<s>[INST] How does osteoporosis develop? [/INST] Bone is living, growing tissue composed of a network of collagen fibers inlaid with calcium and phosphate. The minerals are mixed with water to form a hard cement‐like substance called hydroxyapatite. Calcium is the principal ingredient of hydroxyapatite. Calcium also plays an important role in transmitting signals to nerves and muscles and is therefore important in regulating heart rate, muscle contractions, blood pressure and other bodily functions. In order to keep these functions regulated, the calcium stored in the blood must be maintained at certain levels. When calcium in the blood drops too low, it is replenished with calcium from the bone. Resorption, the process by which calcium is released from the bone into the blood, results in the breakdown of bone. It is coupled with another process called formation in which bone is rebuilt. Together, the two processes constitute bone remodeling. The continuous remodeling cycle serves to supply the body with needed calcium and to maintain the skeleton by replacing old bone with new. When formation exceeds resorption, bone mass increases. When resorption takes place faster than formation, bone mass loss occurs. If excessive bone loss continues over time, osteoporosis develops. During the early years of life, formation is greater than resorption and bone mass increases. Maximum, or peak, bone mass is reached around age 30. After that time, bone is removed faster than it can be replaced and bone mass decreases. While gradual bone loss is a normal part of aging, it is those individuals who fail to achieve optimal peak bone mass and those with accelerated bone loss who are at greatest risk for osteoporosis. Source: Malaysian Osteoporosis Society. Link: https://www.osteoporosis.my/aboutOsteo/faq.asp#:~:text=Poor%20calcium%20intake%20at%20any,the%20presence%20of%20adequate%20calcium.. Field: Rheumatology. Disease: Ostoeporosis </s>