Vitamin D deficiency refers to a series of related diseases in the human body due to a lack of vitamin D, which is an important cause of rickets in children, osteoporosis in the elderly, and fragility fractures.

In most areas of the country, the incidence of vitamin D deficiency or insufficiency exceeds 60%, with the elderly and pregnant women at the highest risk of vitamin D deficiency.

Common causes of vitamin D deficiency in infants and young children include insufficient perinatal reserves, insufficient sunlight, insufficient intake of vitamin D through food, and increased requirements. 

The causes of vitamin D deficiency in adults include insufficient intake, insufficient synthesis, the effects of age and other diseases.

Children may experience irritability, hyperhidrosis, bone deformities and muscle relaxation. The main symptoms in adults are osteoporosis, muscle weakness, fall and fracture.Vitamin D levels in the blood can be tested to determine whether there is a deficiency, and other bone X-rays and bone density tests can be used to help diagnose.

The supplementary methods for different populations are different, it is recommended to choose the appropriate supplement program under the guidance of doctors. In addition to vitamin D, appropriate supplements of calcium and other trace elements can improve symptoms, promote bone development in children, and improve bone density in the elderly.