Association between platelet-to-lymphocyte ratio and blood urea nitrogen levels in pediatric populations: evidence from the NHANES (2009-2018).

Background: Blood urea nitrogen (BUN) reflects renal function and protein metabolism, while the platelet-to-lymphocyte ratio (PLR) is a common inflammatory marker. Though studied in adults, their relationship with children is unclear. This study aims to explore this association in children aged 12-18 years using National Health and Nutrition Examination Survey (NHANES) 2009-2018 data and evaluate PLR as a potential non-invasive marker for renal function.

Methods: Given the physiological differences between children and adults, this study utilized data from the NHANES to explore the association between PLR and BUN levels in a pediatric population. This cross-sectional study used NHANES data collected between 2009 and 2018. A total of 2,086 participants were included after excluding individuals with missing data or an age range beyond 12-18 years.

Results: A significant negative correlation between PLR and BUN was found in this study, which remained consistent even after adjusting for a wide range of variables (P<0.001). Subgroup analyses further confirmed the robustness of this association across sex, race, and body mass index categories. Restricted cubic spline analysis revealed a significant non-linear negative association with an inflection point at PLR of 118.45. The decline in BUN levels became more pronounced when PLR exceeded the threshold.

Conclusions: This study demonstrated a negative correlation between PLR and BUN levels in children, suggesting that PLR could be used as a potential non-invasive marker for assessing renal function. More large-scale prospective studies are needed to substantiate our findings.