Plasma vitamin C concentrations and risk of incident respiratory diseases and mortality in the European Prospective Investigation into Cancer-Norfolk population-based cohort study.

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Wilson, Andrew M 
Clark, Allan B 
Wareham, Nicholas J 

BACKGROUND/OBJECTIVES: Cancerous and non-cancerous respiratory diseases are common and contribute significantly to global disease burden. We aim to quantify the association between plasma vitamin C concentrations as an indicator of high fruit and vegetable consumption and the risk of incident respiratory diseases and associated mortality in a general population. SUBJECTS/METHODS: Nineteen thousand three hundred and fifty-seven men and women aged 40-79 years without prevalent respiratory diseases at the baseline (1993-1997) and participating in the European Prospective Investigation into Cancer (EPIC)-Norfolk study in the United Kingdom were followed through March 2015 for both incidence and mortality from respiratory diseases. RESULTS: There were a total of 3914 incident events and 407 deaths due to any respiratory diseases (excluding lung cancers), 367 incident lung cancers and 280 lung cancer deaths during the follow-up (total person-years >300,000 years). Cox's proportional hazards models showed that persons in the top quartiles of baseline plasma vitamin C concentrations had a 43% lower risk of lung cancer (hazard ratio (HR) 0.57; 95% confidence interval (CI): 0.41-0.81) than did those in the bottom quartile, independently of potential confounders. The results are similar for any non-cancerous respiratory diseases (HR 0.85; 0.77-0.95), including chronic respiratory diseases (HR 0.81; 0.69-0.96) and pneumonia (HR 0.70; 0.59-0.83). The corresponding values for mortality were 0.54 (0.35-0.81), 0.81 (0.59-1.12), 0.85 (0.44-1.66) and 0.61 (0.37-1.01), respectively. Confining analyses to non-smokers showed 42% and 53% risk reduction of non-smoking-related lung cancer incidence and death. CONCLUSIONS: Higher levels of vitamin C concentrations as a marker of high fruit and vegetable consumption reduces the risk of cancerous and non-cancerous respiratory illnesses including non-smoking-related cancer incidence and deaths.

Adult, Aged, Ascorbic Acid, Female, Humans, Male, Middle Aged, Prospective Studies, Respiratory Tract Diseases, Risk Factors
Journal Title
Eur J Clin Nutr
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Springer Science and Business Media LLC
Medical Research Council (MC_UU_12015/1)
Department of Health (via National Institute for Health Research (NIHR)) (NF-SI-0617-10149)
Medical Research Council (G0401527)
Medical Research Council (G1000143)
Medical Research Council (MR/N003284/1)
The authors would like to thank the participants of the EPIC-Norfolk cohort. We thank the nutritionist team and data management team of the EPIC-Norfolk cohort. The EPIC-Norfolk study was supported by grants from the Medical Research Council and Cancer Research UK. Funders and sponsors had no role in design and the data collection, analysis, and interpretation of data and the writing of the article and the decision to submit it for publication.