Night Work and Breast Cancer Risk in Nurses: Multifactorial Risk Analysis

Abstract

Night work has been highlighted by the International Agency for Research on Cancer (IARC) as a likely carcinogenic factor for humans, associated with breast cancer and professions that require continuity of work. Knowing the impact that short and long-term night work has on the nurses’ collective seems a priority, therefore, this study aims to analyse the relationship between night work and the development of breast cancer risk factors in nurses. For this, a cross-sectional study through an online questionnaire on breast cancer risk variables and working life was designed. The study was conducted in Spain and the sample consisted of 966 nurses, of whom 502 were healthy participants and 56 were breast cancer patients. These two groups were compared in the analyses. A descriptive analysis was performed, and the relationship was tested using χ2 independence test and OR calculation. The CHAID (Chi Square Automatic Interaction Detection) data mining method allowed for the creation of a segmentation tree for the main risk variables. The most significant risk variables related to working life have been the number of years worked, nights worked throughout life, and years working more than 3 nights per month. Exceeding 16 years of work has been significant for women and men. When the time worked is less than 16 years, the number of cases increases if there is a family history of cancer and if there have been more than 500 nights of work. High-intensity night work seems more harmful at an early age. The accumulation of years and nights worked increase the risk of breast cancer when factors such as sleep disturbance, physical stress, or family responsibilities come together.

How the Intensity of Night Shift Work Affects Breast Cancer Risk

“…These authors observed that the long duration of shift work throughout the years is also related to the development of estrogen- and progesterone-positive tumors, especially among young women with intensive (12 h) shifts [ 17 ]. In a cross-sectional study on nurses, Gómez-Salgado et al found that higher breast cancer risk was found for nurses who had been working night shifts for more than 16 years, ≥500 night shifts, and those who had been regularly working ≥3 nights per month for >10 years [ 32 ].…”

Night shift occupational risk related to breast cancer in nurses: A systematic review. [Riesgo laboral en turno nocturno relacionado al cáncer de mama en enfermeras: Una revisión sistemática]

“…Regarding the findings, the following categories are highlighted: Breast cancer is related to nocturnal work activity. International studies in various countries report that there is a greater predisposition to breast cancer in women nurses who work night shifts more than 3 times per month, as well as prolonged work shifts (Fagundo-Rivera et al, 2020;Gómez-Salgado et al, 2021;Fagundo-Rivera et al,2021). In addition, they suggest that the increased risk of cancer according to scientific evidence is due to the alteration of circadian rhythm markers significantly affecting work performance (Clarke, 2021;Cheng-Ting et al, 2021;Fagundo-Rivera et al,2021;Rosa et al, 2019;Asmat et al, 2018).…”

Arbeitsplatz OP-Saal – Was muss der Chirurg über die Arbeitsmedizin wissen? Ein Update

“…Verschiedene große Studien bestätigen den Verdacht. Insbesondere lange Nachtschichten (über 10 Stunden) und viele Nachtschichten am Stück (mehr als 3 Nachtschichten pro Woche) erhöhen das Brustkrebsrisiko [42].…”