Body Composition and Biomarkers to Explore Disparities in Sarcopenia and Inflammation of Lung Cancer

In Cook County, IL, Non-Hispanic Blacks (NHB) and individuals of low socioeconomic status (SES) have higher lung cancer mortality compared with Non-Hispanic Whites (NHW) and those of high SES. Sarcopenia, or low muscle strength and quantity or quality, and inflammation are each independent predictors of mortality in lung cancer. It is unknown if sarcopenia and/or inflammation may be contributing to these racial and SES disparities. The purpose of this study was to assess skeletal muscle quantity through the skeletal mass index (SMI) and sarcopenia prevalence using fully automated body composition analysis, as well as to assess inflammation through the neutrophil to lymphocyte ratio (NLR), in individuals with lung cancer. We aimed to determine differences by race and neighborhood SES. A retrospective, cross-sectional study was conducted (n=263) to include an approximate equal number of NHB and NHW by sex diagnosed with lung cancer with a residential address in IL. A sub-set was used to validate agreement of skeletal muscle and adipose tissue measurements between fully automated body composition analysis and a reference program. Electronic medical records were reviewed, and demographic and clinical information was collected relative to cancer diagnosis date. Computerized tomography scans were analyzed to obtain SMI. Sarcopenia prevalence was determined using various published criteria, while the degree and prevalence of inflammation were assessed via NLR as a continuous and a categorical variable. Fully automated body composition analysis produced skeletal muscle and adipose tissue measurements that were in excellent agreement with the reference program. There were no significant differences in either SMI or sarcopenia prevalence by race or neighborhood SES. The prevalence of sarcopenia in lung cancer varied greatly depending on the methodology used, including the choice of vertebral landmark and the criteria used. The degree and prevalence of inflammation at lung cancer diagnosis were significantly lower in NHB compared to NHW, and prevalence was significantly lower in those from the most disadvantaged compared to those from the least disadvantaged neighborhoods. Further research is needed to identify sarcopenia and inflammation in diverse populations and determine whether these two conditions are contributing to racial and SES disparities in lung cancer mortality.