Les hôtesses de l’air sont-elles à risque accru de cancer du sein ?

Thyroid cancer risk in airline cockpit and cabin crew: a meta-analysis

BACKGROUND

Airline crew are exposed to ionizing radiation as part of their occupation and have a documented increased risk of melanoma and cataracts. However, whether their occupation predisposes them to an increased risk of thyroid cancer is not established. The purpose of this systematic review and meta-analysis was to assess the risk of thyroid cancer in airline cockpit and cabin crew compared with the general population.

METHODS

The MEDLINE database accessed via PubMed and Cochrane Database were searched. We included cohort studies reporting the standardized incidence ratio (SIR) or standardized mortality ratio (SMR) of thyroid cancers in any flight-based occupation.

RESULTS

Of the 1777 citations retrieved in PubMed, eight studies with a total of 243,088 aircrew members and over 3,334,114 person-years of follow-up were included in this meta-analysis. No relevant studies were identified on Cochrane Database. The overall summary SIR of participants in any flight-based occupation was 1.11 (95% CI, 0.79-1.57; p = 0.613; 6 records). The summary SIR for cockpit crew was 1.21 (95% CI, 0.75-1.95; p = 0.383; 4 records) and the summary SIR for cabin crew was 1.00 (95% CI, 0.60-1.66; p = 0.646; 2 records). The overall summary standardized mortality ratio for airline crew was 1.19 (95% CI, 0.59-2.39; p = 0.773; 2 records).

CONCLUSION

Airline crew were not found to have a significantly elevated risk of thyroid cancer incidence or mortality relative to the general population. Future research should capitalize on the growing occupational cohort dataset and employ innovative methods to quantify lifetime radiation exposure to further assess thyroid cancer risk in airline crew.

[Night work, shift work: Breast cancer risk factor?]

OBJECTIVE

The aim of this review was to determine the link between night/shift work and breast cancer.

METHODS

The analysed articles were taken from the PUBMED database between 1996 and 2015. The keywords used were "breast cancer risk", "night work" and "shift work". In total, 25 articles were selected.

RESULTS

Night/shift workers are more at risk to develop a breast cancer (relative risk (RR) between 1.09; 95% CI: 1.02-1.20 and 1.48; 95% CI: 1.36-1.61 in the meta-analyses). However, this risk is not found by some cohort and case-control studies. The circadian rhythm disruption, responsible of disorderliness of melatonin secretion, could be one of the mechanisms involved in the increase of that risk. Hormonal status of night/shift workers, their geographic origin, their lifestyle and their vitamin D deficiency appear as other mechanisms potentially responsible for increased risk of cancer in this professional population. Moreover, a dose-effect connection may exist, with an increase of the risk with the number of years of night/shift work.

CONCLUSION

Night/shift work is associated with a moderate increased risk of breast cancer, especially among women who worked over 20 years. Recommendations concerning the breast monitoring in this population could be diffused. The benefit of melatonin supplementation remains to be assessed.