The incidence of breast cancer among female flight attendants: an updated meta-analysis.
BACKGROUND
Several studies have indicated an increased risk of breast cancer (BC) among female flight attendants (FFAs); however, the results from epidemiological studies were not consistent. We thus conducted an updated meta-analysis to re-assess the risk of BC among FFAs, according to the MOOSE guideline.


METHODS
A systematical search of PubMed and Embase for relevant observational studies up to March 2016 was performed, supplemented by manual reviews of bibliographies in relevant studies. A random effect model was conducted to calculate the combined standard incidence ratio (SIR) and 95% confidence interval (95% CI) in BC risk.


RESULTS
Of the 719 citations retrieved, 10 were included, with more than 31 679 participants and 821 new cases. The combined SIR (95% CI) for BC in FFAs was 1.40 (95%CI 1.30-1.50), with no significant heterogeneity (P = 0.744; I(2 )=( )0.0%) or publication bias (Begg's test: z = 0.72, P = 0.474; Egger's test: t = 0.25, P = 0.805) among the included studies. The results were not significantly modified by publication year, geographic area, study quality or whether the fertility variables were adjusted.


CONCLUSIONS
Our meta-analysis suggests that FFAs have a higher risk of BC compared with the general population. More vigorous studies with larger sample sizes based on other populations, including the Chinese, are needed.
Civil Aviation Medicine Center, Civil Aviation Administration of China, Beijing, People's Republic of China ltbing@yeah.net.
Tiebing
T
Liu
Department of Clinical Laboratory, Civil Aviation General Hospital, Beijing, People's Republic of China.
Chanyuan
C
Zhang
Department of Information Engineering, Cangzhou Technical College, Cangzhou, Hebei, People's Republic of China.
Chong
C
Liu
D017677:Age Distribution; D000401:Aircraft; D001943:Breast Neoplasms / Q000453:epidemiology*; D002940:Circadian Rhythm; D015897:Comorbidity; D003359:Cosmic Radiation / Q000009:adverse effects*; D005260:Female; D006801:Humans; D008297:Male; D009784:Occupational Diseases / Q000453:epidemiology*; D016273:Occupational Exposure / Q000009:adverse effects*; D012307:Risk Factors
Breast cancer incidence; circadian disruption; cosmic radiation; female flight attendants; meta-analysis