The association between occupation and the incidence of knee disorders in young military recruits

Objective: To investigate the association between occupational risk factors and the incidence of knee disorders in a young adult population. Methods: Israeli recruits to the Israel Defense Forces go through a rigorous medical investigation. Study participants were classified by prior knee condition status and divided into 5 categories of prospective occupational exposure to physical activity according to their assigned military duties, and were then followed for 30 months for the development of severe knee disorders (SKD). Logistic regression analysis was used to estimate the occupational risks for incident SKD, adjusted for any previous mild or moderate disorder, body mass index, and body height at induction. Results: The study population consisted of 76,491 males. SKD developed in 615 (0.8%). Compared to administrative workers as referents, a higher risk of developing SKD was manifest among high intensity combat occupations, (odds ratios [OR]2.15), those in moderate intensity combat occupations (OR 2.57) and maintenance (OR 1.59). Drivers did not demonstrate increased risk of knee disorders compared to referents. Conclusions: Occupational factors during military service are associated with incident SKD, even when taking into account previous knee disorders, body mass index, and height, which also had independent effects in our study population.