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

SIMPLE SUMMARY: The incidence of breast cancer worldwide has increased in recent decades in women, and shift work, which implies night work, has been identified as a likely carcinogenic factor for humans due to the biological and lifestyle alterations it entails. Nurses, mainly represented by the female collective, undertake working conditions with intensive rotative and night shifts. Therefore, it is appropriate to describe the association between breast cancer and rotating night shifts in nurses, analysing the effect of consecutive night shifts, sleep disruption, work-family stress and medication intake, among others. This article demonstrates that preventive measures must be considered from healthcare managers to reduce occupational breast cancer hazards. In this way, it is important to consider the constant exposition of nurses to a stressing environment while stopping their biological clock to maintain the continuity of care “24/7”. 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.