Anthropometry

• Nutritional Anthropometry


  Measurements of the variations of the physical dimensions and the gross composition of the human body at different age levels and degrees of nutrition
• Generalized Scheme of the Development of a Primary Nutritional Deficiency

  1. Sequence will vary for different nutrients

  2. Sequence of reversal in response to re-supply of the nutrient
• An understanding of the time sequences in depletion/repletion of specific nutrients of concern is crucial in selecting a methodology that will provide the information required to evaluate nutritional impact of various types of programmes

  
• Anthropometric methods


  Involve measurements of the physical dimensions and gross composition of the body
• Objectives of Anthropometric Measurements

  • Identify mild, moderate, severe states of malnutrition
  • Identify individuals and populations at risk to malnutrition
  • Evaluate changes in nutritional status over time
  • Serve as proxy indicators of constraints to human welfare
  • Monitor nutritional problems
  • Evaluate the impact of interventions designed to enhance nutrition, health, economic and/or environmental factors
• Advantages of anthropometry measurements in nutritional assessment

  • Simple, safe, noninvasive techniques
  • Inexpensive equipment required
  • Relatively unskilled personnel can perform the measurement procedures
  • Methods can be precise and accurate
  • Retrospective information is generated on past long-term nutritional history
  • Mild to moderate undernutrition, as well as severe states of under- or overnutrition, can be identified
  • Changes in nutritional status over time and from one generation to the next can be evaluated
  • Screening tests that identify individuals at high risk to under- or overnutrition can be devised
• Limitations of anthropometric measurements

  • Relatively insensitive to detect changes in nutritional status over short periods of time
  • Cannot identify any specific nutrient deficiency
  • Non-nutritional factors can lower the specificity and sensitivity
• Two types of anthropometric measurements


  • Body size
  • Body composition
• Body size measurements

  Most widely used measurements of body size are stature, weight, and head circumference
• Body composition measurements

  Based on the classical "two component model" - fat mass and fat free mass
• Skinfold thickness measurements are used to estimate the size of the subcutaneous fat deposit, which provides an estimate of total body fat</b>
• Measurement of waist circumference is used to estimate the distribution of body fat, with the measurement of waist circumference used increasingly as a proxy for the amount of intra-abdominal visceral fat
• Waist circumference is recommended for use in population studies as well as in clinical practice for the evaluation and management of patients with overweight or obesity
• Uses of anthropometry

  • For individuals in low-income countries
  • For individuals in clinical settings
  • At the population level
  • In public health emergencies
• Requirements for nutritional anthropometry

  • Standard equipment
  • Accuracy / Consistency
  • Appropriate techniques
  • Training & Standardization
  • Correct assessment of age
  • Reference values
  • Classification
• Measurements can be done for all age groups and in different settings
• Cut-off values (and trigger levels) for public health significance

  • Stunting
  • Wasting
  • Overweight
• Body size measurements

  • Head circumference
  • Recumbent length
  • Standing height
  • Knee height
  • Arm span
  • Weight
  • Elbow breadth
• If by mistake a child aged <2 year was measured by his/her height instead of length, or vice-versa a child > 2 year measured by his/her length and not height, a correction factor of 0.7 cm will be deducted from length to obtain height measurement, and vice-versa
• Weight


  Represents the sum total of the four chemical compartments of the body: muscle protein or fat free mass, fat, water, and bone mineral mass
• Elbow breadth


  A measure of frame size, less affected by adiposity and highly associated with lean body mass and muscle size
• Equipment have to be calibrated regularly, using standard weights, metal rods of known length, and calibration blocks of varying widths
• Body composition


  An assessment of body composition through the anthropometric methods considers the body as consisting of two distinct compartments: the fat and the fat-free mass
• Measurements of thigh circumference and mid-upper-arm circumference (MUAC) can be used to assess skeletal muscle mass
• Measurement of MUAC is useful for young children < 5y in emergency settings such as famines and refugee crises, as changes in MUAC tend to parallel changes in muscle mass
• Skinfold Thickness


  The size of the subcutaneous fat depot provides an estimate of total body fat
• Assumptions in the estimation of total body using skinfold thicknesses include that the thickness of the subcutaneous adipose tissue reflects a constant proportion of the total body fat, and the sites represent the average thickness of the subcutaneous adipose tissue
• Common Sites for Skinfold Measurement

  • Triceps
  • Biceps
  • Subscapular
  • Suprailiac
  • Midaxillary
• Combination of triceps skinfold and mid-upper-arm circumference

  Can be used to estimate mid-upper-arm fat area and mid-upper-arm muscle circumference or area, surrogates for total body fat content, and muscle mass, respectively
• Waist-Hip Ratio (WHR)


  An index of the distribution of body fat which can be measured more precisely than skinfolds, and appears to be a stronger independent risk factor for risk of myocardial infarction, stroke and premature death than BMI, especially among men
• Regardless of overall obesity, central obesity is considered a risk factor in the development of certain diseases, such as coronary heart disease and type 2 diabetes mellitus
• The accuracy of waist and hip circumference measurements depends on the tightness of the measuring tape, and on its correct positioning
• Waist circumference alone could replace waist–hip ratio and BMI as a single risk factor for all-cause mortality
• Waist-Hip Circumference Ratio (WHR)


  Waist circumference and waist-hip ratio are both related to increased risk of all-cause mortality, throughout the range of adult BMIs
• Waist-Hip Circumference Ratio (WHR)


  • Waist circumference and waist-hip ratio are strongly predictive in young and middle aged adults compared to older people and those with low BMI
• Waist-Hip Circumference Ratio (WHR)


  Waist circumference alone could replace waist-hip ratio and BMI as a single risk factor for all-cause mortality
• If the difference between the two measurements exceeds 1 cm, the two measurements should be repeated
• Moderate WHR


  0.9 or less in males and 0.85 or less in women (according to the World Health Organization)
• A WHR of 1.0 or greater raises the risk of heart disease and other diseases connected to being overweight in both men and women
• Mid-upper arm circumference (MUAC)


  Reflects total body muscle mass and muscle tissue changes