To what extent is severe osteoarthritis preventable? Occupational and non-occupational risk factors for knee and hip osteoarthritis

Abstract

Objectives: To explore the relative contribution of cumulative physical workload, sociodemographic and lifestyle factors, as well as prior injury to hospitalization due to knee and hip OA.

Methods: We examined a nationally representative sample of persons aged 30-59 years, who participated in a comprehensive health examination (the Health 2000 Study). A total of 4642 participants were followed from mid-2000 to end-2015 for the first hospitalization due to knee or hip OA using the National Hospital Discharge Register. We examined the association of possible risk factors with the outcome using a competing risk regression model (death was treated as competing risk) and calculated population attributable fractions for statistically significant risk factors.

Results: Baseline age and BMI as well as injury were associated with the risk of first hospitalization due to knee and hip OA. Composite cumulative workload was associated with a dose-response pattern with hospitalizations due to knee OA and with hospitalizations due to hip OA at a younger age only. Altogether, prior injury, high BMI and intermediate to high composite cumulative workload accounted for 70% of hospitalizations due to knee OA. High BMI alone accounted for 61% and prior injury only for 6% of hospitalizations due to hip OA.

Conclusion: Our results suggest that overweight/obesity, prior injury and cumulative physical workload are the most important modifiable risk factors that need to be targeted in the prevention of knee OA leading to hospitalization. A substantial proportion of hospitalizations due to hip OA can be reduced by controlling excess body weight.

Keywords: body mass index; competing risk model; cumulative physical workload; epidemiology; hip OA; injury; knee OA; register study.