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Chronic infections are associated with increased composite inflammation index in adult residents of central North Carolina
Citation:
Egorov, A., S. Griffin, J. Styles, E. Klein, L. Wickersham, R. Ritter, J. Kobylanski, J. Scott, E. Sams, E. Hudgens, AND Tim Wade. Chronic infections are associated with increased composite inflammation index in adult residents of central North Carolina. International Society for Environmental Epidemiology (ISEE) annual conference, Washington, DC, August 23 - 27, 2020.
Impact/Purpose:
This abstract summarizes preliminary results of an ongoing study on subclinical health effects of the community environment. It supplements other ORD research on non-chemical health stressors under the Sustainable and Healthy Communities research program. An observational epidemiological study in the Raleigh-Durham-Chapel Hill metropolitan area involves analysis of serum samples for multiple biomarkers of immune system and chronic inflammation, and as well as serological markers of chronic latent infections including Helicobacter pylori, Toxoplasma gondii and cytomegalovirus (CMV) – the pathogens infecting approximately 20%, 10% and 50% of US adults, respectively. H. pylori and CMV are transmitted from person to person and associated with low socioeconomic status, while T. gondii can be transmitted environmentally. Previously presented results of this study showed that greater amount of time spent outdoors and greater tree cover near residence were associated with reduced composite index of inflammation based on 17 biomarkers. This new analysis shows that common chronic infections affect the same outcome, and that adjusting for chronic infections is important when assessing subclinical effects of the community environment. These findings are important because chronic inflammation has been linked with increased risks of cardiovascular and other systemic diseases, as well as premature mortality. The results of this project help to characterize factors in the community environment that affect vulnerability/resiliency to adverse health impacts of environmental pollutants.
Description:
Background. Our previously presented results of the ongoing epidemiological study in North Carolina showed that residential tree cover was associated with a reduced composite index of chronic inflammation in individuals who spent at least 30 min per day outdoors. The objective of present analysis was to assess the effects of chronic infections on the same outcome. Methods. This cross-sectional study involved 335 adults residing in the Raleigh-Durham-Chapel Hill, NC urban area. Blood samples were tested for biomarkers of immune, neuroendocrine, and metabolic functions. Serum immunoglobulin G responses to Toxoplasma gondii, Helicobacter pylori and cytomegalovirus were measured using diagnostic ELISA assays. A Poisson-distributed index of immune function activation/chronic inflammation was estimated as a sum of potentially unhealthy values of the following biomarkers: interferon (IFN)-γ, interleukin (IL)-1β, IL-4, IL-6, IL-8, IL-10, IL-17, tumor necrosis factor (TNF)-α, C-reactive protein, myeloperoxidase, serum amyloid A, chromogranin A, vascular cell adhesion molecule (VCAM)-1, intracellular adhesion molecule (ICAM)-1, eosinophils, monocytes, and neutrophils. Results. Each chronic infection had an independent effect on the immune function index. Preliminary results show that individuals who were seropositive to one, two or three chronic infections had 24% (95% confidence interval: 0%, 55%), 71% (32%, 122%), and 135% (60%, 247%) greater mean inflammation index compared to individuals who were seronegative to all three pathogens, respectively, after adjusting for sociodemographic and behavioral covariates, and body mass index. In the same model, self-reported sleep problems and daily screen time greater than 2 hours were associated with 22% (1%, 47%) and 40% (14%, 73%) greater inflammation index, respectively, while greater amounts of time spent outdoors had significant protective effects. Conclusions. Adjusting for the effects of chronic infections on chronic inflammation is important in epidemiological research on health effects of chronic stress and the community environment. This abstract does not represent EPA policy.