Faculty of Medicine and Biosciences, University of Tampere, Tampere, Finland.
Cancer Epidemiology Unit, NDPH, University of Oxford, Old Road Campus, Oxford OX3 7LF, UK.
Environ Res. 2018 Oct;166:466-472. doi: 10.1016/j.envres.2018.06.035. Epub 2018 Jun 23.
When evaluating environmental exposures, residential exposures are often most relevant. In most countries, it is impossible to establish full residential histories. In recent publications, childhood leukaemia and background radiation have been studied with and without full residential histories. This paper investigates the consequences of lacking such full data. Data from a nationwide Finnish Case-Control study of Childhood Leukaemia and gamma rays were analysed. This included 1093 children diagnosed with leukaemia in Finland in 1990-2011. Each case was matched by gender and year of birth to three controls. Full residential histories were available. The dose estimates were based on outdoor background radiation measurements. The indoor dose rates were obtained with a dwelling type specific conversion coefficient and the individual time-weighted mean red bone marrow dose rates were calculated using age-specific indoor occupancy and the age and gender of the child. Radiation from Chernobyl fallout was included and a 2-year latency period assumed. The median separation between successive dwellings was 3.4 km and median difference in red bone marrow dose 2.9 nSv/h. The Pearson correlation between the indoor red bone marrow dose rates of successive dwellings was 0.62 (95% CI 0.60, 0.64). The odds ratio for a 10 nSv/h increase in dose rate with full residential histories was 1.01 (95% CI 0.97, 1.05). Similar odds ratios were calculated with dose rates based on only the first dwelling (1.02, 95% CI 0.99, 1.05) and only the last dwelling (1.00, 95% CI 0.98, 1.03) and for subjects who had lived only in a single dwelling (1.05, 95% CI 0.98, 1.10). Knowledge of full residential histories would always be the option of choice. However, due to the strong correlation between exposure estimates in successive dwellings and the uncertainty about the most relevant exposure period, estimation of overall exposure level from a single address is also informative. Error in dose estimation is likely to cause some degree of classical measurement error resulting in bias towards the null.
在评估环境暴露时，住宅暴露通常是最相关的。在大多数国家，建立完整的居住史是不可能的。在最近的出版物中，已经研究了儿童白血病和背景辐射，既有完整的居住史，也有无完整的居住史。本文研究了缺乏这种完整数据的后果。这项研究的数据来自芬兰全国性的儿童白血病病例对照研究和伽马射线。该研究包括 1990 年至 2011 年在芬兰确诊的 1093 名白血病患儿。每个病例都按性别和出生年份与 3 名对照相匹配。提供了完整的居住史。剂量估算基于户外背景辐射测量值。室内剂量率通过特定于住宅类型的转换系数获得，个体红骨髓剂量率的时间加权平均值通过年龄特异性室内居住时间、儿童年龄和性别计算。包括切尔诺贝利沉降物的辐射，并假设 2 年潜伏期。连续居住点之间的中位数分离为 3.4 公里，红骨髓剂量的中位数差异为 2.9 纳希沃特/小时。连续住宅的室内红骨髓剂量率之间的 Pearson 相关系数为 0.62（95%CI 0.60，0.64）。在有完整居住史的情况下，剂量率增加 10 纳希沃特/小时的比值比为 1.01（95%CI 0.97，1.05）。根据仅第一个住宅（1.02，95%CI 0.99，1.05）和仅最后一个住宅（1.00，95%CI 0.98，1.03）以及仅居住在一个住宅中的受试者的剂量率计算出了类似的比值比（1.05，95%CI 0.98，1.10）。了解完整的居住史总是首选方案。然而，由于连续住宅之间暴露估计值之间存在很强的相关性，以及对最相关暴露期的不确定性，从单个地址估算总体暴露水平也是有信息的。剂量估计的误差可能会导致一定程度的经典测量误差，从而导致向零值的偏差。
