Medical Management of Childhood and Adolescent Obesity: Developmental Characteristics, Metabolic Disorders, and Early Life Intervention

The fundamental difference between children and adults during their growth and development period is that children are in a constantly changing process of growth and development.

Fetal period: from the 9th week of pregnancy to birth. This period is characterized by rapid growth of tissues and organs and gradual maturation of their functions. This period, up to 2 years of age, is known as the first 1000 days of life, and nutritional status during this stage is closely related to later chronic metabolic diseases.

Neonatal period: from the time the umbilical cord is cut until 28 days.

Infancy: From 28 days to 1 year of age. This is the first peak in growth, with the baby's weight approximately three times their birth weight at 12 months.

Early childhood: 1-3 years old. Growth rate slows down compared to infancy, and all primary teeth have erupted.

Preschool age: 4-6 years old. A balanced diet should be followed, and good habits of eating at regular times and not being picky about food should be developed.

School age: After 7-8 years old. Growth rate increases slightly, and subcutaneous fat begins to accumulate again.

Adolescence: The second growth spurt in life. Boys can grow 79cm, even 10-12cm, per year; girls grow 6-8cm per year. Due to hormonal changes, the incidence of obesity increases. II. Pathophysiological Characteristics of Early Life Obesity Childhood obesity is divided into simple obesity and pathological obesity. Environmental factors (sedentary lifestyle, sugary drinks, increased screen time) and genetic factors (genetic susceptibility accounts for 64%-84%) are the main causes. III. Endocrine and Metabolic Disorders of Obesity Obesity can lead to multiple endocrine and metabolic disorders: 1. Growth Hormone: One of its physiological functions is to promote fat breakdown. When plasma free fatty acids are elevated, growth hormone secretion decreases, increasing fat accumulation. 2. Thyroid Hormones: Serum thyroid-stimulating hormone (TSH) levels in obese children are usually higher than in normal children, decreasing as body fat decreases. 3. Cortisol: Participates in water and electrolyte metabolism and promotes gluconeogenesis. Cortisol secretion in obese individuals is often pathologically regulated, easily developing into metabolic syndrome (MS). 4. Insulin and Leptin: Obese children exhibit hyperinsulinemia and insulin resistance. Insulin can stimulate leptin secretion, and obese children often exhibit leptin resistance. 5. Obesity and sex hormones: Obesity in adolescent girls is often accompanied by early sexual development and menarche. In boys, obesity can lead to decreased serum testosterone levels, mainly manifested as delayed development of secondary sexual characteristics. IV. Environmental and nutritional factors during critical periods of metabolic programming development can continuously influence an individual's susceptibility to obesity. Pre-pregnancy weight, nutritional status during pregnancy, and gestational weight gain are all important predictors of neonatal birth weight. Birth weight is closely related to later development of type 2 diabetes, heart disease, insulin resistance, and obesity. Therefore, optimizing nutritional status during pregnancy, infancy, and early childhood, and controlling the infant weight gain rate at an appropriate level, is crucial.