Cumulative weight-bearing from workplace caused dose-dependent osteoarthritis of the knee in salt workers
研究了台湾盐业工人工作场所累积负重与膝关节骨关节炎风险的关系，发现负重越大，患病风险越高，且女性比男性更易受影响。
<h3>Objectives</h3> To determine whether cumulative weight-bearing from workplace was dose-dependently related to risk of knee osteoarthritis (OA). <h3>Methods</h3> 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 Lequesne9s 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). <h3>Results</h3> 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 Lequesne9s 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 Lequesne9s index. <h3>Conclusion</h3> 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.