Resumo

FRESNEDA MORENO, Francisco Javier; GOMEZ SANTANA, José Carlos  e  BASCOPE QUINTANILLA, Hugo. Breast cancer risk in night female workers. Med. segur. trab. [online]. 2013, vol.59, n.230, pp.146-158. ISSN 1989-7790.  https://dx.doi.org/10.4321/S0465-546X2013000100010.

Recent epidemiological studies worldwide have shown an association between night shift (15-20% of workers) and an increased risk of breast cancer, this being a highly prevalent disease and the leading cause of neoplasia in women. In 2007, the IARC considered night shift as a probable carcinogen (category 2A). Night shifts produce a circadian rhythm disruption. The exposure to artificial light at night produce an inhibition in the synthesis of melatonin, increasing the estrogenic stimulus, and inhibiting the antimitotic, antiangiogenic and antioxidant effects of this hormone, increasing the risk of neoplasia. The aims of this review are to identify the scientific evidence in the association between night shift and breast cancer, to identify the intrinsic or extrinsic factors that can modify this causal association and to improve the knowledge concerning the scientific sustainability of the effect of melatonin in the chrono-disruption and vulnerabilities for breast cancer in woman. A literature search has been performed from 2006 to December 2012 from the following scientific data- bases: Medline, Wok, Lilacs, OSH, IBECS, Cochrane, Scopus and Embase. 15 articles were selected taking into account the level of evidence, according with SGIN criteria, and the full-filed inclusion and exclusion criteria. The results suggests there are not a conclusive association between risk for breast cancer and night shift. So further studies should be more accurate in different occupations, ethnic groups, minimizing the possibility of bias.

Palavras-chave : Breast cancer; shift work; night shift; melatonin.

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