Lung function, COPD and alternative healthy eating index in US adults

Abstract

Background There is a large burden of COPD in the US. The purpose of this study was to investigate the association between diet quality with lung function, spirometric restriction and spirometrically defined COPD in a nationally representative sample of US adults. Methods Adults (19–70 years of age) from the National Health and Nutrition Examination Survey 2007– 2012 cycles were included (n=10 428). Diet quality was determined using the Alternative Healthy Eating Index (AHEI-2010). Pre-bronchodilator measurements of forced expiratory volume in 1 s (FEV1), forced vital capacity (FVC) and the FEV1/FVC were described. Calibrated lower limit of normal (LLN) estimates were derived to determine prevalence of spirometric restriction (FVC<LLN) and COPD (FEV1/FVC ratio<LLN). Population-weighted linear and logistic regression models were used to investigate the association of AHEI-2010 and respiratory outcomes. Results The mean±SD AHEI was 45.3±12.2, equivalent to meeting 41% of the daily recommendations for optimal diet quality. Those in the highest quartile of AHEI had better FEV1 (adjusted (a)β 47.92, 95% CI 2.27–93.57) and FVC (aβ 80.23, 95% CI 34.03–126.42; p-value interaction (*) of AHEI and smoking >0.05) compared to those in quartile 1. Higher AHEI was also associated with lower odds of spirometric restriction (OR 0.23, 95% CI 0.08–0.67; p-value AHEI*ethnicity >0.05). Conclusions Diet quality was independently associated with better FEV1 and FVC and with lower odds of spirometric restriction. These findings highlight the need fo