VD insufficiency is also known as vitamin D deficiency, the role of vitamin D is mainly to promote intestinal absorption of calcium, increase blood calcium, regulate calcium and phosphorus metabolism, and promote bone development, etc., so the lack of vitamin D is prone to lead to VD-deficiency rickets.The insufficient role of VD can be solved by the following methods: first, drug supplementation, you can use vitamin D injections, or you can take vitamin D3 orally; second, it is recommended to sunbathing more. The skin contains 7-dehydrocholesterol, which can be transformed into vitamin D3 under ultraviolet irradiation, which is the main source of endogenous VD; three, in the process of supplementation of vitamin D should be supplemented at the same time calcium therapy; four, dietary attention to more intake of calcium-rich foods, such as milk, animal liver, sea fish and so on.