Is nutrition important in osteoporosis?

Osteoporosis is a crippling disease that affects millions of people worldwide. It is characterized by loss of bony tissue from the skeleton and deterioration of bone structure, and is associated with enhanced bone fragility and increased risk of fracture (Consensus Development Conference, 1991). Fragility fractures are most common at the wrist, spinal vertebrae and hip, although they can occur throughout the skeleton. The incidence of vertebral and hip fractures increases exponentially with advancing age while that of wrist fractures levels off after the age of 60 years (Compston, 1993). Osteoporosis can be divided into two main categories (Melton 8z Riggs, 1988; Compston, 1993). Type I (postmenopausal) typically occurs between ages 50-75 years and is more common in women than men (women : men 6 : 1 approximately). Fractures occur predominantly in trabecular bone, especially the distal radius (Colles’ fracture) and the spinal vertebrae (crush fracture). Bone loss is accelerated, parathyroid hormone and 1,25-dihydroxycholecalciferol levels are reduced and Ca absorption is decreased. Oestrogen deficiency is regarded as the main pathogenetic factor of Type I osteoporosis, and hormone-replacement therapy is effective in reducing the bone loss and fracture risk associated with the menopause (Compston, 1993; Lindsay, 1993). Type I1 (senile) affects women and men over the age of 70 years (women : men approximately 2: 1). Fractures occur in both cortical and trabecular bone, most commonly in the proximal femur (hip) and the spinal vertebrae (wedge fracture). Unlike Type I, bone loss in senile osteoporosis is not accelerated, and parathyroid hormone levels may be raised. There is increasing evidence that this hyperparathyroidism plays an important role in the pathogenesis of Type I1 osteoporosis and is secondary to vitamin D insufficiency (Compston, 1993; Khaw & May, 1995). Osteoporosis is a major public health problem in the UK, affecting one in three women and one in twelve men (National Osteoporosis Society, 1996). There are currently over three million sufferers in the UK, where approximately 60 000 hip fractures, 50 000 wrist fractures and at least 40 OOO vertebral fractures occur each year. Approximately one-third of orthopaedic beds in the UK are occupied by hip-fracture patients and treatment of osteoporosis costs the National Health Service in excess of f750 million per annum. Osteoporosis is often associated with considerable pain, disability and disfigurement, and can lead to premature death. Approximately 50% of elderly hip-fracture patients do not regain full independence, and 20 % die within 6 months through complications connected with the fracture. Internationally, more than 1.5 million fractures occur annually, and this number is projected to increase 4-fold by the year 2050 (Cooper et al. 1992).