Anthropometric Measurements: Importance and Uses Explained

What Are Anthropometric Measurements?

A second technique that may help reveal nutrition problems is taking anthropometric measures such as height and weight. National nutrition surveys gather information about the population's dietary, nutritional, and related health status by examining individuals using anthropometric measurements. Anthropometric measurements are widely used in the assessment of nutrition status, particularly when a chronic imbalance between intakes of protein and energy occurs. Such disturbances influence the patterns of physical growth and the relative portions of body tissues including body fat, lean body mass or muscle tissue, and total body water. Anthropometric measurements allow the assessment of growth patterns or the presence of over-nutrition or undernutrition. 

How Anthropometric Measurements Work

Anthropometric measurements pick up on the problem only after it causes symptoms. The assessor compares a person’s measurements with standards specific to sex and age or with previous measures on the same individual. Measurements are taken periodically and compared with previous measurements revealing patterns and indicating trends in a person’s overall nutrition status, but they provide little information about specific nutrients. Instead, measurements out of line with expectations may reveal such problems as growth failure in children, wasting or swelling of body tissues in adults, and obesity—conditions that may reflect energy or nutrient deficiencies or excesses. Most anthropometric methods used to assess body composition are based on a model in which the body consists of two chemically distinct compartments: fat and fat‐free mass (e.g. skeletal muscle, non‐skeletal muscle, soft‐lean tissues, and the skeleton). Therefore, variations in the amount and proportion of fat mass versus fat‐free mass, including muscle, can be used as indices of nutritional status.

Types of Anthropometric Measurements:

The use of comparative standards for anthropometrics is encouraged. Body composition data can also be part of anthropometric measurements. Such measurements are routinely collected in clinical practice and, in most cases, no sophisticated equipment is needed. As a result, anthropometry could easily be perceived, incorrectly, as simplistic and mundane. However, careful anthropometric evaluation using standardized measurement protocols followed by reasonable interpretation of results, including understanding methodological limitations, can provide quick, meaningful, cost‐effective information about an individual’s nutritional status and health risk.

Here are the key types of anthropometric measurements:

• Body Weight
• Body Height (or Length)
• Body Mass Index (BMI)
• Waist Circumference and Waist-to-Hip Ratio
• Head Circumference
• Skinfold Thickness

Body Weight

Body weight is a key anthropometric measurement used to assess an individual's overall health and nutritional status. It offers crucial insights into various health conditions and is often combined with other measurements to evaluate growth, development, and body composition. In clinical settings, healthcare providers closely monitor body weight, as changes can indicate shifts in body water due to illness. Notably, involuntary weight loss may signal protein-energy malnutrition (PEM).

• Always Measure, Never Rely on Self-Reports: Self-reported weights are often inaccurate. If weight is self-reported, document it clearly.
• Use Accurate Scales: For valid measurements, use well-maintained, calibrated beam balance or electronic scales. Avoid bathroom scales for clinical use due to their inaccuracy. Weighing Infants: Use a scale with a large tray that supports up to 40 pounds and offers precise graduations (1/2 ounce or 10-gram increments). Weigh infants without clothes or diapers for accuracy, and minimize movement.
• Weighing Standing Children: Use beam balance or electronic scales with a platform large enough for children to stand comfortably.
• Consistent Measurement Conditions: For reliable results, measure weight at the same time each day (ideally before breakfast), in similar clothing, after voiding, and with the same scale. Record weights to the nearest 1/4 pound or 0.1 kilogram.
• Special Equipment for Bedridden Individuals: Utilize scales built into hospital beds or specialized scales designed for those who cannot stand.

Body Height

Standing height in adults and height or length in children are combined with other anthropometric variables, usually weight, to assess nutritional status and estimate energy requirements. Poor growth in children can be a sign of malnutrition. In adults, height measurements alone do not reflect current nutrition status but can be used for estimating a person’s appropriate body weight or energy needs. Length is measured in infants and children younger than 24 months of age, and height is usually measured in older children and adults. Length can also be measured in adults and children who cannot stand unassisted for physical or medical reasons. Higher values are obtained from supine measurements than from vertical height measurements due to gravity.

• Always Measure, Never Rely on Self-Reports: Self-reported heights are often inaccurate. If height is self-reported, be sure to document it as such.
• Measuring Infants and Young Children: To measure the length of infants and young children accurately, use a measuring board with a fixed headboard and a movable footboard. One person should hold the child’s head against the headboard while the other straightens the legs and adjusts the footboard to the feet.
• Measuring Adults: Use a wall-mounted, non-stretchable tape or board. Ensure the person stands straight with heels together, back against the wall, and head level. Use a flat object to mark the top of the head and measure to the nearest 1/8 inch or 0.1 centimeters.

Body Mass Index (BMI)

The formula most frequently used in epidemiological studies is the body mass index (BMI), which is weight in kilograms divided by the square of the height in metres.

BMI = weight (kg) / (height (m) ^ 2)

Body Mass Index (BMI) is closely related to fat mass measurements adjusted for height in middle-aged adults. The World Health Organization classifies BMI into 6 categories, ranging from severe thinness to obesity class III, with a normal range defined as 18.50–24.99 kg/m². While BMI is a useful tool for identifying individuals as ‘obese’ or ‘overweight,’ it has limitations, as it does not differentiate between fat mass and lean mass. Although a higher BMI indicates more body fat and an increased risk of obesity-related illnesses, the exact nature of this relationship, especially in children, remains uncertain.

Why use BMI?

In nutrition support, BMI can provide a quick overview of nutritional status that impacts on clinical risk. BMI is an attractive measure because it is an easy, cheap and non‐invasive means of assessing excess body fat. Prior to the application of BMI, clinicians referred to ‘ideal’ weight tables, which were derived from the weight–height tables provided by the Metropolitan Life Insurance Company (1959), based on subsequent mortality of insured adults in the USA and Canada. However, prospective epidemiological data confirmed the impreciseness of the term ‘ideal’ even within a North American population (despite attempts to sharpen this with measures of body frame size), and its inapplicability when applied in a global context. BMI has been used widely around the world, permitting comparisons between areas, across population sub‐ groups and over a long period.

Waist Circumference and Waist-to-Hip Ratio

An anthropometric measurement used to assess a person’s abdominal fat. The waist circumference was introduced into public health thinking very specifically in 1996, in the SIGN obesity guideline, not as a diagnostic criterion, but as a tool for health promotion. The BMI was too complex and conceptually problematic for health promotion among the general public, even with the weight vs. height charts to compute it. Research found that waist circumference was in fact a marginally better indicator of both total body fat and associated health risks than BMI, in addition to being simpler. A person’s waist circumference is a good indicator of central obesity and its associated health risks. In general, women with a waist circumference of greater than 35 inches (88 centimeters) and men with a waist circumference of greater than 40 inches (102 centimeters) have a high risk of central obesity–related health problems; the average waist circumference among US adults is 38 inches for women and 40 inches for men. To simplify the message, waist circumference should be less than half of a person’s height; the waist-to-height ratio is also a useful measure of disease risks. As waist circumference increases, disease risks increase.

Some researchers use the waist-to-hip ratio as an indicator of disease risks. The ratio requires another step or two (measuring the hips and comparing that measurement to the waist measurement), but it does not provide any additional information. Therefore, waist circumference alone is the preferred method for assessing central obesity in a clinical setting. Waist‐to‐hip ratio (WHR) is associated with increased numbers of CVD events, but how much additional information it adds to BMI is dependent on age and population. In a meta‐analysis of more than 258,000 participants and 4300 CVD events, a 1 cm increase in WC increased the risk of a cardiovascular event by 2%, while a 0.01 unit increase in WHR increased the risk by 5%, with similar effects in men and women.

What Are the Healthy Waist-to-Hip Ratios for Men and Women?

A healthy waist-to-hip ratio (WHR) is crucial for assessing overall health and risk for obesity-related diseases. For women, a WHR of 0.7 is generally associated with good health, while for men, a WHR of 0.9 indicates a similar healthy status. Ratios above these thresholds can signal potential health issues:

• For Women: A WHR greater than 0.8 suggests central obesity and a higher risk of diabetes and hypertension. Values above 0.8 indicate a greater risk of heart disease.
• For Men: A WHR exceeding 1.0 is a strong indicator of central obesity, which increases the risk of related health conditions such as diabetes and hypertension. WHRs above 0.95 also heighten the risk of heart attack. Maintaining a WHR within these healthy ranges helps manage the risk of various health issues and promotes overall well-being.

Head Circumference

A head circumference measurement helps to assess brain growth and malnutrition in children up to 3 years of age, although this measure is not necessarily reduced in a malnourished child. Head circumference values can also track brain development in premature and small-for-gestational-age infants. To measure head circumference, encircle the largest circumference measure of a child’s head with a non-stretchable measuring tape. Place the tape just above the eyebrows and ears and around the occipital prominence at the back of the head.

Skinfold Thickness

Skinfold thickness, measured with calipers, provide a good estimate of total body fat and a fair assessment of the fat’s location. Most body fat lies directly beneath the skin, and the thickness of this subcutaneous fat correlates with total body fat. In some parts of the body, such as the back of the arm over the triceps muscle, this fat is loosely attached. If a person gains body fat, the skinfold increases proportionately; if the person loses fat, it decreases. Skinfolds are useful in the estimation of fatness in children, for whom standards have been published. However, the measurements are more difficult to make in adults (particularly in the very obese), are subject to considerable variation between observers, require accurate calipers and do not provide any information on abdominal and intramuscular fat. In general, they are not superior to simpler measures of height and weight.

The Fun of Anthropometric Measurements

Anthropometric measurements are more than just numbers—they're like a backstage pass to your body's health story! From tracking your growth with precision to using cool tech like 3D body scanners, these measurements reveal the secrets of your body's composition and wellness. Imagine getting to know how your body changes over time with just a few simple tools. Whether you're measuring height, weight, or waist-to-hip ratio, anthropometric measurements help you understand and optimize your health in an engaging and insightful way.

Closing Remarks

Thank you for reading our exploration of anthropometric measurements! These essential tools offer valuable insights into body composition, growth, and overall well-being. By mastering measurements like body weight, BMI, waist-to-hip ratio, and skinfold thickness, you gain a clearer understanding of nutritional status and health. Employing accurate techniques and reliable equipment is crucial for effective health monitoring. We appreciate your interest and look forward to bringing you more articles to support your wellness journey!