LAUSR

Background: The neutrophil-to-lymphocyte ratio (NLR) is an established marker of subclinical inflammation, and a high NLR is associated with poorer clinical outcomes in cancer patients. Despite this, factors that influence the magnitude of NLR independently of disease are poorly understood. Here, we systematically assess the influence of socio-demographic and lifestyle factors on NLR to identify a) potential confounders and effect modifiers in the relationship between NLR and cancer outcomes, and b) possible targets for intervention in patients with high NLR at diagnosis. Methods: Based on a total participant cohort of 48,023 adults with available NLR data, we identified 20 factors of interest relating to patient demographics, socioeconomic status and lifestyle that were included in the National Health and Nutrition Examination Survey (NHANES) between 1999 and 2016. Multivariable regression analysis identified factors significantly associated with the magnitude of NLR after adjusting for comorbidities and medications. Interactions between factors of interest were evaluated, and effect modification by demographic characteristics including age, sex and race was quantified. Results: Seven demographic and lifestyle factors were found to be significantly and independently associated with NLR: age, sex, race, marital status, physical activity, smoking history and alcohol use. Females, under 60s and non-Hispanic blacks demonstrated significantly lower NLR than males, over 60s and non-Hispanic whites. Participation in vigorous activity for at least ten minutes at a time was associated with decreased NLR, as was never-smoker status. Moderate drinking was also associated with a decreased NLR as compared to complete abstinence from alcohol. Conclusions: Multiple demographic and lifestyle factors are independently associated with elevated NLR. For an accurate assessment of the prognostic power of the NLR in the clinical setting, these factors should be routinely adjusted for in studies of the association between NLR and cancer outcomes. The present study reiterates that physical activity may have the potential to improve clinical outcomes by way of reducing systemic inflammation. Citation Format: Rachel Howard, Aaron Scheiner, Kathleen M. Egan. Socio-demographic and lifestyle factors associated with the neutrophil-to-lymphocyte ratio: A systematic evaluation of the United States National Health and Nutrition Examination Survey [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 3299.