public schools, Natal, Brazil / Fontes e razões de variância para estimar a ingestão de energia e nutrientes de uma amostra de adolescentes de escolas públicas

OBJECTIVE: The aim of this study was to describe the sources of dietary variance, and determine the variance ratios and the number of days needed for estimating the habitual diet of adolescents. METHODS: Two 24 hour food recalls were used for estimating the energy, macronutrient, fatty acid, fiber and cholesterol intakes of 366 adolescents attending Public Schools in Natal, Rio Grande do Norte, Brazil. The variance ratio between the intrapersonal and interpersonal variances, determined by Analysis of Variance, was calculated. The number of days needed for estimating the habitual intake of each nutrient was given by the hypothetical correlation (r)>0.9 between the actual and observed nutrient intakes. RESULTS: Sources of interpersonal variation were higher for all nutrients and in both genders. Variance ratios were <1 for all nutrients and higher in women. Two 24 hour dietary recalls were enough to assess energy, carbohydrate, fiber and saturated and monounsaturated fatty acid intakes accurately. However, the accurate assessment of protein, lipid, polyunsaturated fatty acid and cholesterol intakes required three 24 hour recalls. CONCLUSION: Interpersonal dietary variance in adolescents was greater than intrapersonal variance for all nutrients, resulting in a variance ratio of less than 1. Two to three 24 hour recalls, depending on gender and the study nutrient, are necessary for estimating the habitual diet of this population.

OBJETIVO: O objetivo deste estudo foi descrever as fontes de variância da dieta, determinar as razões de variâncias e o número de dias necessários para estimar a dieta habitual em adolescentes. MÉTODOS: A ingestão de energia, macronutrientes, ácidos graxos, fibra e colesterol foram estimadas por meio de dois recordatórios de 24 horas, aplicados em 366 adolescentes de escolas públicas de Natal, Rio Grande do Norte. A razão de variância foi calculada entre o componente da variância intrapessoal e interpessoal, determinada pela Análise de Variância. A definição do número de dias para a estimativa da ingestão habitual de cada nutriente foi obtida considerando a correlação hipotética de (r)>0,9, entre a verdadeira ingestão de nutrientes e a observada. RESULTADOS: As fontes de variância interpessoal foram maiores para todos os nutrientes e em ambos os sexos. As razões de variâncias foram <1 para todos os nutrientes, e mais elevadas no sexo feminino. Dois dias de recordatórios de 24 horas seriam suficientes para avaliar com precisão o consumo de energia, carboidratos, fibra, ácidos graxos saturados e monoinsaturados, exceto para proteínas, lipídeos, ácidos graxos poliinsaturados e o colesterol, que necessitariam de três dias. CONCLUSÃO: A variância interpessoal da dieta dos adolescentes foi maior do que a intrapessoal, para todos os nutrientes, repercutindo em uma razão de variância menor que 1. Para estimar a dieta habitual nesta população, uma variação de dois a três dias é necessária considerando o sexo e o nutriente avaliado.

Dietary patterns of young adolescents in urban areas of northeast Brazil.

BACKGROUND: Temporal trends in dietary patterns reveal associations between food consumption and increased prevalence of non-communicable chronic disease. OBJECTIVES: This study characterized dietary patterns in adolescents in urban area located in northeast of Brazil, relating it to the markers of a healthy diet. METHODS: A cross-sectional study used two 24-hour recalls to assess dietary intake in 430 public school students from Natal-RN, Brazil. Principal component analysis was used to derive dietary patterns according to consumption of food based on weight (grams), energy (Kcal), or fiber (grams). The analysis results yielded 3 distinct principal components: 7, 8, and 4 (cumulative variance >70%; factor loadings >0.4). The association between independent variables and the factor scores of all components obtained was determined by the Prevalence Ratio (CI 95%). RESULTS: The dietary patterns derived were: (1) Pure Traditional Food System, the highly representative pattern in young adolescents and the first component of the analytical models, (2) Combined and Risk Food System; extraction of total food weight and energy revealed markers of unhealthy diets based on high sugar, saturated fat, and salt consumption, and (3) Modified Traditional Food System represented by fiber; pattern 1 was observed within this model too. The associations observed, predominantly from the TFSm pattern, distinguished by sex, age and nutritional status. CONCLUSIONS: Patterns 1 and 3 are characterized by preserved regional food practices that prevent chronic disease, whereas pattern 2 is characterized by health risks. These inter-sectorial findings should be considered in the development of health care policies for children and adolescents.

Introducción: Estudios nacionales de evolución temporal encuentran que la tendencia del consumo alimentario se asocia con aumento de la prevalencia de las enfermedades crónicas. Objetivos: Caracterizar los hábitos alimentarios de los adolescentes en un área urbana del Noreste de Brasil, relacionándolos con los marcadores dietéticos saludables. Métodos: Estudio transversal con adolescentes (n=430) de las escuelas públicas de Natal-RN, Brasil. El consumo alimentario se evaluó mediante dos recordatorios 24h. La técnica de Análisis de Componentes Principales fue utilizada para derivar patrones dietéticos, de acuerdo con: alimentos en gramos (g), la energía en Kcal y la fibra en gramos, lo que resulta, respectivamente, en 3 componentes principales distintos: 7, 8 y 4 (varianza acumulada >70%; cargas factoriales >0,4). La asociación entre las variables independientes y los escores de los factores de todos los componentes obtenidos, se determinó por la razón de prevalencia (IC 95%). Resultados: Los patrones dietéticos fueron: el (1) Sistema Alimentario Tradicional puro representó el primero componente de los modelos; el (2) Sistema Alimentario Combinado y de riesgo reveló marcadores de alimentación no saludables, debido a la alta frecuencia de azucares refinados, grasas saturadas y sal; y el (3) Sistema Alimentario Modificado fue identificado en el modelo de las fibras, el patrón 1 de nuevo fue observado en este patrón. Las asociaciones observadas, en particular del patrón SATm, distinguen por sexo, edad y estado nutricional. Conclusiones: Los patrones dietéticos 1 y 3 se caracterizaron por la preservación de las prácticas regionales de alimentos, muy saludables, desde el punto de vista de la prevención de las enfermedades crónicas, mientras que el 2 representó alerta y riesgo para la salud. Los hallazgos pueden subvencionar Políticas de Atención a la Salud para infancia y adolescencia en carácter intersectorial.

Prediction equations for fat and fat-free body mass in adolescents, based on body circumferences.

BACKGROUND: Fat mass (FM) and fat-free body mass (FFB) are important parameters for assessing nutritional status, since they are associated with higher prevalence of excess body fat and malnutrition worldwide. AIM: To develop prediction equations for fat and fat-free body mass in adolescents using body circumferences. SUBJECTS AND METHODS: This cross-sectional study included 218 adolescents (10-16 years) with normal weight as defined by body mass index. FM(Pred) and FFB(Pred) were estimated using stepwise multiple linear regression, considering age and body circumferences. Response variables, FM(BIA) and FFB(BIA) were estimated using bioelectric impedance analysis (BIA). The accuracy of the prediction equations was evaluated using the coefficient of determination (R(2)) and Akaike's Information Criterion (AIC). RESULTS: The best prediction equations for males were FM(Pred) = -7.114 - 0.592(age) - 0.958(wrist)+0.191(hip)+0.295(abdomen); R(2) = 0.552; AIC = 416.04 and FFB(Pred) = - 52.180+1.913(age)+1.954(wrist)+1.635(forearm); R(2) = 0.869; AIC = 578.24. For females, the best equations were FM(Pred) = -17.580 - 0.678(wrist)+0.221(abdomen)+0.241(hip)+0.202(proximal thigh) - 0.228(calf); R(2) = 0.838; AIC = 415.36 and FFB(Pred) = -31.066+0.90(age)+1.090(wrist) - 0.139(abdomen)+0.326(hip)+0.632(calf); R(2) = 0.878; AIC = 512.48. CONCLUSION: The equations developed to estimate fat body mass in females and fat-free body mass in both genders had high adjusted coefficients of determination and are therefore preferable to those derived using BIA.