Knee Problems in Young Adults

Abstract

Abstract

Obesity and physical inactivity have been identified as risk factors for knee pain in elderly populations. There has been an increase in the prevalence of obesity and physical inactivity in younger adults. Therefore, it is important to investigate whether they are risk factors for knee disorders among young adults. This thesis explored the epidemiology of knee problems in young adults.

A literature review, using systematic methods, identified 19 studies reporting on the incidence of and/or risk factors for knee disorders in young adults. Knee disorder incidence varied across studies (0.07% to 42.0%), because of the different knee conditions and study populations (military and sports) investigated. There was conflicting evidence on whether obesity and physical activity were risk factors for knee disorders; and physical inactivity had not been investigated.

A longitudinal study was undertaken to estimate the incidence of knee problems in young adults and explore whether physical activity, physical inactivity and obesity were risk factors. It was designed as a feasibility study to inform a large-scale cohort study in the general population. Three hundred and fourteen staff and students of the University of Central Lancashire, Preston campus were recruited and followed up for 12 months. Data was collected through self-report questionnaire and where possible direct measurement of weight and height was taken. Logistic regression was used to investigate any plausible relationship between knee problems and body mass index (BMI), physical inactivity, and physical activity levels.

The mean (SD) age was 22 (5.2) years. There were more men (n=176, 56.1%) than woman (n=138, 43.9%). At baseline, the mean (SD) score for the Hopkins Symptoms Checklist-10 (mental distress) was 1.5 (0.4); mean (SD) BMI was 24.3 (4.1) and mean (SD) total hours spent sitting per day was 5.6 hours (2.6). Over half of the participants (n=165, 52.9%) reported low physical activity with similar proportions reporting moderate (n= 75, 24.0%), and high (n= 72, 23.1%) physical activity levels. The prevalence of knee problems was high (31.8% [95% CI 26.9% to 37.2%]); knee pain was the most prevalent symptom. Multivariate logistic regression analysis on cross- sectional data showed that 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. Only 126 (40.1%) participants responded to the follow up at 12 months: 76.9% still had knee problems and 11.5% had a new knee problem.

Knee problems are common in young adults. The study provided an estimate of incidence to inform the design of a large-scale population based study but attention needs to be paid to ensure lower attrition. The study suggests that more attention may need to be paid towards prevention of knee problems and that further work on the economic burden of knee problems among young adults is warranted. This is particularly important as there is increasing emphasis in public health policy on promoting physical activity.