Dietary inflammatory potential associated with increased risk of chronic bronchitis morbidity and mortality

Chronic bronchitis (CB) is a major public health concern linked to persistent inflammation, yet the role of dietary inflammatory potential remains unclear. We hypothesized that higher dietary inflammatory index (DII) scores would be associated with increased CB prevalence and higher mortality among CB patients. Using data from the National Health and Nutrition Examination Survey (2001-2002 to 2017-2018), we included 37 734 participants (representing 180.1 million U.S. adults). In this study, dietary intake was assessed using two 24 h dietary recalls, and DII scores were calculated to reflect dietary inflammatory potential. Restricted cubic spline, multivariable logistic regression, and Cox regression were used to analyze the relationships between DII and CB prevalence, and between mortality in CB patients. Subgroup analyses were conducted to assess the consistency of these associations across different subgroups. We found that Greater DII was linearly associated with increased CB prevalence (P for overall <0.001, P for nonlinear = 0.238) and elevated all-cause mortality in CB patients (P for overall = 0.015, P for nonlinear = 0.131). Each unit increase in DII corresponded to a 11% higher CB risk (OR = 1.11 [1.08-1.15], P < 0.001) and a 10% greater mortality risk (HR = 1.10 [1.03-1.18], P = 0.007). Subgroup analysis showed that these associations were generally consistent across most subgroups. Our findings suggest that reducing dietary inflammatory potential may lower both the risk and mortality of CB.