Prevention of Osteoporosis

Article submitted by: Imogen


Regular Wheelchair Activity and the Prevention of Osteoporosis

Evidence suggests that wheelchair users are at increased risk of osteoporosis. This bone-thinning disease, not only leads to broken bones – most commonly of the wrist, hip and spine - but can impair quality of life and increase someone’s risk of mortality. While our bones are constantly being broken down and replaced with new tissue, as we age the rate at which bone is lost exceeds the formation of new bone, but in osteoporosis bone loss occurs more quickly still. Certainly studies amongst people who have experienced spinal cord injuries and use a wheelchair show that the rate at which bone loss occurs hastens and within the first 16 months following damage to their spinal cord, a reduction of up to a third of someone’s bone mass can occur; such a large fall in bone density can place someone at significant risk of experiencing a fracture. It has been suggested that bone loss occurs more quickly in wheelchair users, as they do not undertake weight bearing activity – that is activity when on your feet, where the weight of your body stimulates the growth of new bone in the lower body thus strengthening the bones of the legs, pelvis and lumbar spine. However, there is some evidence that activity undertaken whilst in a wheelchair can have a positive impact on bone density and therefore reduce osteoporosis risk.

Scientific research

A study which investigated the difference in bone density between athletes who used a wheelchair and those who did not, found that although the leg bone density of wheelchair users was around a quarter lower than the able bodied athletes, no difference was observed in the bone density of their arms. Additionally those athletes who commenced activity sooner after treatment showed higher levels of bone density in their legs, torso and body as a whole; these results held true even when other influencing factors such as age and the type of sport were controlled for. Another study found that wheelchair users participating in racket sports had greater bone density in the spine and hip; although the curling wand could not be described as a racket and less force is exerted, the upper body actions required in curling could still prove helpful in preserving bone mass. This provides evidence that wheelchair activity can help to maintain bone density in the upper body and that commencing such activity as soon as is practical to do so can help to preserve bone density throughout the entire body. Therefore, not only can participation in wheelchair sports help with rehabilitation, but it can provide long-term benefits for bone health.

Other lifestyle factors

Whilst undertaking regular wheelchair activities may help to slow the decline of bone mass, it is likely to have most benefit when combined with other lifestyle changes shown to be protective against osteoporosis.

• Smoking is well known for its negative impact on various aspects of health, which extends to that of the bones; smokers are more likely to develop osteoporosis and although the mechanism for this is unclear, this is yet another good reason to quit smoking. 
• While many people are aware of the importance of adequate calcium in the diet to maintain bone strength, not everyone is able to achieve sufficient intake of this important mineral. As a general rule, including three servings daily of dairy produce or their equivalent –a serving would be a third of a pint of milk, a 6oz pot of yogurt and an ounce of cheese – as well as other calcium rich foods such as tinned fish with bones, green leafy vegetables, dried fruit, pulses and nuts will help to ensure enough calcium is obtained through the diet. 
• Vitamin D aids calcium absorption and our main source of this is through the action of sunlight on our skin; though as many of us now spend less time outdoors and use sunscreen, the amount we produce is suboptimal. A few dietary sources of Vitamin D exist – oily fish, eggs, as well as cereals, margarine and milk fortified with the vitamin – but it would be difficult to meet the recommended daily intake. If you are concerned you are not obtaining adequate calcium or Vitamin D, speak with your doctor or pharmacist, as a supplement may be indicated. 
• Besides calcium and Vitamin D a range of other vitamins and minerals play a role in preserving bone strength, so the best way to achieve an adequate intake of these is to eat a balanced diet including all food groups – namely carbohydrates, fruit and vegetables, protein rich foods and dairy foods. 
• Salt is composed of sodium and chloride, and high levels of both in the blood are associated with adverse effects on the body. Diets high in salt can contribute to a fall in bone mass. This is thought to be due to the fact that an excess of sodium in the blood is associated with increased urinary calcium excretion; this calcium is thought to largely come from the bones. Reducing salt intake has been shown to lower urinary calcium losses and halving daily salt intake from 10g to 5g has the same benefit on bone density as taking a high strength calcium supplement. As well as directly increasing calcium losses, the increase in blood pressure seen with high salt intakes is itself thought to further increase calcium losses via the kidneys. 
• A high alcohol intake is another known risk factor for osteoporosis. Alcohol interferes with the body’s ability to absorb calcium, triggers the release of stress hormones that signal increased loss of bone and may directly damage the cells involved in bone formation. If you wish to drink alcohol stick within the recommended guidelines, which in Canada have been set as no more than 10 alcoholic drinks a week for women and a maximum of 15 for men; though drinking less than this is likely to carry greater benefits.

Through a combination of regular exercise and other lifestyle modifications, wheelchair users can help to preserve the strength of their bones and reduce their chance of developing osteoporosis. Taking part in wheelchair curling or similar activities may therefore play an important role in the prevention of fractures.