What is the definition and classification of malnutrition in children?

Definition and Classification of Malnutrition in Children

Malnutrition in children is defined as a state resulting from lack of intake or uptake of nutrition that leads to altered body composition, diminished physical and mental function, and impaired clinical outcomes, which can be classified based on etiology, chronicity, and severity. 1

Definition of Malnutrition

Malnutrition in children represents an imbalance between nutrient requirements and intake that results in cumulative deficits of energy, protein, or micronutrients with potential negative effects on:

• Growth and development 2
• Physical and mental function 1
• Clinical outcomes from disease 1, 3

The pathological state can manifest as:

• Undernutrition (protein-energy malnutrition) due to insufficient intake 4
• Overnutrition (overweight and obesity) due to excessive consumption 4
• Micronutrient deficiencies due to insufficient intake of specific vitamins or minerals 4

Classification of Malnutrition

1. Etiology-Based Classification

Malnutrition can be classified into three main categories based on etiology:

• Disease-related malnutrition (DRM) with inflammation 1

  • Chronic DRM with inflammation (cachexia) - associated with conditions like cancer, chronic infections 1
  • Acute disease- or injury-related malnutrition - characterized by strong inflammatory response 1

• Disease-related malnutrition (DRM) without inflammation 1

  • Caused by conditions that limit food intake or nutrient absorption without significant inflammation
  • Examples: dysphagia, neurological disorders, malabsorption syndromes 1

• Malnutrition/undernutrition without disease 1

  • Hunger-related malnutrition - caused by food deprivation 1
  • Socioeconomic or psychological related malnutrition - due to poverty, poor care, self-neglect 1

2. Classification Based on Chronicity

• Acute malnutrition - rapid onset, often associated with recent illness or food shortage 3
• Chronic malnutrition - develops over a longer period, often associated with persistent inadequate nutrition 3

3. Classification Based on Anthropometric Parameters

Diagnostic criteria for malnutrition in children include:

• Weight-for-height/length - indicates wasting (acute malnutrition) 4, 3
• Height/length-for-age - indicates stunting (chronic malnutrition) 4, 5
• Weight-for-age - indicates underweight (can reflect both acute and chronic malnutrition) 4
• Body Mass Index (BMI)-for-age - for children over 2 years 4

According to ESPEN criteria, malnutrition can be diagnosed by either:

• BMI <18.5 kg/m² (WHO underweight definition), or
• Combined weight loss with reduced BMI (age-dependent cut-offs) or reduced gender-dependent fat-free mass index (FFMI) 1

4. Classification Based on Severity

Severity of malnutrition can be assessed using Z-scores (standard deviations from the median of reference population):

• Mild malnutrition: Z-score between -1 and -2 4
• Moderate malnutrition: Z-score between -2 and -3 4
• Severe malnutrition: Z-score below -3 4, 3

Special Considerations in Pediatric Malnutrition

• Growth failure is a critical manifestation of malnutrition in children, seen in 15-40% of children with inflammatory conditions like IBD 1
• Micronutrient deficiencies are common in malnourished children, particularly iron, folic acid, zinc, calcium, and vitamins A, B12, D, E, and K 1
• Disease-specific manifestations vary by underlying condition, with children with chronic diseases being particularly vulnerable 6
• Double burden of malnutrition - undernutrition increasingly coexists with overweight in many regions 5

Assessment Approach

Assessment of malnutrition in children should include:

• Anthropometric measurements (weight, height, BMI) compared to reference standards 4
• Growth velocity assessment and plotting on growth charts 1
• Clinical evaluation for signs of micronutrient deficiencies 1
• Evaluation of dietary intake 1
• Laboratory assessment for nutritional deficiencies and inflammatory markers when appropriate 1

Clinical Implications

• Early detection and treatment of malnutrition are essential to prevent adverse outcomes 3
• Children with malnutrition have increased risk of serious illness and death, primarily from infectious diseases 3
• Regular nutritional screening is recommended for all children, especially those with chronic diseases 1
• Documented malnutrition should be treated promptly as it worsens prognosis, complication rates, mortality, and quality of life 1