Maternal fish and shellfish consumption and wheeze, eczema and food allergy at age two: a prospective cohort study in Brittany, France

Background: Environmental exposures, including dietary contaminants, may influence the developing immune system. This study assesses the association between maternal pre-parturition consumption of seafood and wheeze, eczema, and food allergy in preschool children. Fish and shellfish were studied separately as they differ according to their levels of omega-3 polyunsaturated fatty acids (which have anti-allergic properties) and their levels of contaminants. Methods: The PELAGIE cohort included 3421 women recruited at the beginning of pregnancy. Maternal fish and shellfish intake was measured at inclusion by a food frequency questionnaire. Wheeze, eczema, and food allergy were evaluated by a questionnaire completed by the mother when the child was 2 years old (n = 1500). Examination of the associations between seafood intake and outcomes took major confounders into account. Complementary sensitivity analyses with multiple imputation enabled us to handle missing data, due mostly to attrition. Results: Moderate maternal pre-parturition fish intake (1 to 4 times a month) was, at borderline significance, associated with a lower risk of wheeze (adjusted OR = 0.69 (0.45-1.05)) before age 2, compared with low intake (<once/month). This result was not, however, consistent: after multiple imputation, the adjusted OR was 0.86 (0.63-1.17). Shellfish intake at least once a month was associated with a higher risk of food allergy before age 2 (adjusted OR = 1.62 (1.11-2.37)) compared to low or no intake (<once/month). Multiple imputation confirmed this association (adjusted OR = 1.52 (1.05-2.21)). Conclusions: This study suggests that maternal pre-parturition shellfish consumption may increase the risk of food allergy. Further large-scale epidemiologic studies are needed to corroborate these results, identify the contaminants or components of shellfish responsible for the effects observed, determine the persistence of the associations seen at age 2, and investigate potential associations with health effects observable at later ages, such as allergic asthma.