Answer: We're all getting shorter with age. Blame gravity. There are 23 discs between the vertebrae that make up our spine. Over time and over the years, these shock-absorber discs dry out a bit and get compressed from all the weight of gravity they bear. That causes them to shrink a bit.

Let's say that you lose 1 to 2 millimeters of height from each disc. That may seem pretty small, but if every disc loses that amount, that's between 23 and 46 millimeters of height. There are 25.4 millimeters to an inch, so it's easy to shrink an inch or so with age.

Even our daily height varies by 1/4 to 1/2 inch, depending upon the time of day. At the end of day, we're a little bit shorter, thanks to the effect of gravity; by morning, we've gained that height back. So if you want to feel taller, measure your height first thing in the morning.

But there's another aspect to all this: bone loss from osteoporosis. If there's significant bone loss and decreased bone density, the vertebrae themselves may compress or even fracture. That's why screening for osteoporosis in women at menopause (or earlier, if on chronic steroids) and any men that might be at risk is so important. While we've got drugs to slow the rate of bone loss (estrogen replacement therapy, calcium) and drugs to reverse osteoporosis (Evista, Fosamax, Actonel, and Boniva), we can't restore height to your spine. The only exception is an acute compression fracture, for which an orthopedic surgeon can perform a procedure called "kyphoplasty" to restore height and mend the fracture.

But gravity can be a good thing, too. It stimulates bone activity and helps combat osteoporosis. Astronauts, nearly weightless in space, suffer accelerated loss of bone. The benefit of weight-bearing exercises like walking, jogging, tennis, or dance is clear.

Thyroid nodules are quite common

A: Let me reassure you: Thyroid nodules are very common; one in 12 to 15 women and one in 40 to 50 men will show some sort of thyroid nodule on a thyroid sonogram.

But more than 90 percent of thyroid nodules are benign/noncancerous, which means there's only a 5 percent to 10 percent chance you've got thyroid cancer. Most thyroid nodules occur in folks with perfectly normal thyroid function.

Historically, a nuclear thyroid scan was used to tell if a thyroid mass was solid or a fluid-filled cyst. It identifies a lesion as "hot" or "cold," depending upon whether it takes up the contrast dye. It had been incorrectly assumed that "cold" nodules were cancerous and that "hot" nodules were benign. Since a good many "cold" nodules are benign, a thyroid scan can't make the diagnosis for you; a fine-needle tissue biopsy is needed.

If your biopsy does show thyroid cancer, most of it is slow-growing and unlikely to metastasize (spread beyond the lymph nodes in the neck). Surgery followed by radiation treatment is the usual protocol for most thyroid cancers. In the vast majority of folks, these steps will cure thyroid cancer.