Several studies have reported a high prevalence of osteoarthritis (OA) of the knee among agricultural workers. We investigated work-related factors that increase the risk of knee OA among Korean farmers.

Data were extracted from the Jeonnam Center for Farmer's Safety and Health survey, conducted between 2013 and 2015. The sample included 489 farmers (man 240, woman 249). We defined knee OA as radiographic knee OA (≥ Kellgren-Lawrence grade 2) with symptoms (≥ Western Ontario and McMaster Universities Osteoarthritis, Korean version score 29.5). We considered covariates such as cumulative squatting working time (CSWT), cumulative heavy lifting working time (CLWT), body mass index (BMI), and history of knee injury. Odds ratios (ORs) and their corresponding 95% confidence intervals (CIs) were calculated for knee OA and adjusted for relevant covariates.

The results of multivariate logistic regression analysis indicated that knee OA was correlated by factors such as sex, age, BMI, history of knee injury, CSWT, and CLWT. Particularly, CSWT > 20,000 hours (OR: 2.83; 95% CI: 1.35–5.92; reference < 10,000 hours) and CLWT > 5,000 hours (OR: 2.62; 95% CI: 1.14–6.06; reference < 2,000 hours) were associated with an increased risk of knee OA after adjustment for covariates.

Squatting posture and heavy lifting associated with farm work might increase the risk of knee OA among Korean farmers.

Female farmers have a high prevalence of knee osteoarthritis (KOA) in South Korea. Femoral bowing has been reported to be related to KOA by increasing load on the mechanical axis. This study aimed to investigate factors related to femoral bowing in Korean female farmers.

We analyzed the legs of 264 female farmers registered with the Korea farmers' knee cohort of Jeonnam Center for Farmers' Safety and Health. A structured questionnaire was used to determine sociodemographic variables, agricultural career, cumulative squatting working time (CSWT), and cumulative heavy lifting working time. Femoral bone density was measured and Kellgren-Lawrence (KL) grades were obtained from the knee radiographs. Mechanical axis angle (MAA), femoral bowing angle (FBA), anatomical lateral distal femoral angle (aLDFA), anatomical medial proximal tibial angle (aMPTA), and condylar-plateau angle (CPA) were measured. We examined the relationship between the FBA and related factors by using multiple linear regression.

The proportion of individuals with radiographic KOA (≥ KL grade 2) in this study was 37.9%. As KL grades increased, MAA, FBA, and CPA increased, whereas aLDFA and aMPTA decreased. FBA increased with age. Multiple linear regression analyses using FBA as a dependent variable showed relationship with higher age, lower height, higher BMI, lower bone mineral density, longer CSWT, and longer agricultural careers.

The results of this study suggest that external factors related to agricultural work in female farmers was associated with femoral bowing, in addition to internal factors such as age, bone density, height, and obesity.