Here's an article by Dr. Komaroff, author of the "Ask Dr. K"column published in newspapers and online, about medications that can lower your bone density. Topping the list are corticosteroids for conditions such as asthma. Steroids work in several ways to weaken bone, as the article explains. If you need these medications to treat a serious medical condition, you may not be able to avoid them. However, you can monitor your bone density with dexa scans, eat a healthy diet with plenty of calcium, and include weight-bearing exercise in your lifestyle.