Presented by: M. Reza Roshandel MD
Mayo Clinic, Department of Urology

Introduction

Occupational factors may increase the risk of kidney stone disease. Aviation pilots may be susceptible due to work-related low fluid intake and physical inactivity. However, limited research exists on nephrolithiasis in contemporary pilots. This study investigates incident stone disease and potential risk factors among pilots.

Materials

We reviewed the United States Federal Aviation Administration (FAA) database between 2002 and 2022. Medical exams obtained for FAA certificate renewal were reviewed to assess incident stone events and associations with certificate types, flight hours, medical history, medications, labs, and reported stone events and procedures. Data were summarized for epidemiological analysis.

Results

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A total of 7,615,939 visits for medical license renewal were included, encompassing 1,583,565 pilots evaluated over a span of 20 years. Among these pilots, 859,226 held class I and II [RMRM1] medical licenses. 10,903 unique pilots were reported to have experienced stone events: 2,820 reported prior stones during their initial medical exam during the study period, while 8,127 reported initial stone events during the study period. The average prevalence of kidney stones among the total pilot population was found to be 1.5%. This prevalence remained consistent among class I pilots (1.5%), while among female pilots, it was lower at 0.5%. Over the study period, the prevalence of kidney stones exhibited a steady increase from 1.4% in 2002 to 2.5% in 2022. Among female pilots, this increase was observed from 0.5% to 1.8%. Several factors were found to be associated with stone formation, including male gender, advanced age, and metabolic syndrome (evidenced by higher BMI, hypertension, and diabetes). Additionally, significant relationships were identified between urolithiasis and occupational circumstances, such as increased total flights hours and increased pilot hours in the 6 months prior to the exam (P<0.05).

 

 

 

 

Conclusion

In this national cohort of commercial aviation pilots, the prevalence of kidney stones has increased steadily of the past 20 years, mirroring disease trends in the general population. However, the magnitude of stone prevelance was noted to considerably lower, suggesting that the impact of occupational risk factors may be attenuated relative to rising prevalence of general medical risk factors in the population.

Funding

N/A

Lead Authors

Anthony P. Tvaryanas, MD, PhD, MPH&TM
Federal Aviation Administration (FAA), Civil Aerospace Medical Institute

Michael Ding, PhD
Federal Aviation Administration (FAA), Health Safety Information

Kevin Koo, MD, MPH
Mayo Clinic, Department of Urology