Anthropometry literally means human measurements. It derives from the Greek words “anthropos” meaning “human”, and “metron” meaning “measure”. Anthropometric measurements are used to assess the size, proportions and composition of the human body.
Examples of anthropometric measurements
Anthropometric measurements can be combined with each other or with other information to calculate anthropometric indices. These indices can be used to make inferences about body composition, growth and development.
Examples include body mass index (BMI), which adjusts weight for height to infer "fatness" or "thinness". Waist-to-hip ratio and waist-to-height ratio are used as to infer central distribution of body fat.
Examples of anthropometric indices
Anthropometric measurements can be adjusted for non-anthropometric parameters (e.g. age and sex) to infer childhood growth and states of under or over-nutrition. These adjustments can be performed internally, using means and standard deviations from the study population at hand, or externally, by comparison against published growth reference data. The resulting values are expressed as percentiles or Z-scores (or standard deviation scores), which quantify the extent to which an individual deviates from the population average.
In epidemiological studies, anthropometry is often used to evaluate disease risk as well as assessing body composition changes.
Anthropometric measurements can provide valuable information about health and development status, either as standalone or as combined measurements. For instance, waist circumference is often used as an indicator of central obesity, whereas changes in height or head circumference over time reflect rates of somatic growth.
Anthropometry can also be used to evaluate the nutritional status of an individual or a population, such as obesity resulting from over-nutrition or emaciation caused by malnutrition. Simple anthropometric measures are often implemented as proxy measures of overall and central fat in epidemiological studies.
Threshold values commonly used to indicate nutritional status
Note: in children, nutritional status is typically inferred by percentile thresholds
Specific characteristics of anthropometric methods will be discussed on specific pages, but they are generally:
These methods generally demonstrate good feasibility, but they do require:
The estimation of body composition is an important component of health and fitness assessments in individuals and populations. In particular, the amount and distribution of fat and lean mass are important for health throughout the lifespan.
Levels of human body composition
Body composition can be studied at different levels of complexity (as shown in Figure A.1.1 and Table A.1.1):
Figure A.1.1 The five body composition levels.
Abbreviations: Extracellular solids (ECS) and extracellular fluid (ECF).
1Nitrogen and other elements
2Minerals, carbohydrates and other molecules
Source: adapted from .
Table A.1.1 Examples of methods for measuring body composition by level.
|Level||Information obtained||Examples of methods|
|Atomic||Elemental: O, C, Ca, P, S, Cl, Na||Whole body counting of total body potassium Neutron Activation analysis Isotope dilution|
|Molecular||Water, protein, lipid, minerals and glycogen||Isotope dilution, Magnetic Resonance Spectroscopy (MRS), multi-component models, Dual-Energy X-ray Absorptiometry (DEXA)|
|Cellular||Fat, cell mass, extracellular fluids, extracellular solids||Isotope dilution, Bioelectrical Impedance Analysis (BIA)|
|Functional /Tissue-organ||Adipose, bone, muscle, organ||Computer Tomography (CT), Magnetic Resonance Imaging (MRI), ultrasound, near Infrared Interactance, DEXA|
|Whole body||Circumferences, linear dimensions, lengths, skinfolds, body volumes and body surface area||Anthropometry, densitometry, Bioelectrical Impedance Analysis (BIA), 3D photonic scan|
There is no single method that allows for the measurement of all tissues and organs, and no method is free from error. The ultimate method for assessment of body composition is chemical analysis of the human cadaver, which is clearly infeasible in most settings and there are no in vivo techniques that meet such high accuracy. Multi-component models (also known as multi-compartment models) are considered to be the reference method for the assessment of body composition (discriminating fat mass from fat free mass), and other methods are generally validated against these techniques.
When selecting a method, the following factors should be considered:
Research question and clinical application:
Feasibility and Resources:
Assessment of body composition can use either direct methods, which provide output in the desired units (e.g. fat free mass in g), or indirect methods, which provide anthropometric parameters as proxy measures of body composition. As is the case for other anthropometric outcomes, body composition data can be combined with other data to derive indices (e.g. lean mass index).
The following methods can be used to directly, or indirectly, assess body composition. They are categorised according to their likely study location.
Laboratory (or clinic) based methods: