How Bones Change and Grow

Because osteoporosis is a disease of the bones, it is important to know some basic information about bones. Your bones are made up of three major components that make them both flexible and strong:

Collagen, a protein that gives bones a flexible framework
Calcium-phosphate mineral complexes that make bones hard and strong
Living bone cells that remove and replace weakened sections of bone

Some people think of bones as hard and lifeless. But, your bones are actually living, growing tissue. Did you know that throughout your life, you constantly lose old bone while you make new bone at the same time?

Children and teenagers form new bone faster than they lose old bone. In fact, even after they stop growing taller, young people continue to make more bone than they lose. This means their bones get denser until they reach what experts call peak bone mass. This is the point when you have the greatest amount of bone you will ever have. It usually happens between the ages of 18 and 25.

Think of your bones as a savings account. There is only as much bone density in your account as you deposit. The critical years for building bone density start before your teen years and may last until your early or mid-20s.

After you reach peak bone mass, the balance between bone formation and bone loss might start to change. In other words, you may start to slowly lose more bone than you form. In midlife, bone loss usually speeds up in both men and women. For most women, bone loss increases after menopause, when estrogen levels drop sharply. In fact, in the five to seven years after menopause, women can lose up to 20 percent or more of their bone density.

Osteoporosis happens when you lose too much bone, make too little bone or both. The more bone you have at the time of peak bone mass, the less likely you are to break a bone or get osteoporosis later in life. But it’s never too late at any age to take steps to protect your bones.