BACKGROUND: The association between coffee and caffeine intake and the risk of COPD and lung function has not been thoroughly discussed in Americans, with subgroup and threshold effects remaining unclear. OBJECTIVES: This study investigated the association between coffee and caffeine consumption and the risk of chronic obstructive pulmonary disease (COPD) as well as lung function utilizing data from the NHANES 2007-2012. METHODS: We assessed the associations of coffee and caffeine consumption with the risk of COPD and lung function parameters, including FEV1 and FVC, adjusting for common demographic and disease characteristics in a cross-sectional analysis of NHANES data. RESULTS: A total of 9763 participants were included in the study, and 592 were diagnosed with COPD. Multivariate regression models revealed positive associations between coffee and caffeine consumption and the risk of COPD and lung function. Subgroup analyses stratified by sex, DM, hypertension status, and smoking habits identified potential effect modifiers as well as inflection points from threshold effect examinations. CONCLUSIONS: The results of this cross-sectional study indicated significant positive correlations between coffee and caffeine consumption and the risk of COPD. Additionally, positive correlations between exposure variables and FEV1 and FVC were detected. Among the stratification factors, smoking status exhibited the most potential for modifying effects. Future practices and research are needed to validate the results and explore the underlying mechanisms.
BACKGROUND: Coffee is one of the most consumed beverages in the world, coffee consumption has been growing in the United States over the past 20 years. Periodontitis is defined by the pathologic loss of the periodontal ligament and destruction of the connective tissue attachment and alveolar bone loss and is related to different systemic diseases and conditions. However, the causality has remained unclarified, thus we regarded discovering the causal relationship between coffee consumption and the liability to periodontitis as the objective of the study. METHODS: Coffee consumption was subdivided into binary coffee consumption and continuous coffee consumption to refine the study design. Genetic instruments were stretched from the MRC-IEU's (MRC Integrative Epidemiology Unit) output from the GWAS pipeline using phesant-derived variables based on the UK Biobank, the Gene-Lifestyle Interactions in Dental Endpoints (GLIDE) project, and the joint meta-analysis of a recent GWAS. The IVW (Inverse Variance Weighted) was regarded as the primary method to estimate the causality, a scatter plot revealed the intuitive result, and tests for stability were also carried out. RESULTS: An effect of continuous coffee consumption on the risk of periodontitis was found, with per SD of coffee consumed increases, the risk of periodontitis rises by 1.04% (Odds Ratio of IVW is 1.0104), while the effect of binary coffee consumption on periodontitis did not meet the requirement of indicating a strong causal association, neither were the reverse causality analyses. CONCLUSIONS: The study indicated the causality of continuous coffee consumption to the risk of periodontitis with a relatively small scale of effect estimate and no strong evidence for an effect of binary coffee-consuming behavior on periodontitis. There was also no intensive evidence suggesting reverse causality.
