OBE2026 - Effect of One Year Intensive Lifestyle Treatment in Children With ISO-BMI Over 30kg/m² and Their Families.

Childhood and adolescent overweight and obesity have increased significantly in Finland and other Western countries, beginning at younger ages than before. In 2023, approximately 26% of boys and 17% of girls aged 2-16 years were overweight. Obesity has major physical, psychological, social, and economic consequences. Prevention and treatment aim to halt weight gain, reduce comorbidities, and improve quality of life, with strong involvement of the child's family.

Childhood obesity often persists into adulthood; obese children are at significantly higher risk of becoming obese adults. Therefore, monitoring weight development throughout childhood is essential, particularly in primary care and school health services. Obesity is assessed using height-weight ratios and ISO-BMI, which adjust BMI according to age and sex.

The causes of obesity are multifactorial, involving genetic predisposition alongside environmental, behavioral, and societal influences. The fundamental mechanism is an imbalance between energy intake and expenditure. Family-related factors, including parental obesity, dietary habits, and daily routines, play a central role.

Dietary patterns strongly influence weight gain. High consumption of energy-dense foods, refined grains, sweets, and sugary drinks increases risk. Problematic eating behaviors such as emotional eating, uncontrolled eating, and binge eating are also common contributors. Regular meals and appropriate portion sizes help regulate intake and prevent overeating.

Low physical activity and excessive sedentary behavior are key risk factors. Recommendations suggest 1-2 hours of daily physical activity for school-aged children, with screen time limited to two hours, but these targets are increasingly unmet. Insufficient or poor-quality sleep also contributes to weight gain.

Obesity in children is associated with multiple comorbidities, including hypertension, type 2 diabetes, metabolic syndrome, dyslipidemia, and fatty liver disease. It also increases early risk factors for cardiovascular disease, such as inflammation and insulin resistance. Type 2 diabetes developing in adolescence is particularly severe. Early identification and lifestyle intervention can reduce these risks.

The cornerstone of treatment is sustained lifestyle change, combining dietary improvements and increased physical activity. Effective interventions require sufficient intensity, long-term follow-up, and strong family commitment. Psychosocial challenges may reduce adherence. Pharmacological treatments, such as GLP-1 analogues, may be used in selected adolescents but often result in weight regain after discontinuation.

The purpose of the described study is to develop an effective, closely monitored lifestyle intervention for obese children (ISO-BMI >30 kg/m²). The intervention combines nutritional counseling, physical activity guidance, psychological support, and family participation. Physical activity is tracked using wearable devices, and metabolic health-including liver status-is monitored.

The primary objective is to assess adherence and its impact on weight reduction in children aged 10-16 years undergoing intensive lifestyle treatment. Secondary outcomes include changes in metabolic markers such as glucose, HbA1c, lipids, and insulin resistance. Additional measures include BMI change, waist circumference, blood pressure, and physical fitness over a 59-week follow-up.

Inclusion criteria

• Informed consent of parent(s) or legally acceptable representative of subject and child assent, as age-appropriate, obtained before any trial-related activities. Trial-related activities are any procedures that are carried out as part of the trial, including activities to determine suitability for the trial
• Male or female, aged 10 to 16 years
• Tanner stage 1-5 pubertal development at the time of signing informed consent
• ISO-BMI ≥30kg/m2
• History of failing to lose sufficient weight with lifestyle modification as judged by the

Exclusion criteria

• Treatment with any medication for the indication of obesity within the past 90 days before screening
• Type 1 diabetes
• Type 2 diabetes
• Subjects with secondary causes of obesity (for example hypothalamic, monogenic or endocrine causes)
• Uncontrolled thyroid disease at screening, in the opinion of the investigator
• Subjects with secondary causes of obesity (for example hypothalamic, monogenic or endocrine causes)
• History of major depressive disorder within 2 years before screening
• Diagnosis of other severe psychiatric disorders (e.g., schizophrenia, bipolar disorder)
• A lifetime history of suicidal attempt
• Subjects with confirmed diagnosis of bulimia nervosa disorder
• History or presence of pancreatitis (acute or chronic)
• Impaired renal function defined as serum-creatinine >UNR for age in children unless renal function is proven normal by further assessments at the discretion of the investigator
• History of malignant neoplasms within the past 5 years prior to the day of screening
• Any medical condition or laboratory abnormality, including any clinically significant out-of-range vital signs, that may increase the risk of study participation or, in the investigator's judgment, make the participant inappropriate för the study
• Surgery scheduled for the duration of the trial, except for minor surgical procedures, in the opinion of the investigator
• Known or suspected abuse of alcohol or recreational drugs
• Previous participation in this trial. Participation is defined as signed informed consent
• Participation in any clinical trial of an approved or non-approved investigational medicinal product within 90 days before screening
• Female who is of child-bearing potential and not using an adequate contraceptive method (adequate contraceptive measure as required by local regulation or practice)
• Treatment with glucose-lowering agent(s) within 90 days before screening (except for metformin)
• Treatment with a GLP-1 receptor agonist within 180 days before screening
• Known history of, or documented positive hepatitis B or C or HIV infection
• Aspartate transaminase (AST) or alanine transaminase (ALT) ≥ 3 x upper-limit of normal
• Creatinine clearance (CrCl) < 60 ml/min measured by 24-hour urine collection or estimated from the Cockcroft and Gault formula
• Clinically significant ECG findings as judged by the investigator ((including history of clinically significant arrhythmias or conduction delays on electrocardiogram [ECG]) within 180 days before screening, new clinically significant arrhythmias, or conduction delays on ECG identified at screening)
• Known history of other heart diseases
• History of major depressive disorder within 2 years before screening
• Diagnosis of other severe psychiatric disorders (e.g., schizophrenia, bipolar disorder)
• A lifetime history of suicidal attempt
• Suicidal behavior within 30 days before screening
• Suicidal ideation corresponding to type 4 or 5 based on the Columbia-Suicide Severity Rating Scale (C-SSRS) within the past 30 days before screening
• Participants with confirmed diagnosis of bulimia nervosa disorder