Foreword: In life, some parents are relatively tall, so they also have great confidence in their children's height, thinking that their children will definitely grow to a satisfactory height, without special attention; However, there are parents who are relatively short in height, they will be too worried and afraid of their children's height, afraid that their children will not grow tall, so they give their children a variety of big supplements, and each meal forces the children to eat full, and even eat support, hoping that the children can grow tall. So is a child's height absolutely determined by heredity? What other factors besides genetics affect height?
Today, we have the honor to invite Professor Shi Changsong, director of the Department of Pediatrics of Henan Provincial People's Hospital, to explain the issues related to children's height.
Highlights of this issue:
Question 1: Hello Director Shi! The child's height problem has always been the most concerned by parents, some parents will also calculate the child's genetic height, to estimate how tall the child will grow in the future, then Director Shi, what is the genetic height? How should a child's genetic height be calculated?
Director Shi: First of all, genetic factors are indeed very important, and the characteristics, potential, and tendencies of children's height development are all affected by the genetic factors of both parents. The height of the child is closely related to the height of the parents, and the approximate range of the height of the child after adulthood can be calculated according to the height of the parents.
The first calculation method is also called CMH (the corrected midparental height) method (the units are all cm):
Genetic height of boys = average parent height + 6.5 (cm)
Genetic height of girls = average parental height - 6.5 (cm)
The second calculation method is also called FPH (the final height for parental height) method (all units are cm), which some people think is suitable for parents with an average height of less than 180 cm.
Genetic height of boys = 45.99 + 0.78 × average height of parents (cm)
Genetic height of girls = 37.85 + 0.75 × average height of parents (cm)
[For example, if a boy has a father height of 178 cm and a mother of 164 cm, then the child's genetic height is:
CMH method: predicted height = (178 + 164) / 2 + 6.5 = 177.5 (cm)
FPH method: Predicted height = 45.99 + 0.78 × (178 + 164) / 2 = 179.37 (cm)】
Question two: through the genetic height calculation formula can be very simple to calculate the child's genetic height, that may now face a problem, parents through this formula, calculate the child's genetic height did not meet the expectations of parents, then parents may be more anxious, what to do?
Director Shi: Parents have their own expectations for their children's height, which is the expected height, for example, I want my son to grow to 180cm and the girl to 165cm. The genetic height calculated by the genetic height formula is inconsistent with the expected height, and parents do not have to be too anxious, because the value of the child's genetic height calculated by the genetic height formula is an average, and the average ± within 6.5 cm, which is normal. In addition to calculating the genetic height formula, it is also possible to estimate the adult height according to the child's current height.
Question three: Director Shi, you just mentioned the child's current height, so how to look at the child's current height, for example, a five-year-old boy, now 110cm tall, then this level is normal? Whether it is high or low, how to judge?
Director Shi: The evaluation of the current height of the body, that is to say, what is the current height of the child, can be seen through the height and weight percentile value table of 0-18-year-old boys or girls in China (displayed on the big screen). Normal height is divided into 7 grades, from low to high are 3 quants, 10 quans, 25 quans, 50 quans, 75 quans, 90 quans, 97 quan points, you can compare the level of children in the relative number of quantiles by age and gender. For example, I am now 5 years old, in the 50th quantile, looking down the table, to the last row of 18 years old, the height of the child is 172.7cm. According to this quantile, a rough assessment of the child's future body level can be made, and the disease is at high risk:
Question four: Just now I noticed that according to the genetic height formula and the children's height and weight percentile value table, the child's adult height can only be speculated, so do we have a more scientific and objective evaluation of the child's height indicators in medicine?
Director Shi: In medicine, bone age can more accurately reflect the growth and development of the human body and the growth space of height. Human growth and development can be expressed by two ages, the first is the age of life, also known as calendar age, which is the actual age. The second is called biological age, which is bone age, which represents the actual biological age of the child. To put it bluntly, bone age is the age of the bone, and it is also measured in years, and the maturity of the bone is different at each stage. Bone age can be calculated by taking X-rays of the left wrist area. Once bone age matures, height loses the opportunity to grow linearly.
Question five: It turns out that bone age can be determined by X-ray on the wrist area, so what is the relationship between bone age and the age we usually say? Is it that the child is one year older and the bone age is also one year older?
Director Shi: It's not like this, it's not that the child is one year older, and the bone age is one year older. After calculating the bone age through X-ray, and then comparing it with the actual age of the child, if the bone age and age difference are within ±1 year old, it means that the development is normal. Bone age > age 1 year, but not more than 2 years old--- development ahead of time (precocious puberty); Abnormal development of bone age > age over 2 years ---; Bone
Question 6: You just said that once bone age matures, height also loses the opportunity to grow. At what age will the child stop growing taller?
Director Shi: The gap between the epiphysis and the backbone of the long bone is called the growth plate (or growth plate), which is an important part of the height growth process and predicts the growth potential of height, when the radius and ulna and all the metacarpocarpal growth plates are calcified and fused, the height basically stops growing, at this time the bone age of boys is 16 years old, and the bone age of girls is 14 years old.
Question seven: Director Shi, now we return to a more direct question, which may also be a question that parents are more eager to know the answer to, can the height of the child break through the limit of genetic height, and the parents' expectations for the height of the child are higher than the genetic height, can they reach the desired height?
Director Shi: First of all, let's clarify a concept, height is determined by genetic and environmental factors, environmental factors here include: diet, sleep, exercise, mood, nutrients and so on. The growth of children's height must be accompanied by a well-developed supply of nutrients, and nutrition needs to be balanced; Adequate sleep: In the state of deep sleep, every night from 11 pm to 1 am is the peak period of growth hormone secretion, and children should be allowed to sleep peacefully and avoid being disturbed. To promote normal secretion of nocturnal growth hormone, it is recommended that your child fall asleep before 10 p.m. The younger the age, the longer sleep is required, and preschoolers are guaranteed at least 10 hours a day; Exercise can promote growth hormone secretion, improve sleep, promote nutrient absorption, reduce the proportion of body fat, delay bone age, exercise time, frequency can be determined according to children's age and athletic ability, advocate outdoor sports, walking, running, jumping, climbing, throwing balls, etc.; In addition, a pleasant mood is conducive to growth hormone secretion, conducive to nutrient absorption, improve sleep quality, can be more praise and encouragement for children, to create a relaxed family environment. While achieving the above conditions, parents should also pay attention to disease prevention. Manage from many aspects of the environment at the same time to promote children to grow taller.
Question 8: Just mentioned diet and nutrients, how exactly can children eat to help them grow taller?
Director Shi: Diet and nutrients are the key to children's physical growth, and it is necessary to provide high-quality protein foods, such as fish, meat, eggs, milk, etc., and appropriate amounts of carbohydrates, such as various staple foods, fruits, etc.; There are also vitamins, such as various types of vegetables. In addition, minerals such as calcium, phosphorus, etc. are also needed. Calcium is the main component of bone tissue, and bones concentrate 99% of the body's calcium, which is the secret that bones are so hard enough to support the weight of the whole body. Supplementing with sufficient calcium to meet the needs of bone development, it can be said that calcium is the basic raw material for bone growth, and calcium is directly related to height. When the supply of calcium is insufficient or the body is deficient in calcium, it may lead to poor bone development, hindered bone growth and development, and affect the growth and height of the body. The best calcium supplement foods are milk and dairy products, which not only contain high calcium content, but also contain calcium that is easily absorbed.
The calcium content in meat, fish and shrimp, soy products and nuts is also rich, but it is slightly inferior to milk and dairy products.
Vitamin D is the guarantee of calcium absorption, the skin can produce vitamin D after ultraviolet irradiation by the sun, which helps the absorption of calcium, which is also the reason why children's sun exposure can prevent calcium deficiency, so the sun is not calcium, but vitamin D. It can also be supplemented with vitamin D preparations.
In addition, parents need to pay attention to the fact that they should avoid giving their children high oil, high salt, and high sugar foods; Don't be afraid of children growing tall, blindly force children to eat more, eat support, this is likely to cause children to be obese, overweight or obese will accelerate bone age, but is not conducive to growing tall.
Question nine: Calcium is an indispensable mineral for growing tall, so how to determine whether a child is deficient in calcium?
Director Shi: The nutritional status of calcium in children can be evaluated by bone density. The detection interval is generally 6 to 12 months. Bone density levels in children, expressed in Z-values or percentiles. The normal range of the test results is generally represented by 5 curves, the bottom curve is the lowest value of the normal range, if the detection value is below the bottom curve, it is calcium deficiency. From the second curve below, it indicates that bone mineral content is at the lower and middle levels, and there is a risk of calcium deficiency. The middle curve is the mean. The top curve indicates that bone mineral content is high and calcium is well nourished.
Question 10: You can find out whether your child is deficient in calcium by measuring bone density, so if your child wants to supplement calcium, there are so many calcium agents on the market, how to choose the right calcium for your child?
Director Shi: You can choose from the following principles:
Elemental calcium content: The effective part of various calcium preparations is the content of "elemental calcium". With the same unit weight, the highest elemental calcium content is calcium carbonate.
Bioavailability: it is an important parameter that should be considered in the selection of calcium preparations, which is determined by the calcium content and absorption rate of calcium preparations.
Dosage form: calcium supplementation usually takes a long time, should choose children to take conveniently, the taste is easy to be accepted by children, for infants and young children, granules are more convenient to take dosage forms, for children over 3 years old with chewing ability, chewable tablets are more convenient to take.
Taste: For infants and young children, we must pay attention to protecting children's taste buds and pay attention to the lightness of diet. Children under one year of age should try not to consume salt and sugar (except in special cases). Therefore, in the choice of calcium, infants and young children should also choose light taste calcium, the closer to the taste of breast milk, the better, to avoid sweet and sour taste of calcium to stimulate the development of children's taste buds, after growing up to develop a bad habit of anorexia. For older children, at this time, you can choose bright colors, fruit flavors, small animal shape calcium tablets, which are loved by children and can improve the degree of children's active acceptance of calcium supplements. However, at the same time, it should be noted that when choosing calcium for children, it is necessary to pay attention to the formula as much as possible not to contain sucrose/white sugar and other ingredients, sugary formulas are not good for children's dental health.
Guests in this issue:
Shi Changsong, Chief Physician, Master's Degree Supervisor, Director of pediatrics and Director of Pediatric Intensive Care Unit of Henan Provincial People's Hospital. He is a member of the Respiratory Critical Care and Mechanical Ventilation Professional Committee of the Pediatric Critical Care Physicians Branch of the Chinese Medical Doctor Association, the vice chairman of the Pediatric Branch of the Henan Medical Association, the deputy leader of the Scientific Group of the Intensive Care Medicine Branch of the Henan Medical Association, the standing committee member of the Pediatric Branch of the Henan Medical Doctor Association, the standing committee member of the Intensive Care Medicine Branch of the Henan Hospital Association, and the member of the Allergy Branch of the Henan Medical Association. He is a visiting scholar at Harvard Medical School and The Schneider Children's Medical Center in Israel.
Professional direction: Good at pediatric digestive system respiratory system common diseases and frequent diseases, especially children's critical illness.