1. How can I prevent osteoporosis before it starts?

Experts now think osteoporosis is a largely preventable disease. And prevention starts early. Getting enough calcium as a child and teenager can dramatically cut your risks of developing osteoporosis later in life. Even if you're an adult, eating a good diet, getting enough calcium and vitamin D, exercising, and avoiding lifestyle habits such as smoking and excessive drinking, can help prevent osteoporosis. To learn about osteoporosis prevention techniques you should talk to your doctor.

2. Am I getting enough calcium -- and how much is too much?

The amount of calcium you need depends on your age. Adolescents need 1,300 milligrams of calcium a day. Adults need 1,000 milligrams up to age 50 and 1,200 milligrams after age 50.

The best way to figure out if you're getting enough calcium is to add up the amount of calcium in the foods you eat. For example, an 8-ounce glass of milk has nearly 300 milligrams of calcium, an 8-ounce cup of yogurt has between 250 and 400 milligrams of calcium, and 1.5 ounces of cheddar cheese has about 300 milligrams of calcium. Check the labels. Then compare what you're getting to the recommended amounts of calcium for your age group.

If you're coming up short, talk to your doctor about ways you can boost your calcium levels, like changing your diet or taking supplements. But don't assume that more calcium is always better. Some studies have shown that women who take a lot of calcium supplements are at higher risk of developing kidney stones. The recommendation for the highest tolerable intake of daily calcium is 2,500 milligrams of calcium a day. More than this amount may increase your risk of kidney stones and other problems.

3. Is calcium from dairy products better than from other sources?

Dairy products have high levels of calcium per serving, which is why they're often recommended for bone health. But calcium from other sources -- like spinach, bok choy, and mustard greens, beans, tofu, almonds, fish, and many fortified cereals and juices -- can be just as beneficial. However, it may be difficult to get adequate calcium from food if you don't eat dairy. And osteoporosis experts do say the best source of calcium is from foods, not supplements. Food contains other important nutrients that help the body use calcium.

4. Does osteoporosis affect children -- and should I give them calcium supplements?

Osteoporosis in children is rare. It's usually the result of a chronic health condition such as asthma or cystic fibrosis that is treated with corticosteroid medications. Anticonvulsant drugs used to manage epilepsy, bipolar disorder, and other conditions may also interfere with calcium and vitamin D metabolism, leading to weak bones. Treatment usually depends on controlling the underlying disease or changing the medication. Sometimes, children will develop osteoporosis with no clear cause. It's called idiopathic juvenile osteoporosis, and the good news is that it usually goes away on its own within two to four years.

Of course calcium -- the most important nutrient for strong bones -- is important for all children whether they have osteoporosis or not. Even if children are healthy now, low levels of calcium in their diets can greatly increase their risk of osteoporosis later in life. So keep track of how much calcium your children get from food. If they aren't getting enough, supplements may be an option. But never give your child a supplement without talking to your doctor first.

5. Am I likely to develop vitamin D deficiency in winter -- and why is vitamin D essential for calcium absorption?

Our bodies create vitamin D from sunshine, and all we really need is 10 to 15 minutes of sunshine on our skin a day. During winter, we spend less time outdoors, and we're bundled up against the cold. So some experts think the risk of vitamin D deficiency is higher in winter.

But year-round, many of us don't get the Vitamin D we need. The National Institutes of Health recommends:

• 200 IU (international units) a day for adults under 50
• 400 IU a day for ages 51-70
• 600 IU a day for ages 70 or over

Vitamin D plays a vital role in getting calcium into the bloodstream from the intestines and the kidneys. Without enough vitamin D, a lot of the calcium you take in from food or supplements could pass out of the body as waste. If you don't get outdoors a lot, ask your doctor about vitamin D supplements.

6. Can genetics predispose me to low bone density and osteoporosis?

Your genes can play a big role in your risk of developing osteoporosis. For instance, studies show that if your parents had a history of bone fractures, you're more likely to have weaker bones and a higher risk of fractures yourself.

Your risk of getting osteoporosis is also higher if other family members, like aunts or siblings, had it too. A genetic risk for osteoporosis can be inherited from either your mother or father's side.

If osteoporosis does run in your family, talk to your doctor. You need to take extra steps to prevent it.

7. Why would I have low bone density if I haven't gone through menopause?

Although the drop in estrogen levels during menopause can result in dramatically worsening osteoporosis, it isn't the sole cause of the disease. Many other factors -- like your genes, some diseases and treatments, eating disorders, and deficiencies of calcium and vitamin D -- can play an important role. Remember that men can get osteoporosis too, even though they don't go through menopause either.

8. What is a bone density test and what do the scores mean?

A bone mineral density test is the typical way of diagnosing osteoporosis and predicting your risk of fractures. It's a kind of X-ray that reveals the hardness of your bones. The most common type is called a dual-energy x-ray absorptiometry (DEXA or sometimes called DXA.) Usually, the scans look at the weight-bearing ability of your hip and spine, then uses this information to estimate your risk of fractures.

After the test, your doctor will work out your "T-score." This indicates how dense your bones are compared to those of younger, healthy women. Usually, a T-score defines your score as being above or below the norm.

A normal bone density is a T-score of plus one (+1) to a score of a minus one (-1). A low bone mass (osteopenia) is a bone density T-score of -1 to -2.5. Osteoporosis is defined as a bone density score of -2.5 or below.

9. How do the main osteoporosis medications differ?

The various medicines used to treat osteoporosis work in different ways. Bisphosphonates, including drugs like Fosamax, Actonel, and Boniva, work by blocking the effects of certain bone- destroying cells. In this way, bisphosphonates can slow down bone loss, and lower your risk of fracture. Evista is a different sort of medicine called a selective estrogen receptor modulator, or SERM. It works by mimicking some of the effects of the hormone estrogen, which has a beneficial effect on bone mass.

Other treatments are available. Bone is constantly remodeling -- old bone is removed by cells called osteoclasts, and new bone is laid down by cells called osteoblasts. Calcitonin, a hormone made within the thyroid gland, inhibits bone removal by osteoclasts, and promotes bone formation by osteoblasts. Fortéo (a synthetic hormone) may also help build bone mass by enhancing the actions of osteoblasts.

10. What can I do about medication side effects?

Unfortunately, medicines for osteoporosis -- like any drugs -- can cause side effects. Before you start taking any medicine, your doctor should go over any side effects that may be a cause for concern. If you find that the side effects are unpleasant, go back to your doctor. He or she may be able to help by changing your dosage or switching medications.

11. Why aren't all osteoporosis medications right for me?

Getting the right osteoporosis medication depends on a lot of things: your health, your age, how advanced your osteoporosis is -- even your gender. So the medicine that's right for your sister or neighbor may not be right for you.

Also, when trying any medication, there's always a bit of trial and error. Unfortunately, your doctor can't always know which medicine will work best for you beforehand. Although it may be frustrating, you might need to try several different medicines until you find the right one.

12. Can alternative treatments like soy or cod liver oil help strengthen my bones?

Although a number of supplements are marketed as bone strengtheners, there's very little evidence that they help. Cod liver oil may have some effect, but that might only be because it contains vitamin D. Some small studies have also shown benefits from phytoestrogens found in soy, flaxseed, and other plants, but other studies have not found benefits.

Until more research is done, play it safe. To strengthen your bones, most experts recommend that you stick with the basics: calcium, vitamin D, appropriate exercise, and a good diet. Also, avoid habits that can weaken bones, such as smoking and excess alcohol.

13. Does treatment reverse osteoporosis damage, or just stall it?

Most treatments for osteoporosis -- like bisphosphonates and SERMS -- work by slowing down the process of bone loss. Since your body is always naturally remodeling bone, slowing down the rate of bone loss may allow it to make new bone faster than you lose it. So in a sense, these treatments can reverse the damage. They allow your bones to become denser and stronger, although your body is doing all the repair work.

However, a new treatment with a synthetic hormone called Fortéo is the first treatment that directly spurs the growth of bone. It's usually given as an injection once a day in the thigh or abdomen.

14. What new treatments are on the horizon for osteoporosis?

A number of exciting treatments for osteoporosis are in the works. Some are improvements on old approaches, while others are wholly new. One new bisphosphonate (sold in other countries as Aclasta) seems to improve bone density and significantly cut the risk of fractures -- and it requires just one infusion a year. Denosumab, a monoclonal antibody, is a protein that can block the effects of cells that break down bone. Research indicates that it might be a powerful treatment for osteoporosis.

Since osteoporosis treatment is always changing and improving, check in with your doctor regularly about new approaches that are available.

15. Should men worry about osteoporosis -- and what are the signs of it in men?

Although osteoporosis is often thought of as a disease that only affects women, about 20% of cases are in men. But osteoporosis in men is often unrecognized and untreated. And since osteoporosis is a silent disease, the first symptom is often a broken bone.

Men who are at higher risk for osteoporosis should focus on prevention. Risk factors for osteoporosis in men include taking certain medicines (like steroids, anticonvulsants, and some cancer treatments), some chronic diseases, smoking, lack of exercise, low testosterone, and a family history of weak bones. If you think you might be at risk, talk to your doctor.