All of the following are suggested procedures for skinfold measurements except

Skinfold thickness

Measurement of skinfold thickness, obtained using calipers, is useful in assessing and monitoring nutritional status in patients who cannot be weighed, and also has a place in epidemiological surveys. However, the technique is prone to large variations, both within and between observers. The imprecision arises in identification of the exact location for measurement; the way the skinfold is picked up; the way the calipers are placed on the fold; the compression of the fold by the calipers and the exact timing of the reading. Some improvement in performance may be achieved by taking the mean of three readings, usually on the left (or non-dominant) side. As with circumference measurements, the presence of oedema at the measurement site may be a further confounding factor.

A variety of sites have been used for skinfold measurement, but the most common are triceps, biceps, subscapular and suprailiac. Equations are available for calculation of total body fat from these measurements (usually for research purposes), but this assumes that subcutaneous fat reflects total body fat, which is not always the case: obese men tend to lay down more intra-abdominal fat than women, and visceral fat and subcutaneous fat have been shown to be biologically distinct. In clinical practice, body weight is more useful than skinfold thickness in the management of obesity, but in undernourished patients the latter may be useful. Age- and sex-related reference standards are published (e.g. for triceps skinfold thickness) and so measurement at presentation may identify severe malnourishment: a triceps skinfold of < 5 mm almost always reflects low body fat stores. Serial measurements can help in monitoring nutritional support but, again, short-term changes are more likely to reflect imprecision in measurement than sudden changes in fat stores.

Anthropometry

Triceps and subscapular skinfold thicknesses provide an index of body fat and midarm muscle circumference provides a measure of muscle mass. Although these measurements seem to be useful in population studies, their reliability in individual patients is less clear. The most commonly used standards for triceps skinfold thickness and midarm muscle circumference are not universally applicable. The use of these standards to identify malnutrition in many patients is problematic because of the restricted database and the absence of correction factors for age, hydrational status, and physical activity on anthropometric parameters. Several studies have demonstrated that 20–30% of healthy control subjects would be considered malnourished based on these standards. These measurements do not reflect muscle and fat mass in sick patients, especially those in ICU and those with liver and renal disease, where edema is a major problem in assessing skin folds and arm circumference.

C Adipose Tissue Characterization

Clinical research indicates characteristic changes in skin-fold thickness at particular sites among individuals with certain forms of lipodystrophy, but these vary over a wide range and may not be definitive or pathognomonic in specific patients. Similarly, noninvasive imaging using computed tomography or magnetic resonance imaging (MRI) and quantification of subcutaneous and visceral fat depots show significant mean differences between individuals with particular molecular subtypes of lipodystrophy, but there are no clinical standards for these measurements, and the range of individual values is wide even among individuals with the same molecular lesion. We have found that the mid-thigh is the most specific site for depletion of adipose tissue across several forms of lipodystrophy; this could be the single most useful site for noninvasive visualization of subcutaneous fat. However, noninvasive imaging is not currently recommended for lipodystrophy diagnosis, although selected images—when compared to appropriate controls—can be of academic interest and, if lipoatrophy is obvious radiologically, might be helpful for diagnosis. We recently showed that among female patients with partial lipodystrophy, no simple clinical anthropometric measure correlates well with visceral adipose tissue mass quantified on MRI scanning, while BMI correlates well with subcutaneous adipose stores.4

Abdominal ultrasound examination can sometimes document gross hepatosteatosis, which is a common feature in many lipodystrophy types. More advanced noninvasive imaging tools include spectroscopic evaluation to quantify hepatic and myocellular accumulations of adipose tissue.5

Skinfolds

A reasonably valid method is the measurement of skinfold thickness to assess (subcutaneous) body fat and/or body fat distribution. As subcutaneous fat distribution varies between individuals, it is advisable to measure the thickness of more than just one skinfold to get insight in the amount of subcutaneous fat. Yet often only the thickness of the triceps skinfold is measured. There is a crude relation between subcutaneous fat and total body fat, hence skinfold thickness allows prediction of total body fat (Durnin et al., 1974). The prediction error is, however, considerable and often exceeds 5 percentage points. The prediction formulas are age, gender and ethnicity dependent. Generally, for the same skinfold thickness, women have more total body fat than men and elderly have more total body fat than younger adults. Skinfold measurements per se are also useful to follow up without converting the thickness to total fat.

Measuring skinfold thickness reliably requires skills and measurements are more difficult to take in elderly, as it is more difficult to distinguish between fat and muscle tissue. Measurements are also difficult to take in bed-ridden persons. Sometimes skinfold thickness is used in combination with body circumferences to adjust for subcutaneous fat. For example, the upper arm circumference as indicator for upper arm muscle could be biased towards too high values by large amounts of subcutaneous fat.

Anthropometric Techniques

Anthropometric indices used to measure fat patterning include skinfold thicknesses, circumferences, sagittal diameter, and ratios such as waist-to-hip, waist-to-thigh, waist-to-height, and subscapular-to-triceps skinfolds. Skinfold thicknesses and skinfold ratios have not been found to be very well correlated with metabolic measurements or with visceral fat and are not recommended for use as indicators of fat patterning. Numerous equations using combinations of anthropometric measurements to predict the amount of visceral fat have not offered substantial improvement over the simpler measurements, and an accurate equation has yet to be developed.

Waist circumference (WC) alone and waist-to-hip ratio (WHR) are the most popular anthropometric methods used to measure fat distribution in both clinical and community settings. Both measures are correlated with visceral fat, with a correlation coefficient (r) generally ranging from 0.5 to 0.8. It is problematic that there is no uniform method of defining the location at which the waist and hip measurement should be assessed (Table 1). Waist circumferences measured at four sites (immediately below the lowest rib, at the narrowest point, midpoint between the lowest rib and the iliac crest, and immediately above the iliac crest) have been compared and found to differ from each other. Other work has shown that the highest correlations with risk factors were obtained when WHR was calculated as the waist measured at the point midway between the lower rib margin and iliac crest (approximately 1 inch (∼2.5 cm) above the umbilicus) or when the waist was measured at the umbilicus and hips measured at the widest point of the buttocks. Although two different waist measurements have been demonstrated to perform equally well, the bony landmark measurement (the point midway between the lower rib margin and iliac crest) may be preferred since the umbilicus may shift position when an individual gains or loses weight. The World Health Organization (WHO) has recommended measuring the waist at the midpoint between the lowest rib and the iliac crest, whereas immediately above the iliac crest is the site recommended by the National Institutes of Health (NIH).

Table 1. Anatomical locations used to measure waist and hip circumferences

Waist circumferenceOne-third between the xyphoid process and umbilicusNarrowest part of torsoMidway between xyphoid process and umbilicusMidway between lower rib and iliac crestOne inch (∼2.5 cm) above umbilicusLevel of umbilicusLevel of iliac crestImmediately below the lowest ribImmediately above the iliac crestHip circumferenceLargest horizontal circumference around the buttocksLevel of iliac crestMaximal circumference between superior border of iliac crest and thigh region 4 cm below superior iliac crest

Sagittal diameter, the height of the abdomen measured with the subject in the supine position, can be measured anthropometrically or by imaging. Figure 3 shows a technique for the anthropometric measurement of sagittal diameter using a caliper. Measurement is usually taken at the largest supine anteroposterior diameter between the xyphoid process and umbilicus. Some studies have found sagittal diameter to be a better indicator of visceral fat than WHR. Correlations between sagittal diameter and amount of visceral fat range from r = 0.51 to r = 0.87, with higher correlations occurring when sagittal diameter is measured using imaging techniques. In general, correlations tend to be higher in men than women.

The Anthropometric Measures, Biochemical Data, Clinical Assessment, Dietary Data and Economic Assessment (the ABCDEs)

1.

Anthropometric data. Body weight, height, skinfold thickness, and waist circumference provide a general nutritional status of the individual. These data are easy to obtain and can be collected from large populations without much financial burden by trained health care personnel. These data can then be compared to age- and gender-specific standards or previous measures from the same individual (longitudinal measures). The longitudinal measures will reveal the trend of a person's overall health status. Even though obesity is a major health hazard in the general population and in the elderly, weight loss is also common in this population and is associated with reduced functionality and increased mortality (Gazewood & Mehr, 1998; Huffman, 2002). The most frequently reported anthropometric data is BMI, which is based on body weight and height [body weight (kg)/height (m)2]. BMI has been widely used to indicate the disease risks. BMI is classified into the categories as shown in Table 14.3.

Table 14.3. Classification of Overweight and Obesity

Disease Risk Relative to Normal Weight and Waist CircumferenceBMI &gt;102 cmObesity Class Men &lt;102 cmWomen &lt; 88 cm&gt;88 cmUnderweight&lt;18.5––Normal18.5–24.9––Overweight25.0–29.9IncreasedHighObesity30.0–34.9IHighVery high35.0–39.9IIVery highVery highExtreme obesity≥40.0IIIExtremely highExtremely high

Biochemical data. These measurements are usually obtained from an individual's blood, urine or feces samples. The concentrations of nutrients, metabolic byproducts of these nutrients, as well as hormone and some enzymes, can be measured from these samples. Some commonly used biochemical data include blood or urine glucose (as an indicator for diabetes), blood lipid levels (as indicators for cardiovascular diseases), red blood cell count, hemoglobin level or hematocrit percent (as indicators for anemia), blood urea nitrogen (for kidney function), and stool blood (for colorectal cancer), etc. Medical equipment and trained personnel are required to operate the necessary equipment and interpret the results.

Clinical assessment. This assessment, performed by health care professionals, examines physical signs of nutrient-related diseases. Every part of the body, such as eyes, hair, neck, fingernails, skin, etc., can provide a clue for nutrient deficiencies or toxicity. Poor wound healing indicates a potential vitamin C deficiency. Prolonged bleeding signals vitamin K deficiency. Trained personnel with knowledge in nutrients and their functions are required to make these observational data accurate.

Dietary data collection to confirm the dietary issues. All the anthropometric, biochemical, and clinical data only provide a clue for the potential diet-related problems. In order to accurately identify the sources of the health problems, a dietary history is required. There are several assessment methods to obtain dietary records. The most commonly used includes: a 24-hour dietary recall; three-day dietary recalls (two weekdays and one weekend day); and the food frequency questionnaires. The 24-hour recall only provides food items consumed in a 24-hour period, hence deviation to the individual's typical food intake is high. Due to variations in daily intake, a three-day 24-hour recall is more representative of an individual's typical intake pattern. One example of a 24-hour dietary record is shown in Table 14.4.

Table 14.4. Example of a 24-hour Dietary Recall

FoodMethod of PreparationMethod of Cooking or BrandAmount ConsumedBreakfastBreadWhole wheatToasted2 slicesButterUnsalted1 tablespoonEggsw/1 T butterScrambled2Mid-morning snackAppleFresh1 mediumLunchPepperoni pizzaThin crustTony's2 slices of a medium pizzaSoft drinkRegular colaFaygo12 ozAfternoon snackChocolate chip cookies3.5″ diameterPepperidge Farm1 pieceDinnerChicken breastSkin and fat removedRoasted½ of a breastBroccoli floweretsSteamed with 1 T butter1 cupDinner roll3″ diameterBaked1Ice cream, vanillaEddy's0.5 cupBefore bed snackMilkSkimBorden's8 oz

The dietary recall is only necessary when the elderly still have the ability to consume ordinary foods by mouth. The recall procedure may pose some difficulties for the elderly. They must be able to see, read, and write in order to record the food items. With the memory loss common in the elderly, the records may not be accurate. Hence, sometimes it is the caregiver's responsibility to record the food intake in order to make the records meaningful. This complication can also decrease the accuracy if the caregiver is overburdened or not present for all eating episodes.

Food frequency questionnaires ask individuals how many servings of the following foods they consume in a typical day/week/month: breads, cereals or grain products; vegetables; fruits; meat, poultry, fish or alternative protein products; dairy products; fats; oils; and sweets. The Block Food Frequency Questionnaire is the most validated and frequently used questionnaire. The full questionnaire contains 110 questions and takes about 30–40 minutes to complete. The brief version contains 70 questions and takes about 15–20 minutes to complete, although it may underestimate the nutrient intake levels (//www.nutritionquest.com/products/questionnaires_screeners.htm). The food frequency questionnaire in combination with dietary recall provides a more accurate description of each individual's nutrient intake patterns. The USDA maintains a database for the analysis of food composition (//www.ars.usda.gov/Services/docs.htm?docid=5720). There are other software programs to be used for diet analysis, such as Food Processor SQL (ESHA Research, Salem, OR).

Economic assessment. The latest survey in 2007 indicates that 3.6 million elderly (9.7%) are living below the poverty level (//www.census.gov/prod/2008pubs/p60-235.pdf) and another 2.4 million living at “near-poor” level. Financial condition affects an individual's ability to purchase and prepare foods (Klesges et al., 2001). This is especially important when examining the nutritional status of the elderly because most of the elderly are living on a fixed income and may not be able to afford purchasing fresh fruits or vegetables as well as other high-quality foods.

Anthropometry

For routine clinical use, anthropometric measurements (circumference measures and skinfold thickness) have been preferred due to ease of measurement and low cost. Waist circumference and the waist-hip ratio measurements are commonly used surrogates of fat distribution, especially in epidemiology studies. Waist circumference is highly correlated with visceral fat and was recently included as a clinical risk factor in the definition of the metabolic syndrome. Specifically, waist circumferences greater than 102 cm (40 in) in men and greater than 88 cm (35 in) in women are suggestive of elevated risk.

Skinfold thicknesses which estimate the thickness of the subcutaneous fat layer are highly correlated with percent body fat. Because the subcutaneous fat layer varies in thickness throughout the body, a combination of site measures is recommended, reflecting upper and lower body distributions. Predictive percent body fat equations based on skinfold measures are age and sex specific in adults and children.

Which of the following is a recommendation when assessing skinfold measurements?

Which of the following is the best way to measure muscular endurance?

Which test below is the best measurement of muscular strength?

Which of the following is an example of an indirect method of body composition?