Can bone age be younger than your chronological age?



I have a few questions to ask:

  • Can bone age be younger than the chronological age, and if so what happens then?
  • Do teenagers gain weight before a growth spurt?
  • Does hyperthyroidism affect growth? 

Thank you.


Bone age is a measure of the progress of development. Instead of dividing the progress into five stages as Dr. Tanner, the Bone Age Test uses the average age of people as they develop. Thus, a bone age of 14 means the average 14-year-old has equivalent bone development as you do. But since this is an average, this means that there are people who are older who have this point of development and there are people younger who have this point of development. But then, no one grows exactly the same as other people.

Most teenagers naturally gain some weight during stage 2 as the body stores energy for the growth that takes place in stages 3 and 4. That extra fat is lost during growth, even though your total weight may continue to increase because of your larger body.

Hyperthyroidism, which includes Grave’s Disease, does impact a person’s development if it is not kept under control. Exactly how it impacts development is not well documented. Common symptoms are nervousness, anxiety, insomnia, high heart rate, and eye problems. See Should I have surgery or radiation to treat my hyperthyroidism or wait?