Elevated platelet-to-lymphocyte ratio is associated with increased breast cancer risk: A cross-sectional analysis of the NHANES 2009 to 2020
Yanting Li, Yanpeng Li, Xurui Li, Peiling Zhu, Mengsi Zhou
Inflammation is a recognized driver of tumorigenesis, particularly in breast cancer. The platelet-to-lymphocyte ratio (PLR) has emerged as a readily available inflammatory indicator; however, its independent association with breast cancer risk in a nationally representative civilian cohort has not been quantified. We aimed to evaluate the cross-sectional relationship between PLR and breast cancer prevalence among U.S. adults and to examine whether this association is modified by sociodemographic or clinical factors. We analyzed 14,152 women aged ≥20 years from the continuous National Health and Nutrition Examination Survey cycles from to 2009 to 2020. Breast cancer cases (n = 419) were defined using a self-reported physician diagnosis. We excluded male participants and individuals with missing data on blood cell counts (platelets, neutrophils, lymphocytes) or key covariates. After natural-log transformation, PLR and systemic immune-inflammation index (SII) were entered as primary exposures. Multivariable logistic regression was adjusted for age, race/ethnicity, body mass index, smoking, alcohol, age at menarche, parity, hormone use history, poverty-income ratio, and comorbidities. Generalized additive models with penalized splines and 2-piece logistic regression were fitted to detect threshold effects. Subgroup, interaction, and leave-one-out sensitivity analyses were performed to test the robustness. Each 1-unit increase in ln-PLR was independently associated with 78 % higher odds of breast cancer (OR = 1.78; 95 % CI 1.00–3.17;