The structural damage due to osteoarthritis of the knee may be delayed by a decrease in the body mass index (BMI), suggests a study from Australia published in the journal Arthritis and Rheumatology.¹

In this prospective study, researchers enrolled patients with knee osteoarthritis to examine the association between the radiological features and the changes in BMI. Women comprised nearly 60% of the study population.

Radiological data was sourced from the Osteoarthritis Initiative (OAI), Multicenter Osteoarthritis Study (MOST) and Cohort Hip and Cohort Knee (CHECK) study and grouped into two.

A total of 5774 participants (9683 knees) without osteoarthritis structural defects at baseline were examined to study the incidence, while the progression of disease was studied in 3988 participants (6075 knees) with the structural defects (increase of one or more grades among those with knee osteoarthritis). The knee x-rays were analysed at the time of recruitment and at 4-5 years.

Results showed that a decrease in BMI was positively associated with both the incidence with an adjusted odds ratio of 1.05. A similar positive association was also noted for progression of the knee osteoarthritis with aOR of 1.05. Decline in BMI by 1 reduced the probability of incidence and disease progression by almost 5%. A decrease of 5 units in BMI reduced the probability of incidence and disease progression by 21%. A decrease in degeneration of the medial joint space and femoral and tibial surfaces was seen on the medial side of the knee; no such changes were observed laterally in both groups. However, the study does not establish a cause and effect relationship.

The benefits of weight reduction on the symptoms of osteoarthritis are well-established. This study has shown that weight loss also slows down the degenerative process in patients with knee osteoarthritis.

Reference

1. Zubeyir Salis, et al. Decrease in body mass index is associated with reduced incidence and progression of the structural defects of knee osteoarthritis: a prospective multi-cohort study. Arthritis Rheumatol. 2022 Aug 16. doi: 10.1002/art.42307.