Association of neutrophil percentage to albumin ratio with gallstones: a cross-sectional study from the United States NHANES

The neutrophil percentage to albumin ratio (NPAR) is an emerging, costimulatory indicator of inflammation that is associated with a variety of diseases, such as non-alcoholic fatty liver disease, liver fibrosis, stroke, and cardiovascular disease. However, the relationship between NPAR and gallstones (GS) has not yet been explored. Therefore, this study aimed to evaluate the association of the NPAR with the odds of GS and the age of patients at the time of their first GS surgery. Participants were selected from the National Health and Nutrition Examination Survey (NHANES) in the United States, a nationally representative survey. Logistic regression analysis and dose-response curve were performed to analyze the relationship between NPAR and the prevalence of GS. Multiple linear regression analysis and dose-response curve were used to analyze the association between NPAR and the age of patients at the time of their first GS surgery. Subgroup analyses further explored the relationships between NPAR and age, sex, race, body mass index, hypertension, and diabetes. In total, 7805 adults aged > 20 years were included in this study, of whom 838 had a history of GS. After adjusting for all potential confounders, each 1-unit increase in NPAR was found to be associated with a 4% increase in the prevalence of GS (odds ratio (OR): 1.04, 95% confidence interval (CI): 1.02, 1.07) and an advancement in the age of the patient at the time of the first GS surgery by 0.35 years (β = − 0.35, 95% CI: − 0.68, − 0.02). Dose-response curves further confirmed that NPAR was positively associated with the prevalence of GS and negatively associated with the age of patients at the time of their first GS surgery. The results of the subgroup analyses suggested that after adjusting for all potential confounders, the positive association of NPAR with the prevalence of GS was more pronounced in the 40–59-year-old (OR: 1.07, 95% CI: 1.02, 1.12), male (OR: 1.07, 95% CI: 1.02, 1.12), non-Hispanic Black (OR: 1.06, 95% CI: 1.01, 1.12), non-hypertensive (OR: 1.06, 95% CI: 1.02, 1.10), and non-diabetic populations (OR=: 1.05, 95% CI: 1.02, 1.08). The higher the NPAR, the higher the prevalence of GS, and the earlier the age of the patient at the time of the first GS surgery. Due to the nature of cross-sectional study, it is not possible to determine a causal relationship between them.