Knee problems are common in young adults and associated with physical activity and not obesity: the findings of a cross-sectional survey in a university cohort

Background: Obesity and sedentary behaviour, risk factors for knee osteoarthritis in middle-age, are increasing in younger adults. The objectives of this study were to estimate the prevalence of knee problems in young adults, to characterise these problems and explore the relationship with physical activity, physical inactivity and obesity. Methods: Presence of knee problems was collected through self-report questionnaire from staff and students of one university aged 18-39; direct measurement of weight and height was taken and activity measured using the International Physical Activity Questionnaire. Twelve-month prevalence of knee problems was estimated. Logistic regression was used to investigate the relationship between knee problems and physical activity levels, sitting time and body mass index. Results: The prevalence of knee problems was high (31.8% [95% CI 26.9% to 37.2%]) among the 314 participants; knee pain was the most common dominant symptom (65%). Only high physical activity levels (OR 2.6 [95% CI 1.4-4.9]) and mental distress (OR 2.3 [95% CI 1.2-4.6]) were independent risk factors for knee problems. Conclusions: Knee problems were common among young adults, who were staff and students of a university. With increasing obesity prevalence, populations are being encouraged to become more active. More attention may need to be paid towards prevention of knee problems in such programmes, and further research is warranted