Two experts not involved in the study welcome its results
Kai Sun, MD, MS, assistant professor of medicine, rheumatology, and immunology at Duke University, Durham, N. C., said it makes mechanical sense that less weight bearing decreases knee damage over time, but she was somewhat surprised that even people who started with normal BMI improved their outcomes by decreasing BMI further.
Dr. Kai Sun
“Knee osteoarthritis and obesity prevalence are both growing,” Dr. Sun said. “Knee osteoarthritis may one day be considered an obesity-related comorbidity like hypertension and diabetes and be used as additional justification for pharmacologic or nonpharmacologic interventions to treat obesity.”
She noted that the study’s major strengths include its large sample size, long follow-up, and separate inclusion of disease incidence and progression, but also noted some limitations.
“BMI data at only two time points does not consider BMI fluctuations between those times,” she added. “Limited data were presented on physical activity levels, and most participants being White and elderly limited the generalizability of the results.”
Dr. Eduardo Grunvald
Eduardo Grunvald, MD, professor of medicine and medical director of the weight management program at the University of California, San Diego, agreed about the study’s strengths and pointed out its lack of information about the cause of BMI changes.
Dr. Grunvald would like to know whether the BMI changes contributed to the knee changes or vice versa. “An individual’s worsening knee pain could lead to less physical activity and possible increased BMI.
“Long-term weight-loss maintenance is extremely challenging, and for optimal outcomes, medical professionals who treat joint disease should partner with clinicians trained to treat obesity,” he advised.
The authors are planning further related research. “We’re looking forward to running a randomized, controlled clinical weight-loss trial,” Dr. Sainsbury said.The study was supported by scholarship and fellowship funds from the Australian government. Mr. Salis and Dr. Sainsbury each own 50% of shares in a company that provides educational resources and services in adult weight management. Dr. Sainsbury and one coauthor reported relevant financial relationships with various pharmaceutical companies. Dr. Sun and Dr. Grunvald reported no relevant financial relationships.