Efficacy of vitamin E from dietary, circulation system, and supplementation on chronic obstructive pulmonary disease (COPD): a systematic review and meta-analysis

Background: In recent years, the efficacy of antioxidants in the management of various diseases has garnered significant attention. Vitamin E, a natural supplement with potent antioxidant properties, has been utilized in the prevention of chronic obstructive pulmonary disease (COPD) and the treatment of patients with COPD. This systematic review and meta-analysis aimed to clarify the association between vitamin E consumption and COPD. Methods: We conducted a systematic search of eligible studies from PubMed, Web of Science, Scopus, and the Cochrane Library databases, performed a meta-analysis using random-effects models and assessed the association of vitamin E dietary intake, serum levels, and supplementation with COPD. Results: The study included a total of 10 studies involving 65 425 participants. The meta-analysis results indicated that the odds ratio (OR) between vitamin E intake and the onset risk of COPD was 0.60 (95% CI: 0.46-0.80, P < 0.0001), which indicated a significant protective effect. However, no significant correlation was observed between vitamin E consumption and the risk of death from COPD (OR = 0.79, 95% CI = 0.55-1.12, P = 0.07). In addition, subgroup analysis revealed that different subtypes of vitamin E, such as vitamin E (OR = 0.78, 95% CI = 0.68-0.91, P = 0.01) and α-tocopherol (OR = 0.43, 95% CI = 0.23-0.84, P = 0.03), as well as various sources of vitamin E, including dietary intake (OR = 0.68, 95% CI = 0.54-0.86, P = 0.007), serum levels (OR = 0.49, 95% CI = 0.25-0.98, P = 0.02), and supplementation (OR = 0.90, 95% CI = 0.82-0.99, P = 0.03) were all significantly inversely associated with COPD. Conclusion: Vitamin E consumption, including the intake of different subtypes and from various supplementation sources, demonstrates a protective effect against the risk of COPD and may contribute to improved clinical outcomes in patients with COPD. However, further research is required to fully elucidate the potential role and mechanism of vitamin E in COPD.