Prevalence of leukocyturia in a cohort of French asymptomatic aircrews.

Objectives: Sexually transmitted infections (STIs) can cause leukocyturia. We aimed to estimate the prevalence of leukocyturia in asymptomatic aircrews and the proportion of STIs in those presenting leukocyturia.

Methods: The LEUCO survey was a prospective cohort study conducted among aircrews between 14th October 2019 and 13th March 2020 at the Toulon aeromedical centre in France. All participants performed a dipstick urinalysis. Those positive for leukocyturia were offered STI screening by nucleic acid amplification test (NAAT) for Chlamydia trachomatis, Neisseria gonorrhoeae, Mycoplasma genitalium and Trichomonas vaginalis.

Results: Among the 2236 included asymptomatic participants (1912 men and 324 women), 127 (36 men and 91 women) were positive for leukocyturia. The prevalence of leukocyturia was 1.9% (1.3-2.6) in men and 28.1% (23.3-33.3) in women (p < 0.001). In men positive for leukocyturia, the NAAT positivity rate for C. trachomatis, N. gonorrhoeae, M. genitalium and T. vaginalis was 28.6% (3.7-71.0) in the age group 18-24, 20.0% (0.5-71.6) in the age group 25-34, and zero in the older age group (p 0.65). In women positive for leukocyturia it was 16.7% (4.7-37.4) in the age group 18-24, 18.2% (2.3-51.8) in the age group 25-34, and zero in the older age group (p 0.16).

Conclusions: In asymptomatic individuals, leukocyturia is rare in men and more common in women. In asymptomatic adults under 35 years of age with leukocyturia, multiplex NAAT shows a high proportion of STIs and might be useful in improving STI detection.