Medical scientists have identified a number of factors that appear to increase the risk of osteoporosis. To understand how osteoporosis occurs, we need to understand the process of bone building. Bone formation and shaping starts in the womb and continues throughout our lives. Cells called osteoblasts add bone while others, called osteoclasts , break it down. Calcium and phosphorus must be obtained from the food we eat, while hormones are produced by glands in various locations in the body.
Most vitamin D is created by the skin when exposed to sunlight and is also present in some foods.
Osteoblasts use calcium and phosphorus supplied by the bloodstream to produce a hard mineral salt called calcium phosphate. They deposit this chemical outside their cell walls until eventually they become trapped by their own endeavours. At this point they stop building bone, but they continue to attend to the nutritional needs of the bone around them. They are then known as osteocytes . Osteocytes maintain contact with other osteoblasts and osteocytes via a network of tunnels, which also act as passages for nerves and blood vessels.