Table 4.
Prevalence of Symptomatic Osteoarthritis (SOA) in Non-Swimmers compared to Swimmers (dichotomous). Prevalence of SOA among those participating in 3 levels of activity: low, middle, and high. Results are presented unadjusted and adjusted with 95%CIs.
| Swimming Time Period | Unadjusted Prevalence of SOA (95% CI) | Adjusted* Prevalence of SOA (95% CI) |
|---|---|---|
| Any History of Swimming | ||
| Non-Swimmers (n = 1554) | 29.5% (27.3 – 31.8%) | 27.0% (24.7 – 29.4%) |
| Swimmers (n = 1052) | 24.4% (21.9 – 27.1%) | 21.9% (19.4 – 24.7%) |
| Low (n =397) | 26.9% (25.2 – 28.7%) | 23.3% (21.4 – 25.2%) |
| Middle (n = 305) | 24.7% (22.3 – 27.3%) | 21.5% (19.0 – 24.1%) |
| High (n = 350) | 22.7% (19.3 – 26.5%) | 21.2% (17.7 – 25.1%) |
| p for trend=0.007 | p for trend=0.08 | |
| Ages 12 – 18 years old | ||
| Non-Swimmers (n = 1873) | 28.7% (26.7 – 30.8%) | 26.4% (24.3 – 28.6%) |
| Swimmers (n = 733) | 24.3% (21.3 – 27.5%) | 22.2% (19.2 – 25.5%) |
| Low (n = 296) | 26.7% (24.8 – 28.7%) | 22.0% (20.0 – 24.1%) |
| Middle (n = 222) | 25.2% (22.3 – 28.5%) | 24.3% (21.2 – 27.6%) |
| High (n = 215) | 23.8% (19.7 – 28.7%) | 22.7% (18.5 – 27.7%) |
| p for trend=0.1 | p for trend=0.9 | |
| Ages 19 – 34 years old | ||
| Non-Swimmers (n = 2093) | 28.6% (26.7 – 30.5%) | 26.2% (24.2 – 28.2%) |
| Swimmers (n = 513) | 22.8% (19.4 – 26.7%) | 21.1% (17.7 – 25.0%) |
| Low (n = 179) | 25.7% (23.7 – 27.8%) | 24.3% (22.1 – 26.7%) |
| Middle (n = 144) | 23.1% (19.8 – 26.7%) | 19.8% (16.7 – 23.3%) |
| High (n = 190) | 20.6% (16.3 – 25.8%) | 19.7% (15.3 – 25.0%) |
| p for trend=0.007 | p for trend=0.05 | |
| Ages 35 – 49 years old | ||
| Non-Swimmers (n = 2201) | 27.7% (25.8 – 29.6%) | 25.4% (23.5 – 27.4%) |
| Swimmers (n = 405) | 26.2% (22.1 – 30.7%) | 23.8% (19.8 – 28.5%) |
| Low (n = 143) | 26.8% (24.5 – 29.1%) | 24.0% (21.7 – 26.6%) |
| Middle (n = 140) | 25.9% (22.0 – 30.1%) | 22.7% (18.9 – 27.0%) |
| High (n = 122) | 25.0% (19.5 – 31.4%) | 23.4% (17.8 – 30.0%) |
| p for trend=0.4 | p for trend=0.5 | |
| Ages > 50 years old | ||
| Non-Swimmers (n = 2248) | 27.7% (25.9 – 29.6%) | 25.3% (23.4 – 27.3%) |
| Swimmers (n = 358) | 26.0% (21.7 – 30.8%) | 23.6% (19.3 – 28.5%) |
| Low (n = 129) | 26.7% (24.4 – 29.2%) | 24.3% (21.8 – 27.0%) |
| Middle (n = 114) | 25.8% (21.7 – 30.3%) | 22.2% (18.2 – 26.7%) |
| High (n = 115) | 24.9% (19.1 – 31.7%) | 23.4% (17.5 – 30.5%) |
| p for trend=0.4 | p for trend=0.2 |
*
Adjusted for age, sex, BMI, BMI at age 25, history of knee injury, and all other leisure activities correlated with swimming during the respective age ranges.