Dietary Fiber Intake and Risk of Chronic Obstructive Pulmonary Disease: A Prospective Cohort Study of Men.
Epidemiology. 2017 Sep 7. Epub 2017 Sep 7. PMID: 28901975
BACKGROUND: The limited literature suggests that dietary fiber intake from whole grains, fruits, and vegetables is negatively associated with chronic obstructive pulmonary disease (COPD) via fiber's anti-inflammatory properties. Therefore, we investigated the association between total fiber and fiber sources and risk of COPD in the population-based prospective Cohort of Swedish Men (45,058 men, aged 45-79 years) with no history of COPD at baseline.
METHODS: Dietary fiber intake was assessed with a self-administered questionnaire in 1997 and was energy-adjusted using the residual method. Cox proportional hazard regression models were used to estimate hazard ratios (HRs) with 95% confidence intervals (95% CIs) adjusted for potential confounders.
RESULTS: During a mean follow-up of 13.1 years (1998-2012), 1,982 incident cases of COPD were ascertained via linkage to the Swedish health registers. A strong inverse association between total fiber intake (≥36.8 vs.<23.7 g/day) and COPD was observed in current smokers (hazard ratio [HR]=0.54; 95% confidence interval [CI]=0.43-0.67) and ex-smokers (HR=0.62, 95%CI=0.50-0.78) but not in never smokers (HR=0.93; 95%CI=0.60-1.45;P-interaction=0.04). For cereal fiber, HRs for highest vs. lowest quintile were 0.62 (95%CI=0.51-0.77,P-trend<0.001) in current smokers and 0.66 (95%CI=0.52-0.82,P-trend<0.001) in ex-smokers; for fruit fiber the HR was 0.65 (95%CI=0.52-0.81,P-trend<0.001) in current smokers and 0.77 (95%CI=0.61-0.98,P-trend=0.17) in ex-smokers; for vegetable fiber it was 0.71 (95%CI=0.57-0.88,P-trend=0.003) in current smokers and 0.92 (95%CI=0.71-1.19,P-trend=0.48) in ex-smokers.
CONCLUSION: Our findings indicate that high fiber intake was inversely associated with COPD incidence in men who are current or ex-smokers.