Breast Cancer Rate and Mortality in Female Flight Attendants: A Systematic Review and Pooled Analysis

Previous reports have suggested that breast cancer is more common among flight attendants than that in the general population. Constant exposure to cosmic radiation and circadian disruption are postulated to be the culprits of the problem. A systematic review was performed by 2 independent reviewers with predefined search strategy, in line with the PRISMA protocol. A total of 43 studies were identified using the preset keywords defined in the study protocol. After excluding irrelevant papers, 12 studies were included for pooled analysis. Ten studies evaluated the breast cancer prevalence in flight attendants, whereas 3 studies evaluated the breast cancer-related deaths. Pooled analysis found that, of the 45,111 flight attendants censored, 1061 (2.35%) had breast cancer. The standardized prevalence ratios were 1.08 (95% confidence interval [CI], 0.37-1.59) and 1.09 (95% Cl, 0.37-1.60), respectively, when compared with the American and European general population. Pooled analysis of the 3 studies on breast cancer mortality found that, of the 44,508 flight attendants censored, 139 (0.32%) had breast cancer-related mortality. Standardized mortality ratios to the American/European general population were 1.8 (95% CI, 0.63-4.25) and 1.3 (95% CI, 0.47-3.15), respectively. A review of the available literature indicates that there is insufficient evidence to suggest an association between cosmic irradiation, circadian disruption, and breast cancer in flight attendants. Breast cancer prevalence and mortality among flight attendants are comparable with that of the general population.