What is osteoporosis and what affects bone density?
The Royal Osteoporosis Society explain what osteopenia and osteoporosis mean and how diet, lifestyle and genetic factors can affect bone density.
Osteoporosis is often thought of as a condition that only impacts elderly people – but did you know that diet and lifestyle at every stage of life can significantly affect your bone health? BBC Good Food asked the Royal Osteoporosis Society to explain the difference between osteopenia and osteoporosis, which ages are most crucial for bone formation and their top tips for building healthy bones.
What is osteoporosis?
Osteoporosis is a condition in which bones lose their strength and are more likely to break (‘fracture’), usually following a minor bump or fall. Fractures that occur because of reduced bone strength are described as ‘fragility fractures’ and many of these will be caused by osteoporosis. One in two women and one in five men over the age of 50 experience fractures, mostly as a result of low bone strength. Fragility fractures can happen in various parts of the body, but the wrists, hips and spine are the most commonly affected sites.
After the age of about 35 years, the difference between the amount of bone that is removed and the amount of bone that is laid down starts to get slightly out of balance as part of the ageing process. As a result, the total amount of bone tissue starts to decrease. This is often described as ‘bone loss’ or ‘bone thinning’. It doesn’t mean your bones look any different from the outside. However, inside, the cortical ‘shell’ thins and the struts that make up the inner structure become thinner and sometimes break down. This results in the holes in the honeycomb structure becoming larger – hence the description ‘osteoporosis’, literally meaning ‘porous bone’.
This change in the quality of your bones is much more likely and more significant as you move into later life, which explains why bones become more fragile and fractures become more common in old age.
Who is more at risk of osteoporosis?
There are many factors that can increase your risk of osteoporosis and broken bones, including:
Genes: Bone health is dependent on inherited genes from our parents.
Age: As we get older, bones become more fragile and more likely to break.
Race: People who are of Caucasian or Asian origin are more at risk than those of Afro-Caribbean origin.
Gender: Women are at greater risk than men because they have smaller bones and experience a higher rate of bone loss around the time of menopause.
Low body weight: If you have a low BMI (body mass weight index) below 19kg/m2 you are
at greater risk of developing osteoporosis and fractures.
Smoking: Current smokers are more likely to break bones.
Alcohol: Excessive alcohol consumption appears to be a significant risk factor for osteoporosis and fractures.
Some medical conditions: These include rheumatoid arthritis, low levels of oestrogen in women (e.g. due to anorexia, excessive exercise or hysterectomy), low levels of testosterone in men, thyroid conditions, conditions that affect the absorption of food such as Crohn’s or coeliac disease and conditions that cause long periods of immobility such as stroke.
Some medicines also increase the risk. You can find out more by visiting the ROS website or by asking your doctor.
When are the crucial times for bone formation?
It is vitally important to maximise bone strength during childhood, adolescence and early adulthood, when the skeleton is growing. ‘Banking’ plenty of bone in these years puts the skeleton in a better position to withstand the bone loss that occurs with advancing age.
Children can build strong bones by taking plenty of weight-bearing exercise and eating a well-balanced, calcium-rich diet.
Which dietary factors can affect bone health?
Although getting enough calcium is important, a healthy, balanced diet is essential to provide all the vitamins, minerals and other nutrients that your bones need. People should aim to eat meals that incorporate a wide variety of foods from the four main groups, including fruit and vegetables; carbohydrates like bread, potatoes, pasta and cereals; dairy and alternatives; beans, pulses, fish, eggs, meat and other proteins.
Calcium is vital for strong teeth and bones because it gives them strength and rigidity. Most people should be able to get enough calcium through healthy eating, without the need for additional supplements. To find out how much calcium you need, read our guide on the best calcium-rich foods.
Vitamin D helps the body absorb calcium and keeps muscles strong, which helps prevent falls in older people. You can get vitamin D through sunlight exposure, from certain foods and drinks or from dietary supplements. Try to get short periods (about 10 minutes) of sun exposure to your bare skin, once or twice a day, between late March and the end of September, without sunscreen (but taking care not to burn). A UK government advisory committee have recommended that, in addition to sensible sunlight exposure, everyone over 1 year of age should get 10 micrograms (10 μg) of vitamin D every day (8.5 - 10 micrograms for all infants under a year old).
Talk to your doctor if you are concerned that you aren’t getting enough vitamin D or if you are considering taking a supplement.
Excessive alcohol consumption appears to be a significant risk factor for osteoporosis and fractures. If you are older, even minor alcohol intoxication is associated with an increase in falls, which can result in fractures. Try not to exceed the government’s guidelines of no more than 14 units of alcohol in a week, spread over at least three or four days, making sure you also have alcohol free days.
Which lifestyle factors can affect bone health?
Exercise is important for bone health as it helps your skeleton to grow stronger. Weight-bearing exercise is particularly helpful and includes physical activity where you are supporting the weight of your own body, such as jogging, aerobics, tennis, dancing and brisk walking. Staying active as you age through exercises such as swimming, gardening, golf and Tai Chi can help improve muscle strength, balance and co-ordination and reduce the risk of falling.
People who have been diagnosed with osteoporosis may need to be careful of high-impact exercise and certain stretches. Your doctor will be able to advise you if this is the case.
Smoking is well known to have an adverse effect on general health and has been shown to slow down the work of the bone-building cells, osteoblasts. Smoking may also result in an earlier menopause in women and increase your risk of a broken hip later in life. The good news is that fracture risk is reduced in those who give up smoking.
Aim to maintain a healthy body weight, as being underweight or overweight can increase the risk of osteoporosis and fractures. Talk to your doctor if you are concerned about your weight.
Even after menopause, women who are a healthy weight can continue to produce small amounts of bone-protecting oestrogen in the fatty layers under the skin. Ensuring that you aren’t too thin also helps to provide some protection to the bones in the form of ‘padding’ in the event of a fall. However, being overweight isn’t helpful to bones – it increases your fracture risk as well as your risk of developing many other medical conditions.
What is a bone density scan (DXA)?
A bone density scan, using a densitometry X-ray (DXA), measures how much ‘bone mineral’ is in the area being measured – usually, one hip and the lower part of your spine. Research has shown that the lower your bone density is, the greater your risk is of having a fracture.
What is osteopenia?
The scan results are commonly given as a ‘standard deviation’ (SD) – the number of units above or below average. If your bone density is 2.5 SD below average, this is described as ‘osteoporosis’. If your bone density is between the lower end of the normal range and the ‘osteoporosis’ range, you are said to have ‘osteopenia’.
What are your top tips for better bone health?
Make the lifestyle changes described above, including exercising and staying active, eating a healthy, balanced diet with enough calcium and vitamin D, getting enough sunlight exposure to top up vitamin D levels, stopping smoking and avoiding excessive alcohol intake.
You can find out more about risk factors on the ROS website. Talk to your doctor if you are concerned or have further questions.
This article was published on 10 May 2017.
The information was supplied by Sarah Leyland, Osteoporosis Nurse Consultant at the Royal Osteoporosis Society in collaboration with the ROS's expert clinical and scientific advisors. It has been reviewed by Professor Susan Lanham New, Professor of Nutrition at the University of Surrey.
The Royal Osteoporosis Society are a UK-wide charity dedicated to ending the pain and suffering caused by osteoporosis. You can find out more information by visiting their website.
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