Not only does dwarfism seriously affect the future development of children, but also children with dwarfism are often ridiculed and teased, thus making them introverted, autistic or even depressed, which causes many inconveniences in learning, working and living, and even leads to serious psychological problems, such as introversion, emotional instability and social withdrawal. Therefore, with the development of society and the increasingly fierce competition for higher education, employment, love and marriage, dwarfism has been widely concerned by the society.
In recent years, the average height of adult males in China, Japan and Korea are 1.697m, 1.707m and 1.74m respectively, and their world rankings are 32nd, 29th and 18th respectively; the average height of Chinese boys aged 7 to 17 is 2.54cm lower than that of Japanese boys of the same age. This gap is even greater when compared to the average height of 182.5 adult males in the Netherlands. There is no doubt that taller bodies are preferred by both men and women, so height – a real and serious issue – is once again the focus of national attention. So what are the factors that determine a person’s height, and how can we make our children grow taller so that they can say goodbye to the embarrassing situation of being “inferior”? We must clarify the definition, causes and treatment of dwarfism.
I. What is dwarfism?
Clinically, there are strict criteria for diagnosing dwarfism, i.e., the height is lower than the negative 2 standard deviations (-2SD) or the 3rd percentile (P3) of the normal height standard for children of the same age, sex and race, which is equivalent to ranking 100 children from low to high, the first 3 belong to dwarfism, and the 4th to 25th belong to dwarfism. For specific values, please refer to the table of height standard curves for normal children in China. Parents can also roughly determine whether their child is short or dwarf based on the following simple methods.
① Slow growth, the same pair of pants can be worn for two or three years without showing short, or the height growth is less than 5 cm per year.
②The child is always half a head or even a head shorter than the children in the same class or of the same age.
③According to the average height formula for children aged 2 to 10 years: height = age (years) × 7 + 70 (cm), if you find that your child’s height is 5 to 10 cm below the average, it may belong to dwarfism or short stature. You should promptly take your child to a hospital that specializes in children’s endocrinology, have the appropriate tests done, actively search for the cause of your child’s short stature, and give targeted treatment. Don’t take any chances and hope that your child will grow taller when he/she reaches puberty or if you give him/her more “nutrients”. Even influenced by the concept of “early growth and late growth”, “parents are tall, the child will not be low” and so on, resulting in missed treatment time and regret for life. For example, a large number of parents believe that their children will only grow fiercely at the age of 13 or 14, but unfortunately, some of them are no longer growing at this age, for many reasons, such as precocious puberty, congenital adrenocortical hyperplasia and other endocrine diseases. Only 8 or 9 years old epiphysis has closed, and the growth of height has stopped.
What are the factors that determine a child’s lifelong height?
There are many factors that affect children’s height, mainly genetic factors and acquired factors. For boys, the genetic target height (height given by parents) is the average height of parents plus 6.5 cm, and for girls it is the average height of parents minus 6.5 cm, obviously this formula is not applicable to all people.
Acquired factors include nutrition, exercise, sleep, disease, etc. In fact, children who are over-nourished or obese have higher estrogen levels in their fat cells, which can lead to earlier bone age or early epiphyseal closure, resulting in lower adult lifetime height. . In fact, during the famine years, many people could not even fill their stomachs, let alone talk about nutrition, but it does not seem to have much effect on most people’s height, not to mention that in today’s era, children’s nutrition should not be a problem. Since growth hormone is more abundantly secreted during exercise and deep sleep, exercise and sleep help to grow taller. Of course, short stature due to diseases, especially endocrine and genetic metabolic diseases, such as growth hormone deficiency, hypothyroidism, congenital ovarian hypoplasia (Turner syndrome), chondrodysplasia, mucopolysaccharidosis, and small for gestational age (i.e., birth weight not up to the standard according to gestational age) cannot be ignored.
What tests are needed?
As mentioned above, there are many causes of dwarfism, therefore, relevant examinations are needed to clarify the causes so that corresponding treatment measures can be taken.
1. Bone age measurement Bone development is a very good objective indicator to assess the development of the organism, and can be used for height prediction, therefore, bone age measurement is a mandatory test for dwarfism. It is simple, convenient, economical and safe to perform. The amount of X-ray exposure received in one bone age film is very small, about 4 millirad, which is equivalent to the amount of natural X-ray exposure received by a child during a week of outdoor activities.
2.Routine examination Blood and urine examination; liver and kidney function, thyroid hormone level test should be routinely performed; blood gas and electrolyte analysis are appropriate for suspected renal tubular toxicity; chromosome karyotype analysis is required for all girls and boys suspected of having chromosomal disorders.
3.Hypothalamus and pituitary gland imaging examination All children with short stature should undergo cranial magnetic resonance imaging (MRI) to rule out the possibility of congenital developmental abnormalities or tumors.
4.Growth hormone stimulation test Since the secretion of growth hormone is pulsatile, it is difficult to determine whether there is a lack of growth hormone by only drawing blood once to measure the level of growth hormone, so growth hormone stimulation test must be done for children with short stature. The principle is that after stimulation with drugs, the secretion of growth hormone shows a continuous peak secretion within a period of about 2 hours, and within this period of time, blood is drawn every half hour to check the growth hormone, as long as the peak is greater than 10ng/ml, it indicates no growth hormone deficiency; in order to exclude false negative results as far as possible, two drugs with different mechanisms of action are required. Insulin-like growth factor-1 and insulin-like growth factor binding protein-3 are also measured.
IV. How to treat?
1.Treatment for the cause. For example, the growth rate of children with renal tubular acidosis and hypothyroidism will be increased after the relevant factors are eliminated.
2. Growth hormone therapy. Since 1985, when the US FDA approved recombinant human growth hormone (rhGH) for the treatment of growth hormone deficiency, the diseases approved one after another include chronic renal failure, congenital ovarian insufficiency, Prader-Willi syndrome, small for gestational age, idiopathic dwarfism, short bowel syndrome, Noonan syndrome, Shox gene defect without growth hormone deficiency, etc. Depending on the condition, the dosage of growth hormone varies. It is injected subcutaneously once a night at bedtime (or six times a week), and the commonly used injection sites are around the umbilicus, the lateral side of the upper arm, and the outer and anterior flanks of the mid-thigh. Because of its efficacy and safety, growth hormone has been used in clinical practice for nearly 30 years. Nevertheless, the following side effects can be seen (but the incidence is low).
(i) Hypothyroidism, which is mild and usually asymptomatic and improves with discontinuation or dose reduction, or can be corrected with oral L-thyroxine tablets.
(ii) May cause a slight increase in blood glucose, but does not cause diabetes mellitus.
(iii) Idiopathic benign intracranial pressure elevation. All of the above are improved after stopping or reducing the dosage. It is required to follow up after every 3 months to monitor the side effects and clinical efficacy.