The aim of this study was to investigate the associations of moderate-intensity PA (MPA) and vigorous-intensity PA (VPA) with the incidence of and recovery from knee pain among older adults.
We invited all community-dwelling older adults aged 65 and older living in Tsuru, Yamanashi, Japan, to respond to the surveys. Mail surveys were conducted in January 2016 (baseline) and January 2019 (follow-up). Of 6,661 eligible participants, 3,683 completed both surveys and were included in the analyses. Knee pain was assessed with a self-reported item to determine whether participants experienced knee pain on most days in the past month. PA levels were assessed using the International Physical Activity Questionnaire Short Version (IPAQ). Participants reported the time spent in VPA, MPA in an average week. Weekly VPA was categorized as 0 minutes, 1–74 minutes, 75–149 minutes, and ≥150 minutes; weekly MPA was divided into 0 minutes, 1–149 minutes, 150–299 minutes, and ≥300 minutes. Logistic regression models were conducted to identify the associations of MPA and VPA with knee pain, and to compute odds ratios (OR) and 95% confidence intervals (CI). Participants without knee pain at baseline (n = 2,480) were included in the analysis to identify the association between PA and the incidence of knee pain. For the association of PA with recovering from knee pain, older adults with knee pain at baseline (n = 1,203) were included. Each model was adjusted for sociodemographic factors (age, gender, years of education, and marital status), health conditions (self-rated health, osteoarthritis, frailty, and body mass index), and behaviors (drinking and smoking status, and sitting time).
At baseline, 32.7% of participants reported knee pain, with higher prevalence in women, older individuals, and those with osteoarthritis, poor health, frailty, or obesity. Among participants without knee pain at baseline, 16% developed it during follow-up, while 43.8% of those with baseline knee pain recovered. The multivariable analyses showed that older adults, with and without knee pain at baseline, who reported ≥300 min/week of MPA were less likely to suffer from knee pain three years later. Engaging in MPA for ≥300 min/week was associated with lower odds of knee pain onset (odds ratio [OR [95% CI], 0.72 [0.53, 0.97]) and persistent knee pain (OR [95% CI], 0.64 [0.46, 0.90]).
Higher levels of MPA would significantly decrease the risk of onset and persistence of knee pain among community-dwelling older adults. Our findings support promoting MPA to prevent knee pain and improve joint function in community-dwelling older adults.
Incorporating MPA into routine care for older adults may reduce the prevalence of knee pain, leading to improved quality of life, preventing functional decline and reducing healthcare costs.
subjective measurements
intensity-specific physical activity
