A concerning rise in obesity rates across Canada is prompting warnings from health experts about a likely increase in osteoarthritis cases in the years ahead. Recent Statistics Canada data indicates that 68% of adults aged 18-79 were classified as overweight or obese between 2022 and 2024, a notable increase from 60% just a few years prior[[1]]. this trend is not simply a matter of physical strain on joints, but a complex interplay involving inflammation and metabolic changes, as explained by leading researchers.
A growing obesity epidemic across all age groups in Canada is likely to lead to an increase in osteoarthritis cases in the coming years, according to health experts. While a rise in other forms of arthritis is also possible, the extent to which obesity will contribute remains less clear.
Osteoarthritis, a common type of arthritis, involves the breakdown of cartilage within joints. Dr. Diane Lacaille, scientific director of Arthritis Research Canada, explains the process.
“When we use our joints, we put weight on the cartilage, so it breaks down a little and constantly regenerates,” she said. “With osteoarthritis, people lose their ability to effectively regenerate cartilage in response to the daily stress on their joints.”
Other types of arthritis are primarily inflammatory, Dr. Lacaille continued. “These are autoimmune diseases where the immune system reacts against the body, causing inflammation in the joints. This inflammation then causes pain and swelling. Over time, this also damages the cartilage and the joint, but it’s secondary to the inflammation.”
Recent data from Statistics Canada reveals a concerning trend: 68% of Canadian adults aged 18 to 79 were classified as overweight or obese between 2022 and 2024, up from 60% between 2016 and 2019. This increase in obesity rates is a significant public health concern, as it’s linked to a variety of chronic conditions.
“We expect to see increases in osteoarthritis due to obesity,” Dr. Lacaille confirmed. “With inflammatory arthritis, it’s a bit more difficult to say because inflammatory arthritis, like rheumatoid arthritis, has so many contributing factors that even if obesity increases the incidence, it’s hard to determine exactly how much it will affect the overall prevalence in the population.”
It’s More Than Just Weight
The connection between obesity and osteoarthritis isn’t new, but the understanding of that link has evolved. Previously, it was believed that increased weight simply put more stress on joints, leading to wear and tear.
“In recent years, we’ve realized there’s a connection that isn’t solely about weight,” Dr. Lacaille explained. “Adipose tissue is metabolically active and causes inflammation, contributing to both osteoarthritis and inflammatory arthritis, and even gout, another type of arthritis that increases inflammation in the joints.”
This means that the benefits of weight loss extend beyond reducing physical stress on joints; it also reduces inflammation throughout the body. Losing weight can positively impact the progression of these conditions.
Furthermore, imaging studies show a clear correlation between higher body mass index (BMI) and greater cartilage degradation. “When BMI decreases, the radiographic progression of the disease is slower. So, weight loss is one way we can affect the course of the disease over time,” Dr. Lacaille noted. Joint replacement surgery remains another treatment option.
For other types of inflammatory arthritis, effective medications are available to interrupt the autoimmune reaction causing inflammation. While these medications don’t offer a cure – inflammatory arthritis is a chronic condition – they can effectively manage symptoms long-term.
A Vicious Cycle
For osteoarthritis, particularly affecting the knees or hips, weight loss through physical activity can be especially challenging.
“It’s easy to say ‘go walk and exercise,’ but when exercise is painful, it’s difficult,” Dr. Lacaille said. “This creates a vicious cycle: weight increases pain, increased pain makes physical activity harder, lack of activity leads to weight gain, and that worsens the osteoarthritis.”
Dr. Lacaille emphasized the importance of shifting the approach to obesity and avoiding judgment. For too long, she said, blame has been placed on a lack of willpower, assuming individuals simply eat too much and don’t exercise enough. “We really need to change these stereotypes,” she stated.
The positive effects of weight loss on arthritis and osteoarthritis will be felt regardless of the method used to achieve it, whether through medication, surgery, or lifestyle changes, Dr. Lacaille clarified.
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