Assessment of chronic stress among nurses in Sri Lanka through nail hormone biomarkers

Abstract The COVID-19 pandemic placed immense pressure on healthcare systems, especially in low- and middle-income countries (LMICs) with limited occupational health and psychological support. In Sri Lanka, nurses faced long hours, limited protective gear, and severe psychosocial stress. While short-term stress impacts are well-documented, chronic physiological effects remain underexplored in LMIC settings. This study investigates long-term psychophysiological stress in nurses using fingernail hormone analysis. It aims to evaluate the association between prior COVID-19 ward exposure and persistent hormonal variations revealing chronic stress. Nail samples were collected from 200 nurses working in two major hospitals in Sri Lanka, with and without prior deployment to COVID-19 wards. Five hormones (cortisol, dehydroepiandrosterone (DHEA), testosterone, progesterone, and estradiol) were extracted and quantified using enzyme-linked immunosorbent assays. Unlike blood or saliva, nail matrices reflect cumulative hormone levels over several months, providing a stable retrospective marker of chronic stress. Multivariate regression analyses, adjusted for age, sex, and body mass index, revealed significantly elevated cortisol (p < 0.001) and increased/decreased sex hormone levels (ps < 0.01) in nurses with COVID-19 ward exposure. The results indicate prolonged activation of the hypothalamic-pituitary-adrenal (HPA) axis and hormonal dysregulation, even months after the acute pandemic response had ended. Our findings suggest that frontline healthcare workers experience lasting physiological stress, underscoring the need for ongoing occupational health monitoring and mental health support. This study shows the feasibility of nail hormone profiling as a field-adaptable, retrospective tool for assessing occupational stress. It offers a promising approach for public health surveillance in resource-limited settings, where conventional mental health assessments may be inaccessible or stigmatized. Key messages • We introduce nail hormone analysis as an innovative, field-ready method to assess chronic stress in healthcare workers, especially where mental health resources are limited. • This study highlights the hidden, lasting impact of COVID-19 ward duty on nurses and supports the integration of biomarker-based monitoring into public health practice.