The influence of abdominal visceral fat on inflammatory pathways and mortality risk in obstructive lung disease

Background: Low-grade systemic inflammation, particularly elevated IL-6, predicts mortality in chronic obstructive pulmonary disease (COPD). Although altered body composition, especially increased visceral fat (VF) mass, could be a significant contributor to low-grade systemic inflammation, this remains unexplored in COPD. Objective: The objective was to investigate COPD-specific effects on VF and plasma adipocytokines and their predictive value for mortality. Design: Within the Health, Aging, and Body Composition (Health ABC) Study, an observational study in community-dwelling older persons, we used propensity scores to match n = 729 persons with normal lung function to n = 243 persons with obstructive lung disease (OLD; defined as the ratio of forced expiratory volume in 1 s to forced vital capacity < lower limit of normal). Matching was based on age, sex, race, clinic site, BMI, and smoking status. Within this well-balanced match, we compared computed tomography acquired visceral fat area (VFA) and plasma adipocytokines, analyzed independent associations of VFA and OLD status on plasma adipocytokines, and studied their predictive value for 9.4-y mortality. Results: Whereas whole-body fat mass was comparable between groups, persons with OLD had increased VFA and higher plasma IL-6, adiponectin, and plasminogen activator inhibitor 1 (PAI-1). Both OLD status and VFA were independently positively associated with IL-6. Adiponectin was positively associated with OLD status but negatively associated with VFA. PAI-1 was no longer associated with OLD status after VFA was accounted for. Participants with OLD had increased risk of all-cause, respiratory, and cardiovascular mortality, of which IL-6 was identified as an independent predictor. Conclusion: Our data suggest that excessive abdominal visceral fat contributes to increased plasma IL-6, which, in turn, is strongly associated with all-cause and cause-specific mortality in older persons with OLD. Am J Clin Nutr 2012;96:516-26.