Childhood obesity: The threatening apprentice of the adiposity empire

Figures

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  Fig. 1. Genetic obesity classification. There are three main presentations of obesity associated to genetic causes: monogenic, syndromic, and polygenic obesity. Monogenic obesity occurs at early ages, and it is a rare and severe form caused by a single gene mutation. Syndromic obesity involves development abnormalities, neurodevelopmental deficits, and dysmorphic features. Polygenic obesity, known as common obesity, is triggered by the simultaneous presence of defects in multiple genes. Some representative examples are shown in the present figure. FTO: fat mass and obesity-associated protein, LERP: leptin receptor, MCR4: melanocortin receptor, PCSK1: proprotein convertase Subtilisin/Kexin type 1, POMC: proopiomelanocortin

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  Fig. 2. Energy homeostasis. Regulatory mechanisms involved in the obesity development may affect energy intake and energy expenditure. The total daily energy expenditure (TEE) is made up of the sum of calories that the human body burns in 24 h, and results from resting energy expenditure (REE), diet-induced thermogenesis or thermic effect of feeding (TEF), exercise energy expenditure (ExEE) and non-exercise activity thermogenesis (NEAT). REE represents the minimal amount of energy that is required to maintain all the body functions at the basal state and contributes about 55–75% of the TEE, TEF is related to the amount of energy required for the digestion, absorption, usage and storage of nutrients after eating and represents 5–15% of the TEE, ExEE is the most variable component and is defined as the energy burned during physical activity and is about 15–30% of the TEE, and NEAT involves the energy expenditure that is not typically consider and results from spontaneous physical activity that is not the result of voluntary exercise, as the energy expended in maintain and changing posture and other activities of daily living that requires low energy consumption, NEAT is responsible for…

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  Fig. 3. Childhood obesity comorbidities. Children and adolescents with overweight and obesity have a high risk of developing multiple comorbidities such as IR, T2D, dyslipidemia, HT, coronary disease, among others during their adulthood, which increases the morbidity and mortality of these patients. The high prevalence of this comorbidities associated with overweight, or obesity emphasizes the importance of early interventions to prevent unfavorable outcomes. AHI: apnea hypopnea index, DBP: diastolic blood pressure, FPG: fasting plasma glucose, GERD: gastroesophageal reflux disease, HT: hypertension, IR: insulin resistance, LDL: low density lipoproteins, MASLD: metabolic dysfunction-associated steatotic liver disease, Non-HDL: Non-high density lipoproteins, OGTT: oral glucose tolerance test, OSA: obstructive sleep apnea. PCOS: polycystic ovary syndrome, SBP: systolic blood pressure, T2D: type 2 diabetes, TC: total cholesterol, TG: triglycerides, US: ultrasound

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  Fig. 4. Metabolic syndrome definition in pediatric population according to the IDF criteria. Metabolic syndrome (MS) increases the risk of cardiovascular disease. Children and adolescents with MS have at least 3 of the following components: high blood pressure, abnormal basal glucose levels, low HDL, high triglycerides or high abdominal circumference. BP: blood pressure, CV: cardiovascular disease, HDL-c: high density lipoproteins, HT: hypertension, IDF: International Diabetes Federation, T2D: type 2 diabetes, TG: triglycerides

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  Fig. 5. Body composition components in the 2C, 3C and 4C (multicompartmental) models. Different techniques are available to evaluate the body composition in children and adolescents, each one of them with its advantages and limitations. The body is divided into numerous compartments for the body composition assessment in the different models. The 2-compartment model (2C-Model) separates the body into fat-free mass and fat mass; this model is widely used in clinical practice because of its simplicity and easy use. The 3-compartment model (3C-Model) divides the body into fat-free mass, fat mass and bone; children´s body composition has been evaluated employing this technique. In addition, the gold standard, the 4-compartment model (4-Model) expands the previous compartments to fat mass, protein, total body water and bone; due to the possibility of extracting the protein and mineral content from the fat-free mass, the most precise measurement between the available techniques is guaranteed. 2-C Model: 2 compartment model, 3-C Model: 3 compartment model, 4-C Model: 4 compartment model, BAT: brown adipose tissue, EC: extracellular, IC: intracellular, SC: subcutaneous, VAT: visceral adipose…

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  Fig. 6. Body composition techniques (direct and indirect methods). Over the years, different body composition measuring methods have been developed. Body composition was quantified by dissecting cadavers, which was considered a direct method. Subsequently, new methods were design to measure body composition indirectly, such as hydrodensitometry, air displacement plethysmography (ADP), dual energy X ray absorptiometry (DXA), CT-scan, MRI and other indirect measuring methods as bioelectrical impedance analysis (BIA) and anthropometrics. The 4-compartment model (4-C Model), ADP and DXA are used as reference methods in adult and pediatric population. ADP: air displacement plethysmography, BF: body fat, BIA: bioelectrical impedance analysis, BMI: body mass index, CT: computed tomography, DXA: dual energy X ray absorptiometry, FFM: fat-free mass, FM: fat mass