The bone age of a 9-year-old child is just equivalent to 7 years old, may be caused by calcium deficiency, you can sunbathe more, supplement vitamin D, calcium tablets and so on. 1. More sunshine: children’s bone age is generally considered to be caused by a lack of calcium, daily life can be more sunshine, appropriate exercise, do some jumping sports, speed up the metabolism, the sun can promote the body’s absorption of calcium, is conducive to the development of bones, bone age growth, to maintain an adequate intake of nutrients for the absorption of the body. 2. Supplemental vitamin D calcium tablets: the reason for children’s small bone age is the lack of vitamin D, calcium and other causes, daily life can be supplemented with vitamin D, calcium tablets, reduce the gap in bone age, such as oral vitamin D calcium, but also in the daily food choices, such as dairy, lean meat and other foods with high calcium content, fresh fruits and vegetables, vitamin D-rich foods. If you exclude the small bone age caused by vitamin D and calcium deficiency, you should go to the hospital for growth hormone examination, exclude the causative factors and treat the symptoms.