Why DO you have arthritis in your knees?
Knee osteoarthritis has doubled in prevalence since the mid-20th century
Remember all those discussions about why we develop knee arthritis
“It is because you played too much sport when you were young” or
“Its because he/she is overweight” or
“No wonder – he/she is 75, what do you expect?” or even
“They have eaten a diet of too much ‘acid forming foods’ in their life so no wonder they have arthritis”.
All interesting ideas to discuss but are ANY of them correct or are all just ‘old wives’ tales’? A recent study in the USA has investigated the causes of knee osteoarthritis (degeneration) to try to find out what really are the causes and why it is since the mid 20th Century that knee osteoarthritis has doubled in prevalence.
Dr Ian Wallace, a postdoctoral research fellow in the Department of Human Evolutionary Biology at Harvard University, studied over 2,000 skeletons from three different time periods. He also looked at 176 prehistoric skeletons in all and came to the conclusion that the most obvious reason to explain the increase in knee osteoarthritis is the modern decline in physical activity. This also means that osteoarthritis may be more preventable than previously thought.
The study investigated large samples of skeletons that spanned from prehistoric times to the present. They found that for many years there was only low incidences of knee degeneration but that sudden increase has happened. They analysed the data and said that the idea that “of course there is more degeneration – we are living so much longer than we used to and we are so FAT now” that is prevalent is actually wrong. Furthermore they showed that there needs to be further studies of risk factors that have come into play within the last half century in order to really be able to say what definitely causes osteoarthritis, and that these risk factors are probably largely preventable – i.e. we can control whether we develop knee arthritis ourselves! But HOW and WHAT should we be doing to stop getting knee arthritis? The study examined people’s skeletons who lived in the early industrial era between 1800’s and early 1900’s and those who lived in the modern post industrial era between the late 1900’s to the early 2000’s and were over 50 years old and whose BMI was recorded at their death – i.e. whether they were obese or not. Knee degeneration among those over 50 years of age was also examined in those people who lived between 6000 and 300 BC i.e. prehistoric hunter gatherers and early farmers. They looked for a lack of cartilage covering the bone surface where there was bone on bone contact rather than as should be cartilage on cartilage and knee arthritis was found to be 16% among the postindustrial sample but only 6% and 8% among the early industrial and prehistoric samples, respectively. Thus, knee degeneration prevalence was 2.1-fold higher in the postindustrial sample than in the early industrial sample. Genes were examined for their influence on knee arthritis susceptibility but environmental aspects have been found to be the main cause.
What we DO know is that nearly all cases of knee osteoarthritis are linked to load induced damage – due to the fact that the tissues around the knee are structurally weak – the bones the cartilage, tendons, ligaments or muscles. Why and how has loading on the joints changed recently to cause more degeneration though? Possible factors to consider are:
Footwear - high heels change the way your knees absorb impact from the floor and irritate the knees.
Physical inactivity – means those less active have less cartilage over their bone so less protection along with weaker muscles to protect the joints from instability so the joint surfaces move over each other too much and wear out quicker.
Low grade inflammation is aggravated by inactivity. Diets high in refined carbohydrates speed up load induced damage to joint tissues.
Why Are We More Likely To Get Osteoarthritis Now than Years Ago?
How do we know which of these is the culprit responsible for the sudden increase in degeneration of our knees? The truth is, nobody knows. The information they derived from the old studies may have been flawed, however, what we DO know is that knee arthritis is what is called a “mismatch disease”, so called because there are certain diseases that are much more prevalent because we as human beings have not adapted to modern environments well enough. An interesting point to bear in mind too is that other of these “mismatch diseases” that have been studied in depth such as hypertension (high blood pressure), atherosclerotic heart disease (blocked arteries to the heart) and type 2 diabetes have also become epidemic over the same period, a fact that infers common causes and risk factors as for knee osteoarthritis. Age, sex and genes can influence our susceptibility to developing these diseases but as can be seen from the historical and evolutionary aspects examined by the study, we may be able to actually prevent many modern cases of knee osteoarthritis once the risk factors have been re-examined.
How Can We Help You?
The bottom line is that many recent cases of knee osteoarthritis and the other ‘mismatch diseases’ show that we really do need to look at our physical activity patterns and become more active and also alter our diets ….. but maybe, deep down, we all do realise that we often don’t do the best for our bodies by being so inactive and eating so much ‘rubbish’. I think that like a lot of our health problems, we are the masters of our own destiny and maybe instead of reading about things like this and thinking ‘really I should do something about it’, we change what we do NOW – it doesn’t need to be radical –just a few minutes exercise every day and eating a few less biscuits or crisps or other inflammation causing foods might make a HUGE difference to the comfort of our old ages.
If you DO have knee arthritis, however, we can help you with mobilisation; appropriate exercises; acupuncture; dietary advice and we can see how you do what you do and change things so you are not overloading those already irritated joints. Give us a call at the clinic now and see if we can help you to feel more comfortable.