Around 10 million American adults (8 million women and 2 million men) have osteoporosis, putting them at risk for bone fractures caused by everyday motions such as bending, coughing, and lifting. Or they can even happen spontaneously.

Why is bone health such a challenge for around 17% of people ages 65 and older?

A new look at data on almost a million people reveals that some unexpected lifestyle choices — along with some expected ones — may be to blame.

The study, published in the Journal of the Endocrine Society, found that skipping breakfast and eating a late dinner were surprisingly major risks, increasing a person's chance of fracturing his or her humerus (the bone that runs from the shoulder to the elbow), spinal vertebrae, and the hip.

Such eating patterns amplified the chance of developing brittle bones, which excess alcohol consumption, smoking, deficient dietary calcium and vitamin D, sedentary behavior, and chronic lack of sleep also contribute to.

To prevent fragile bones, it’s important to do both aerobic and weight-bearing exercise every week, and to get plenty of calcium from low-fat or nonfat dairy, dark leafy greens, sardines, canned salmon, and tofu.

If you’re at increased risk because of long-term steroid use, smoking, excess alcohol intake, or low blood levels of calcium and vitamin D, talk to your doctor about taking calcium and vitamin D supplements.

Menopausal women should also consider hormone replacement therapy.