24th May 2020, Dr Chee L Khoo
In primary care, we are frequently preventing disease or at least we try to. Apart from lifestyle measures, we prescribe statins, anti-hypertensive, aspirin and beta-blockers to reduce cardiovascular events. What about arthritis? In patients who do not have arthritis (yet) but are at high risk of degenerative osteoarthritis, is there something we can do to reduce the patients’ risk of progressing to full blown arthritis? And if you stop and think, you probably know who are at risk of arthritis. We see them in our practice every day.
Patients with high risk of knee osteoarthritis
Who are these patients? We know who they are. These are patients who are overweight or obese, have a previous history of significant knee injury, have Heberden nodes or engaged in activities with repetitive knee bending. Type 2 diabetes (T2D) is an independent risk factor for osteoarthritis. Up to 47.3% of patients with T2D have some form of arthritis (1).
Participation in exercise, sports, or recreational activities provides health benefits, preserves function, and prevents disability development. Sedentary behaviour, on the other hand, has been associated with adverse health outcomes. Promoting physical activity and reducing sedentary behaviour are low-cost, easy-to-implement strategies to improve health and quality of life.
The only problem is that while there are health benefits of regular physical activity, uncertainty about whether strenuous activity will accelerate joint damage is a common concern. So, what should we tell our patients who are at risk but do not have radiographic evidence of arthritis yet?
In the Osteoarthritis Initiative, a large cohort of community-recruited individuals at high risk for knee osteoarthritis (KOA), 1194 participants aged 45-79 years old were followed up for up to 8 years. Participants were eligible if they had:
- Frequent knee symptoms (most days of 1 mo in the past 12 mo)
- Excess body weight
- Prior knee injury causing walking difficulty for at least 1 wk
- Previous knee surgery
- Family history of knee replacement
- Heberden nodes
- Repetitive knee bending
Patients are excluded if they had:
- Inflammatory arthritis
- Severe bilateral joint space narrowing
- Knee replacement and severe contralateral narrowing
- Bilateral knee replacement or plan for it within 3 y
- Magnetic resonance imaging contraindications
- Use of aids for >50% of ambulation (except 1 cane)
- Severe comorbidity
Assessment of physical activity and extensive sitting
Weekly hours of engagement in strenuous physical activities (eg, jogging, swimming, cycling, singles tennis, aerobic dance, and skiing) were estimated over the 8-year follow-up period. Based on the trajectories over the 8 years, participants were classified into the persistently no exercise, low frequency, moderate frequency and high frequency subgroups.
Extensive sitting was defined as 5 or more days of sitting activities over the past week and 4 or more hours per day during those days.
Relationship between physical activity, extensive sitting and radiographic KOA
Over the 8 year follow up period, In persons at high risk but without radiographic evidence of KOA, engaging in long-term strenuous physical activity did not increase the risk of incident radiographic KOA. In fact, the more strenuous and regular the activities were, the lower the rates of radiographic KOA was. The rates of KOA were:
- Persistently no exercise – 15.3%
- Low frequency exercises – 10.7%
- Moderate frequency exercises – 9.3% and
- High frequency – 12.6%
On the other hand, the more extensive the sitting was, the higher the rates of radiographic KOA was. The rates of KOA were
- high frequency – 14.0%
- moderate frequency – 13.7, and
- low frequency – 12.4%
These findings tell us that some level of strenuous physical activity, especially in low and moderate amounts (eg, 1-2 hours/wk), may be protective. Older adults at high risk for KOA may safely engage in strenuous physical activity at a moderate level to promote their general health and well-being.
- CDC. Prevalence of doctor-diagnosed arthritis and arthritis-attributable activity limitation – United States, 2010-2012 Morb Mortal Wkly Rep, 62 (44) (2013), pp. 869-873
- Alison H. Chang, PT, DPT, MS; Jungwha (Julia) Lee, PhD; Joan S. Chmiel, PhD; Orit Almagor, MA; Jing Song, MS; Leena Sharma, MD. Association of Long-term Strenuous Physical Activity and Extensive Sitting With Incident Radiographic Knee Osteoarthritis. JAMA Network Open. 2020;3(5):e204049. doi:10.1001/jamanetworkopen.2020.4049