Cardiovascular Disease and Osteoarthritis? Have We Found a Connection?
Many of the same things that are linked to arthritis are also linked to heart disease. For example, the average high-carb US diet and low exercise are both associated with arthritis and cardiovascular disease. So is there a real connection between these two, or is it just coincidence that the two seem to go hand in hand?
What Is Osteoarthritis?
Breaking it into its basic medical terminology, osteoarthritis means inflammation (-itis) of the bone (osteo-) and joint (arthr-). Applying a broader scope, osteoarthritis is a degenerative joint disease that progresses as the cartilage breaks down with wear and tear over time. According to the Arthritis Foundation, in the U.S., about 27 million people have osteoarthritis (OA), making it the most common chronic joint disease. In addition to swelling and cartilage loss, those with OA can also develop bone spurs in the unstable joint and experience stiffness and pain.
There have been some interesting OA findings discovered in recent years. While we know OA occurs when the cartilage begins to break down from wear and tear, OA may actually start as a reaction from stress placed on the bone following a cartilage injury. In other words, the cartilage injury itself may not lead to OA, but the reaction of the bone weakens the cartilage, making it more susceptible to wear and tear and, therefore, OA.
Another interesting finding is that OA in one joint may not be the same as OA in another joint. For example, despite only being one joint apart and the fact that the upper end of the femur makes up the hip joint while the lower end makes up the knee joint, research has shown that knee and hip OA are really different diseases. One example is that knee OA tends to progress slowly and over many years, while hip OA can go from mild to severe in a year or two. The study found the reason for the difference lies in the chronological age of the cartilage—in fact, hip OA cartilage was found to be 30 years older than knee OA cartilage, so the “older” hip was less able to repair wear-and-tear damage than the “younger” knee. Read about the fascinating study at the link above.
What Is Cardiovascular Disease?
Cardiovascular disease (CVD) is a broad term that encompasses many diseases of the heart (cardio-) and blood vessels (vascular). When you see the term “cardiovascular disease,” however, it’s most commonly associated with atherosclerosis of arteries, which is plaque build-up along the interior arterial walls that can slow blood flow and increase the risk of clots. If a complete obstruction of an artery occurs, this can cause a sudden heart attack or stroke. Other conditions under the umbrella of cardiovascular disease include arrhythmias, heart failure, valve diseases, and much more, but these diagnoses are typically stated more specifically (e.g., “congestive heart failure,” “atrial fibrillation,” “mitral valve prolapse,” etc).
We know that two of the most effective ways to minimize your risk of cardiovascular disease and keep your heart as healthy as possible is to exercise and consume a proper diet. Even someone who’s always lived a generally sedentary lifestyle can reap heart benefits from beginning and maintaining an exercise regimen.
So how in the world is it possible that osteoarthritis (OA), a bone and joint disease, and cardiovascular disease (CVD), a heart and blood-vessel disease, could be connected? Let’s take a look at the study.
Cardiovascular Disease and Arthritis: Increased Risk?
The purpose of the new study was to determine a possible mechanism through which cardiovascular disease and osteoarthritis may be related. The study consisted of 152 subjects, 70 with end-stage osteoarthritis and 82 control subjects (age-matched subjects without OA). Researchers analyzed arterial stiffness as well as the blood serum in both groups, comparing the metabolites, or compounds, produced from lipid metabolism.
Lipid metabolism begins when we take in lipids, or fats, via the diet. They are first digested, and then a series of biological processes occurs that allows lipids to break down into fatty acids and then be absorbed by the intestines. From here they are metabolized, or broken down, further by the cells into more complex compounds. At this point, the body can now utilize the metabolized fats as an energy source or store if unused.
Researchers found lowered levels of a number of compounds produced during lipid metabolism in the blood of the OA subjects, but one—acylcarnitines—was not only lower than normal, but this decrease was also associated with stiffer arteries (a sign of CVD) in the OA subjects as well as a high severity of OA. The study concluded that a connection to cardiovascular disease may be linked to a decrease in this specific compound produced during lipid metabolism in those with osteoarthritis.
The upshot? It looks like there may be a real link between heart disease and arthritis. My guess is that vascular disease of the type described here (stiff arteries) also likely wreaks havoc with the nutrition of bones that make up joints. Bad bones mean bad cartilage, and this may lead to joint breakdown. So take your diagnosis of arthritis seriously; it may also mean that heart disease is around the corner!