The main danger of low 25 hydroxyvitamin D3 is that it can easily affect the absorption of calcium and thus induce abnormal diseases. The specific hazards should be analyzed according to the age stage, and different age stages are prone to different hazards, which require timely vitamin D supplementation. 1, infants and young children: in infancy, the presence of low 25 hydroxyvitamin D3 in the body usually directly affects calcium absorption, which can affect the growth and development of fractures, thus triggering rickets, the child is prone to square skull, chicken chest, rickets 2, young people: for young people, if there is a deficiency of 25 hydroxyvitamin D3, it is easy to produce the phenomenon of calcium deficiency in the body, which can lead to bone and joint pain, such as knee pain or low back pain symptoms; 3, the elderly: the phenomenon of 25 hydroxyvitamin D3 deficiency in the elderly, usually easy to lead to abnormal calcium absorption, will induce the problem of osteoporosis, which can lead to pathological fractures. This can lead to pathological fractures, such as compression fractures in the spine. If the degree of low 25 hydroxyvitamin D3 in the body is more serious, you need to seek medical examination as soon as possible, and then targeted treatment to prevent abnormal disease problems later. In life, pay attention to regular medical checkups, if there is a lack of nutrients, to timely supplementation. Diet can be appropriate to eat more calcium-rich foods, such as silverfish, shrimp, and more exposure to outdoor sunlight to promote calcium absorption.