Dietary fats and asthma in teenagers: analyses of the first Nutrition and Health Survey in Taiwan (NAHSIT)

Background The occurrence of asthma may be associated with dietary factors. Objective To examine the association between nutrient intake and physician-diagnosed asthma and allergic rhinitis. Methods A stratified, multiple-staged sampling design was used to select study areas, in which household interviews were carried out to gather information on health status and 24-h food recall. Data from 1166 adolescents, 13-17 years of age, were analysed. Results In univariate analysis, total calorie and energy-adjusted fat intake were associated with the prevalence of asthma, whereas vitamin A and vitamin C intake showed negative association with asthma. Multivariate logistic regression was used to adjust for sex and levels of urbanization; intake of saturated fats was associated with increased risk (OR = 2.02 for an increase of one SD, 95% CI 1.40-2.90), while monounsaturated fats were inversely related to asthma (OR = 0.65 for an increase of one SD, 95%CI 0.43-0.99). Vitamin C intake in the lowest quartile was associated with elevated risk for asthma with marginal significance (OR = 1.81, 95%CI 0.88-3.71, P = 0.10). None of the nutritional factors was associated with allergic rhinitis. Conclusion Results from this cross-sectional survey suggest that saturated and monounsaturated fats may have different effects on airway inflammation.