Cartilage loss: body weight matters

Your knee is a very essential anatomical part in order to be mobile. That is why the bones of the knee are well-protected by the tibio-femoral cartilage. However, the protective cartilage sometimes gets damaged due to a wide range of factors, leading to pain, loss of mobility and even disability. Cartilage damage can lead to osteoarthritis, a progressive and painful disease caused by breakdown of the cartilage. It is the most common form of arthritis, afflicting approximately 27 million Americans.

According to lead researcher Dr. Frank Roemer

“Osteoarthritis is a slowly progressive disorder, but a minority of patients with hardly any osteoarthritis at first diagnosis exhibit fast disease progression. So we set out to identify baseline risk factors that might predict rapid cartilage loss in patients with early knee osteoarthritis or at high risk for the disease.”

The researchers looked at 336 people with 347 osteoarthritic knees. The majority of the study participants were women (65.2%), with an average age of 61.2 years and an average body mass index (BMI) of 29.5. The participants were followed up for 30 months. During this period, cartilage loss was monitored using whole organ magnetic resonance imaging. The results showed that

• 20.2% of participants had slow cartilage loss during the follow-up period
• 5.8% experienced a rapid rate of cartilage loss.

The researchers also identified the top risk factors that might influence the rate of cartilage loss, namely:

• preexisting cartilage damage at baseline
• evidence of tear or injury to the meniscus (the cartilage that cushions the knee joint)
• high BMI
• evidence of inflammation in the synovitis which lines the joints.

Of these, the high BMI is the only modifiable factor. Age, sex and ethnicity don’t seem to play a role in cartilage loss.

The rate of cartilage loss increased with increasing BMI. BMI is the ratio of body weight to height and a range of 18.5 to 25 is considered normal. BMI values above this range indicate being overweight or obesity. For every one unit increase in BMI, the likelihood of rapid cartilage loss increased by 11%

Dr. Roemer continues

“As obesity is one of the few established risk factors for osteoarthritis, it is not surprising that obesity may also precede and predict rapid cartilage loss. Weight loss is probably the most important factor to slow disease progression.”

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