Grajewski Barbara, Waters Martha A, Yong Lee C, Tseng Chih-Yu, Zivkovich Zachary, Cassinelli Rick T
Industrywide Studies Branch, Division of Surveillance, Hazard Evaluations, and Field Studies, National Institute for Occupational Safety and Health, Centers for Disease Control and Prevention, Cincinnati, OH 45226, USA.
Ann Occup Hyg. 2011 Jun;55(5):465-75. doi: 10.1093/annhyg/mer024. Epub 2011 May 24.
US commercial airline pilots, like all flight crew, are at increased risk for specific cancers, but the relation of these outcomes to specific air cabin exposures is unclear. Flight time or block (airborne plus taxi) time often substitutes for assessment of exposure to cosmic radiation. Our objectives were to develop methods to estimate exposures to cosmic radiation and circadian disruption for a study of chromosome aberrations in pilots and to describe workplace exposures for these pilots.
Exposures were estimated for cosmic ionizing radiation and circadian disruption between August 1963 and March 2003 for 83 male pilots from a major US airline. Estimates were based on 523 387 individual flight segments in company records and pilot logbooks as well as summary records of hours flown from other sources. Exposure was estimated by calculation or imputation for all but 0.02% of the individual flight segments' block time. Exposures were estimated from questionnaire data for a comparison group of 51 male university faculty.
Pilots flew a median of 7126 flight segments and 14 959 block hours for 27.8 years. In the final study year, a hypothetical pilot incurred an estimated median effective dose of 1.92 mSv (absorbed dose, 0.85 mGy) from cosmic radiation and crossed 362 time zones. This study pilot was possibly exposed to a moderate or large solar particle event a median of 6 times or once every 3.7 years of work. Work at the study airline and military flying were the two highest sources of pilot exposure for all metrics. An index of work during the standard sleep interval (SSI travel) also suggested potential chronic sleep disturbance in some pilots. For study airline flights, median segment radiation doses, time zones crossed, and SSI travel increased markedly from the 1990s to 2003 (P(trend) < 0.0001). Dose metrics were moderately correlated with records-based duration metrics (Spearman's r = 0.61-0.69).
The methods developed provided an exposure profile of this group of US airline pilots, many of whom have been exposed to increasing cosmic radiation and circadian disruption from the 1990s through 2003. This assessment is likely to decrease exposure misclassification in health studies.
与所有飞行机组人员一样，美国商业航空公司飞行员患特定癌症的风险增加，但这些结果与特定客舱暴露之间的关系尚不清楚。飞行时间或轮挡时间（飞行时间加上滑行时间）常被用来替代对宇宙辐射暴露的评估。我们的目标是开发方法，以估计飞行员染色体畸变研究中宇宙辐射暴露和昼夜节律紊乱情况，并描述这些飞行员的工作场所暴露情况。
对一家美国大型航空公司的83名男性飞行员在1963年8月至2003年3月期间的宇宙电离辐射暴露和昼夜节律紊乱情况进行了估计。估计基于公司记录和飞行员日志中的523387个单独航班段，以及其他来源的飞行小时汇总记录。除了0.02%的航班段轮挡时间外，所有其他时间的暴露均通过计算或推算得出。从51名男性大学教师组成的对照组的问卷数据中估计暴露情况。
飞行员在27.8年中平均飞行7126个航班段，轮挡时间为14,959小时。在研究的最后一年，一名假设的飞行员因宇宙辐射估计有效剂量中位数为1.92毫希沃特（吸收剂量，0.85毫戈瑞），穿越362个时区。该研究中的飞行员可能平均每3.7年工作时间中经历6次或1次中度或大型太阳粒子事件。对于所有指标而言，在研究航空公司工作和军事飞行是飞行员暴露的两个最高来源。标准睡眠间隔期间的工作指数（SSI旅行）也表明一些飞行员可能存在慢性睡眠障碍。对于研究航空公司的航班，从20世纪90年代到2003年，航班段辐射剂量中位数、穿越的时区数和SSI旅行显著增加（P趋势<0.0001）。剂量指标与基于记录的时长指标中度相关（斯皮尔曼相关系数r = 0.61 - 0.69）。
所开发的方法提供了这组美国航空公司飞行员的暴露概况，其中许多人从20世纪90年代到2003年一直暴露于不断增加的宇宙辐射和昼夜节律紊乱中。这种评估可能会减少健康研究中的暴露错误分类。
