Gardening/yardwork over a lifetime is associated with less symptomatic knee osteoarthritis: data from the Osteoarthritis Initiative

Objectives: Gardening/yardwork is one of the few physical activities with greater participation with age. We aimed to evaluate the relationship of gardening/yardwork with the prevalence of symptomatic knee osteoarthritis in the Osteoarthritis Initiative (OAI), a community-based cohort not recruited based on gardening/yardwork status. Method: This is a retrospective cross-sectional study of OAI participants. A lifetime physical activity survey defined gardening/yardwork status. Posteroanterior semi-flexed knee radiographs were scored for Kellgren–Lawrence (KL) grade (0–4). Radiographic osteoarthritis (ROA) was defined as KL grade ≥ 2. Person-based definitions were used for frequent knee pain, ROA, and symptomatic ROA (SOA). Logistic regression analyses were performed with gardening/yardwork as the predictor, and the outcomes were frequent knee pain, ROA, and SOA adjusted for age and sex. Results: Of 2607 participants, 56% were female, the mean age was 64.3 (SD 9.0) years, and the mean BMI was 28.5 (SD 4.9) kg/m²; 64% participated in gardening/yardwork at some time in their lives. Adjusted odds ratios of frequent knee pain, ROA, and SOA for those who participated in the activity compared to those who did not were 0.71 (95% CI 0.60–0.83), 0.75 (0.63–0.88), and 0.71 (0.60–0.85), respectively. Conclusion: Gardening/yardwork is a common leisure physical activity. Those who participated in gardening/yardwork were less likely to have frequent knee pain, ROA, and SOA, suggesting that it is good for overall knee health. The implications from a public health perspective are potentially substantial. Our findings support a possible recommendation to the general public that participation in gardening/yardwork, an activity already commonly practiced among those at highest risk for OA, might also have benefits from a knee health perspective. (Table presented.)