Q: I was just diagnosed with osteoporosis (thin bones). I know this can lead to pain and hunchback due to spine fractures. How can I prevent this?

A: Don't forget hip fractures, which can be devastating — 1 in 3 victims become totally dependent or end up in nursing homes. Slender Caucasian and Asian women have especially weak bones. All women 65 or older should get a bone-density test, and if you weigh less than 150 pounds or have other risks, get screened at age 60. Avoid smoking and excessive alcohol, which thin the bones. Walk or dance regularly to strengthen your hips. It's unclear whether phytoestrogens reduce fractures.

Most Americans don't get enough calcium or vitamin D — both are needed to decrease the possibility of fractures. Men and premenopausal women need at least 1,000 milligrams of calcium a day, while women after menopause need 1,200 to 1,500 milligrams a day. Extra calcium also reduces polyps — lumps of tissue in the colon that sometimes become cancers.

Each dairy serving (a cup of milk or yogurt) and cup of fortified orange juice has 300 milligrams of calcium. Tofu processed with calcium salts can have as much as 300 milligrams — read the label. Tally up your total to see if you need extra supplements. Many natural calcium carbonate products such as oyster shell, bone meal and dolomite have lead contamination, so go with something like Tums (yes, the chewable antacid) or Citracal. Tums Ultra has 400 milligrams of calcium and Citracal has 250, 315 or 400 milligrams of calcium as the citrate form, which is more easily absorbed by the elderly. You may need to take these two or three times a day.

The frail elderly are especially prone to vitamin D deficiency because of lack of exposure to sunlight. Ten to 15 minutes exposure of hands, arms and face two to three times a week is usually enough. Older adults need 600 to 800 International Units (IU) of vitamin D a day, which may also increase muscle strength. It's only toxic above 2,000 IU a day. Milk contains about 100 IU of vitamin D per cup. Also add the amounts present in some calcium supplements.

But don't rely on calcium and vitamin D alone — drugs such as alendronate and risedronate are much more effective in reducing spine and hip fractures. Raloxifene reduces spine but not hip fractures. It may possibly lower heart disease and breast cancers but can cause hot flashes, leg cramps and, occasionally, dangerous blood clots in the leg veins.

Dr. Landis Lum is a family-practice physician for Kaiser Permanente and an associate clinical professor at the University of Hawai'i's John A. Burns School of Medicine. Send your questions to Prescriptions, Island Life, The Advertiser, P.O. Box 3110, Honolulu, HI 96802, islandlife@honoluluadvertiser.com or fax 535-8170. This column is not intended to provide medical advice.