Risk and Protective Factors of COPD Among Smokers: A Cross-Sectional Study Using NHANES Database.

Purpose: Smoking plays a significant role in the pathogenesis of chronic obstructive pulmonary disease (COPD), underscoring the importance of smoking cessation. Nevertheless, not all smokers who do not quit will necessarily develop COPD. This study aimed to examine the risk and protective factors associated with COPD among individuals who smoke. Patients and Methods: The study included a cohort of 2619 adult smokers with lung function data, whose demographic characteristics, health status, lifestyle behaviors, and dietary patterns were examined using T-tests, Chi-square tests, and logical analysis. Results: Among the study participants, 441 individuals were identified as having COPD by analyzing pulmonary function data. Advanced age (p<0.001), low body mass index (BMI, p<0.001), ethnicity (p=0.019), and comorbid asthma (p<0.001) were found to be statistically correlated with the presence of COPD. Additionally, a higher intake of fruits and vegetables (p=0.026) was shown to have a beneficial impact. After considering factors related to type 2 inflammation, nutrient intake from vegetables and fruits, and other variables, it was observed that vitamin C (p<0.001) exhibited a protective effect against COPD in smokers. Additionally, advanced age (p<0.001), low BMI (p<0.001), comorbid asthma (p<0.001), and higher consumption of fruits and vegetables (p=0.032) remained significant independent risk factors for COPD in smokers. Furthermore, subgroup analysis revealed that COPD patients who consumed fewer fruits and vegetables had lower levels of vitamin C intake (p=0.004). Conclusion: The findings of our study suggest that smokers who are older, have a lower BMI, and comorbid asthma are at an increased risk of developing COPD. Conversely, higher consumption of fruits and vegetables, as well as increased intake of vitamin C, may help reduce this risk. Additionally, our results indicate that among smokers with lower fruit and vegetable intake, COPD patients tend to have lower levels of vitamin C consumption.