Institute for Occupational Epidemiology and Risk Assessment of Evonik Industries AG, Essen, Germany.
J Occup Environ Med. 2013 Sep;55(9):1027-34. doi: 10.1097/JOM.0b013e318297327a.
To estimate a threshold value for the respirable quartz dust concentration and silicosis incidence (1/1, ILO 1980/2000) in the German porcelain worker cohort.
Forty incident cases occurred among 17,144 workers. Estimation of the relationship to cumulative respirable quartz dust exposures by using Cox regression with restricted cubic splines (7 knots or less) and fractional polynomials (degrees 5 or less). Threshold estimates were obtained by subtracting candidate values from the time-dependent concentration data (setting the result to zero if negative) and recalculating cumulative exposure.
Best threshold estimate was 0.25 mg/m (95% confidence interval: 0.15 to 0.30 mg/m).
A concentration threshold for silicosis risk is plausible. A threshold Cox model fitted the data significantly better than a nonthreshold model, summarized the cohort information without a loss in extracted information and more simply than restricted cubic splines and fractional polynomials.
估算德国陶瓷工人群体中可吸入石英粉尘浓度和矽肺发病率（1/1，ILO 1980/2000）的阈值值。
在 17144 名工人中发生了 40 例发病病例。使用 Cox 回归和限制性立方样条（7 个结或更少）和分数多项式（度 5 或更少）来估计与累积可吸入石英粉尘暴露的关系。通过从时变浓度数据中减去候选值来获得阈值估计值（如果为负，则将结果设置为零），并重新计算累积暴露量。
最佳阈值估计值为 0.25mg/m（95%置信区间：0.15 至 0.30mg/m）。
矽肺风险存在浓度阈值。与非阈值模型相比，阈值 Cox 模型更能显著拟合数据，在不损失提取信息的情况下更简洁地总结队列信息，并且比限制性立方样条和分数多项式更简单。
