Boning Up

The answer is true. The most common bone density test, called a dual-energy x-ray absorptiometry (DXA) test, measures the density of minerals in your bones and compares that measurement to an established norm, according to the National Institute of Arthritis and Musculoskeletal and Skin Diseases (NIAMS) (www.niams.nih.gov).

There are two ways of measuring bone density: by comparing your score to that of a healthy young adult (called a T-score) or by comparing your score to that of a typical person your age (called a Z-score). T-scores are used to confirm osteoporosis, while Z-scores are used to determine an underlying condition that may be causing bone loss.

A T-score of O means the patient's bone mineral density is equal to that of a healthy young adult. Any difference between the score and the established norm are measured in units called standard deviations. The more SDs below zero, the higher the risk of osteoporosis. A bone density score of -1, for example, is considered normal, but a score of -2.5 or lower confirms a diagnosis of osteoporosis, according to NIAMS.

The U.S. Preventative Service Task Force recommends that all women age 65 and older get regular bone density testing.

The answer is true. For this reason, it's critical that girls, teenagers, and young women get enough calcium and vitamin D, as well as regular weight-bearing exercise, to ensure the development of strong bones. Good sources of calcium include dairy products, such as low-fat or nonfat milk, cheese, and yogurt; dark leafy vegetables, like bok choy and broccoli; calcium-fortified foods, such as cereal, orange juice, or bread; and almonds. Good weight-bearing exercises include running, tennis, field hockey, basketball, dancing, hiking, soccer, and weight lifting.

The answer is true, according to a study published in the June 2007 issue of the Journal of the American Geriatrics Society. The study, which followed more than 4,000 women for four years, revealed that the more depressive symptoms a woman had, the greater the rate of bone loss. Prior studies have shown an increased risk of fractures in depressed women, and researchers at the University of Minnesota School of Medicine say further research is needed to fully understand the findings.

A second study, conducted by the same group of researchers, found that older women who take selective serotonin reuptake inhibitor (SSRI) antidepressants also lose bone mass at a higher rate. This study, results of which were published in the June 25, 2007, issue of the Archives of Internal Medicine, is considered preliminary, meaning that women should not stop their antidepressant use based on the results. The researchers note that the findings cannot definitively determine whether the medication or other factors are responsible for the higher bone-loss rate.

The answer is false. Hip fractures actually account for three times that number, according to a Surgeon General's report on bone health from the U.S. Department of Health & Human Services (www.surgeongeneral.gov). What's more, about 20 percent of older Americans who suffer a hip fracture die within a year of that injury, and about 20 percent of people who fracture their hip end up in a nursing home within a year, the report says. The Surgeon General's report includes several recommendations for improving and maintaining healthy bones, including getting the recommended amounts of calcium and vitamin D through food and supplements, maintaining a healthy weight, getting 30 minutes of exercise every day, and performing balance or coordination exercises to prevent falls.