Objective: Spirometric lung function is usually used to evaluate respiratory health. However, the impact of lung function on extra-pulmonary diseases and all-cause mortality has not been fully elucidated, especially in people without chronic obstructive pulmonary disease (COPD).
Patients and Methods: Participants aged ≥ 20 and underwent spirometry test from the US National Health and Nutrition Examination Surveys (NHANES) 2007– 2012 were analyzed in this study. Multivariate logistic and Cox regressions were used to evaluate the impact of forced expiratory volume in 1 second percent of predicted (FEV₁% predicted) and forced vital capacity percent of predicted (FVC% predicted) on 14 extra-pulmonary diseases and all-cause morbidity after adjusting for multiple confounders.
Results: During 2007– 2012, 1800 COPD patients and 11,437 non-COPD subjects were included. The prevalence of hypertension, diabetes mellitus (DM), dyslipidemia, metabolic syndrome (MS), congestive heart failure (CHF), coronary disease, stroke, chronic kidney disease (CKD), arthritis, cancer, underweight and osteoporosis in COPD patients was higher than that in the non-COPD population. After adjusting for confounders, the decrease of FEV₁% predicted and FVC% predicted was related with higher odds of having hypertension, DM, obesity, MS, CHF, coronary disease and depression (OR > 1, P < 0.05) in both the COPD and non-COPD populations. These 2 indices were also related with higher odds of dyslipidemia, CKD, arthritis and osteoporosis in the non-COPD population. The risk of stroke, anemia and cancer was not related with the decrease of lung function. In addition, the decrease of lung function was independent risk factors for the increase of all-cause mortality. These risks were gradually increased with the decrease of lung function.
Conclusion: The decrease of FEV₁% predicted and FVC% predicted was related with higher risk of multiple extra-pulmonary diseases and all-cause mortality in both the COPD and non-COPD population.
Keywords: lung function, mortality, extra-pulmonary diseases, COPD