A Answers (3)
David Slovik, Endocrinology, Diabetes & Metabolism, answeredTime alone increases the risk for osteoporosis. The researchers in the Study of Osteoporotic Fractures noted that, on average, bone mass fell by approximately 5% every five years after age 65. The risk for a fracture also increases with age. For example, among white women under age 35 there are just two hip fractures per 100,000, but that number soars to 3,000 hip fractures per 100,000 at age 85 or older.
Healthy bones are in a state of continuous breakdown and rebuilding. This process is called remodeling and is performed by specialized cells called osteoclasts, which resorb (break down) old bone, and osteoblasts, which form new bone. In young adults, remodeling happens in a balanced fashion that maintains bone density over time. But as we age, and particularly when women reach menopause and estrogen levels plummet, the process is no longer balanced -- more bone is broken down, and bone building is unable to keep up. The result is reduced bone mineral density (BMD), an increased risk of osteoporosis, and brittle bones that are prone to fracture.
An average adult will have bones the strongest around the mid 30s. After this, advanced age, decreased hormones and lack of exercise all lead to an increased chance of osteoporosis.
As we age our bones are constantly being built up and broken down at the cellular level. However, with advanced age, there is more bone breakdown than formation, making bones weaker with age.
Women are more prone to osteoporosis because of the sudden decrease in estrogen at menopause.
Exercise, specifically weight-bearing exercise, can help to keep bones stronger, but as we age, we lose 10-20% of our muscle strength/power per decade past 50. People who do not exercise are at greater risk for osteoporosis.