Farming and the risk of developing osteoarthritis in Alberta, Canada

Introduction: Because farming is a physically demanding occupation, farmers may be susceptible to developing osteoarthritis (OA). The aim of this study is to determine the risk of developing OA in Canadian farm, non-farm rural and urban residents.
Methods: A retrospective cohort study of 5 Alberta health administrative databases examined the risk of developing OA among 3 groups: farm (n=143,431), non-farm rural (n=143,431) and urban (n=143,431) residents over the fiscal years 2000-2001 through 2020-2021. The algorithm for OA ascertainment defined cases based on criteria including one hospital admission, two physician visits within a two-year interval, or two ambulatory care visits within two years. Incidence rates, lifetime risk, and mortality rates were calculated. Cox proportional hazard models compared the incidence of OA for the 3 groups over the 21 years.
Results: 26,957 OA cases were identified among 1,706,256 person-years (PYs) in the farm cohort. The crude incidence rate of OA over 21-year period ranged from 19.1 per 1000 PYs (95%CI 18.6, 19.6) in 2001 to 10.0 per 1000 PYs (95%CI 9.6, 10.5) in 2021. The overall incidence rate was higher in the farm group (15.8 (95%CI 15.6, 16.0) /1000 PYs) as compared to the non-farm rural (14.7 (95%CI 14.5, 14.9)/1000 PYs) and the urban groups (13,3 (95%CI 13.1, 13.4)/1000 PYs). After adjusting for age and sex, the farm (6%; 95%CI 4%, 8%), and non-farm rural (9%; 95%CI 7%, 12%) group had higher incidence rates than the urban group. The unadjusted non-injury mortality rate for the farm group with OA was lower (13.2 (95%CI 12.9, 13.5)/ 1000 PYs) than both the urban (14.5; 95%CI 14.1, 14.8) and rural (18.0; 95%CI 17.6, 18.4) groups. After adjusting for mortality, the lifetime risk of developing OA was 27.7% for farm residents, 25.6% for the non-farm rural cohort, and 24% for the urban cohort
Conclusions: When accounting for age and sex, farm and non-farm rural residents have a higher risk of developing OA as compared to the urban population. The higher mortality-adjusted lifetime risk of developing OA among farm residents highlights the necessity of specific interventions aimed at reducing the impact of this condition in rural communities. Further research is required to identify specific occupational and lifestyle risk factors associated with OA among farmers and to develop effective strategies for prevention and management.
Keywords: agriculture, farming rural, incidence, mortality, osteoarthritis, urban