Eating disorders and overactivity: Women with eating disorders often have lower bone density, says Goldberg. If there's a problem with your menstrual periods, see your doctor. Over-exercise and anorexia can interrupt your period, possibly signaling inadequate bone density.

Medications: Ask your doctor about the side effects of certain medications. The asthma treatment Prednisone, for example — like other corticosteroids — can adversely affect bone density.

Cigarettes: Smokers need to snuff their butts — for the sake of their bones as well as their heart. "Smokers are at higher risk for osteoporosis," says Goldberg. "If you take a cigarette within the first ten minutes of awakening, you're highly addicted and need nicotine replacement and medication." Ask your doctor about Wellbutrin or Chantix, which alter your brain chemistry to squelch addiction.

More Know-5 Facts: Find out what you need to know about heart health, emotional health, colon health and breast health.