Association of occupational activity with radiographic knee osteoarthritis and lumbar spondylosis in elderly patients of population-based cohorts: a large-scale population-based study.
OBJECTIVE
To investigate the risk of radiographic knee osteoarthritis (OA) and lumbar spondylosis associated with occupational activity in elderly Japanese subjects using the large-scale population-based cohort of the Research on Osteoarthritis Against Disability (ROAD) study.


METHODS
From the baseline survey of the ROAD study, 1,471 participants age > or =50 years (531 men and 940 women) living in mountainous and seacoast communities were analyzed. Information collected included a lifetime occupational history and details of specific work place physical activities. Radiographic severity at the knee and lumbar spine was determined by the Kellgren/Lawrence (K/L) grading system.


RESULTS
The prevalence of K/L grade > or =2 knee OA and lumbar spondylosis among agricultural, forestry, and fishery workers was significantly higher than among clerical workers and technical experts in the overall population. For occupational activities, sitting on a chair had a significant inverse association with K/L grade > or =2 knee OA and lumbar spondylosis. Standing, walking, climbing, and heavy lifting were associated with K/L grade > or =2 knee OA, but were not associated with K/L grade > or =2 lumbar spondylosis. Kneeling and squatting were associated with K/L grade > or =3 knee OA.


CONCLUSIONS
This cross-sectional study using a population-based cohort suggests that sitting on a chair is a significant protective factor against both radiographic knee OA and lumbar spondylosis in Japanese subjects. An occupational activity that includes heavy lifting appears to have a greater effect on knee OA than on lumbar spondylosis.
Muraki
Shigeyuki
S
University of Tokyo, Tokyo, Japan. murakis-ort@h.u-tokyo.ac.jp
Akune
Toru
T
Oka
Hiroyuki
H
Mabuchi
Akihiko
A
En-Yo
Yoshio
Y
Yoshida
Munehito
M
Saika
Akihiko
A
Nakamura
Kozo
K
Kawaguchi
Hiroshi
H
Yoshimura
Noriko
N
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D015331:Cohort Studies; D015897:Comorbidity; D004185:Disability Evaluation; D004651:Employment; D005260:Female; D006801:Humans; D007564:Japan / Q000453:epidemiology; D008159:Lumbar Vertebrae / Q000000981:diagnostic imaging / Q000473:pathology; D008297:Male; D008875:Middle Aged; D009784:Occupational Diseases / Q000000981:diagnostic imaging / Q000453:epidemiology* / Q000503:physiopathology; D020370:Osteoarthritis, Knee / Q000000981:diagnostic imaging / Q000453:epidemiology* / Q000503:physiopathology; D015995:Prevalence; D011859:Radiography; D012307:Risk Factors; D013166:Spondylitis / Q000000981:diagnostic imaging / Q000453:epidemiology* / Q000503:physiopathology; D055815:Young Adult