Osteoporosis Patient friendly summary

  • UVB light may lower osteoporosis risk by producing vitamin D.
  • Vitamin D increases calcium absorption and improves calcium metabolism.
  • Calcium helps strengthen bones.

Osteoporosis is characterized by low bone mass density and strength. It is an important risk factor for falls and fractures.

In the United States, 26% of women 65 years of age or older have osteoporosis. Osteoporosis is a serious health concern. Each year, the disorder causes:

  • More than 1.5 million fractures
  • 500,000 hospitalizations
  • 800,000 emergency room visits
  • 2.6 million physician visits
  • 180,000 nursing home placements
  • $12–$18 billion dollars in direct healthcare costs

Risk factors

Risk factors include:

  • Low vitamin D blood levels
  • Low calcium and magnesium intake
  • Lack of exercise
  • Smoking
  • Glucocorticoids used to treat inflammation
  • Diet high in saturated animal fats, polyunsaturated vegetable oils, fats, and simple carbohydrates (refined flours, sugar)

Protein increases bone mineral density. Monosaturated fatty acids, green leafy vegetables, and whole grains lower the risk of osteoporosis. These factors are important throughout life. Bones continue to develop through the late teens and must be maintained for life.

Sunlight exposure and osteoporosis risk

Ultraviolet-B (UVB) sunlight is the most important source of vitamin D for most people. Vitamin D helps increase bone mineral density.

Researchers studied hospitalized elderly women with Alzheimer’s disease in Japan. Bone mass density increased by 2.7% in the group exposed to sunlight. Bone mass density decreased by 5.6% in the sunlight-deprived group.

Vitamin D and osteoporosis

Vitamin D levels

There is limited evidence that higher vitamin D levels are linked to lower risk of osteoporosis.

Vitamin D and calcium

Older adults taking both vitamin D3 (cholecalciferol) and calcium had small increases in bone mineral density compared to those taking a placebo.

How vitamin D works

Vitamin D reduces osteoporosis risk by:

  • Increasing calcium absorption
  • Regulating calcium metabolism

Vitamin D and parathyroid hormone (PTH) act in tandem to regulate calcium levels. Vitamin D helps the intestines absorb calcium. PTH obtains calcium from the bones. When vitamin D levels increase, PTH levels decrease rapidly until vitamin D levels reach 30-40 ng/mL [75-100 nmol/L]), after which there is little additional effect on PTH levels.

Vitamin D also helps with calcium metabolism. It directs calcium to the bones and teeth. Vitamin D also prevents calcium deposits in the soft tissues (such as the blood vessels).


Vitamin D and calcium

Vitamin D helps prevent falls and fractures more by stabilizing neuromuscular control rather than increasing bone mineral density.

Studies of vitamin D and calcium supplements are largely related to prevention of falls and fractures rather than enhancing bone mineral density. Vitamin D helps prevent falls and fractures more by stabilizing neuromuscular control rather than increasing bone mineral density. However, together, vitamin D and calcium may slightly increase bone mineral density.


Following diagnosis of osteoporosis, bone mineral density may be increased by:

  • Vitamin D and calcium supplements
  • Vitamin D production from UVB light

Find out more...

We will be adding a detailed evidence summary on this topic in the near future.  Please check back soon to find out more.

Page last edited: 22 May 2011