Sociodemographic and lifestyle factors associated with the neutrophil-to-lymphocyte ratio.

PURPOSE: The neutrophil-to-lymphocyte ratio (NLR) is a marker of systemic inflammation with established prognostic value in patients with cancer. Although high NLR is associated with poorer clinical outcomes, factors that influence the magnitude of NLR independently of disease are poorly understood.
METHODS: We identified 48,023 adults who participated in the National Health and Nutrition Examination Survey (1999-2016). Demographic, socioeconomic, and lifestyle factors associated with the magnitude of NLR after adjusting for comorbidities including heart disease, cancer, diabetes, and hypertension, and medications including aspirin, were identified. Effect modification by comorbidity status and demographics was explored.
RESULTS: Female gender, age less than 60 years, and non-Hispanic black race/ethnicity were associated with lower NLR. Marital statuses of widowed, separated, or never married demonstrated increased NLR as compared with those who were currently married. Never-smoking and moderate alcohol consumption were associated with lower NLR. Participation in physical activity was associated with decreased NLR after adjustment for potential confounders, primarily among non-Hispanic whites.
CONCLUSIONS: Multiple demographic and lifestyle factors are independently associated with NLR. Sex, age, race, marital status, body mass index, physical activity, smoking history, and alcohol consumption should all be routinely collected and adjusted for to improve the accuracy of assessment of the prognostic power of NLR.