2. ASSESSMENT OF NUTRITIONAL STATUS
___________________________________________________________________
Robert Karp, MD
Downstate medicalm Center
Brooklyn, NY
Grace HoYoun Lee, MS
Institute of Human Nutrition
School of Public health
Columbia University
New York, NY
Nancy Ngai, MD
Downstate medicalm Center
Brooklyn, NY
___________________________________________________________________
PRE-TEST
Q1. True or False. Serum albumin level is a good indicator of early protein-energy malnutrition (p-e.m.).
Q2. Types of malnutrition found in populations include:
a. Caloric undernutrition
b. Specific nutrient deficiencies
c. Caloric overnutrition
d. Nutrient imbalance
e. All of the above
Q3. Select the false statement.
a. The poverty level is defined as 3 times the cost of the U.S.
Department of Agriculture’s Low Cost Food Plan
b. Food insecurity is common for those families with incomes
between 1 and 3 times the poverty level
c. The appearance of discretionary income (funds available
after obtaining necessities) has a profound effect on
nutritional status
d. Malnutrition only affects the poor
Q4. Chronic malnutrition in childhood is not associated with may cause
a. Growth failure
b. Hair changes
c. Skin changes
d. Malignant diseases later in life
e. It’s associated with all of the above
Q5. True or False. Overweight and obese children have low circulation levels of insulin.
OBJECTIVES
This introduction to assessment of nutritional status will prepare
users to:
1. Appreciate the impact of social environment on nutritional status
2. Define malnutrition in four overlapping categories
3. Develop risk assessment strategies to identify malnourished
children
4. Recognize the impact of negative nutrient balance on nutritional
status
5. Establish a protocol for assessing nutritional status of children
FACILITATOR’S PREPARATION
1. Jelliffe DB. Assessment of Nutritional Status of the Community. World Health Organization, 1963.
2. Olson C, Rauschenbach BS, Frongillo EA Jr, Kendall A. Factors contributing to household food insecurity in a rural upstate New York county. Family Economics and Nutrition Review. 1997;10:2 17.
3. Herbert V. Folic acid. In: Modern Nutrition in Health and Disease. 9th Ed. Baltimore:Williams & Wilkins, 1999:433-46.
4. Solomons NW. International priorities for clinical and therapeutic nutrition in the context of public health realities. In: Modern Nutrition in Health and Disease. Baltimore:Williams & Wilkins, 1999:1769-82.
5. Karp RJ. The ‘at-risk' concept as applied to the identification of malnourished hospitalized patients: How a two step process improves clinical acumen. Nutrition in Clinical Practice. 1988;2:150-15.
6. Frongillo EA, et al. Low family income and food insufficiency in relation to overweight in US children: is there a paradox?. Arch Pediatr Adolesc Med. 2001 Oct;155(10):1161-7
7. Frisancho AR. Triceps skin fold and upper arm muscle size norms for assessment of nutritional status. Am J Clin Nutr. 1974;27:1052.
INTRODUCTION
Until recently, short stature in a population has been ascribed to “racial characteristics,” that is, the growth of parents influencing the growth of their children. It was thought, for example, that members of different racial groups have different potentials for growth. As the 1962 edition of the text Pediatrics states:
“It is certainly true that there are tall and short races and nations. The question may well be asked, however, whether postnatal influences, such as better nutrition and less illness, do not seriously obscure that this difference is heredity.” (p4)
Subsequent observations with large population groups (the older view may be correct for smaller tribal groups such as the African Bantu) suggest that a reversal of concern should be made in assessment of nutritional status. Widespread differences in growth may obscure the impact of deteriorated services to a community including inadequate food, clean water, sanitation, and access to effective medical services.
This section of the Teacher's Guide will provide the reader with a framework for recognizing what is known about assessing health and nutrition and an ability to incorporate new conceptualizations for evaluation. As much or more than what happens within families (the “microsocial” environment), the occurrence of malnutrition in its various forms differs greatly according to the economic development of a society as a whole and how much that society is willing to invest in resources serving children and families (the “macrosocial” environment). We will consider overlapping categories of malnutrition and how to identify them effectively using risk assessment strategies.
BACKGROUND
The field of "Nutrition," in its broadest sense, is the study of metabolism, diet and nutritional status. The last of these is a set of outcome measures taken to establish how the interaction of metabolism and diet affect what can be seen or measured objectively. “Normality” in nutritional status assessment is never a fixed point. Rather, it is contained within a distribution of measurements. The Recommended Daily Allowance (RDA) in assessment of diet quality represents normality at two Standard Deviations above mean intake for a hypothetically well-nourished population, e.g., children 3 years of age to adolescence, or pregnant women. (See figure 1)
Figure 1. - RDA
TEACHING CAPTION: RDA is set at two standard deviations above mean intake for a healthy reference population. “Average Intake” and “Minimum Daily Intake” standards are archaic and have no place in nutritional recommendations as they leave some individuals with inadequate nutrient intake.
Intakes at RDA levels were set for prevention of the classic nutrient deficiency diseases such as rickets and scurvy. Moreover, what we mean by “well-nourished” is a phenomenon highly influenced by time and place. For example, measures of serum cholesterol up to 300 mg/dl were considered “normal” through the 1980s. Having glistening layers of fat on the body has been desired in populations with a history of starvation.
One should not equake "NORMAL" = measures within 2 standard deviations of the mean in a Gaussian distribution with "NORMAL" = healthy.
An alternative methodology for assessing normality, discussed more fully in Nutrition Notes, [Hyperlink] is to consider the likelihood of disease or dysfunction later in life or the consequences of having insufficient storage of nutrient. This concept informs the “Daily Recommended Intake” or DRI. For example, a hemoglobin level of 10.5 g/dL is unlikely to be associated with consequences in the daily life of a two-year-old child, but that level of hemoglobin is associated with learning difficulties later in life. Intakes of antioxidant nutrients at the RDA levels are sufficient to prevent scurvy (Vitamin C deficiency) or the dry skin of Vitamin A deficiency. These intakes may not be sufficient to prevent esterification of LDL cholesterol into its more toxic forms affecting the occurrence of coronary heart disease. RDA intake for folate will prevent megaloblastic anemia, but higher levels of folate may be required to prevent neural tube defects in pregnancy and coronary heart disease among genetically “at-risk” adolescents and adults.
Because DRI levels are generally higher than RDA, it is quite important to set an upper limit (UL) as a caution for potential toxicity levels for intake of all micronutrients – both water and fat-soluble vitamins as well as for minerals. Any gain from increasing intake with DRIs must be balanced by potential toxicities of exceeding RDA. Thus, it becomes essential to use an assessment of nutritional status in seemingly healthy children asking “what tissue levels or clinical findings might reflect deficiency or toxicity?” As will be discussed in Section 4, periods of negative nutrient balance trigger a sequence of events. These may occur early, with loss of storage, or later -- after metabolic compensation mechanisms fail.
Figure 2. – The cascade of negative nutrient balance
TEACHING CAPTION: Negative nutrient balance leads to a cascade of events. First, storage levels decline, second intermediary metabolism changes. The onset of disease may begin earlier or later in the course of depletion.
1. THE IMPACT OF SOCIAL ENVIRONMENT ON NUTRITIONAL STATUS
Variables associated with socioeconomic status (SES) affect nutrition. Correctly defined, however, SES represents an interaction between education level of the head of household and source rather than quantity of income of the family. SES alone tells little about individual within any SES grouping. Rather, SES informs about limitations and opportunities for nutritious food and a supportive environment with a gradient from lowest (least educated/income from day labor) to highest (best educated/income from professions or management). Moreover, levels of economic development within nations and regions of the world have a profound effect on social environments, nutritional status in the community, and among individual children.
Finding out about the community
DB Jelliffe begins his classic 1963 monograph, Assessment of Nutritional Status of the Community, (WHO monograph #53, 1963) with two recommendations. The first is to enter a community aware of statistics showing its health and nutritional status. These include infant mortality, weight of children at birth, weight and length of small children, and the height of children past three years of age. As Stanley Garn points out, “the dimensions of poverty can be spelled out in the growth of children.”
Jelliffe’s second piece of advice was to walk the streets and alleys of a town to learn about the culture. Learn about the conduct of commerce and availability of resources from the people themselves. As he writes,
“Knowledge of the local culture pattern is essential for successful investigation …., for an understanding of the local etiology of malnutrition, and for the ultimate implementation of any program aimed at improving the situation.” (p121) and “The local ‘indicators’ of wealth must be discovered, and – if easily identified – carefully noted.” (p126).
When considering individual children, it is necessary to recognize that they live in the world of their parents and the institutions that serve them directly. This is their "microsocial environment." [Hyperlink to Diet Assessment] For the casual observer, failures in the nurturing of children within that proximal environment seem obvious. These may be seen as the sole cause for nutritional consequences found among children from poorer families. What is not seen is the way that the "macrosocial environment" - those factors distal to the child's life including the schools, health care system, opportunities for work - fails the family and affect child welfare indirectly. These failures deprive the poor of real opportunities to have minimally adequate lives. [Hyperlink to diet and behavior assessment] Thus it is necessary to integrate an appreciation for the lives of people as they live them and the opportunities available to them from the larger socioeconomic environment.
2. MALNUTRITION IN FOUR OVERLAPPING CATEGORIES
In his 1963 monograph, Jelliffe described four types of malnutrition found in communities. These are: 1) caloric under nutrition, 2) specific nutrient deficiencies, 3) caloric over nutrition, and 4) nutrient imbalance.
TEACHING CAPTION: All forms of malnutrition are highly influenced by poverty and often coexist with one another.
"Static" (Single) versus "Dynamic" (Multiple) measurements
In clinical practice, a single measure of weight, length or height, weight for length, Body Mass Index, and head circumference may inform you of whether a child is under- or over-nourished. This single measure, however, is insufficient to determine whether the child is well nourished. Think for a moment of a 3,700 gram 4 week old infant. Is she well nourished? The percentiles would indicate "yes," but she is not if the birth weight was 3,700 grams or greater. Actual weight gains are needed in the new born period. The gains expected in the first years of life are shown in the table below.
TEACHING CAPTION: In early infancy you will calculate weight gain per day. Keep growth curves for weight, length or height, and head circumference. A BMI curve should be maintained for every child.
Growth Curves are available with adjustments for age and sex from www.cdc.gov. A set of curves for children with Failure to Thrive can be found in the case study "Why is Jimmy Small" in the Curriculum for Poor and Undeserved children of the Ambulatory Pediatric Association— www.servingtheunderserved.org. Difficult to obtain growth curves are found as an appendix.
Children must have measurements of growth accurately measured and plotted over a period of time. There are three reasons for this.
First, single measurements taken at a mass screening are useful for the assessment of the nutritional status of the community only. A reduction in measurements means little about the nutritional status of any one child.
Second, chronic malnutrition leads to stunting of linear growth. Unless there is concomitant acute malnutrition with wasting, the child will appear to be younger than his or her chronological age. It is only by plotting measurements that undernutrition will be identified.
Third, calculation of the "height age," "weight age," and "ideal weight for actual height" from the growth curves is necessary in the treatment of the affected children.
The impact of poverty, "food insecurity," or an available discretionary income
Under usual circumstances, under nutrition (protein-energy malnutrition and specific nutrient deficiencies) affects the poorest children while over nutrition and nutrient imbalance affect those who have escaped extreme poverty. The later phenomena are most likely in those families living at the cusp of poverty and self-sufficiency.
In the figure below, an "Engel curve," the poverty level is defined as three times the cost of the United States Department of Agriculture's Low Cost Food Plan (USDA-LCFP). Theoretically, at the poverty level, the total income goes to pay the cost of necessities — 1/3 for food, 1/3 for housing, and 1/3 for other necessary expenses. Only past poverty incomes does discretionary income appear. Discretionary (alternatively "disposable”) income refers to funds available after obtaining necessities. These would include food, housing, health care and the expenses of maintaining employment — day care, clothes and transportation.
When this absolute definition of poverty was created, welfare-
dependency was an accepted norm for the miner's widow and her children as the model. The costs of working — clothing, day care, and transportation — were not considered. In reality, there is no metropolitan area in the United States where 1/3 of income will suffice for unsubsidized housing and/or good nutrition.
Food Insecurity
This term refers to a sequence of conditions within a family beginning with doubts by an adult that there will be sufficient food progressing to adults depriving themselves to feed their children, making alterations in food resources for their children, and finally, frank hunger. Studies in the United States show that about 15% of families experience the first levels of food insecurity. Changes in behavior (sending children to eat in school or with friends and family) or frank hunger occur in 1 to 3 percent of families.
A simple addition to a screening evaluation is to assess income expenses, resources for food and food insecurity. The first three questions of the USDA/Cornell Radimer food insecurity surveys are used in our work to determine which children are “at-risk.”
TEACHING CAPTION: These questions are adapted from the CDC and Cornell/Redeemer Food Insecurity Questionnaires. They are highly sensitive and likely to capture all children affected by food insecurity or hunger. From Frongillo EA, et al. Low family income and food insufficiency in relation to overweight in US children: is there a paradox?. Arch Pediatr Adolesc Med. 2001 Oct;155(10):1161-7.
The relationship between income and expenses for necessities at all income levels is shown figure 3. For lowest income families (below poverty level) most of the last dollar earned will be spent on food. This is not so for those families with income greater than 3 times the poverty level when food expenditures rise very little with increased income. “Food insecurity” is common for those families with incomes between 1 and 3 times the poverty level. The appearance of discretionary income has a profound effect on nutritional status. It is a marker for the opportunity to be “plump and healthy.” Once sufficient income is obtained, concern for the cost of necessities recedes. Neither under- nor over nutrition is likely.
Figure 3. An Engel curve with lean and plump figures from Shils
TEACHING CAPTION: As shown in the figure, poorer workers’ increased earnings do not generate discretionary income until the total of income from earnings plus supplementation reaches poverty level. By contrast, the affluent have more than enough income to cover the costs of necessities, and every new dollar is spent on something of their own choosing – not necessarily food, housing or other necessities of life. Those in-between are often food insecure and overweight.
3. THE "AT-RISK" CONCEPT IN NUTRITIONAL ASSESSMENT
DB and EFP Jelliffe have suggested a category for children “at-risk” for malnutrition, meaning the presence of “a) biologic or environmental factors that predispose to disease... and, b) easily recognizable warning signs that malnutrition is impending.”
Any of the following would make a child at risk for malnutrition: poverty, lack of social support, signs of child abuse or neglect, parent-child problems, lack of parental education or illiteracy, drug or alcohol abuse, teen pregnancy, chronic illness and food cult behavior in the family.
The macrosocial factors increasing risk to whole communities include lack of economic support, child welfare, education, repression of women’s rights, and an inability to manage a clean water supply.
4. THE IMPACT OF NEGATIVE NUTRIENT BALANCE
The `at-risk' model of the Jelliffes is similar to one proposed by the late Victor Herbert who looked at nutrient balance in the diet. The presence of metabolic changes prior to the onset of disease is an indicator for the need to intervene. The Jelliffe’s were applying Bayes’ Theorem to investigation. The presence of a risk factor increases the prevalence of whatever is being looked for and therefore the predictive value of any specific test.
Victor Herbert uses folate metabolism to illustrate his theory (see section on Iron deficiency in Nutrition Notes and in ID module [hyperlink] for additional example.
Stage 1: Early negative nutrient balance is characterized by a fall in serum folate to below 3 ng/ml. Body folate stores are not affected; red cell folate level is above 200 ng/ml.
Stage 2: Folate depletion is indicated by low serum folate and characteristically by a fall in erythrocyte folate below 160 ng/ml. There is defective DNA synthesis, abnormal diagnostic deoxyuridine suppression test result correctable in vitro by folic acid, and granulocyte nuclear hypersegmentation.
Stage 3: Clinical deficiency of folate is manifested by gross macro-ovalocytosis, elevated mean corpuscular volume (MCV) and anemia. Of note, in some diseases deficiencies occur in stage 2. (Hyperlink to ID model and Nutrition Notes)
Similarly, Noel Solomons has suggested identification of functional changes associated with nutritional imbalance as indicators of disease. Functional measures of nutritional status, although not widely available, offer the possibility of monitoring pathophysiological processes created by nutrient deficiencies. Examples include measures of delayed hypersensitivity reactions as a marker of Vitamin A adequacy, and hand-grip strength as a marker of muscle function.
A third approach, suggested by Robert Karp, is to use highly sensitive “at-risk” criteria to improve the predictive value of more specific nutrition assessment indicators. As suggested by Bayes’ theorem, the predictive value of any test is proportional to the prevalence of the condition in the population studied. Creating the smallest possible pool of affected individuals increases prevalence in the population studied and maximizes positive predictive value. This can be achieved by using a two-step screening process. First use a highly sensitive screening test that captures all or almost all affected individuals. Then use a highly specific test to eliminate all unaffected individuals.
A Case Study
Amelia H is a 16 year old girl. Her mother is an immigrant from Mexico. She is undocumented (“an illegal alien), but she hopes to get a “green card” – working papers and a first step to citizenship. Amelia was brought to a food pantry with her mother as occurs at least once month when the money Mrs. H receives as a night cleaner in a private school runs out.
You are a pediatric resident doing a community pediatrics and advocacy rotation. There are little resources – a scale, a tape measure and a chance to talk. Amelia weighs 66 kg. She is 150 cm tall. What can you determine from this?
Her weight is >95th percentile; height is at the 60th percentile. You calculate the BMI as 29.3 kg/m2 and the BMI percentile as >95th percentile.
Ask the residents “Any thoughts on this?”
Obesity is very common in immigrant children from Central America. A difference here is that it is not associated with increased stature. We are taught to look for endocrine or metabolic abnormalities with short stature obesity, but it is unlikely that in this high risk population group such pathologies will be found.
You take a birth history from Mrs. H and find that Amelia was a low birth weight infant. Mrs. H compensated by feeding her often and “a lot.” She gained her weight back quickly. A diet history from the mother and find that Amelia is having abundant fried and fatty foods. There is some excess milk consumption but more so the juice, soda, and various “chips.” She does not take a vitamin/mineral supplement
What other nutritional risk is a concern?
Minneapolis was chosen as the site for this family and child because it was here that the phenomenon of “double burden” was identified in the United States. The double burden here is micronutrient deficiency and obesity as seen in children from families needing to maintain a caloric intake but unable to do so with high nutrient content. [hyperlink to Intro to food costs and food culture. See also micronutrient deficiency at early school age.] The family is “illegal” and has been afraid to apply for food support. “Food insecurity” is associated with obesity. Low income without support is also associated with iron deficiency. Amelia is a she. Teenage girls require an iron rich diet to sustain hematopoiesis.
FIGURE 6 – Maximum Sensitivity With Least Loss Of Specificity
Two-Step Nutritional Assessment
TEACHING CAPTION : The goal is to find Point “A” where there is maximal sensitivity with least loss of specificity. This will provide the smallest possible pool containing all or almost all afflicted individuals. From Karp RJ. The ‘at-risk’ concept as applied to the identification of malnourished hospitalized patients: How a two step process improves clinical acumen. Nutrition in Clinical Practice. 1988;2:150-15.
While the models provided by the Jelliffes, Herbert, Solomons, and Karp differ, each increases the likelihood of identifying risk factors, affected children, providing effective therapy, and developing programs to decrease the prevalence of malnutrition.
5. A PROTOCOL FOR ASSESSING NUTRITIONAL STATUS
OF CHILDREN
5a. Begin with an assessment of the macro- and microsocial environments. Ask “what is this child’s place in society?” “What is this family like?” “What nutritional outcomes are probable, likely, possible, or improbable?” [Hyperlink to assessing diet and behavior]
5b. Take a detailed history of the family and of the child. The dynamics of the family should be described, not just what is happening right now. Drs. Shepard, Kjolhede and Scranton provide details of history taking elsewhere in the Teacher’s Guide. [Hyperlinks]
One must look for any of the following six potential causative factors for nutrient deficiencies:
TEACHING CAPTION: Never assume that inadequate intake is the single cause for nutrient deficiency.
5c. Assess the dynamic of somatic growth. Measurements of weight, length, and head circumference at birth are important as there may be a syndrome such as Fetal Alcohol Syndrome for which these measures are suggestive.
With respect to assessing growth of older infants and toddlers, the “Waterlow” system is most popular in clinical practice. This considers weight for age and weight for length or height first separately and then together as show in the table below. “Wasting” (decreased weight for length) is associated with acute malnutrition and is distinguished from “stunting (decreased length or height for age) as is seen with chronic malnutrition.
Table 5. Classification and definition of protein-energy malnutrition: The Waterlow system for assessing early growth.
TEACHING CAPTION: The Waterlow system is highly effective for children from birth to 3 years of age. The weight, length, weight for length and head circumference (from birth to 18 months of age) should be charted for a visual representation of the growth patterns. BMI would substitute for weight-for-height past two years of age.
Up until three years of age, the progression of weight, says Gopalan is the single best measure of nutritional status, and for group measures, of the nutritional status of the community. Past this age, height becomes the better indicator of nutritional status. Measures to be taken include weight and height. The Body Mass Index (weight/height2) has replaced weight for length charting. It is especially valuable in the assessment of obesity where a BMI of 85 to 95th percentile is considered “overweight while >95th percentile is considered obese. There is a caveat, however to be considered.
Limitations of BMI
Weight drives height. Overweight and obese children have high circulating levels of insulin. Their increased weight leads to increased height. Thus an overweight 5 year old is likely to have a “height age” of 7 years. That is, his height is at the 50th %ile for a 7 year old, and your eye, as well as the parent’s eye, will make the assumption that he is 7 years old. The BMI curves show a phenomenon of “Adiposity Rebound”. There is an upswing in the curves that begin at age 4 for overweight children and at 7 years of age for lean children. The physician and parental eye will tell you that the child is not overweight. The other problem is that the child might be heavy but not at all obese in that the BMI does not distinguish between fat and muscle.
FIGURE 7. Showing how the eye fools with BMI
Stature BMI
5 years of age Weight = 24 kg Height = 1.2 m BMI = 16.7 k/m2 Height age = 7 years
TEACHING CAPTION: A 5 year old with a "height age"of 7 years is "overweight" at chronologic age and "normal" weight at "height age."
A Case Study
Melissa is a 5-year-old girl with no significant medical illness. When you step into your office, you see a girl who looks like she’s 6 or 7 years old, not 5 years old. Her mom says she's bigger than most of the children her age, but that's because she's tall.
Her height and weight are 118 cm and 23.8 kg, respectively, which are both >95th percentile for her age. Her BMI is calculated to be 17.1, which is in the 85-90th percentile for her age, putting her in the overweight category. Her height age is that of a 6-year-old and her weight age is that of a 7-year-old. Her weight is more advanced for her age than her height so to the eye, she looks “chubby”, but you would not say that she is overweight.
If she brings her weight down to 21 kg (90th percentile), her BMI decreases dramatically to 15, which is at the 50th percentile for her age. This demonstrates how a small change in weight can make a big difference in the BMI value.
Use Fat-fold measures OR waist circumference
There are two ways to address this problem. The first is to use fat fold calipers and a tape measure to perform upper arm anthropometrics. A table is appended to this module for assessing fat and muscle mass for children. If the muscle mass is high (>85%ile) while the triceps fat fold is moderate (<85%ile), the child can be assumed not to be obese. The second is to use the tape to measure the waist and the hips. In pre-pubertal children, a waist measure (over navel) greater than the largest hip measure possible suggests obesity. This is a simpler method and also one that correlates well with later consequences, as suggested by Noel Solomons (2002).
Fernandez, et al. have determined %ile measures for waist circumferences by gender and ethnicity calculated from NHANES III data. The table below shows the mixed population 90th percentiles by gender, The numbers have been rounded and are appropriate for clinical use, only.
CAPTION: A child with an elevation in BMI and an elevation in Waist Circumference is overweight or obese. Elevation in BMI alone, however, suggests that this is a muscular child who is not obese.
See Also (Solomons NW. Methods for the measurement of nutrition impact and adaptation of laboratory methods into field settings to enhance and support community-based nutrition research.
Nutr Rev. 2002 May;60(5):S126-31.)
5d. Do a careful physical examination looking for signs of nutrient deficiencies or imbalance.
Chronic malnutrition not only produces growth failure and wasting, but also causes notable changes in hair, skin, and oral mucosa, as well as behavioral abnormalities, such as psychomotor retardation and failure of normal interaction with caregivers and the outside world.
5e. Perform laboratory tests to assess:
1. Visceral proteins (for protein-energy malnutrition). These include:
a. Serum albumin is used in population studies as an indicator of visceral protein depletion. Albumin is a poor indicator of early protein malnutrition because serum levels fall and recover slowly with changes in nutrition.
b. Serum transferrin is believed to reflect acute changes in the status of visceral protein more accurately than the serum albumin level because transferrin exists in a smaller body pool and has a shorter half.
c. Thyroxine-binding prealbumin is a carrier protein for retinol-binding protein and also plays a major role in the transport of thyroxine. The body pool of thyroxine-binding prealbumin is small. For these reasons sudden demands for protein synthesis, which occur with infection and trauma, for example, rapidly depress serum prealbumin levels.
d. Retinol-binding protein is the specific protein for vitamin A alcohol transport. It may be elevated in kidney disease, despite visceral protein compartment depletion.
e. Urinary 3-methyl histidine is an amino acid present almost exclusively in myofibrillar protein. A 24-hour urinary measurement of 3-methyl histidine excretion therefore approximates total muscle turnover during the time of collection.
f. 24-hour urinary nitrogen excretion is often measured to assess the adequacy of protein repletion during nutritional therapy.
2. Parietal proteins (to assess chronic protein loss)
a. Use of arm anthropometric measures (muscle and fat stores) are quite effective here with arm anthropometrics as most easily performed. In a classic study of three populations, Alice Dugdale and her colleagues showed that achieving either normal height or normal muscle mass is proof of adequate protein and energy intake. Thus, if the arm muscle circumference is normal, decreased fat fold measures do not suggest under nutrition. Where muscle circumference and height are decreased, however, a decrease in fat deposition is diagnostic of protein-energy malnutrition.
b. Creatinine/height index is also widely used to evaluate body muscle mass. The 24-hour creatinine excretion is adjusted by body height to give an indication of parietal muscle stores and is a means of determining the degree of the patient’s somatic protein depletion.
3. Plasma Vitamin and Mineral Levels
Vitamin deficiencies in plasma are common in malnourished patients. However, clinical vitamin deficiencies are not common. Usually, measures of storage (e.g. ferritin for iron) or intermediate metabolism (e.g., methylmalonic acid for B12 deficiency) give a better indicator of vitamin depletion. See Figure 2 above.
1. Use of special curves
a. Dynamic (velocity) growth curves A single point measure almost never gives an accurate description of nutritional status. A child whose measures are currently in the normal range may not have grown in six months. Usually, weight gain desists before there are changes in height. It is unusual for head circumference measures to falter prior to diagnosis of failure to thrive. [Hyperlink to FTT] Special curves for velocity are shown in the appendix. It is essential to use these curves for slow growing children as the patterns of growth may not be abnormal.
b. Adolescence This is a difficult time in the life cycle as there are different growth patterns that are considered “normal.” Tanner has published growth curves for early, mid-level, and slowly maturing women.
c. (Mid) Parental height It is also necessary to adjust the levels in the curve for parental height. Tables are available to adjust child’s length or height by expectations based on mid-parental height. If, however, the parental heights have been affected by early childhood malnutrition or disease, one should not adjust growth of the child for their parent’s growth. To repeat Garn’s aphorism. “The dimensions of poverty,” writes Stanley Garn, “are spelled out in the growth of children.”
d. Use of special curves for special circumstances. Children with Down or Turner/Noonan Syndromes do not grow at the same rate as other children. Curves showing expected growth patterns for Down Syndrome are shown in the appendix.
How to take an accurate measure of fat and muscle mass using calipers
1. Triceps fat-fold thickness (TFF). It is necessary to determine the midpoint of the patient’s arm by measuring halfway between the acromial process and the olecranon process in the non-dominant arm.
2. Subscapular skin-fold thickness. It is taken 1 centimeter below the tip of the right scapula. The skin and subcutaneous tissues are grasped below the border of the scapula.
3. Midarm muscle circumference (MAMC). It is obtained by locating the upper arm midpoint of the non-dominant arm, as described for the triceps skin-fold thickness test.
FIGURE 8. How to perform arm anthropometrics
TEACHING CAPTION: From Frisancho AR. Triceps skin fold and upper arm muscle size norms for assessment of nutritional status. Am J Clin Nutr. 27:1052:1974.
A True-to-Life Case Study
Let residents hypothesize why the following occurred in north central Philadelphia.
In your first research project after residency, you have examined the nutritional status of children from kindergarten to third grade living in North Central Philadelphia. See micronutrient deficiency at early school age for details of actual experience. [Hyperlink]
As you evaluate the data you notice that all of the malnourished and lead poisoned children live on numbered streets – 15th, 16th, 17th, and 18th. The children living on Carlyle, Sydenham, Smedley-Willington, and Bouvier streets – those running between – seem unaffected. Why is this?
Some questions
Q1. What is the first thing you do?
A1. Follow Dr. Jelliffe’s advice. Take a walk through the neighborhood.
Below is a map of the neighborhoods in north Central Philadelphia on the west side of Broad Street.
Notice that the numbered streets run straight through the city. The named streets run a block or two, and then they stop to start again farther north.
Q2. Might this phenomenon affect the quality of life on numbered as compared to named streets?
A2. Yes it does. The numbered streets have all the buses, trucks, and commuter cars avoiding Broad St. There are also many stores including taverns on the numbered streets. The named streets are quiet and the children can mark up the street with lines and play football. Check out Bill Cosby’s stories on tape or disc as this is where he grew up.
Q3. How does this affect the quality of housing?
A3. At the time this study was done (mid 1970s) the houses on numbered streets had been broken up into small overcrowded apartments with as many as four families residing in one house. The named streets still had trees on the side walk and single family homes.
Q4. And who lived where?
A4. Most people living on numbered streets were economically dependent, single parent families. They had no other option except “The projects”.
[Much of my 10 year experience in north central Philadelphia was spent walking through the neighborhood, but I only went in the projects once and promised myself and family that I’d never do that again. RK]
By contrast, families living on the named street were more often employed and intact. This was where the bus drivers, construction workers, and lower level civil servants lived.
Q5. So why was there more malnutrition on numbered streets?
A5. There are many more risks including poverty, unemployment, and economic dependency (macrosocial); and single parenting, limited parenting skills, and an inability or unwillingness to use health and other available resources effectively (microsocial). These lead to an increased prevalence of malnutrition – iron deficiency and growth retardation.
Residence on named or numbered streets was not in itself a causative factor. For further information see the module on micronutrient deficiency at early school age. [Hyperlink]1
__________
1. For the record, I lived at 6224 N. 16th St in Philadelphia from birth until high school graduation. That far north in the city, however, 16th St ran only 2 blocks without interruption. My father was a carpenter who became a shop teacher until he earned a college degree at 40 and became a guidance counselor. He never taught me how to use carpentry tools with the expectation that I was going to become a physician. His graduation present (only after my actual diploma was in hand) was his set of hand tools.
ANNOTATED ANSWERS
Answer 1 - False. You’ve waited to long! The serum albumin falls well after the child has lost fat stores and parietal muscle proteins. Albumin is considered a “visceral protein” and will fall late in the course of the disease especially in marasmus (p-e.m without edema). In kwashiorkor (p-e.m with edema), the serum albumin will be low, but other signs of malnutrition precede the fall.
Answer 2 - E. These are the four types of malnutrition described by the World Health Organization. The 4 types may occur simultaneously. Consider the over-nourished child or adult living on a high energy nutrient depleted diet with excess salt and sugar. Three types are present. Were this patient to languish in a hospital and become protein depleted, she could actually have p-e.m and obesity and micronutrient deficiency and nutrient imbalance all at once.
Answer 3 - D. Affluent populations see the same distribution as the poor albeit within a different social environment. Anorexia nervosa, for example, is characterized by both micronutrient deficiency and protein energy malnutrition from caloric deprivation.
Answer 4 - D. No direct cause and effect relations have been found for chronic malnutrition in childhood and malignancy though one can find abundant associations between selenium content in soil and GI and bladder cancer in China and other developing societies. Growth failure is the universal response to undernutrition, and there are many skin and hair changes as a result of impaired hormone production and missing essential nutrients.
Answer 5 - False. The actual circulating insulin levels in overweight and obese children, including those with Type 2 Diabetes Mellitus is likely to be high. The level may not, however, be adequate for the insulin requirement for the body weight.
