Osteoporosis is a disease characterised by brittle bones, resulting in an increase in fracture risk. In the UK, 1 in 2 women and 1 in 5 men over the age of 50 suffer from osteoporotic fractures (National Osteoporosis Society, 2016) and this high prevalence causes a substantial cost to the National Health Service, writes Dr Jacky Forsyth – who works in the centre for Sport, Health and Exercise Research at Staffordshire University.
Osteoporosis is not limited to old age – deterioration in bone health can start at a young age due to inappropriate lifestyle choices – however, osteoporosis is generally not diagnosed until later in life. For this reason, osteoporosis has been described as a ‘silent disease’, in that an individual will not realise that they have it until they suffer from their first osteoporotic fracture, by which time, it is often too late to repair the damage already done.
Preventing the occurrence of osteoporosis, through changes in exercise and diet, is key to ensuing that this disease does not progress in our burgeoning ageing population. The role of the fitness professional in promoting positive lifestyle changes to improve people’s bone health is important in this prevention. The purpose of this article is to provide background information on bone remodelling and osteoporosis, and to suggest some novel, research-informed ideas that can be used to promote good bone health.
An individual is said to have osteoporosis if they have a T score, as measured using DXA (which stands for Dual-Energy X-Ray Absorptiometry) below -2.5, which means that their bone mineral density is 2.5 standard deviations below that of a healthy, young adult (World Health Organisation, 1994). A Fracture Risk Assessment Tool (FRAX®) has also been developed, which uses risk factors such as sex, age, family history of osteoporosis, and smoking status, to ascertain the likelihood of sustaining a fracture over a given period of time. Worldwide, an osteoporotic fracture is estimated to occur every three seconds (Jonell & Kanis, 2006), and as a result, wellbeing and quality of life can deteriorate (Forsyth & Babatunde, 2015). Determining risk of fracture by understanding the risk factors is the first step in preventing osteoporosis.
Bone is in a constant state of remodelling, whereby osteoclasts – which are the bone-absorbing cells – break down the bone leaving spaces, termed resorption pits. Osteoblasts – which are the bone-building cells – migrate towards these pits, secreting collagen and various proteins, to rebuild and re-mineralise the bone. This process is constantly happening in all parts of the bone, but at different stages, and takes approximately three months to complete (Forsyth & Davey, 2008).
Bone remodelling is determined by several factors, including the amount of calcium available in the blood, and the availability of hormones, such as oestrogen, growth hormone and testosterone. For instance, when blood calcium levels are low, bone is resorbed (breaks down), so that calcium stored within the bone is made available in the bloodstream. Conversely, when blood calcium levels are optimal