Flight attendants, breast cancer, and melatonin

Abstract

The report by Anthony Mawson (Aug 22, p 626)1Mawson AR Breast cancer in female flight attendants.Lancet. 1998; 352: 626Summary Full Text Full Text PDF PubMed Scopus (36) Google Scholar is a chain of assumptions that seems to provide an explanation for the increased risk of developing breast cancer in female flight attendants. In fact, he presents no evidence that is connected to the main topic.It is well known that flight attendants are exposed to high-energy cosmic radiation2Barish RJ Health physics concerns in commercial aviation.Health Phys. 1990; 59: 199-204Crossref PubMed Scopus (17) Google Scholar that per se may contribute to an increased risk of malignant diseases. Similarly, the lifestyle of flight attendants is hardly comparable with the general population with respect to nutrition, stress, and c. Thus, the comparison of incidence of breast cancer in flight attendants versus the general population is not applicable because of confounding factors—ie, there is no proper control group.Even if there were lower rates of melatonin production in flight attendants compared with a proper control group, this difference would not mean that low melatonin causes breast cancer. Low melatonin may only be an epiphenomenon. Indeed, a study that addresses the melatonin problem was not cited by Mawson; Härma and colleagues3Härma M Laitinen J Partinen J Suvanto S The effect of four-day round trip flights over 10 time zones on the circadian variation of salivary melatonin and cortisol in airline flight attendants.Ergonomics. 1994; 37: 1479-1489Crossref PubMed Scopus (39) Google Scholar showed that the melatonin rhythm in flight attendants persists during and adjusts after flights across ten time zones without a significant drop in the amplitude. This finding challenges any connection between increased risk of breast cancer and low melatonin concentrations in female flight attendants. The report by Anthony Mawson (Aug 22, p 626)1Mawson AR Breast cancer in female flight attendants.Lancet. 1998; 352: 626Summary Full Text Full Text PDF PubMed Scopus (36) Google Scholar is a chain of assumptions that seems to provide an explanation for the increased risk of developing breast cancer in female flight attendants. In fact, he presents no evidence that is connected to the main topic. It is well known that flight attendants are exposed to high-energy cosmic radiation2Barish RJ Health physics concerns in commercial aviation.Health Phys. 1990; 59: 199-204Crossref PubMed Scopus (17) Google Scholar that per se may contribute to an increased risk of malignant diseases. Similarly, the lifestyle of flight attendants is hardly comparable with the general population with respect to nutrition, stress, and c. Thus, the comparison of incidence of breast cancer in flight attendants versus the general population is not applicable because of confounding factors—ie, there is no proper control group. Even if there were lower rates of melatonin production in flight attendants compared with a proper control group, this difference would not mean that low melatonin causes breast cancer. Low melatonin may only be an epiphenomenon. Indeed, a study that addresses the melatonin problem was not cited by Mawson; Härma and colleagues3Härma M Laitinen J Partinen J Suvanto S The effect of four-day round trip flights over 10 time zones on the circadian variation of salivary melatonin and cortisol in airline flight attendants.Ergonomics. 1994; 37: 1479-1489Crossref PubMed Scopus (39) Google Scholar showed that the melatonin rhythm in flight attendants persists during and adjusts after flights across ten time zones without a significant drop in the amplitude. This finding challenges any connection between increased risk of breast cancer and low melatonin concentrations in female flight attendants. Flight attendants, breast cancer, and melatoninAuthor's reply Full-Text PDF