Knowledge Synthesis: Obesity and Musculoskeletal Disease

For those who are overweight, weight loss is a commonly recommended management strategy for osteoarthritis (OA). However, the evidence suggests that the effect of weight loss on knee pain is comparable to taking paracetamol. Despite the limited evidence, we found that practically all clinical guidelines recommend weight loss for knee and hip osteoarthritis. While most people with OA are aware that weight contributes to their OA, they also report having tried and failed to lose weight.   

The continued focus on weight loss, which is difficult to achieve and maintain, may do unintended harm. Instead, we need to challenge commonly held beliefs about managing obesity. We estimate that about 28% of knee replacements per year at a cost saving of over 300 million dollars a year could be prevented by slowing the weight gain from age 18 to the mid-60s.

Obesity is a major modifiable risk factor for musculoskeletal conditions with a major impact in women as evidenced by data on lower back pain from the Australian Longitudinal Study on Women’s Health (ALSWH) [1]. The evidence suggests that obesity effects joints through loading and meta-inflammation. We examined this in the back2 and found that metabolically driven inflammation is important in low back pain as we had previously found at the knee and hands. 

Targeting obesity is important in order to prevent and manage musculoskeletal conditions.  In clinical practice guidelines for osteoarthritis (OA) there is a focus on weight loss in those who are overweight and obese as key to managing obesity in OA. However, the evidence suggests that weight loss has a modest effect on knee pain, comparable to paracetamol, and that 7.5% of weight loss is needed for a clinically significant effect. The focus on weight loss is based on the notion of ‘no harm’ and some good.  We reviewed the clinical practice guidelines and found that virtually all advise weight loss for knee and hip OA, despite the limited evidence [3].  

Weight loss is difficult to achieve and maintain.  Most people with OA are aware that it is a significant contributor to their OA and report having tried unsuccessfully to lose weight. A major focus on weight loss may do unintended harm. Losing weight and maintaining weight loss is difficult because our bodies will defend their body weight set point. This body weight set point is determined by genetic and epigenetic factors, mostly set in early life with no evidence yet that it can be set at a lower level4. However, there is potential to prevent the slow weight creep that occurs over adult years [4].  

The potential health benefit and cost savings are considerable if we can prevent weight gain at a population level. We estimate that about 28% of knee replacements per year at a cost saving of over $300 million dollars a year could be preventing by slowing the weight gain from the age of 18 to mid-60 years [5]. We are not winning in our management of obesity. We need to challenge some of the commonly held myths about how we should manage obesity. We examined a very common one, that breakfast eating prevents obesity. Our meta-analysis of randomized trials clearly debunks this popular belief6. 

Evidence challenging the dogma that breakfast is important for preventing obesity has had significant media reach.  

The Altmetric top 100, 50th most discussed scientific report (of 2.7 million papers) globally of any field in 2019 https://www.altmetric.com/top100/2019/.  

Altmetric score >3800, 95th percentile for related to outputs of same age; covered by 211 news outlets. 

1. Brady SRE, Hussain SM, Brown WJ, Heritier S, Wang Y, Teede H, Urquhart DM, Cicuttini FM. Course and Contributors to Back Pain in Middle-aged Women Over 9 Years: Data From the Australian Longitudinal Study on Women’s Health. Spine. 43(23):1648-1656, 2018 12 01. 
2. Lim YZ, Wang Y, Cicuttini FM, Hughes HJ, Chou L, Urquhart DM, Ong PX, Hussain SM. Association Between Inflammatory Biomarkers and Nonspecific Low Back Pain: A Systematic Review. Clin J Pain. 2020 May;36(5):379-389.  
3. Lim YZ, Wong J, Hussain SM, Estee MM, Zolio L, Page MJ, Harrison CL, Wluka AE, Wang Y, Cicuttini FM. Recommendations for weight management in osteoarthritis: A systematic review of clinical practice guidelines. Osteoarthritis and Cartilage Open 2022; 4(4): 100298 
4. Cicuttini F, Proietto J, Lim, YZ. Our biology working against us in obesity: A narrative review on implications for management of osteoarthritis. Osteoarthritis and Cartilage Open 2023; 5(4): 100407. 
5. Hussain SM, Ackerman IN, Wang Y, et al. Trajectories of body mass index from early adulthood to late midlife and incidence of total knee arthroplasty for osteoarthritis: findings from a prospective cohort study. Osteoarthritis Cartilage. 2023;31(3):397-405. doi:10.1016/j.joca.2022.11.013 
6. Sievert K, Hussain SM, Page MJ, Wang Y, Hughes HJ, Malek M, Cicuttini FM. Effect of breakfast on weight and energy intake: systematic review and meta-analysis of randomised controlled trials. BMJ. 2019 Jan 30;364:l42. doi:10.1136/bmj.l42. PubMed PMID: 30700403; PubMed Central PMCID: PMC6352874.