STUDY: Prevalence of Arthritis Doubles Since World War II

STUDY: Prevalence of Arthritis Doubles Since World War II

By Staff.

Harvard scientists published a paper stating that the average American today is two times as likely to be diagnosed with arthritis than in the years before World War II.  They also point out that the reasons are not quite what you’d expect.

The researchers examined more than 2,000 skeletons across the US, and concluded for the first time that the prevalence of knee osteoarthritis has increased at a dramatic rate in recent decades. Their work is published in this week’s Proceedings of the National Academy of Sciences.

The research also upends the notion that knee osteoarthritis is a wear-and-tear disease that is more common due to the fact that Americans are living longer and are much heavier.

“Before this study, it was assumed without having been tested that the prevalence of knee osteoarthritis has changed over time,” said Ian Wallace, the study’s first author and a post-doctoral fellow in the lab of Daniel Lieberman, the Edwin M. Lerner II Professor of Biological Sciences and senior author of the study. “We were able to show, for the first time, that this pervasive cause of pain is actually twice as common today than even in the recent past. But the even bigger surprise is that it’s not just because people are living longer or getting fatter, but for other reasons likely related to our modern environments.”

The two said that understanding the disease is important because it is responsible for more disability than almost any other musculoskeletal disorder.

“Understanding the origins of knee osteoarthritis is an urgent challenge because the disease is almost entirely untreatable apart from joint replacement, and once someone has knee osteoarthritis, it creates a vicious circle,” Lieberman said. “People become less active, which can lead to a host of other problems, and their health ends up declining at a more rapid rate.”

Wallace and Lieberman think that this study has the potential to shift the popular perception of knee osteoarthritis as an inevitable consequence of aging, and instead focus on efforts to prevent the disease – much like we now do with heart disease.

“There are a lot of well-understood risk factors for heart disease, so doctors can advise their patients to do certain things to decrease their chances of getting it,” Lieberman said. “We think knee osteoarthritis belongs in the same category because it’s evidently more preventable than commonly assumed. But to prevent the disease more work needs to be done to figure out its causes.”

To do that, Wallace and Lieberman are currently addressing the question of the etiology of knee osteoarthritis from a variety of methodological approaches including studies of living human populations and animal models, but their first goal was to figure out how ancient the disease actually is, and whether it really is on the rise.

“There are famous examples in the fossil record of individuals, even Neanderthals, with osteoarthritis,” Lieberman said. “But we thought, let’s look at the data, because nobody had really done that in a comprehensive way before.”

To find those data, Wallace undertook the daunting task of crisscrossing the country to examine thousands of skeletons spanning more than 6,000 years of human history to search for evidence of eburnation – a tell-tale sign of osteoarthritis.

“When your cartilage erodes away, and two bones that comprise a joint come into direct contact, they rub against each other causing a glass-like polish to develop,” Wallace said. “That polish, called eburnation, is so clear and obvious that we can use it to very accurately diagnose osteoarthritis in skeletal remains.”

The data Wallace collected was combined with analyses from other contributors to the study, making this the largest sample ever studied of older-aged individuals from three broad time periods – prehistoric times, early industrial times (mainly the 1800s), and the modern post-industrial era.

“The most important comparison is between the early industrial and modern samples,” Lieberman said. “Because we had data on each individual’s age, sex, body weight, ethnicity, and in many cases, their occupation and cause of death, we were able to correct for a number of factors that we considered important covariates. So using careful statistical methods, we are able to say that if you were born after World War II you have approximately twice the likelihood of getting knee osteoarthritis at a given age or BMI than if you were born earlier.”

Wallace and Lieberman are now working to identify what factors may be behind the increase, and said the evolutionary approach to the study is a critical part of that ongoing work.

“Epidemiology typically looks at large cohorts of individuals living today to search for associations between a disease and risk factors,” Lieberman said. “That’s a powerful and valuable method, but it has one critical imitation, which is that the world today is different in many ways from the world in the past, hiding important risk factors that are either no longer prevalent or have become ubiquitous. An evolutionary perspective opens new opportunities to test for associations we might not be able to study in populations like modern day America.”

That perspective, Wallace and Lieberman said, allows researchers to zero in on specific things that changed pre- to post-World War II, and understand how they might contribute to the rise in knee osteoarthritis prevalence.

“This is an example of how evolutionary thinking can contribute to our understanding of what causes certain diseases,” Wallace said. “We identified the post-war period as a critical time…and it’s only with an evolutionary perspective that we gain that insight.”

Ultimately, Wallace and Lieberman hope their study inspires new research to prevent knee osteoarthritis.

“Knee osteoarthritis is not a necessary consequence of old age. We should think of this as a partly preventable disease,” Lieberman said. “Wouldn’t it be great if people could live to be 60, 70 or 80 and never get knee osteoarthritis in the first place? Right now, our society is barely focusing on prevention in any way, shape or form, so we need to redirect more interest toward preventing this and other so-called diseases of aging.”

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Authored by: Staff

There are 2 comments for this article
  1. Kathy C at 9:49 am

    The only “Paradigm” the U.S Health Industry is evolving towards is increasing profitability. The Diet of Americans is still being ignored. It is hard to even find health food anymore. The Medical Industry ignored diet and peddled a number of Food Industry Myths. Now they are peddling “Wellness” which has been weaponized to blame the Patient. Sick low income people are labeled because they can ‘t find or afford healthy food.
    Herbs might very well be helpful but once again, instead of standardizing, or any quality control, the benefits are pretty random. One would have to grow their own, and run a Chemistry Lab to figure out if they even contain the beneficial compounds. Food often barely contains the micro nutrients, anymore. Modern farming techniques, transport and storage have us buying old, expensive, and improperly stored produce, with barely any nutrition.
    Then we have the popular misleading “Studies.” Once we look at these “Studies” we find that they are virtually meaningless. We are being subjected to a barrage of misinformation, meant to sell us a Product, or Treatment, or even worse cast doubt on science. There has not been much research on our current “Environment. The damage to our health and well being has been ignored or downplayed. The effect of Advertising on young children, or our continual exposure to it was not “Studied.” We have a nation of Pod People, who believe, the Advertising. We have a couple of generations who were raised on advertising, they mindlessly buy the garbage they were exposed to countless times. The Sugar Industry got Physicians to tell their patients to exercise rather than cut down on Sugar Consumption. The Industry paid very well for these guidelines, which have resulted in an Epidemic of Obesity and Diabetes.
    The only Paradigm Shift here is that “Alternative Treatments” of limited effectiveness are being peddled alongside, what we are told is “Scientific” Medicine. The problem is that what we are told is Scientific is not. Scientific implies a certain standard. Citing a “Study” of herbs versus NSAIDS is misleading. NSAIDS are not very effective in the first place. So comparing Herbs to the already ineffective NSAIDS is not very Scientific. A steady diet that includes these beneficial compounds is probably helpful What they don’t tell us is that we won’t get these benefits from supplements. We have no way of even knowing if these supplements contain the active ingredients. Supplements have been Scientifically proven to be mostly useless. They very often contain no or very little active ingredients. In the case of Fish Oil Supplements, they found many were rancid, the oil was too old to contain any active Ingredients. It was also very possible that these rancid oils a trigger inflammation. They created a Billion dollar Industry around useless, ineffective and unnecessary Supplements. Instead of eating healthy varied and nutritious foods, which most of us do not even have access to anymore, they peddled Supplements.
    The only Paradigm Shift here is that we no longer rely on Science. Science was not conducive to Profitably. The only “Science we here about, is distorted, they just leave out the inconvenient facts. There is nothing Scientific about comparing Herbs to NSAIDS. Some NSIADS are not effective at all, so any random thing could appear to be better. Th only Science we are seeing applied is the science of deception.

  2. Jacob Teitelbaum MD at 2:33 pm

    Although our initial reaction would be to think that this is because of increased weight or people living longer, this study explored this as well and found that this was not the cause.
    Why is this important?
    Standard medicine has little to offer for arthritis except for:
    1 – arthritis medications called NSAIDs. But a recent study of about ½ million people found that these medications increase heart attack and stroke risk dramatically. When analyzing the numbers, these medications are associated with an extra 30,000 – 50,000 preventable US deaths each year.
    2 – knee replacement. For all too many people though, this begins a downward spiral of inactivity and other healthcare problems
    Looking at how common an illness is now compared to in the past offers paradigm changing insights. For example, the study authors note “ the historical and evolutionary perspective afforded by our data underscores that many modern cases of knee OA may be preventable. Prevention, however, will require a reappraisal of potential risk factors that have emerged or intensified only very recently. As with other mismatch diseases, it is likely that any effective prevention strategy will involve adjusting physical activity patterns and diets to approximate more closely the lifestyle conditions under which our species evolved.”
    The term “mismatch diseases” is simply a way of saying that our genetics are not a match for the current environment. Arthritis is just one example. Others include heart attack, strokes, diabetes, many cancers, and a host of conditions that used to be quite rare before our current modern diet (appropriately called the “ Standard American Diet” or SAD). This data was well explored in an excellent 1981 scientific textbook, Western Diseases: Their Emergence and Prevention (HC Trowel ed: Harvard University Press) , which creates the foundation for our understanding “mismatch diseases.”
    Key factors that have changed in our diet, which contribute strongly to arthritis, heart attack, diabetes, and a host of other conditions, include:
    1-18% of our calories now come from sugar added to the diet in food processing
    2- another ~ 18% comes from white flour
    3- fully half of the vitamins and minerals that should be a in our diet are lost in food processing
    4-fiber intake has decreased dramatically
    5 – intake of Omega 3 oils have decreased dramatically, markedly increasing the tendency to inflammation in both joints and blood vessels
    Fortunately, these are areas where nutritional and herbal medicine can be remarkably helpful. For example, in head on studies a number of herbs have been shown to be as or more effective than NSAIDs for arthritis. But instead of the side effects, including 30,000 – 50,000 deaths, these herbs cause side benefits. For example, a special highly absorbed mix of curcumin and boswellia was shown to be more effective for arthritis than Celebrex in two head on studies. Instead of side effects, these 2 herbs have the “side benefits” of being associated with a significantly lower cancer risk, being more effective for depression than antidepressants, and even helping asthma and colitis.
    Our healthcare system is evolving to a new paradigm. We are starting to recognize that in addition to medication and surgery, there are numerous other scientifically proven instruments available in the healthcare toolkit. Tools that can help people to thrive in the current modern environment.

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