Low bone mass, also known as reduced mineral content in the bones, is commonly seen in patients with osteoporosis and rickets, and is indicative of a calcium deficiency in the human body. It occurs in the middle-aged and elderly due to a decrease in sex hormone levels or a decrease in estrogen levels in women during menopause, resulting in increased destruction of osteoblasts and active osteoclasts. It is also seen in hyperparathyroidism, impaired absorption of vitamin D and calcium due to digestive system pathology, excessive loss of vitamin D or calcium due to severe kidney disease, and in patients who frequently apply hormonal drugs, heparin, and cyclosporine. While rickets is mainly caused by insufficient vitamin D intake, vitamin D deficiency, impaired absorption or excessive loss related, also seen in insufficient light and other reasons.