Association between dietary niacin intake and lung function among American adults: A cross-sectional analysis from national health and nutrition examination survey, 2007-2012

Background: The pathogenesis of pulmonary senescence involves immune system dysregulation, oxidative stress, and mitochondrial dysfunction. The effects on lung function of niacin, an essential coenzyme involved in mitochondrial energy metabolism with known antioxidant properties, are poorly understood. Methods: This cross-sectional study used data from the 2007-2012 National Health and Nutrition Examination Survey, including spirometry data and niacin intake information of 9706 adults. This study investigated various spirometry measures, such as forced expiratory volume in 1 s, forced vital capacity, pulse expiratory flow, (forced expiratory volume in 1 s)/(forced vital capacity) ratio, and predicted forced expiratory volume in 1 s and forced vital capacity percentages. Additionally, a secondary analysis was conducted using Global Initiative for Chronic Obstructive Lung Disease and chronic obstructive pulmonary disease. Foundation Spirometry Grade criteria to assess the relationship between niacin intake, airflow limitation, and obstruction. Multivariate regression models were used to adjust for relevant covariates. Results: The study included 9706 U S. adults (4788 men and 4918 women) with a median age of 46.2 years. After adjusting for relevant factors, a positive correlation was observed between niacin intake and lung function. Compared to the lowest quintile of niacin intake (Q1, <= 14.5 mg/ day), individuals in the highest quintile (Q5, >34.5 mg/day) exhibited significant increases in lung function parameters, including forced expiratory volume in 1s (69.84 mL, p = 0.003), pulse expiratory flow (254.48 mL, p < 0.001), (forced expiratory volume in 1 s)/(forced vital capacity) (0.01, p = 0.041), percent predicted forced expiratory volume in 1 s(2.05, p = 0.002), and percent predicted forced vital capacity(1.29, p = 0.042). Subset analyses of individuals with spirometry-defined airflow obstruction showed associations of high niacin intake with significantly improved forced expiratory volume, pulse expiratory flow, and percent predicted pulse expiratory flow and an interaction among race, education, and smoking status with respect to the relationship between niacin intake and lung function parameters. Conclusions: Higher niacin intake was associated with increased measures of lung function. A diet rich in niacin-containing foods may play a role in improving lung health.