The role of vitamin D in the management of osteoporosis

  • Vitamin D plays a major role in calcium absorption and bone health. It regulates synthesis and secretion of PTH, stimulates osteoblast function and promotes mineralisation of osteoid, regulates calcium and phosphate absorption and has a probable role in muscle by promoting strength, tone and balance. It is now considered to also stimulate immunogenic and anti tumour activity.
  • International data consistently demonstrate that vitamin D deficiency is almost universal in hip fracture patients and world wide, more than half of women diagnosed with osteoporosis are shown to be vitamin D deficient regardless of age, latitude or season.
  • Adequate vitamin D is generally not obtained in the diet of the elderly in whom additionally, sunshine exposure tends to be minimal.
  • Adults under the age of 50 need 400-800IU of vitamin D daily and adults aged 50 and older need 800-1000IU. (National Osteoporosis Foundation: Updated Recommendations for Calcium and Vitamin D Intake, July 26 2007).
  • In the elderly patient previously untreated, vitamin D insufficiency might be assumed, corrected by calciferol 50,000IU daily for 10 days, and maintained by 50,000IU monthly (with or without oral vitamin D 400IU daily as multivitamin or combined with alendronate). This regimen should maintain levels and is well within safety limits.
  • Activated vitamin D metabolites (calcitriol and alfacalcidiol) are regarded as inadequate mono-therapies for the treatment of osteoporosis and will not reverse deprivational vitamin D deficiency. Data regarding their efficacy is mixed and there is some evidence they accelerate bone resorption if used alone.