Suvi Ahonen

Maternal vitamin D intake during pregnancy is inversely associated with asthma and allergic rhinitis in 5‐year‐old children

Background Vitamin D is known to have a number of immunological effects and it may play a role in preventing allergic diseases.

Age at the Introduction of Solid Foods During the First Year and Allergic Sensitization at Age 5 Years

OBJECTIVE: The goal was to examine the relationship between age at the introduction of solid foods during the first year of life and allergic sensitization in 5-year-old children. METHODS: We analyzed data from the Finnish Type 1 Diabetes Prediction and Prevention nutrition study, a prospective, birth cohort study. We studied 994 children with HLA-conferred susceptibility to type 1 diabetes mellitus for whom information on breastfeeding, age at the introduction of solid foods, and allergen-specific immunoglobulin E levels at 5 years was available. The association between age at the introduction of solid foods and allergic sensitization was analyzed by using logistic regression. RESULTS: The median duration of exclusive breastfeeding was 1.8 months (range: 0–10 months). After adjustment for potential confounders, late introduction of potatoes (>4 months), oats (>5 months), rye (>7 months), wheat (>6 months), meat (>5.5 months), fish (>8.2 months), and eggs (>10.5 months) was significantly directly associated with sensitization to food allergens. Late introduction of potatoes, rye, meat, and fish was significantly associated with sensitization to any inhalant allergen. In models that included all solid foods that were significantly related to the end points, eggs, oats, and wheat remained the most important foods related to sensitization to food allergens, whereas potatoes and fish were the most important foods associated with inhalant allergic sensitization. We found no evidence of reverse causality, taking into account parental allergic rhinitis and asthma. CONCLUSION: Late introduction of solid foods was associated with increased risk of allergic sensitization to food and inhalant allergens.

Maternal diet during pregnancy and allergic sensitization in the offspring by 5 yrs of age: a prospective cohort study

Nwaru BI, Ahonen S, Kaila M, Erkkola M, Haapala A‐M, Kronberg‐Kippilä C, Veijola R, Ilonen J, Simell O, Knip M, Virtanen SM. Maternal diet during pregnancy and allergic sensitization in the offspring by 5 yrs of age: a prospective cohort study.
Pediatr Allergy Immunol 2010: 21: 29–37.
© 2009 John Wiley & Sons A/S

Timing of infant feeding in relation to childhood asthma and allergic diseases

BACKGROUND Emerging evidence questions current recommendations on the timing of infant feeding for the prevention of childhood allergies. The evidence for asthma is inconclusive. OBJECTIVE We sought to investigate the associations between the duration of breast-feeding and timing of introduction of complementary foods and the development of asthma and allergies by the age of 5 years. METHODS Data were analyzed for 3781 consecutively born children. The dietary exposures were categorized into thirds and analyzed as time-dependent variables. Asthma, allergic rhinitis, and atopic eczema end points were assessed by using the International Study of Asthma and Allergies in Childhood questionnaire, whereas IgE antibodies were analyzed from serum samples at the age of 5 years. Cox proportional hazard and logistic regressions were used for the analyses. RESULTS The median duration of exclusive and total breast-feeding was 1.4 months (interquartile range, 0.2-3.5 months) and 7.0 months (interquartile range, 4.0-11.0 months), respectively. Total breast-feeding of 9.5 months or less was associated with an increased risk of nonatopic asthma. Introduction of wheat, rye, oats, or barley at 5 to 5.5 months was inversely associated with asthma and allergic rhinitis, whereas introduction of other cereals at less than 4.5 months increased the risk of atopic eczema. Introduction of egg at 11 months or less was inversely associated with asthma, allergic rhinitis, and atopic sensitization, whereas introduction of fish at 9 months or less was inversely associated with allergic rhinitis and atopic sensitization. CONCLUSION Early introduction of wheat, rye, oats, and barley cereals; fish; and egg (respective to the timing of introduction of each food) seems to decrease the risk of asthma, allergic rhinitis, and atopic sensitization in childhood. Longer duration of total breast-feeding, rather than its exclusivity, was protective against the development of nonatopic but not atopic asthma, suggesting a potential differing effect of breast-feeding on different asthma phenotypes.

Introduction of complementary foods in infancy and atopic sensitization at the age of 5 years: timing and food diversity in a Finnish birth cohort

To study the associations between timing and diversity of introduction of complementary foods during infancy and atopic sensitization in 5‐year‐old children.

Food consumption and advanced β cell autoimmunity in young children with HLA-conferred susceptibility to type 1 diabetes: a nested case-control design

BACKGROUND Evidence for the role of food consumption during childhood in the development of β cell autoimmunity is scarce and fragmentary. OBJECTIVE We set out to study the associations of longitudinal food consumption in children with the development of advanced β cell autoimmunity. DESIGN Children with advanced β cell autoimmunity (n = 232) (ie, with repeated positivity for antibodies against islet cells) together with positivity for at least one of the other 3 antibodies analyzed or clinical type 1 diabetes were identified from a prospective birth cohort of 6069 infants with HLA-DQB1-conferred susceptibility to type 1 diabetes who were born in 1996-2004, with the longest follow-up to the age of 11 y. Repeated 3-d food records were completed by the families and daycare personnel. Diabetes-associated autoantibodies and diets were measured at 3-12-mo intervals. Four control subjects, who were matched for birth date, sex, area, and genetic risk, were randomly selected for each case. RESULTS In the main food groups, only intakes of cow-milk products (OR: 1.05; 95% CI: 1.00, 1.10) and fruit and berry juices (OR: 1.09; 95% CI: 1.02, 1.12) were significantly, although marginally, associated with advanced β cell autoimmunity. The consumption of fresh milk products and cow milk-based infant formulas was related to the endpoint, whereas no evidence was shown for consumption of sour milk products and cheese. The intake of fat from all milk products and protein from fresh milk products was associated with risk of advanced β cell autoimmunity. CONCLUSION Intakes of cow milk and fruit and berry juices could be related to the development of advanced β cell autoimmunity. This trial was registered at clinicaltrials.gov as number NCT00223613.

Food diversity in infancy and the risk of childhood asthma and allergies

BACKGROUND Recently, the bacterial diversity of the intestinal flora and the diversity of various environmental factors during infancy have been linked to the development of allergies in childhood. Food is an important environmental exposure, but the role of food diversity in the development of asthma and allergies in childhood is poorly defined. OBJECTIVE We studied the associations between food diversity during the first year of life and the development of asthma and allergies by age 5 years. METHODS In a Finnish birth cohort we analyzed data on 3142 consecutively born children. We studied food diversity at 3, 4, 6, and 12 months of age. Asthma, wheeze, atopic eczema, and allergic rhinitis were measured by using the International Study of Asthma and Allergies in Childhood questionnaire at age 5 years. RESULTS By 3 and 4 months of age, food diversity was not associated with any of the allergic end points. By 6 months of age, less food diversity was associated with increased risk of allergic rhinitis but not with the other end points. By 12 months of age, less food diversity was associated with increased risk of any asthma, atopic asthma, wheeze, and allergic rhinitis. CONCLUSION Less food diversity during the first year of life might increase the risk of asthma and allergies in childhood. The mechanisms for this association are unclear, but increased dietary antigen exposure might contribute to this link.

Maternal intake of fatty acids during pregnancy and allergies in the offspring

Fatty acids (FA) are known to have a number of immunological effects and, accordingly, may play a role in the development of allergic diseases. We investigated the effect of maternal intake of FA during pregnancy on the risk of allergic rhinitis, wheeze and atopic eczema in children aged 5 years. The present study analysed data from the Finnish Type 1 Diabetes Prediction and Prevention Nutrition Study, a population-based birth cohort study with a 5-year follow-up. Complete information on maternal diet (assessed by a validated FFQ) and International Study of Asthma and Allergies in Childhood-based allergic outcomes was available for 2441 children. Cox proportional regression and logistic regression were used for the analyses. After adjusting for potential confounding variables, high maternal consumption of butter and butter spreads (hazard ratio (HR) 1.33; 95 % CI 1.03, 1.71) and higher ratio of n-6:n-3 FA (HR 1.37; 95 % CI 1.07, 1.77) during pregnancy were associated with an increased risk of allergic rhinitis in the offspring by 5 years of age. High maternal intakes of total PUFA (HR 0.71; 95 % CI 0.52, 0.96) and α-linolenic FA (HR 0.73; 95 % CI 0.54, 0.98) were associated with a decreased risk of allergic rhinitis. However, these results lost their significance after adjustment for multiple comparisons. Overall, our data suggest that maternal consumption of butter, the ratio of n-6:n-3 FA and intake of PUFA and α-linolenic FA during pregnancy may be potential determinants of allergic rhinitis in the offspring.

Determinants of breast-feeding in a Finnish birth cohort

OBJECTIVE To assess milk feeding on the maternity ward and during infancy, and their relationship to sociodemographic determinants. The validity of our 3-month questionnaire in measuring hospital feeding was assessed. DESIGN A prospective Finnish birth cohort with increased risk to type 1 diabetes recruited between 1996 and 2004. The families completed a follow-up form on the age at introduction of new foods and age-specific dietary questionnaires. SETTING Type 1 Diabetes Prediction and Prevention (DIPP) project, Finland. SUBJECTS A cohort of 5993 children (77 % of those invited) participated in the main study, and 117 randomly selected infants in the validation study. RESULTS Breast milk was the predominant milk on the maternity ward given to 99 % of the infants. Altogether, 80 % of the women recalled their child being fed supplementary milk (donated breast milk or infant formula) on the maternity ward. The median duration of exclusive breast-feeding was 1.4 months (range 0-8) and that of total breast-feeding 7.0 months (0-25). Additional milk feeding on the maternity ward, short parental education, maternal smoking during pregnancy, small gestational age and having no siblings were associated with a risk of short duration of both exclusive and total breast-feeding. In the validation study, 78 % of the milk types given on the maternity ward fell into the same category, according to the questionnaire and hospital records. CONCLUSIONS The recommendations for infant feeding were not achieved. Infant feeding is strongly influenced by sociodemographic determinants and feeding practices on the maternity wards. Long-term breast-feeding may be supported by active promotion on the maternity ward.

Intake of antioxidants during pregnancy and the risk of allergies and asthma in the offspring

Background/Objectives:The potential immune functions related to the damages induced by oxygen-free radicals suggest that antioxidants may have a role in the development of allergies. The objective was to investigate the association between maternal intake of antioxidants during pregnancy and the risk of asthma, rhinitis and eczema in 5-year-old children.Subjects/Methods:This study was on the basis of the Finnish Type 1 Diabetes Prediction and Prevention Nutrition Study, a population-based birth cohort study with 5-year follow-up. Complete information on maternal food frequency questionnaire data and ISAAC (International Study of Asthma and Allergies in Childhood)-based allergic outcomes were available for 2441 children. Cox proportional regression and logistic regression were used for the analyses.Results:Maternal intake of any of the antioxidants was not significantly associated with the risk of asthma, rhinitis or eczema in the offspring, except for dietary intake of magnesium, which was independently associated with protection against eczema (OR 0.78; 95% CI 0.62–0.97).Conclusion:Maternal intake of dietary magnesium during pregnancy may protect against the risk of eczema in the offspring. We did not confirm previous observations concerning other antioxidants. This may be due to the variable amount of antioxidant intake across studies and also indicative of the hypothesis that there may be a critical time window in pregnancy during which antioxidants might modify the risk of allergies in the offspring.