MedWire News: Having a job that involves a heavy physical workload increases a person's risk for developing hip or knee osteoarthritis (OA) and risks are higher with cumulative exposure, report researchers.
"Occupational workload has been associated with an increased risk of OA, but only little research has been conducted among female workers," write Susan Andersen (University of Southern Denmark, Copenhagen) and colleagues in Occupational and Environmental Medicine.
They therefore carried out a follow-up study of the Danish working population from 1981 to 2006 to evaluate the incidence of hip and knee OA related to professional occupation.
The occupational groups in the registry included floor- or bricklayers (group one), construction workers (group two; including but not exclusively floor- or bricklayers), farmers (group three), healthcare assistants (group four), and office workers (group five). Groups one to four were considered to have exposure to heavy physical work, and group five was used as a control.
The team found that male floor- or bricklayers and male and female healthcare assistants had the highest risk for developing knee OA and farmers of both genders the highest risk for hip OA.
More specifically, the incidence rate (IR) per 100,000 person-years for knee OA was 59.6 for male floor- or bricklayers and 56.6 and 78.9 for male and female healthcare assistants, respectively. Male and female farmers had an IR per 100,000 person-years of 157.7 and 103.7, respectively.
In general there was a significant dose-response relationship between the number of years spent doing a job with a high physical workload and risk for OA, but this effect seemed to be more prominent for some professions than others.
For example, farmers who had worked for over 20 years had a maximum 4.20-fold increased risk for hip OA, and already had a significant 1.63-fold increased risk after 1-5 years' work.
However, the cumulative maximum increased risks associated with construction or healthcare work on risk for knee OA for over 20 years exposure were 2.79-fold and 3.50- and 2.88-fold in male construction workers and male and female healthcare assistants, respectively, and 1-5 year risks were negligible.
"Long-term strenuous working conditions are an important public health issue," say Andersen and co-workers. "Occupations with heavy physical workload present a strong risk for hip and knee OA in both men and women."
They conclude: "Future preventive strategies may benefit from assessment of occupational physical load to prevent physical wear."
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