This is the figure obtained by dividing the weight and kilograms by the square of the height and meters. It is a widely used international standard to measure the degree of obesity and health.
The concept of height and body mass index was first put forward by Belgian statistician and mathematician kettler in the middle of19th century. It is defined as follows:
Body mass index = W÷ H?
W= weight, unit: kg;
H= height in meters;
Body mass index = height and body mass index in kg/m2.
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Extended data
Body mass index was originally designed as a statistical tool for public health research.
When we need to know whether obesity is the cause of a disease, we can convert the patient's height and weight into body mass index, and then find out whether there is a linear relationship between this value and the incidence.
Because the body mass index mainly reflects the overall weight, it is impossible to distinguish between adipose tissue and non-adipose tissue (including muscles and organs) in weight. People with the same height and weight can calculate the same body mass index, but in fact the amount of fat is different, so the body mass index is actually an indicator of the overall nutritional status.
In the past, it was used as an index of obesity, because it was found that body mass index and body fat were highly correlated statistically; However, under the same body mass index, the body fat rate will still be different.
Asian standard
The traditional WHO adult obesity standard is below 30, but the Asian adult index has recently been changed to 27.5. Asian adults with a body mass index of 23 are now considered overweight, while the ideal index is 18.5 to 22.9.
The value of children's body mass index
Children's body mass index values are not only applicable to adults. For growing children, we can also use their body mass index to calculate whether they are overweight. The above formula for calculating body mass index is also applicable to people aged 2-20, but their overweight and body mass index are not determined by a fixed body mass index value.
This is because children in different regions grow at different speeds, and it is easy to make wrong judgments if a fixed value is used. Many countries and regions make statistics on the height and weight of local children every year. These statistics can be converted into body mass index values, and then the distribution of body mass index values of local children can be counted.
According to this distribution, the local health government can calculate the overweight and underweight indicators of local children. Generally speaking, the average body mass index and its standard deviation are used, and then the highest 5% and lowest 5% of its normal distribution are calculated as overweight and underweight indicators. On the other hand, children whose body mass index is within 85%-95% of the normal distribution are at risk of being overweight.
References:
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