Non‐steroidal anti‐inflammatory drugs increase urinary neutrophil gelatinase‐associated lipocalin in recreational runners

OBJECTIVES: To study the effects of running with/without the use of pain killers on urinary neutrophil gelatinase‐associated lipocalin (uNGAL) and other parameters of kidney function in recreational runners. METHODS: Participants of the 10‐ and 21.1‐km Weir Venloop race were enrolled and their urine samples collected before and after the run. Urine dipstick and other conventional tests used to assess kidney function were performed. The presence of ibuprofen, diclofenac, naproxen, and/or paracetamol was assessed by LC‐MS/MS. uNGAL was measured with a two‐step chemiluminescent immunoassay. RESULTS: NSAIDs/analgesics were detected in urine of 5 (14.4%) 10‐km runners and 13 (28.9%) 21.1‐km runners. Only half‐marathon participants showed significant increases in uNGAL (pre: 11.7 [7.1‐34.3] ng/mL; post: 33.4 [17.4‐50.4] ng/mL; P = .0038). There was a significant effect of NSAID/analgesic use on uNGAL increase (F(2, 76) = 4.210, P = .004). Post hoc tests revealed that uNGAL increased significantly in runners who tested positive for ibuprofen/naproxen compared to runners who did not use any medications (P = .045) or those who tested positive for paracetamol (P = .033). Running distance had a significant influence on the increase in uNGAL (F(1, 53) = 4.741, P < .05), specific gravity (F(1, 60) = 9.231, P < .01), urinary creatinine (F(1, 61) = 10.574, P < .01), albumin (F(1, 59) = 4.888, P < .05), and development of hematuria (χ(2)(4) = 18.44, P = .001). CONCLUSIONS: Running distance and use of ibuprofen/naproxen were identified as risk factors for uNGAL increase in recreational runners.