Symptoms of calcium deficiency vary according to age, such as muscle twitching, irritability, weakness of limbs, poor dental development, etc. Infants and young children with calcium deficiency usually show symptoms such as irritability, increased jumping, anorexia, occipital baldness, sparse teeth, and so on. 1. Calcium deficiency in infants and young children: Calcium deficiency in infants and young children usually manifests as irritability, increased jumping, anorexia, occipital baldness, sparse teeth and other symptoms, and those with severe calcium deficiency may also have chicken breast, rib cage beads, X-shaped legs or O-shaped legs and so on. 2. Calcium deficiency in adolescents: Calcium deficiency in adolescents mainly manifests as irritability, poor energy, poor bone development, muscle twitching, weakness of the lower limbs and so on. 3. Calcium deficiency in middle-aged and old people: most of the middle-aged and old people with calcium deficiency will suffer from memory loss, irritability, numbness and weakness of limbs, insomnia and sleeplessness. It is worth noting that calcium deficiency in middle-aged and elderly people causes osteoporosis, which reduces the hardness and strength of bones and makes them prone to fractures. If the above symptoms occur, it is recommended to go to the hospital as soon as possible to clarify the cause of the disease and intervene in a timely manner.