Fish Consumption During the First Year of Life and Development of Allergic Diseases During Childhood

Abstract

Kull I, Bergström A, Lilja G, Pershagen G, Wickman M. Allergy. 2006;61:1009–1015 PURPOSE OF THE STUDY. To assess the association of fish consumption during the first year of life with development of allergic diseases by age 4. STUDY POPULATION. A prospective birth cohort of 4089 newborn infants in Sweden. METHODS. Parental questionnaires at child ages 2 months and 1, 2, and 4 years were administered to collect information on atopic heredity, diet, exposures, and allergic symptoms. When the children were 4 years old, a clinical investigation, including blood sampling for analysis of specific immunoglobulin E (IgE) to common inhalant and food allergens, was performed. RESULTS. The mean age of introduction of fish in the child's diet was 8.3 months. History of parental allergic disease and onset of eczema or wheeze during the first year of life were associated with delayed introduction of fish in the child's diet. Regular fish consumption during the first year of life was associated with a reduced risk for allergic disease by age 4 (adjusted odds ratio: 0.76; 95% confidence interval: 0.61–0.94) and sensitization (adjusted odds ratio: 0.76; 95% confidence interval: 0.58–1.0) after exclusion of children with onset of eczema or wheeze during the first year of life to avoid disease-related modification of exposure. A dose-dependent reduced risk was observed for all outcomes (asthma, eczema, allergic rhinitis, and sensitization). IgE sensitization to fish was present in 18 of the 2614 children. CONCLUSIONS. Regular fish consumption before the age of 1 seems to be associated with a reduced risk of allergic disease and sensitization to food and inhalant allergens during the first 4 years of life. REVIEWER COMMENTS. In recent decades, a decrease in consumption of omega-3 polyunsaturated fatty acids, prevalent especially in oily fish, has been proposed to contribute to the increased prevalence of allergic diseases. The authors postulated that dietary polyunsaturated fatty acids might influence the development of allergic sensitization by increasing the formation of prostaglandin E2, which in turn promotes the formation of a T-helper 2 response and stimulates the formation of IgE. The authors attempted to control for the disease-related modification of exposure by excluding children with very early symptoms of eczema or recurrent wheeze. However, this attempt to control for “reverse causation” added limitation, because the most atopic infants were excluded. As the authors admitted, fish consumption in early life may be associated with a lifestyle that reduces the risk of allergic disease in nondietary ways. Nonetheless, the study presented an interesting observation given concerns about inducing allergy by introducing allergenic foods to infants.