E. Canetti1,2, B. Schram1,2, R. Orr1,2, R. Pope3,2
1Bond University, Faculty of Health Sciences and Medicine, Gold Coast, Australia, 2Tactical Research Unit, Bond University, Gold Coast, Australia, 3Charles Sturt University, School of Community Health, Albury/Wodonga, Australia

Background: Osteoarthritis (OA) is a chronic degenerative musculoskeletal condition. Extrinsic factors, such as exposure to high and repetitive joint loading, particularly in occupations with high physical demands, have been associated with increased risk for development, and worsening, of lower limb OA. The annual incidence rate of OA in military personnel over the age of 40 years, for example, has been reported at 26.91 (95%CI 26.64–27.18) per 1000 person-years; twice that of the general population.

Purpose: To
a) analyse the exposure of Australian Navy Officer trainees to occupational tasks associated with an increased risk of developing lower limb OA, and
b) identify projected timeframes for Navy officers to reach threshold exposures that may increase risk of developing lower limb OA.

Methods: Training program, observation, and survey data were collected from the Navy New Entry Officers’ Course (NEOC) and used to develop a Job Exposure Matrix. Activities undertaken within the program, their durations, distances traversed, loads lifted or carried by trainees, and sea vessel postings during NEOC were recorded. A desktop analysis of the 22-week NEOC was undertaken to identify frequencies and durations of exposures to physically demanding occupational tasks recognised by the Australian Repatriation Medical Authority’s (RMA) Statements of Principles to be associated with increased risk of developing lower limb OA (i.e. lifting or carrying loads >20kg, climbing >150 stairs, kneeling/squatting >1hour). Assuming that the average weekly exposures identified in the NEOC continued as personnel moved into the operational roles for which they were trained, projected cumulative exposures were estimated.

Results: The estimated timepoint at which the RMA-specified threshold for the ‘reasonable hypothesis’ scenario would be met for having lifted weights of over 20kg to a cumulative total of 100,000kg within a 10-year period of service was 6 years and 1 week following commencement of training. Officers posted to a sea vessel following completion of NEOC were likely to meet the RMA-specified threshold of 366 days of climbing > 150 stairs or ladders in any 2 years within 366 days of first posting. Cumulative exposures to carrying loads >20kg and to kneeling or squatting for more than a cumulative total of one hour each day were not projected to meet threshold levels known to increase risk.    

Conclusion(s): There may be an increased risk of Australian Navy officers developing lower limb OA due to cumulative exposure to lifting heavy weights (>20kg) and climbing stairs or ladders, the latter particularly for those posted to sea.

Implications: Given the financial and health burden of OA for Veterans, a review of initial officer training and service demands may be warranted to consider long-term impacts of cumulative exposure to lifting heavy weights (>20kg) and stair and ladder climbing and to reduce these where feasible.  

Funding, acknowledgements: This project was funded by a grant awarded by the Department of Veterans' Affairs.

Keywords: osteoarthitis, occupation, risk

Topic: Occupational health & ergonomics

Did this work require ethics approval? Yes
Institution: Bond University
Committee: Bond University Human Research Ethics Committee
Ethics number: RP02290

All authors, affiliations and abstracts have been published as submitted.

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