Tiebing Liu - Civil Aviation Medicine Center, Civil Aviation Administration of China, Beijing, ۱۰۰۱۲۳, People’s Republic of China
Chanyuan Zhang - Department of Clinical Laboratory, Civil Aviation General Hospital, Beijing, ۱۰۰۱۲۳, People’s Republic of China
Shanshan Wang - Department of Cadiology, China-Japan Friendship Hospital, Peking Union Medical College and Chinese Academy of Medical Sciences, Beijing ۱۰۰۷۳۰, People’s Republic of China
Jin Zhang - Department of Neurosurgery, National Cancer Center/Cancer Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, ۱۰۰۰۲۱, People’s Republic of China

Introduction: Previous studies on Brain and other Nervous System Cancers (BNSC) and aircrew have shown inconsistent results, possibly due to their relatively small sample sizes; therefore, the current study aimed to increase the precision of risk estimates.Methods: Systematic searches of PubMed and Embase for pertinent studies up to August ۲۰۱۶ were performed and supplemented by manual reviews of bibliographies. The pooled standard incidence ratio (SIR) and corresponding ۹۵% CIs were estimated with random effects models.Results: Among the ۹۰۳ studies retrieved, ۷ studies (۵ cohort studies and ۲ pooled analyses) were included in the current meta-analysis. The pooled SIR (۹۵% CI) of BNSC incidence in aircrew was ۱.۰۱ (۰.۷۷, ۱.۳۱) with no significant heterogeneity (I۲ = ۳۶.۱%, P = .۱۹۹). The null association persisted when the analysis was stratified by geographic area (Europe or America), publication year (before or after ۲۰۰۱), air population (pilots or cabin crew), cancer site (brain, nervous system, or brain/nervous system), and gender (male or female).Conclusion: The current evidence is not sufficient to support a significant positive association between aircrew employment and BNSC risk. However, the interpretation and extrapolation of this meta-analysis are restricted by the possible impact exerted by health worker effect and potential clinical heterogeneity. More studies based on other populations, including Asian aircrews, are warranted.

Brain neoplasms, Nervous system neoplasms, Aircrew, Meta-analysis