"Abstract

Aircrew are exposed to in-cabin engine oil and hydraulic fumes during work. A wide spectrum of symptoms, referred to as Aerotoxic Syndrome (AS), has been described in case series and health surveys. In addition, epidemiological studies have consistently shown elevated risks for breast cancer in females and for melanoma in both male and female aircrew members. The concentrations of neurotoxic, endocrine-disrupting, and carcinogenic components of fumes have been too low to explain chronic health effects. Instead, ionizing radiation, elevated ozone levels, and disruption of circadian rhythms have been considered as occupational risk factors for certain cancers in aircrew. This review examines the significance of these factors in the context of AS and cancers. A literature search in MEDLINE was conducted (via PubMed and ScienceDirect) for studies published up to May 2025 on (1) neuro- or immunotoxicity of contaminated cabin air, (2) increased cancer rate of cabin crew, and (3) suspected contributing occupational risk factors. From 672 screened titles and abstracts, 162 relevant full-text papers were selected and grouped into these three categories. An association between organophosphate exposure and elevated levels of neuronal auto-antibodies has been demonstrated with presentation of neurological symptoms of autoimmunity. By-products of ozone degradation appear to be more toxic than ozone itself and are both carcinogenic and neurotoxic. Disruption of circadian rhythms (night shifts) has been shown to influence the immune status of aircrew, change the metabolic degradation of toxic compounds, disrupt hormones (melatonin, cortisol), and could contribute to the risk of breast cancer among female crew members. Exposure to cosmic radiation has a suspected link to breast cancer. Overall, chronic exposure of aircrew to a mixture of neurotoxic compounds in conjunction with auto-immune mechanisms and external factors appears etiologically relevant for increased breast cancer risks in aircrew as well as for symptoms associated with AS. Endocrine-disrupting chemicals, exposure to elevated ozone levels, ionizing radiation, and night-shift work with the disturbed circadian rhythms are contributing factors."