Table 3.
Prevalence of Radiographic Osteoarthritis (ROA) in Non-Swimmers compared to Swimmers (dichotomous). Prevalence of ROA 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 ROA (95% CI) | Adjusted* Prevalence of ROA (95% CI) |
|---|---|---|
| Any History of Swimming | ||
| Non-Swimmers (n = 1554) | 60.3% (57.8 – 62.7%) | 61.1% (58.4 – 63.7%) |
| Swimmers (n = 1052) | 54.4% (51.4 – 57.4%) | 54.3% (51.0 – 57.6%) |
| Low (n = 397) | 57.4% (55.5 – 59.5%) | 55.7% (53.5 – 57.9%) |
| Middle (n = 305) | 55.1% (52.2 – 57.9%) | 54.0% (50.8 – 57.2%) |
| High (n = 350) | 52.7% (48.4 – 57.0%) | 54.1% (49.4 – 58.8%) |
| p for trend=0.007 | p for trend=0.02 | |
| Ages 12 – 18 years old | ||
| Non-Swimmers (n = 1873) | 59.7% (57.5 – 61.9%) | 60.3% (57.8 – 62.7%) |
| Swimmers (n = 733) | 53.3% (49.7 – 56.9%) | 53.4% (49.5 – 57.3%) |
| Low (n = 296) | 56.7% (54.6 – 58.9%) | 52.7% (50.3 – 55.3%) |
| Middle (n = 222) | 54.1% (50.6 – 57.6%) | 55.0% (51.2 – 58.8%) |
| High (n = 215) | 51.5% (46.1 – 56.8%) | 52.8% (47.1 – 58.6%) |
| p for trend=0.01 | p for trend=0.2 | |
| Ages 19 – 34 years old | ||
| Non-Swimmers (n = 2093) | 59.2% (57.1 – 61.3%) | 59.9% (57.6 – 62.2%) |
| Swimmers (n = 513) | 52.4% (48.1 – 56.7%) | 52.3% (47.6 – 57.1%) |
| Low (n = 179) | 56.1% (53.8 – 58.4%) | 57.1% (54.4 – 59.7%) |
| Middle (n = 144) | 53.1% (49.2 – 57.1%) | 51.0% (46.6 – 55.4%) |
| High (n = 190) | 50.1% (44.2 – 56.0%) | 50.7% (44.1 – 57.2%) |
| p for trend=0.007 | p for trend=0.01 | |
| Ages 35 – 49 years old | ||
| Non-Swimmers (n = 2201) | 57.9% (55.8 – 59.9%) | 58.3% (56.0 – 60.5%) |
| Swimmers (n = 405) | 58.0% (53.2 – 62.7%) | 59.2% (53.9 – 64.3%) |
| Low (n = 143) | 57.9% (55.3 – 60.4%) | 57.6% (54.6 – 60.5%) |
| Middle (n = 140) | 57.8% (53.2 – 62.3%) | 57.5% (52.3 – 62.4%) |
| High (n = 122) | 57.8% (50.8 – 64.4%) | 60.5% (52.9 – 67.6%) |
| p for trend=1.0 | p for trend=0.9 | |
| Ages > 50 years old | ||
| Non-Swimmers (n = 2248) | 58.0% (55.9 – 60.0%) | 58.4% (56.1 – 60.6%) |
| Swimmers (n = 358) | 57.5% (52.4 – 62.6%) | 58.0% (52.3 – 63.4%) |
| Low (n = 129) | 58.0% (55.3 – 60.7%) | 56.9% (53.7 – 60.0%) |
| Middle (n = 114) | 58.1% (53.2 – 62.8%) | 56.1% (50.7 – 61.4%) |
| High (n = 115) | 58.2% (50.8 – 65.2%) | 61.0% (53.0 – 68.4%) |
| p for trend=0.9 | p for trend=0.7 |
*
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.