Elsevier

Respiratory Medicine

Volume 97, Issue 2, February 2003, Pages 134-142
Respiratory Medicine

Regular Article
Dietary vitamin C intake is inversely related to cough and wheeze in young smokers

https://doi.org/10.1053/rmed.2003.1439Get rights and content
Under an Elsevier user license
open archive

Abstract

We aimed to investigate whether dietary vitamin C intake, an important antioxidant, is inversely related to self-reported respiratory symptoms in young adults of a community. A random sample of 4300 subjects, aged 20 – 44 years, living in Bergen, Norway, received a postal questionnaire on respiratory symptoms; 80% responded. Vitamin C intake (mg per week) was estimated from a food-frequency questionnaire asking how often the subject, during the last year, had consumed units of orange juice, oranges, potatoes, carrots and tomatoes. Significant differences in the intake of vitamin C were observed across smoking categories with current smokers having the lowest intake, while there was no variation by gender, age or occupational dust exposure. Dietary vitamin C intake was in univariate analyses inversely related to “morning cough”, “chronic cough”, “wheeze” and “wheeze ever”. After adjusting for gender, age, body mass index, “occupational exposure”; pack-years as well as having and stratified on smoking habits in multiple logistic regression analyses, the relationship between dietary vitamin C intake and “cough” and “wheeze” tended to be associated to smoking. The odds ratio (OR) for “morning cough” was 0.68 (95% CI: 0.35–0.95), “chronic cough” OR 0.69 (95% CI: 0.47–1.04) and “wheeze ever” OR 0.75 (95% CI: 0.56–1.01) in current-smokers with dietary vitamin C intake in the upper (≥395 mg/week) vs. the lower (<209 mg/week) tertile. The OR for “wheeze” was 0.56 (95% CI: 0.35–0.88) in ex-smokers. The magnitude of these effects remained after excluding subjects with supplementary vitamin C intake (n=199) from the statistical analyses. Among young Norwegian adults, having a low prevalence of asthma and high prevalences of smoking-related respiratory symptoms, dietary vitamin C intake may act as an antioxidant and thereby reduce cough and wheeze in smokers having high oxidant stress.

Keywords

diet
respiratory symptoms
asthma
vitamin C.

Cited by (0)

f1

Correspondence should be addressed to: Dr Ernst Omenaas, Centre for Clinical Research, Haukeland University Hospital, N-5021 Bergen, Norway. Fax: +47 55976088; E-mail: [email protected]