If you are a young adult, start thinking about your bone health, an expert advises.

Most people reach peak bone mass — the strongest bones they will ever have — between 25 and 30 years of age, according to Dr. Philip Bosha, a physician with Penn State Sports Medicine in State College, Pennsylvania.

"To some extent, genetics determines the peak, but lifestyle influences, such as diet and exercise, are also factors," Bosha said in a Penn State news release.

According to the American Academy of Orthopaedic Surgeons, bone mass starts to slowly decrease after age 40. Taking 1,000 milligrams of calcium and 1,000 International Units (IU) of vitamin D a day can help maintain your bones. You should also do weight-bearing exercises such as running and brisk walking, as well as resistance training to maintain bone and muscle strength.

After age 50, the daily recommended calcium intake for men remains 1,000 milligrams per day, but rises to 1,200 milligrams for women, including those who are entering or have gone through menopause.

Declining estrogen levels due to menopause can lead to rapid bone loss. All women 65 and older – and those between 60 and 64 who have an increased risk of fractures – should get a bone density study, according to Bosha.

"If the bone density study shows osteoporosis, it may be reasonable to start taking a medication called a bisphosphonate, which you can get in a variety of forms," he said. "Some are pills taken on a weekly or monthly basis and other varieties can be taken intravenously."

Other medications to improve bone density include calcitonin, which can be used as a nasal spray; parathyroid hormone, which is taken by injection; and medications called selective estrogen receptor modulators.

Bosha said men and women who are 70 and older should take 1,200 milligrams of calcium per day and 800 IU of vitamin D. At this age, men become far more likely to have lower bone density, increasing their risk of fractures. Some men should consider a bone density study, Bosha said.

"For people of this age, avoiding falls is crucial," he said. "Maintaining balance and muscle strength through exercise and maintaining strong bones through adequate calcium and vitamin D intake can help decrease the risk of severe fractures from falls."