Rice F L, Park R, Stayner L, Smith R, Gilbert S, Checkoway H
National Institute for Occupational Safety and Health, Cincinnati, Ohio 45226-1998, USA.
Occup Environ Med. 2001 Jan;58(1):38-45. doi: 10.1136/oem.58.1.38.
To use various exposure-response models to estimate the risk of mortality from lung cancer due to occupational exposure to respirable crystalline silica dust.
Data from a cohort mortality study of 2342 white male California diatomaceous earth mining and processing workers exposed to crystalline silica dust (mainly cristobalite) were reanalyzed with Poisson regression and Cox's proportional hazards models. Internal and external adjustments were used to control for potential confounding from the effects of time since first observation, calendar time, age, and Hispanic ethnicity. Cubic smoothing spline models were used to assess the fit of the models. Exposures were lagged by 10 years. Evaluations of the fit of the models were performed by comparing their deviances. Lifetime risks of lung cancer were estimated up to age 85 with an actuarial approach that accounted for competing causes of death.
Exposure to respirable crystalline silica dust was a significant predictor (p<0.05) in nearly all of the models evaluated and the linear relative rate model with a 10 year exposure lag seemed to give the best fit in the Poisson regression analysis. For those who died of lung cancer the linear relative rate model predicted rate ratios for mortality from lung cancer of about 1.6 for the mean cumulative exposure to respirable silica compared with no exposure. The excess lifetime risk (to age 85) of mortality from lung cancer for white men exposed for 45 years and with a 10 year lag period at the current Occupational Safety and Health Administration (OSHA) standard of about 0.05 mg/m(3) for respirable cristobalite dust is 19/1000 (95% confidence interval (95% CI) 5/1000 to 46/1000).
There was a significant risk of mortality from lung cancer that increased with cumulative exposure to respirable crystalline silica dust. The predicted number of deaths from lung cancer suggests that current occupational health standards may not be adequately protecting workers from the risk of lung cancer.
运用多种暴露-反应模型，估算职业性接触可吸入结晶二氧化硅粉尘导致肺癌死亡的风险。
对2342名接触结晶二氧化硅粉尘（主要是方石英）的加利福尼亚白种男性硅藻土采矿和加工工人队列死亡率研究的数据，采用泊松回归和考克斯比例风险模型进行重新分析。采用内部和外部调整来控制首次观察以来的时间、日历时间、年龄和西班牙裔种族影响所带来的潜在混杂因素。使用三次平滑样条模型评估模型的拟合度。暴露滞后10年。通过比较模型的偏差对模型拟合度进行评估。采用考虑了竞争性死亡原因的精算方法，估计至85岁的肺癌终生风险。
在几乎所有评估的模型中，接触可吸入结晶二氧化硅粉尘都是一个显著的预测因素（p<0.05），在泊松回归分析中，10年暴露滞后的线性相对率模型似乎拟合最佳。对于死于肺癌的人，线性相对率模型预测，与未接触相比，可吸入二氧化硅平均累积接触导致的肺癌死亡率比值约为1.6。按照美国职业安全与健康管理局（OSHA）目前可吸入方石英粉尘约0.05 mg/m³的标准，对于暴露45年且有10年滞后时间的白种男性，至85岁时肺癌死亡的额外终生风险为19/1000（95%置信区间（95%CI）5/1000至46/1000）。
存在因累积接触可吸入结晶二氧化硅粉尘而导致肺癌死亡的显著风险，且该风险随累积接触量增加。预测的肺癌死亡人数表明，当前的职业健康标准可能无法充分保护工人免受肺癌风险。
