Does shift work increase the risk of kidney stones?

Researchers have evaluated how various shift work patterns contribute to kidney stone risk. Publishing their findings in Mayo Clinic Proceedings (doi: 10.1016/j.mayocp.2025.03.032), the researchers found that shift workers have a 15% higher risk of developing kidney stones, especially younger workers and those with low levels of manual labour. Also playing key roles in contributing to the occurrence of kidney stones were body mass index (BMI), fluid intake and other lifestyle factors.

Identified as an irregular work schedule outside of conventional daytime work hours, especially night shift work, long-term shift work could lead to adverse health outcomes, with the probability of developing chronic diseases, such as cardiovascular diseases, metabolic syndrome and mental disorders, having been reported to be increased among shift workers. Long-term shift work could also disrupt workers’ circadian rhythms, affect metabolism and hormone secretion, and alter lifestyles.

With kidney stone disease among shift workers having been rarely investigated in prior studies, the researchers used data from over 220,000 participants from the UK Biobank Study. The association of shift work — including its type, frequency and duration — with kidney stone events over a median follow-up period of 13.7 years was analysed by the researchers. Additionally, mediation analyses were conducted to investigate whether various lifestyle behaviours could explain this relationship.

“This is the first population-based cohort study to comprehensively evaluate how various shift work patterns contribute to kidney stone risk,” said lead investigator Dr Yin Yang, from the Department of Epidemiology in the School of Public Health at Sun Yat-sen University. “We found that shift work is associated with a higher risk of kidney stone events; an association that is partially mediated by several lifestyle factors, including smoking, sleep, fluid intake and BMI.”

Participants with a longer history of shift work were determined to have a slightly lower risk of kidney stones — something that warrants further investigation but may suggest adaptation over time or a healthy worker effect. “Kidney stones may be silent or cause acute complications, especially pain that may be sufficiently severe so as to necessitate hospitalization,” said Dr Felix Knauf from the Division of Nephrology and Hypertension at the Mayo Clinic, corresponding author of an accompanying editorial.

“A central effect of shift work is the disruption of circadian rhythms,” Knauf wrote. “Homeostasis and health are underpinned by physiologic systems, virtually all of which are governed by the biologic clock that dictates the periodicity, tempo and physiologic effects of circadian rhythms. This also applies to physiologic systems that regulate water balance and the homeostasis of solutes relevant to kidney stone formation.

“Thus, the observed effect of shift work in promoting kidney stone formation reflects, at least in part, its disruptive effect on circadian rhythms. The findings of this study highlight the need to explore initiatives that seek to remediate the risk factors for kidney stones, including greater flexibility in work schedules.”

Yang concluded: “Our findings come at a time when the effect of shift work on urological health is an urgent priority globally. Supporting healthy lifestyle habits among shift workers could have a meaningful impact on their urological health. Workplace health promotion initiatives could integrate educational programs emphasizing the importance of weight management, increased fluid intake, healthy sleep habits, reduced sedentary behavior, and smoking cessation. These interventions have the potential to alleviate the adverse effects of shift work on kidney stone formation and improve workers’ health.”

Image credit: iStock.com/eyesfoto. Stock image used is for illustrative purposes only.