Osteoporosis and Fracture Risk: Osteoporosis is a disease characterised by low bone mass which affects both men and women but with a higher prevalence among women. It is estimated that 1 in 3 women over age 50 will experience fractures due to osteoporosis, as will 1 in 5 men. With people living longer, the lifetime risk of a fracture related to bone fragility is heightened.
Caitriona Cunningham is an Associate Professor at UCD School of Public Health, Physiotherapy and Sports Science. A Chartered Physiotherapist, she and colleagues at UCD cofounded UCD’s Better Bones programme in 2012, which focused on empowering individuals (age 55+) to adopt positive bone building and fracture prevention behaviours
Bone Health across the Lifespan
Childhood and adolescence represent a critical period for the development of strong healthy bones with peak bone mass usually achieved between age 25 to 30. Bone density remains relatively stable until age 50 but begins to decline thereafter. Adopting and sustaining healthy lifestyle behaviours including exercise, a healthy diet (adequate calcium, Vitamin D, Protein intake) and getting sufficient sun exposure (Vitamin D) are advocated to promote bone health across the lifespan. At menopause bone loss may accelerate significantly in women due to the reduction in oestrogen, a key regulator of bone metabolism. Women should actively seek a DXA scan at that time. Where bone loss issues are identified, pharmacological therapy may be required which is based on a number of factors including DXA findings, prior fragility fracture and the risk of future fracture.
Exercise and Bone Health
Exercise for bone health should start in the childhood years with the goal of optimising peak bone mass. In the middle years maintaining bone mass is the goal and in later life, the emphasis is more on slowing down bone loss. As for all exercise programmes achieving an effective exercise dose is critical with consideration of frequency, intensity, type and time (FITT). Some bone health exercise programmes aim to prevent osteoporosis in healthy populations whereas exercise prescription for individuals with osteoporosis requires risk stratification.
What type of exercise is optimal to build bone?
Bone responds to mechanical stimuli with adjustment of skeletal mass and architecture in response to changing mechanical environments. The best types of exercise to build bone (osteogenic exercise) are impact (involves running, hopping and jumping) and resistance (strength) training with a combination of both the most effective. Strength training is also critical to slow down age related loss of muscle mass and function. Walking is a form of impact exercise but higher impact, more unusual activity will likely induce an even better bone formation response. Recent research places more emphasis on the need for higher loads to enhance bone when engaging in resistance training. Most of the studies regarding exercise interventions focusing on enhancing bone have been conducted in post -menopausal women. Mixed loading programmes (impact+ resistance training) conducted two to three times per week for approximately one hour for over six to nine months have shown positive changes in bone mineral density (BMD) on DXA scan. However, the minimal effective exercise dose to enhance BMD has not been established to date.
Exercising if have osteoporosis
Maintaining an active lifestyle is always positive and it is important that individuals with osteoporosis do not become fearful about exercise participation but adapt their exercise as required. ‘Bone building’ may continue to be a key goal of exercise for people with osteoporosis. However, when osteoporosis is more severe the main focus switches to improving muscle strength and balance to maintain and enhance function and reduce the risk of a fall and fracture, rather than aiming for an improvement in bone density. For example, where a person has severe osteoporosis of the spine and/or a history of a fragility fracture, exercises which involve lifting heavier weights with twisting of the spine are to be avoided, consistent with manual handling principles. In addition, higher impact exercises may not be appropriate. A risk benefit assessment and exercise prescription by a physiotherapist is recommended, bearing in mind that maintaining cardiovascular fitness through exercise is always important for health.
• Exercise for bone health should start in the childhood years and continue through all life stages
• A combination of strength and impact exercise is optimal for building bone
• A DXA scan is recommended for women around the time of menopause, with repeat scans thereafter.
• Consultation with healthcare professionals is critical to decide on the need for initiation of pharmacological therapy to enhance bone, a decision which is based on a number of factors including DXA findings, prior fragility fracture and the risk of future fracture.
• Exercise continues to be very important for women with osteoporosis and consultation with a physiotherapist is recommended