Relationship of fish and cod oil intake with adult asthma.

BACKGROUND: A diet rich in fish or cod oil might possibly reduce the risk for asthma and atopic diseases. However, previous studies show conflicting results and no studies have assessed the potential long-term effects of childhood fish intake on adult asthma. OBJECTIVE: To investigate whether childhood and adult fish and cod oil intake was related to adult asthma. METHODS: In a large population-based study, Respiratory Health in Northern Europe (RHINE), 16 187 subjects aged 23-54 years answered a postal questionnaire. The relations of fish and cod oil intake with asthma symptoms and asthma were analysed using multiple logistic and Cox regression analyses, with adjustment for gender, adult hayfever, smoking, age, body mass index, household size, dwelling, parental education and centre, and for maternal smoking and family history of hayfever and asthma in a subsample (n=2459). RESULTS: Subjects from Iceland and Norway reported much more frequent intake of fish both in childhood and adulthood as compared with subjects from Sweden, Estonia and Denmark. Current fish intake less than weekly in adults was associated with more asthma symptoms, while more frequent fish intake did not appear to decrease the risk further. No dose-response association was found between childhood fish intake and adult asthma, but those who never ate fish in childhood had an increased risk for asthma and earlier asthma onset. Adult consumption of cod oil had a u-shaped association with asthma, with the highest risks in those taking cod oil never and daily. CONCLUSION: A minimum level of weekly fish intake in adulthood was associated with protection against asthma symptoms in this large North-European multi-centre study. Subjects who never ate fish in childhood were at an increased risk for asthma. Both indicate a possible threshold effect of fish on asthma.

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

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 (> or =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 ofthese 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.

Serum house-dust-mite antibodies and reduced FEV1 in adults of a Norwegian community.

In this cross-sectional study we investigated whether the presence of specific serum IgE antibodies to house dust mite, timothy, birch, cat, and mold was associated with a reduced FEV1 in adults. We performed complete examinations on 82% of a stratified random sample of 18 to 73-yr-old adults (n = 1,239). Subjects with house-dust-mite antibodies had lower (p = 0.002) sex, age, and height standardized residuals of FEV1 (SFEV1) than those without any specific IgE antibody. This relationship did not differ significantly by sex, age, smoking habit, total serum IgE level, or season, and remained significant after excluding subjects with obstructive lung disease. For house-dust-mite antibodies we also observed a dose-response relationship between antibody levels and impaired lung function. In a final multiple linear regression analysis the presence of house-dust-mite antibodies was the only significant predictor (regression coefficient: -0.425; SE = 0.189; p = 0.02) of reduced SFEV1 after adjusting for smoking habit and lifetime tobacco consumption, season, total serum IgE level, and respiratory-symptom and disease status. Thus, house-dust-mite allergy is an independent predictor of reduced lung function in adults of a wide age range.

Total and specific serum IgE levels in adults: relationship to sex, age and environmental factors.

We studied total and specific serum IgE levels cross-sectionally, potential predictors of obstructive lung disease, in a stratified random sample of 18-73-year-old adults (n = 1512). The attendance rate was 84%. The total IgE level and prevalences of specific IgE antibodies against house dust mite and cat were higher for men than for women. Specific IgE levels decreased by increasing age, while total IgE decreased in women only. Smokers had a higher IgE level than non-smokers, while non-smokers had more often specific IgE antibodies against timothy and birch than smokers. Subjects with occupational dust or gas exposure had a higher total IgE level than unexposed. The general population prevalences were for specific IgE antibodies against timothy 4.5%, house dust mite 3.2%, birch 2.6%, cat dander 1.6% mould 0.2% and against any of these 7.6%. In a multivariate analysis age, occupational dust or gas exposure as well as the interaction terms between sex and age and between smoking and pack-years were independent predictors for total IgE levels. Male sex, young age, never having smoked and the season of the year were independent predictors for having one or more of the five specific IgE antibodies. Subjects with total serum IgE in the highest quintile (> or = 66 kU/l) had an adjusted odds ratio of 37 (95% confidence interval: 11-120) for having one or more of the specific IgE antibodies examined, compared with those in the lowest quintile (< 5 kU/l). Demographic and environmental factors were thus predictors of total and specific IgE levels in this adult community.(ABSTRACT TRUNCATED AT 250 WORDS)