Article Text


Workload and injury
Cumulative weight-bearing from workplace caused dose-dependent osteoarthritis of the knee in salt workers
  1. Yue Leon Guo1,
  2. Hsu-Feng Hsiao2,
  3. Jin-Wun Wang3,
  4. Ginger HF Shu3,
  5. Perng-Jy Tsai4,
  6. Judith SC Shiao5
  1. 1NTU Environmental and Occupational Medicine, Taipei, Taiwan
  2. 2Chi Mei Medical Center, Tainan, Taiwan
  3. 3Chiali Medical Corporation Aggregate Chiali Hospital, Tainan, Taiwan
  4. 4National Cheng Kung University, Tainan, Taiwan
  5. 5NTU Department of Nursing, Taipei, Taiwan


Objectives To determine whether cumulative weight-bearing from workplace was dose-dependently related to risk of knee osteoarthritis (OA).

Methods The registered workers of two Salt Production Societies, Chigu and Beimen, in southern Taiwan between the years 1961 and 2002 were recruited. A structured questionnaire was used to collect occupational history and knee OA symptoms. Those with knee symptoms were seen by a physician, and knee OA was diagnosed according to the American College of Rheumatology Criteria for the Classification and Reporting of OA of the Knee. Symptomatic severity of OA was scored using Lequesne's index. Knee radiographic examination was made available to participants, and evaluated according to the Kellgren/Lawrence (K/L) scale. Cumulative weight-bearing from workplace was calculated as total walking time with weight-bearing (TWW).

Results Of the 316 registered salt workers, 218 completed the study (81 males, 137 females). The prevalence of symptomatic knee OA was 55.6% in men and 67.9% in women. After adjusting for age, smoking, and averaged body mass index, elevated risk of OA and increased Lequesne's index were found among men with TWW ≥15*105 kg-h and among women with TWW ≥5*105 kg-h, in a dose-dependent manner. Radiographic severity measured by K/L scale was found related to symptomatic severity measured by Lequesne's index.

Conclusion Cumulative weight-bearing from workplace was related to knee OA and OA symptomatic severity in a dose-related manner. When considering the risk associated with weight-bearing, women had higher susceptibility to developing knee OA than men in the same cumulative occupational weight-bearing.

Statistics from

Request Permissions

If you wish to reuse any or all of this article please use the link below which will take you to the Copyright Clearance Center’s RightsLink service. You will be able to get a quick price and instant permission to reuse the content in many different ways.