I am 55 years old and seem to be getting shorter as I get older. What causes this?

Many people lose height with age. There are several reasons for this. First, the effect of gravity over many years pulls us forward. Unless we make a conscious effort to stand up straight, our posture changes as we age. This affects our height or stature.

Second, the bones in the spine (vertebrae) change with age. This is true for both men and women. There is a general tendency for the vertebra to collapse inward around its edges. This is referred to as increased concavity. Keeping active helps prevent this from happening.

Third, loss of bone called osteoporosis can cause changes in the spine. The bones can collapse and shift forward, causing a stooped posture and loss of height. This can be prevented or at least managed with a doctor's help.

Finally, discs between the bones can lose height, though this is less common. Discs do get stiffer with age, but they don't usually lose fluid or collapse in the average adult.