Indicators of growth and development evaluation of children and adolescents and some evaluation methods are as follows.
(I) Common evaluation methods
Growth and development evaluation is widely used in pediatric and juvenile health work, mainly for: ① Evaluating the current growth and development level of individual and group children and adolescents, and at what level. ② Screening, diagnosing growth and development disorders, evaluating the impact of nutrition and living environment factors on growth and development, and providing health care consultation recommendations. ③Inclusion in the indicator system of community health levels, evaluation of the effectiveness of various school health measures by observing changes in indicators, and as a basis for implementing school health supervision. According to these needs, the basic content of growth and development evaluation includes three aspects, such as growth and development water, growth and development speed, and the correlation of each index. Summit, Department of Endocrinology, Wuhan Union Hospital
Choosing a reasonable evaluation method is the key to a correct evaluation. So far there is no method that can fully meet the requirements of comprehensive evaluation of the development of individual and group children. Therefore, an appropriate method should be selected according to the purpose of evaluation, striving to be simple and easy to use, intuitive and without additional calculations; it can be combined with physical examination, living environment conditions, health and disease status for comprehensive analysis in order to arrive at a more comprehensive and accurate evaluation result.
(B) Index method
The index method uses mathematical formulas to correlate two or more indexes according to the proportional relationship of body parts, which is transformed into an index for evaluation. This method is convenient to calculate, easy to popularize, the results obtained are intuitive and widely used. Commonly used indices are.
(1) Height-Body Mass Index, which indicates the weight per unit of height, reflects the fullness of the human body and also reflects the nutritional status.
(2) height and chest index, reflecting the development of the thorax, to reflect the body shape.
(3) Height sitting height index, through sitting height and height ratio, reflects the proportional relationship between human torso and lower limbs, reflecting the characteristics of body shape. According to the size of the index, the individual’s body type can be divided into long body type, medium body type and short body type.
(4) BMI (body mass index, BMI, weight kg/height m2), also known as body mass index. In recent years, it has been highly valued by domestic and foreign scholars, who believe that it can not only reflect body fullness and body fat and thinness more sensitively, but also be less affected by height, and has high correlation with sebum thickness, upper arm circumference and other indicators reflecting the degree of body fat accumulation. China has established the “school-age children and adolescents BMI overweight, obesity gender an age screening standards”, is the specific application of BMI in the field of child growth and development. l8 years of age, the index ≥ 24 and ≥ 28, can be screened for overweight and obesity, respectively.
(5) Grip strength index and back muscle strength index: both use the close relationship between muscle strength and body weight, with the help of grip strength and back muscle strength per unit body weight to correct the effect of body weight, respectively, to show the muscle strength of the upper arm and low back, more comparable than the original index.
(6) Spirometry index: The close relationship between spirometry and body weight and height was used to correct spirometry with the help of unit body weight or height, respectively, to reflect more accurately the size of the body’s pulmonary ventilation capacity.
Since there are significant differences in body indices such as race, domain-rural, gender, age and height, they should be applied in conjunction with professional knowledge and attention should be paid to overcome the mechanical weaknesses of the indices. The following issues should be noted when developing and applying evaluation criteria: ① The height factor should not be ignored. Children of the same sex and age with different heights, those who are tall and stout and those who are short and thin can be equally evaluated as “well-proportioned”. The way to overcome this is to use age-specific height criteria to first screen out those with growth retardation. ② Pay full attention to the sharp racial and regional differences in indices (especially those derived from physical indicators). Most indices are not normally distributed. Therefore, it is best to first classify the indices into several grades based on the percentile method and determine the meaning of the grades.
(iii) Rank evaluation method
The grade evaluation method is the most commonly used method for evaluating the growth and development of children and adolescents in individuals and groups. It uses the position of the standard deviation and the mean value to divide the grades. When evaluating the individual, the measured value of the developmental index is compared with the developmental standard of the corresponding index of the same age and gender to determine the developmental grade. The most commonly used five levels of evaluation criteria in China are shown in Table 9-1.
Height and weight are the most commonly used indicators in general growth and development evaluation. The height and weight of an individual within the mean ± 2 standard deviations of the judgment criteria (about 95% of the total number of children) can be considered normal. However, children and adolescents whose values are outside the mean ± 2 standard deviations cannot be considered abnormal on this basis; regular and continuous observation is required, and conclusions should be made carefully in conjunction with other examinations. The weight of an individual may rise or fall, and is easily influenced by the internal and external environment. If a child’s weight decreases for several months in a row, diseases should be excluded before evaluating the nutritional status.
The graded evaluation method can also be used to evaluate the development of a group of children, called the “graded percentage method”. In the evaluation, the data of all the students in two classes or two schools are measured according to different developmental indicators, and the grade of each individual is determined by applying uniform criteria against the corresponding grade evaluation standards. Then, the percentages (%) of the number of individuals in each developmental grade for each indicator were counted separately for each class and school as a whole. The percentage of “good” or “poor” developmental grades for each index can then be analyzed between the two classes and schools to compare their developmental status.
The advantage of the rating method is that it is simple and easy to master, and it provides a more accurate and intuitive understanding of the developmental level of individual children. When evaluating a group of children, the findings are not limited by differences in the gender and age of the members of the two groups. This is because although the membership of the two groups is different, each individual is evaluated according to the respective age and gender evaluation criteria of the index; in other words, the grade percentages of the group are based on the individual grade evaluation. The shortcoming of the grade evaluation method is that it can only evaluate single indexes and cannot accurately judge the developmental proportionality, and its change trend is not intuitive enough in the dynamic observation.
(iv) Curve chart method
Curve chart method is another common evaluation method in the deviation method. When making a curve chart, the mean value, mean ±1, ±2 standard deviation of a certain developmental index of an age group of different sexes in a certain place are pointed on the coordinate chart (the vertical coordinate is the index value, the horizontal coordinate is the age, one for each sex), and then the points of each age group located on the same level are connected into a curve, that is, the developmental standard curve chart of the index is made. If the height or weight of a child is measured for several years in a row and the points are connected into a curve, it is possible to observe the current status of the child’s growth and development and to analyze its development rate and trend. Take height as an example, if the measured value of an individual is within ±1 standard deviation of the mean value, it can be evaluated as medium development; between +1 and +2 standard deviations of the mean value, it can be evaluated as medium to high development; between -1 and -2 standard deviations of the mean value, it can be evaluated as medium to low development; above +2 standard deviations of the mean value, it can be evaluated as high development; and below -2 standard deviations of the mean value, it can be evaluated as high development. -Those below 2 standard deviations can be evaluated as inferior. As mentioned above, children who are outside the mean ± 2 standard deviations should not be evaluated as abnormal, but should be continuously observed for their developmental dynamics to determine whether their developmental curve tends to improve or deteriorate, and then make a correct judgment.
It is also easy to evaluate the developmental status of a group of children and adolescents with a graph. The average value of a certain index of each age group of the group and the same age in the area can be plotted on the same coordinate paper. The “standard” average values of the development of the group can be plotted on the same sheet of paper; the difference between the two curves can be compared in terms of height and distance. Similarly, it is also possible to compare the mean curve of a certain indicator in different ages in a certain place.
The graphical method is widely used and has the following advantages: (1) the method is simple, the results are visual and easy to use. ②It can describe the developmental level grade of children. ③It can track and observe the trend and speed of development of a certain indicator in children. ④It can compare the developmental levels of individual and group children. The disadvantage is that a graph has to be made for each indicator of different sexes, and it is not possible to evaluate several indicators at the same time and analyze and compare the proportionality of development.
(E) Percentile method
The percentile method has various methods of expression, among which the percentile curve method is the most widely used. The production principle and process are similar to that of the percentile method, but the baseline value (P50) and the dispersion (P3, P25, P75 and P97) are expressed in percentile. The advantage is that the dispersion can be accurately displayed regardless of whether the indicator is normally distributed or not.
Currently, the percentile graphs of height, weight, BMI and other indicators made by combining the percentile method and the graph method have become the main criteria used by WHO and many countries to evaluate the current status and development trend of children and adolescents. To evaluate the developmental status, it is only necessary to find the position of the individual’s height or weight on the graph. The results are described according to the range, such as
When evaluating a group of children, each index P50 can be used alone, together with a small number of curves such as P10, P25, P75, P90, etc., to reflect the differences in developmental levels of different regions and groups in the same period, or to compare the trends of different generations of the same group. Those whose developmental levels are outside P3 and P97 should be tracked with emphasis, comparing their changes on the graphs with clinical examination to exclude dwarfism, growth retardation, malnutrition or gigantism, obesity and other disorders.
The disadvantages of this method are the same as those of the outlier graph; the sample size requirement is high when setting the criteria. If the number of people in an age group of each sex is less than 150 (less than 200 in adolescence), the values of the two ends of the standard curve made (P3, P97) swing more, which directly affects the application value of the standard.
(F) Standard deviation method
Standard deviation method is a special form of standard deviation method, referred to as “Z” score. 1 “2 points” value is equivalent to 1 standard deviation value.
(G) Correlation regression method
The correlation regression method uses the close relationship between height and weight, chest circumference and other indicators, and uses one of the indicators as the dependent variable to obtain an equation and prepare a regression evaluation table for developmental evaluation. According to the number of variables in the regression equation can have a univariate regression, binary regression, etc.. The advantage is that the combination of multiple indicators can be applied comprehensively to accurately reflect the level of development and body proportionality, and is highly intuitive. However, the cumbersome production of standard graphs limits its application.
(H) Growth rate evaluation method
Growth rate is an important indicator for evaluating growth and health status, and commonly used indicators include height, weight and head circumference (especially under 3 years old), with height being the most commonly used. The changes produced by a combination of genetic and environmental factors can be reflected by the acceleration or deceleration of growth rate. Even in individuals of the same sex born at the same time, their growth rate varies greatly, especially during the growth spurt phase of puberty. Therefore, evaluation of growth rate can sensitively reflect the dynamic changes in growth. Some children may have impaired growth due to disease or other reasons, but their growth level may still be in the normal range according to the above evaluation methods; in this case, early screening for growth abnormalities can only be based on the slowdown or stagnation of their growth rate.
To evaluate the growth rate of individuals, the criteria used need to be obtained based on tracking data, including different types of growth expectations and their ranges for early, average and late maturity of the same sex and age group, so that the growth rate and its variability can be accurately and comprehensively evaluated. Long-term follow-up surveys should be conducted with a representative group of the same children, and height should be measured regularly at least twice a year. The growth rate varies from season to season, so the normal value of growth rate at any age should be expressed as a whole year’s rate and its degree of variability.
To evaluate the growth rate of a cohort, we mainly use the aforementioned semi-traceability survey or even cross-sectional survey information to develop reference standards for growth rate; the latter is an approximation of the growth rate obtained by using the annual value of increase and annual growth rate as indicators. The calculation methods are as follows.
(1) annual increment: Take height as an example, by continuous measurement of individual height and subtracting the height values measured in two different periods before and after. It is obtained by dividing the time (in years).
(2) Annual incremental rate: The annual incremental rate is still taken as an example for height. Because the base height of individuals at different ages is different, the height incremental value is inevitably limited by the height base. Children with different height bases have different meanings, although the growth values are the same; the smaller the base, the faster the growth rate. Therefore, it is necessary to divide the annual increase value by the height base, so that the absolute number becomes a relative number, in order to derive the annual increase rate (Vt, %) for comparison.
(ix) Developmental age evaluation method
Developmental age, also known as biological age or physiological age, refers to the average level of development of certain morphological, functional and secondary sex characteristics indicators and their normal variation, made of standard age, to evaluate the developmental status of individuals. There are four categories of developmental age: morphological age, age of sexual characteristics, dental age, and skeletal age. The most practical and accurate result is the skeletal age.
Skeletal age is a developmental age obtained by comparing the degree of skeletal development (calcification) of children and adolescents with bone development standards. Bone age is a more accurate indicator of the level of development and maturity of an individual, and can reflect the developmental level of each stage from birth to maturity in a more objective and accurate way, and is the most widely used among various developmental ages. Bone age plays an important role in exploring growth and development patterns, determining growth disorders, selecting athletes, predicting the first menstruation of girls, and predicting the adult height of children and adolescents.
The main method of determining bone age is to use X-ray radiographs. By observing the appearance of ossification centers, the size and shape of bone masses, the appearance of joint surfaces and the degree of epiphyseal healing in the wrist of children and adolescents, and comparing them with the “bone age standard” which is the normal value, we can determine the bone age of an individual.
Theoretically, all parts of the human body can be used to determine the maturity of the bones, but the wrist is the most ideal. The main advantages are: ① The number, type and shape of bones in the hand and wrist are diverse. It includes long bones, short bones, irregular bones and seed bones, which is very representative of the whole body bones. The emergence of each secondary ossification center of the hand and wrist bones and the healing of metacarpal and ulnar epiphysis have a clear time sequence, and the boundaries of different developmental stages are clear and easy to find differences. (③) The film is convenient, the projection conditions are easy to control, the subject receives a small dose of X-ray, which is beneficial to the protection of the health of children and adolescents.
(J) Nutritional status evaluation method
Evaluation of nutritional status refers to the comprehensive analysis of the information obtained on the nutritional status of children and adolescents as individuals or groups; the evaluation made on this basis is an important element of the work of children’s health. The observation indexes are mainly height, weight, sebum thickness, etc. To develop nutrition evaluation standards, the reference population should be those children and adolescents who live in a suitable environment, have reasonable dietary intake, grow and develop well, and have access to good health care services. The standards set by such a sample are higher than the developmental level of the average child and are “ideal standards”, which have the positive effect of accelerating the improvement of the living conditions and health services of children and adolescents.
In the past, the term “weight for age” was used. It is a method of comparing weight size by age in time. After 3 years of age, the weight for age of children is increasingly influenced by height; those who are taller at the same age are heavier, and those who are lower are lighter; if height is not related, it cannot effectively reflect the current nutritional status. The current nutritional status cannot be effectively reflected without linking height. The age-specific weight alone cannot accurately reflect the long-term malnutrition phenomenon which mainly manifests as height growth retardation. Therefore, this method is rarely used in the field of pediatric health.
The following methods are commonly used to evaluate the nutritional status of children and adolescents.
(1) weight for height: It is also called “height standard weight” in China. It is an indicator actively recommended by WHO, which focuses on reflecting the current nutritional status of children. It can effectively eliminate the influence of pre-pubertal differences in body size due to gender, growth level, genetics and racial differences. The WHO recommended reference values for pediatric patients can be shared by both sexes; however, gender-specific criteria should be used for those over 3 years of age.
The “standard weight for height in 1985” still used in some areas of China is obviously lagging behind the current growth and development of children and adolescents in China; continued use will lead to a large number of wrong and missed screening, and should be replaced by the “height and weight of Chinese students in 2000” standard (revised version) in a timely manner. At present, in developed countries, for overweight and obesity screening of school-age children and adolescents, height by weight has been gradually replaced by BMI standards.
(2) height for age: It is a method to compare height by age in time. Due to racial genetic differences, the use of this standard after puberty may lead to errors, so the “Chinese height for age standard for school-age children and adolescents” is being developed. The design concept of age-specific height standards is that malnutrition includes two types of malnutrition, one is current malnutrition, i.e. “wasting”, and the other is long-term malnutrition, which causes stunting. When screening school-age children and adolescents for malnutrition, we should use “height for age” first to exclude those with growth retardation, and then use “height for weight” to screen out those who are wasting; the combination of the two constitutes the entire malnutrition population. If “height-for-age” is not used, children who are underdeveloped in both height and weight (often the former is more prominent) will be easily missed, or even mistaken as “normal weight”, thus affecting the accuracy of screening.
(3) skinfold thickness (skinfold thickness): It is one of the methods to reflect the recent nutritional status of children and adolescents by estimating subcutaneous fat (about 50% or more of the total body fat), and is used to evaluate the degree of obesity with good effect. Skin fat thickness can be measured by X-ray photos, ultrasound, skin fold caliper and other methods. The measurement of skin fold thickness by caliper is the most simple and economical, and the correlation between the measured result and the X-ray measurement value can be as high as 0.85-0.90, and there is no radiological damage to human body. However, this method can inevitably produce measurement errors due to the operator’s proficiency and technical differences. The technical differences mainly come from the stability of the pressure applied when pinching the skin fold by hand; the length of the skin clamping time of the caliper head; the thickness of the skin fold of the subject, etc.
There are several sites for measuring sebum thickness; among them, the triceps area of the upper arm (representing the extremities) and the subscapular angle (representing the trunk) are the most ideal. These areas are well balanced and relaxed, and the subcutaneous fat and muscles can be adequately separated, with clear measurement points, easy measurement, and high repeatability of the measured values. The sum of the measurements of these two areas can represent the development of subcutaneous fat in the whole body. Other measurement points in other parts of the body include the biceps, suprailiac, and abdominal lateral wall.
The correlation between sebum thickness and body fat content is high, with a regression coefficient of about 0.7, so sebum thickness can be used to establish a regression equation to estimate the percentage of body fat content (i.e., fat content as a percentage of body weight, referred to as body fat percentage). The distribution of body fat and skinfold thickness are affected by age, gender, and race, so these equations vary between countries/regions. Body fat percentage can be used to determine the degree of obesity. It is generally accepted that the body fat rate for mild, moderate and severe obesity is ≥20%, ≥25% and ≥30% for males (for each age); ≥25%, ≥30% and ≥35% for females under 14 years old; and ≥30%, ≥35% and ≥40% for females 15 years old and above, respectively. However, the projected body fat percentage and the determined obesity level using this method are susceptible to errors due to height and muscle development. For example, individuals of the same sex and age with the same skinfold thickness may have the same calculated body fat percentage, but their body density and body fat percentage may not be exactly equal due to differences in height and muscle development, but they are assumed to be equivalent in most of these formulas and should be used with due attention.