Old age is the main reason why osteoporosis occurs. From middle age onwards bones become notably thinner and more porous as levels of sex hormones essential for bone replacement decline. As we get older osteoporosis affects nearly everyone to some degree. Women are particularly targeted after the menopause.
Bones are continually being broken down and rebuilt for growth and repair. In young people the rate of bone formation exceeds the rate at which bone cells are reabsorbed. As we get older the rate of re-absorption becomes greater than the rate of regeneration. The skeleton gradually becomes weaker and lighter.
The rate of re-absorption of bone cells by the body can determine how severe osteoporosis is. This rate can be genetic and if your parents have osteoporosis you are more likely to get it as you age.
For more information on bone disorders Click The Human Body Skeletal System