Associations of a Plant-centered Diet and Lung Function Decline across Early to Mid-Adulthood: The CARDIA Lung Study

Lung function throughout adulthood predicts morbidity and mortality even among adults without chronic respiratory disease. Diet quality may represent a modifiable risk factor for lung function impairment later in life. We investigated associations between nutritionally-rich plant-centered diet and lung function decline across early and middle adulthood from the Coronary Artery Risk Development in Young Adults (CARDIA) Study.

Diet was assessed at baseline and years 7 and 20 of follow-up using the validated CARDIA diet history questionnaire. Plant-centered diet quality was scored using the validated A Priori Diet Quality Score (APDQS), which weights food groups to measure adherence to a nutritionally-rich plant-centered diet 1 to 5 points for 20 beneficially rated foods and 5 to 1 points for 13 adversely rated foods. Scores were cumulatively averaged over follow-up and categorized into quintiles. The primary outcome was lung function decline, including forced expiratory volume in 1 second (FEV₁) and functional vital capacity (FVC), measured at years 0, 2, 5, 10, 20, and 30. We estimated the association of APDQS with annual pulmonary function changes in a repeated measures regression model, adjusting for clinically relevant covariates.

The study included 3,787 Black and White men and women aged 18-30 in 1985-86 and followed for 30 years. In multivariable repeated measures regression models, individuals in the lowest APDQS quintile (poorest diet) had declines in FEV₁ that were 1.6 ml/year greater than individuals in the highest quintile (35.0 vs. 33.4 ml/year, ß±SE per 1 SD change APDQS 0.94 ± 0.36, p = 0.009). Additionally, declines in FVC were 2.4 ml/year greater in the lowest APDQS quintile than those in the highest quintile (37.0 vs 34.6 ml/year, ß±SE per 1 SD change APDQS 1.71 ± 0.46, p < 0.001). The association was not different between never and ever smokers (p_int = 0.07 for FVC and 0.32 for FEV₁). In sensitivity analyses where current asthma diagnosis and cardiorespiratory fitness were further adjusted, results remained similar.

In this 30-year longitudinal cohort study, long-term adherence to a nutritionally-rich plant-centered diet was associated with slower decline in lung function, highlighting diet quality as a potential treatable trait supporting long-term lung health.