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首页> 外文期刊>Annals of epidemiology >Quantifying lead-time bias in risk factor studies of cancer through simulation
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Quantifying lead-time bias in risk factor studies of cancer through simulation

机译：通过模拟量化癌症风险因素研究中的前置时间偏差

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Purpose: Lead-time is inherent in early detection and creates bias in observational studies of screening efficacy, but its potential to bias effect estimates in risk factor studies is not always recognized. We describe a form of this bias that conventional analyses cannot address and develop a model to quantify it. Methods: Surveillance Epidemiology and End Results (SEER) data form the basis for estimates of age-specific preclinical incidence, and log-normal distributions describe the preclinical duration distribution. Simulations assume a joint null hypothesis of no effect of either the risk factor or screening on the preclinical incidence of cancer, and then quantify the bias as the risk-factor odds ratio (OR) from this null study. This bias can be used as a factor to adjust observed OR in the actual study. Results: For this particular study design, as average preclinical duration increased, the bias in the total-physical activity OR monotonically increased from 1% to 22% above the null, but the smoking OR monotonically decreased from 1% above the null to 5% below the null. Conclusions: The finding of nontrivial bias in fixed risk-factor effect estimates demonstrates the importance of quantitatively evaluating it in susceptible studies.
机译：目的：提前期是早期发现所固有的，并且在筛选功效的观察性研究中会产生偏差，但并非总是能认识到其可能会导致危险因素研究中的效应估计偏差。我们描述了这种偏见的一种形式，这是常规分析无法解决的，并开发了一个量化模型。方法：监测流行病学和最终结果（SEER）数据构成了估计特定年龄的临床前发生率的基础，对数正态分布描述了临床前持续时间的分布。模拟假设联合零假设对风险因素或筛查对癌症的临床前发生率均无影响，然后根据该零研究将偏倚量化为危险因素比值比（OR）。该偏差可以用作调整实际研究中观察到的OR的因素。结果：对于这个特殊的研究设计，随着平均临床前持续时间的增加，总身体活动的偏倚或单调从无效值的1％增加到22％，但吸烟或从无效值的1％的单调减少到5％在null以下。结论：在固定的风险因素影响评估中发现非平凡的偏见证明了在易感研究中定量评估它的重要性。

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