Interaction of vitamin C with the relation between smoking and obstructive airways disease in EPIC Norfolk

Abstract

Previous studies have reported an association between plasma vitamin C levels and respiratory function, but have not examined the role of vitamin C as an effect modifier of the relation between cigarette smoking and obstructive airways disease (OAD).This question was investigated in a cross-sectional analysis of a population-based study of 3,714 males and 4,256 females aged 45±74 yrs. Undiagnosed OAD was defined as a forced expiratory volume in one second (FEV1) of <80% of the predicted value and FEV1/forced vital capacity of <70% without self-reported OAD.An increase of 20 mmol . L -1 (or 1 SD) in plasma vitamin C concentration was associated with a 13% reduction in the risk of having OAD (adjusted odds ratio (OR) (95% confidence interval) 0.87 (0.77±0.98)). The OR for current smokers relative to never smokers within the lowest quintile of plasma vitamin C concentration was 5.93 (3.03±11.61). The risk in the upper four quintiles was 2.84 (1.92±4.19). Within the lowest quintile of plasma vitamin C concentration, the risk in former smokers was strongly related to the time since quitting (interaction significant, p=0.001).These findings support a protective role for vitamin C against the risk of obstructive airways disease and support the hypothesis that vitamin C may be an effect modifier for the adverse effects of smoking on the risk of obstructive airways disease.

Complete lack of vitamin C intake generates pulmonary emphysema in senescence marker protein-30 knockout mice

“…Presumably, a reduction of VC in the lungs resulted in an enlargement of the air space without alveolar destruction, but complete lack of VC in the lungs generated pulmonary emphysema. Several epidemiologic studies indicate that dietary factors, particularly VC, may be involved in the etiology of COPD (31,41,44). A prospective study of dietary intake of antioxidant vitamins (vitamins A, C, and E) and decline of lung function performed in a general population consisting of 2,663 adults aged 18 -70 living in the United Kingdom identified a significant correlation between declining lung function and intake of VC but not vitamins A or E (31).…”

“…Several reports indicate that VC has a beneficial effect on lung function but, when depleted during aging, may promote chronic obstructive pulmonary disease (COPD; Refs. 41,44). On the other hand, VC also plays an essential role in collagen synthesis because it acts as a cofactor for prolyl hydroxylase to catalyze hydroxyproline synthesis, which is involved in collagen helix stabilization (33,38).…”

Dietary factors in the pathogenesis of asthma and chronic obstructive pulmonary disease

“…Hu et al [20] found that in rural China, vitamin C intake was significantly positively associated with FEV 1 . Sargeant et al [18] found that plasma vitamin C, used as a marker for dietary vitamin C, had a protective effect against the risk of undiagnosed obstructive airways disease defined on the basis of FEV 1 .…”

γ-Tocotrienol reduces human airway smooth muscle cell proliferation and migration

“…Vitamin A deficiency promotes bronchial hypersensitivity in rats [3] and is reduced in asthmatic children [4]. Sargeant et al reported that a 20 mmol/L increase in plasma vitamin C is associated with a 13% reduction in the risk of developing obstructive airway disease [5]. Reduced vitamin D levels are associated with impaired lung function and increased airway hyperresponsiveness in adult asthma [6,7].…”