Diagnostic criteria for child malnutrition

The core judgment thresholds of the growth and development reference standards for children under 7 years old in China's nine cities and the WHO child growth standards are that the corresponding indicators are lower than the median of the reference population of the same age and gender minus 2 standard deviations (-2SD, that is, Z score <-2), and then divided into three levels: mild, moderate and severe according to the degree of deviation.

Last week, I met a mother at the child care clinic. She rushed in with a "Standard Weight Comparison Chart for Children Aged 0-6" made by a parenting blogger and said that her 3-year-old boy was 2 taels lighter than the "standard value" on the chart. He was suffering from mild malnutrition. She even wanted to replace her milk powder with high-calorie special medical powder. I pulled the baby over and measured his height, and then checked his growth curve from birth to now. It has been stable at -1.2SD. Both my parents were tall and thin people who always sat in the front row of the classroom when they were in school. The vitamin and albumin indicators in the blood tests were all normal. They chased me to get the cartoon stickers on my desk. No matter how you look at it, they are not related to malnutrition. I encounter this kind of situation where I use Internet celebrity charts to check my own weight three or four times a week. Many people don’t know that those “standard weight charts” that are accurate to a few tenths of a kilogram are essentially made by extracting the median of the reference population and have no diagnostic value at all.

The two reference systems currently used in the industry actually have their own applicable scenarios, and there have always been small-scale disputes. When conducting mass nutrition screenings, the CDC prefers to use the reference standards for child growth and development in nine Chinese cities released in 2015. After all, they are based on data collected from more than 200,000 healthy children in the country and are more in line with the growth characteristics of Chinese children. ； When pediatric clinical encounters include children with underlying diseases, living across borders, or whose height is different from the general population, they often refer to the WHO growth standards. This set of data covers healthy breastfed children of different races and is more helpful in eliminating biases caused by feeding methods and race. For example, I met a Chinese-Thai mixed-race child who lived with his mother in Thailand until he returned to China when he was 2 years old. His height was -1.8SD based on the nine-city standard, and he was almost judged to be stunted. However, it was within the normal range of -0.7SD based on the WHO standard. Combined with his parents' height, it was completely normal.

Many people think that malnutrition means "thinness". In fact, in recent years, clinical practice has classified overnutrition into the category of malnutrition. A grandmother brought her 4-year-old grandson here before. The baby was chubby and gasped after running for two steps. The grandma proudly said, "My baby is well-raised and weighs ten pounds more than others." The results showed that the serum albumin was normal, but vitamin D was only half of the normal value, zinc was deficient, and the weight exceeded the median +2 SD for the same age. This is a typical malnutrition of excess energy and lack of micronutrients. If you just look at the "Is the weight enough" table, you can't find out this situation. In current routine diagnosis, weight-for-height is used for emaciation, height-for-age is used for growth retardation, weight-for-age is used for underweight, and BMI is used for overweight and obesity. Different types correspond to different indicators and can never be covered by one table.

As for the diagnosis of school-age children and adolescent children over 5 years old, there is currently no completely unified standard in the industry. Most pediatrician doctors are accustomed to following the growth curve. As long as you do not deviate from your own growth track for more than six months, it doesn't matter if you are a little thinner than your peers. ； However, pediatric endocrinologists tend to pay more attention to the match with the stage of sexual development. For example, adolescent children are supposed to have a period of rapid weight gain. If the weight falls during this stage, even if it is still above -2SD, they should be alert to whether there is malnutrition. I met a 12-year-old girl before. In order to lose weight after her period, she lost 8 pounds in half a year. Her weight for age is still within the normal range of -1SD. However, she has stopped menstruating for 3 months and her serum albumin has also dropped. In fact, she is moderately malnourished. If the watch is used, the diagnosis will definitely be missed.

I have been seeing patients myself for so many years, but I rarely face the table card threshold directly. After all, standards are dead and people are alive. Some children are familially thin, and their growth curve has been between -1.5SD and -2SD since childhood. They can eat and sleep, have fewer illnesses, can keep up with exercise, and have normal blood test indicators. There is no need to label them as malnourished. Forcing children to take various supplements can easily cause feeding anxiety.

As for the "standard table" that everyone wants, in fact, the official website of the National Health Commission has a public growth indicator percentile comparison table for children aged 0-7, which is completely sufficient for daily screening. However, be sure to remember that the table is only a screening tool. To truly diagnose malnutrition, a doctor must make a comprehensive judgment based on the child's feeding history, disease history, family history, and laboratory tests. Don't mess with the table by yourself, which will burden the child and yourself.