Burden of allergy diets in Finnish day care reduced by change in practices.

BACKGROUND: Nonessential allergy diets in children with mild symptoms may harm the development of immunological tolerance and impose a burden on families and day care. We aimed to reduce the high prevalence of allergy diets in day care by reforming the practices for inquiring about need of special diets from parents. METHODS: We developed a new special diet form and an information leaflet based on the new allergy guidelines. The new form was implemented into 40 Finnish day care centres in the capital region in 2013-2015. The questionnaires on practices concerning special diets in day care centres and allergy knowledge were collected from the personnel. RESULTS: After 2 years, the new special diet form was used by 64% of families with food-allergic children, and the prevalence of allergy diets in day care centres decreased by 43% to 4.3% (IQ range 3.05-5.96). A significant decrease was found in the prevalence of all basic (milk, grains, egg) and most other allergy diets (P for trend < 0.01). The new practice was well accepted by day care and kitchen personnel. Lack of updated allergy knowledge was noted among day care personnel. CONCLUSIONS: The burden of allergy diets in day care settings could be decreased by simple pragmatic changes based on current allergy guidelines. Old allergy attitudes persisted among day care personnel, indicating the need for continuous education.

Breastfeeding and introduction of complementary foods during infancy in relation to the risk of asthma and atopic diseases up to 10 years.

BACKGROUND: It has been hypothesized that changes in diet during early life may have contributed to the increase in childhood asthma and atopy. The long-term effect of the timing and content of infant feeding on the incidence of asthma and atopic diseases in children is unclear. OBJECTIVE: To investigate the associations between duration of breastfeeding and the timing of introduction of complementary foods during the first 6 months and parental-reported asthma, wheeze and atopic eczema up to 10 years of age. METHODS: Infant feeding practices (breastfeeding and introduction of complementary foods) of 1924 singleton children participating in the Study of Eczema and Asthma To Observe the influence of Nutrition (SEATON) birth cohort were prospectively collected up to 6 months with outcomes (wheeze, atopic eczema and asthma) being assessed at 1, 2, 5 and 10 years. Data were analysed using generalized estimating equations and discrete hazards models with adjustment for confounders. RESULTS: By 6 months, 59% and 35% of mothers had stopped exclusive and total breastfeeding, respectively. Although formula feeding was adversely associated with wheeze in the past 12 months (adjusted OR for no formula feeding: 070, 95% CI 0.50-0.97), and the introduction of biscuits/bread after 5 months of age adversely associated with atopic eczema (adjusted OR 1.34, 95% CI 1.06-1.69), these results lost their statistical significance after adjustment for multiple testing. Stratification of the results by the presence of eczema by 6 months of age and family atopic history did not substantially differ from the results of the whole study population. CONCLUSION AND CLINICAL RELEVANCE: Our results suggest that the nature of infant feeding during the first 6 months seems not to substantially influence the long-term risk of asthma and atopic diseases in children, nor in children at high risk of atopic disease because of a family history of atopic disease.

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

OBJECTIVE: To study the associations between timing and diversity of introduction of complementary foods during infancy and atopic sensitization in 5-year-old children. METHODS: In the Finnish DIPP (type 1 diabetes prediction and prevention) birth cohort (n = 3781), data on the timing of infant feeding were collected up to the age of 2 years and serum IgE antibodies toward four food and four inhalant allergens measured at the age of 5 years. Logistic regression was used for the analyses. RESULTS: Median duration of exclusive and total breastfeeding was 1.4 (interquartile range: 0.2-3.5) and 7.0 (4.0-11.0) months, respectively. When all the foods were studied together and adjusted for confounders, short duration of breastfeeding decreased the risk of sensitization to birch allergen; introduction of oats <5.1 months and barley <5.5 months decreased the risk of sensitization to wheat and egg allergens, and oats additionally associated with milk, timothy grass, and birch allergens. Introduction of rye <7.0 months decreased the risk of sensitization to birch allergen. Introduction of fish <6 months and egg ≤11 months decreased the risk of sensitization to all the specific allergens studied. The introduction of <3 food items at 3 months was associated with sensitization to wheat, timothy grass, and birch allergens; the introduction of 1-2 food items at 4 months and ≤4 food items at 6 months was associated with all endpoints, but house dust mite. These results were particularly evident among high-risk children when the results were stratified by atopic history, indicating the potential for reverse causality. CONCLUSIONS: The introduction of complementary foods was consecutively done, and with respect to the timing of each food, early introduction of complementary foods may protect against atopic sensitization in childhood, particularly among high-risk children. Less food diversity as already at 3 months of age may increase the risk of atopic sensitization.

Early introduction of root vegetables in infancy associated with advanced ß-cell autoimmunity in young children with human leukocyte antigen-conferred susceptibility to Type 1 diabetes.

AIMS: Early introduction of supplementary foods has been implicated to play a role in the development of ß-cell autoimmunity. We set out to study the effects of breastfeeding and age at introduction of supplementary foods on the development of ß-cell autoimmunity. METHODS: A prospective birth cohort of 6069 infants with HLA-DQB-conferred susceptibility to Type 1 diabetes was recruited between 1996 and 2004. Antibodies against islet cells, insulin, glutamate dehydroxylase and islet antigen 2 were measured at 3- to 12-month intervals. The families recorded at home the age at introduction of new foods and, for each visit, completed a structured dietary questionnaire. The endpoint was repeated positivity for islet cell antibodies plus at least one other antibody and/or clinical Type 1 diabetes (n = 265). RESULTS: Early introduction of root vegetables (by the age of 4 months) was related to increased risk of developing positivity for the endpoint [hazard ratio (95% CI) for the earliest third 1.75 (1.11-2.75) and for the middle third 1.79 (1.22-2.62) compared with the last third (> 4 months), likelihood ratio test P = 0.006], independently of the introduction of other foods and of several putative socio-demographic and perinatal confounding factors. Introducing wheat, rye, oats and/or barley cereals (P = 0.013) and egg (P = 0.031) early was related to an increased risk of the endpoint, but only during the first 3 years of life. CONCLUSIONS: Early introduction of root vegetables during infancy is independently associated with increased risk of ß-cell autoimmunity among Finnish children with increased genetic susceptibility to Type 1 diabetes.

Feasibility and compliance in a nutritional primary prevention trial in infants at increased risk for type 1 diabetes.

AIM: The international Trial to Reduce IDDM in the Genetically at Risk (TRIGR) was launched to determine whether weaning to a highly hydrolysed formula in infancy reduces the incidence of type 1 diabetes in children at increased genetic disease susceptibility. We describe here the findings on feasibility and compliance from the pilot study. METHODS: The protocol was tested in 240 children. The diet of the participating children was assessed by self-administered dietary forms, a structured questionnaire and a food record. Blood samples were taken and weight and height measured at birth and at 3, 6, 9, 12, 18 and 24 months. RESULTS: A majority of the subjects (84%) were exposed to the study formula at least for 2 months. Linear growth or weight gain over the first 2 years of life was similar in the two study groups. The levels of IgA and IgG antibodies to cow's milk and casein were higher in the cow's milk-based formula group than in the hydrolysed formula group during the intervention period (p<0.05), reflecting the difference in the intake of cow's milk protein. CONCLUSION: This randomized trial on infant feeding turned out to be feasible, and dietary compliance was acceptable. Valuable experience was gained for the planning and sample size estimation of the study proper.

Grocery purchase data in the study of alcohol use - A validity study.

BACKGROUND: Alcohol use epidemiology is facing challenges as survey response rates decline. In addition, population surveys fail to capture a large proportion of alcohol consumed and are expensive to conduct. This study aims to aid in complementing traditional epidemiological methods by validate grocery purchase data in the research on population alcohol use. METHODS: The LoCard study subjects were loyalty card holders of a grocery retail co-operative, which possessed more than 45 % market share in Finland. One third of those who consented to the analyses of their grocery purchases were presented a questionnaire including a Food Frequency Questionnaire on the web; N = 11,818 responded. The relationship between beer purchase frequency and self-reported beer drinking frequency was studied for association and agreement in different subgroups using crosstabulations and Poisson regression modeling. RESULTS: The association between beer purchase frequency and self-reported beer drinking frequency was good (Gamma = .556). The agreement between beer purchase frequency and drinking frequency was only fair (Kappa = .189). Limiting the data to those single adult households that reported making at least 61 % of their grocery purchases from this grocery retailer and collapsing the frequency categories to three instead of six increased the agreement to good (Kappa = .463). CONCLUSIONS: Information on beer purchase frequency from the loyalty card database can be used to rank people according to their drinking frequency and to estimate beer drinking frequency with fair to good accuracy, depending on what share of grocery purchases they make from the grocery retailer in question.

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. Objectives To study the effect of maternal intake of vitamin D during pregnancy on the emergence of asthma, allergic rhinitis (AR), and atopic eczema by the age of 5 years in children with HLA-DQB1-conferred susceptibility for type 1 diabetes. METHODS: Children (1669) participating in the population-based birth cohort study were followed for asthma, AR, and atopic eczema assessed by validated questionnaire at 5 years. Maternal diet was assessed by a food-frequency questionnaire. RESULTS: The mean maternal intake of vitamin D was 5.1 (SD 2.6) microg from food and 1.4 (2.6) microg from supplements. Only 32% of the women were taking vitamin D supplements. When adjusted for potential confounders, maternal intake of vitamin D from food was negatively related to risk of asthma [hazard ratio (HR) 0.80; 95% confidence interval (CI) 0.64-0.99] and AR [HR 0.85; 95% CI 0.75-0.97]. Vitamin D supplements alone were not associated with any outcome. Adjustment for maternal intake of other dietary factors did not change the results. CONCLUSION: Maternal vitamin D intake from foods during pregnancy may be negatively associated with risk of asthma and AR in childhood.

Association between diet quality measured by the Healthy Food Intake Index and later risk of gestational diabetes-a secondary analysis of the RADIEL trial.

The aim of this study was to find the association between adherence to the Nordic Nutrition Recommendations (NNR) and glucose metabolism. Participants were 137 pregnant obese women or women with a history of gestational diabetes (GDM) from the Finnish Gestational Diabetes Prevention Study. Adherence to the NNR was assessed by the Healthy Food Intake Index (HFII) calculated from the first trimesters' food frequency questionnaires. Higher HFII scores reflected higher adherence to the NNR (score range 0-17). Regression models with linear contrasts served for the main analysis. The mean HFII score was 10.0 (s.d. 2.8). The odds for GDM decreased toward the higher HFII categories (P=0.067). Fasting glucose (FG) and 2hG concentrations showed inverse linearity across the HFII categories (P(FG)=0.030 and P(2hG)=0.028, adjusted for body mass index, age and GDM/pregnancy history). Low adherence to the NNR is associated with higher antenatal FG and 2hG concentrations and possibly GDM.

Association between diet quality measured by the Healthy Food Intake Index and later risk of gestational diabetes-a secondary analysis of the RADIEL trial.

This corrects the article DOI: 10.1038/ejcn.2016.275.

Intake of vitamin D by Finnish children aged 3 months to 3 years in relation to sociodemographic factors.

OBJECTIVE: To study the total daily intake of vitamin D from food and supplements among Finnish children aged 3 months to 3 years, the dietary sources of vitamin D and the association between vitamin D intake and sociodemographic factors. SUBJECTS AND METHODS: The subjects are participants in the Finnish Type I Diabetes Prediction and Prevention Nutrition Study born between October 1997 and October 1998. At the age of 3 and 6 months, 1, 2 and 3 years, 342 (72% of the invited families), 298 (63%), 267 (56%), 233 (49%) and 209 (44%) families, respectively, participated in the present study. Food consumption was assessed by a 3-day food record. A structured questionnaire was used to record the parents' socioeconomic status. RESULTS: The mean dietary vitamin D intake exceeded the recommendation (10 microg/day) at the age of 3 (11.0 microg) and 6 months (12.0 microg), but decreased thereafter being 9.8, 5.0 and 4.1 microg at 1, 2 and 3 years of age, respectively. Among the children 91, 91, 81, 42 and 26% used vitamin D supplements at the age of 3 and 6 months, and 1, 2 and 3 years, respectively. In children not using vitamin D supplements, vitamin D intake was less than 10 microg/day at all ages. Vitamin D intake from food did not differ in children who used and did not use vitamin D supplements. Vitamin D supplements were the main source of vitamin D intake in all age groups studied, followed by vitamin D-fortified infant formula in 3-month-olds and infant formula and baby foods in 6-month-olds. After the age of 1 year, the most important food sources of vitamin D were margarine, fish, baby foods, low-fat milk and eggs. Sociodemographic factors, especially the number of children in the family and maternal age, were associated with the total vitamin D intake and vitamin D supplement use. CONCLUSION: Vitamin D supplements are not used according to the dietary recommendations in a substantial proportion of Finnish children.

Infant feeding patterns in the Finnish type I diabetes prediction and prevention nutrition study cohort.

OBJECTIVE: To investigate infant feeding patterns during the first 2 y and their relation to sociodemographic factors. DESIGN: A population-based cohort study. SETTING: Oulu and Tampere University Hospital district areas 1996-1999, Finland. SUBJECTS AND METHODS: All newborn infants (n=675) with increased genetic risk for type I diabetes were invited to the study in 1996-1997. Of these, 429 (64%) completed the dietary follow-up form by the time they reached 2 y of age. RESULTS: The median duration of exclusive breastfeeding (BF) was 1.8 months (range 0-6 months) and that of total BF 7.0 months (0.3-25 months). Among the infants 20% were exclusively breastfed at least 4 months (recommendation 4-6 months). Infants were introduced to infant formula at the median age of 1.8 months (range 0-25 months) and other supplementary foods at the median age of 3.5 months (1-6 months). Infant's ponderal index at birth was inversely associated with the duration of total BF. The age of introduction of supplementary foods correlated positively with the duration of total BF. Longer parental education and increased maternal age were associated with a longer duration of BF and older age at introduction of supplementary foods. Infant formula and other supplementary foods were added earlier to the diet of the boys than that of the girls. CONCLUSION: Duration of breastfeeding in Finland is shorter than recommended. Compliance with the current recommendations on the timing of introduction of first supplementary food and dairy products is relatively poor. The diet during infancy seems to be conspicuously influenced by the duration of parental education, maternal age and the sex of the infant.

The reliability and validity of a short food frequency questionnaire among 9-11-year olds: a multinational study on three middle-income and high-income countries.

OBJECTIVE: The main aim of this study was to assess the reliability and validity of a food frequency questionnaire with 23 food groups (I-FFQ) among a sample of 9-11-year-old children from three different countries that differ on economical development and income distribution, and to assess differences between country sites. Furthermore, we assessed factors associated with I-FFQ's performance. METHODS: This was an ancillary study of the International Study of Childhood Obesity, Lifestyle and the Environment. Reliability (n=321) and validity (n=282) components of this study had the same participants. Participation rates were 95% and 70%, respectively. Participants completed two I-FFQs with a mean interval of 4.9 weeks to assess reliability. A 3-day pre-coded food diary (PFD) was used as the reference method in the validity analyses. Wilcoxon signed-rank tests, intraclass correlation coefficients and cross-classifications were used to assess the reliability of I-FFQ. Spearman correlation coefficients, percentage difference and cross-classifications were used to assess the validity of I-FFQ. A logistic regression model was used to assess the relation of selected variables with the estimate of validity. Analyses based on information in the PFDs were performed to assess how participants interpreted food groups. RESULTS: Reliability correlation coefficients ranged from 0.37 to 0.78 and gross misclassification for all food groups was <5%. Validity correlation coefficients were below 0.5 for 22/23 food groups, and they differed among country sites. For validity, gross misclassification was <5% for 22/23 food groups. Over- or underestimation did not appear for 19/23 food groups. Logistic regression showed that country of participation and parental education were associated (P⩽0.05) with the validity of I-FFQ. Analyses of children's interpretation of food groups suggested that the meaning of most food groups was understood by the children. CONCLUSION: I-FFQ is a moderately reliable method and its validity ranged from low to moderate, depending on food group and country site.

Association between home and school food environments and dietary patterns among 9-11-year-old children in 12 countries.

OBJECTIVES: We investigated the roles of home and school environments on dietary patterns among children from 12 countries differing widely in geographic region and levels of human and economic development. METHODS: The sample included a total of 6685 (54% girls) 9-11-year-old children. Parents/guardians reported the availability of certain foods in the home, and trained researchers performed school audits recording the availability of foods for sale at schools. Foods were then divided into wholesome (nutrient-dense) and empty-calorie (nutrient-poor) foods and scored according to their availability. Children reported if their school provided school lunch and how many times during the last week they had eaten meals prepared away from home and school. Via principal components analysis, data-driven dietary pattern scores were calculated from food frequency questionnaires. Multilevel models were used to study the associations between home and school food environments (wholesome and empty-calorie foods) and dietary patterns (healthy and unhealthy diet pattern scores). RESULTS: For low unhealthy diet pattern scores, low availability of empty-calorie foods at home was found to be more important than high availability of wholesome foods. More meals eaten outside home and school were associated with the higher unhealthy diet pattern scores. The availability of wholesome foods at home was positively associated with the healthy diet pattern scores. Food availability at school was not associated with the dietary patterns. CONCLUSIONS: In this sample, the home food environment was more significant than the school food environment in predicting the dietary patterns. The availability of empty-calorie foods was associated with the unhealthy dietary pattern even when the availability of wholesome foods at home was high. Meals prepared away from home contributed to the unhealthy dietary pattern. Therefore, parents should be encouraged to limit the availability of empty-calorie foods and eating outside the home.

Folate, vitamin D, and iron intakes are low among pregnant Finnish women.

OBJECTIVE: To evaluate dietary habits and nutrient intake of Finnish pregnant women, to relate these to the use of dietary supplements, and to explore possible dietary variations according to age and education. DESIGN: A random dietary survey using two five day estimated food records. SETTING: Pregnant women from 13 maternity clinics in the city of Oulu, Finland. SUBJECTS: One hundred and eighteen pregnant women in their third trimester. MAIN RESULTS: The main sources of energy were cereal products and milk products. The consumption of fish and poultry was low. Women with a higher educational level consumed more vegetables, fruit, fruit juices, and tea and less sausages, inner organs and coffee than women with a lower educational level. Younger women (< 25 y) consumed more sugar and pork and less berries, butter and inner organs than older women. On average 15% of the total energy was supplied by protein, 33% by fats, 52% by carbohydrates, and 12% by sucrose. Compared to the Nordic nutrition recommendations, the proportion of polyunsaturated fatty acids and the intake of dietary fibre were low and the intake of sugar high. The intakes of vitamins and minerals met or exceeded the recommended allowances, except for vitamin D, folate, and iron. Of the subjects 70% used dietary supplements. With the exception of vitamin D, folate, and iron, both the supplement users and non-users had an adequate nutrient intake from their diet. CONCLUSIONS: A balanced diet covers the increased nutrient requirements during pregnancy, with the exception for vitamin D, folate, and iron. The use of dietary supplements during pregnancy is excessive and partly focused on the wrong nutrients. Young and less educated, and smoking pregnant women need more nutritional guidance.

Maternal vitamin D during pregnancy and its relation to immune-mediated diseases in the offspring.

Vitamin D deficiency during pregnancy is fairly common in many parts of the world. However, currently there is no consensus on the optimal vitamin D intake during pregnancy. Vitamin D is known to be of great importance for the homeostatic functions within the immune system. Maternal vitamin D status during pregnancy may therefore affect the developing immune system of the fetus, thus contributing to the later development of immune-mediated diseases. This chapter introduces the basics of vitamin D during pregnancy and discusses the role of maternal vitamin D intake in the development of asthma, allergic diseases, autoimmune diseases, cancer, and infections in the offspring. So far, the strongest observational evidence underlines the potential of maternal vitamin D intake during pregnancy to influence the likelihood of asthma and allergic outcomes in the offspring. Somewhat conflicting findings imply that there might be critical time windows of exposure to adequate vitamin D levels during pregnancy. More research is needed in order to fully understand the contribution of maternal vitamin D status during pregnancy to the progress of immune-mediated diseases.

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.

Age at introduction of new foods and advanced beta cell autoimmunity in young children with HLA-conferred susceptibility to type 1 diabetes.

AIMS/HYPOTHESIS: Evidence for the role of infant feeding in the development of beta cell autoimmunity is inconsistent. We set out to study the effects of breastfeeding and of age at introduction of supplementary foods on the development of beta cell autoimmunity. SUBJECTS AND METHODS: A prospective birth cohort of 3,565 infants with HLA-DQB1-conferred susceptibility to type 1 diabetes was recruited between 1996 and 2001 from two university hospital areas in Finland. Blood samples were collected at 3- to 12-month intervals to measure antibodies against islet cells, insulin, glutamate dehydroxylase and islet antigen 2. The families kept a record on the age at introduction of new foods, and for each visit completed a structured dietary questionnaire. The endpoint was repeated positivity for islet cell antibodies together with at least one of the other three antibodies. RESULTS: The overall or exclusive duration of breastfeeding was not associated with the risk of developing the endpoint. An early age at introduction of fruits and berries (< or =4 months) was related to increased risk of developing positivity for the endpoint (hazard ratio [95% CI] for earliest tertile 2.02 [1.03-3.95] and for midtertile 1.97 [1.06-3.64] compared with latest tertile >4 months). Also, introducing roots between 3 and 3.9 months (midtertile) was related to increased risk of the endpoint (hazard ratio [95% CI] for the earliest tertile 1.04 [0.57-1.90] and for midtertile 1.82 [1.19-2.79] compared with latest tertile). These associations were independent of several putative socio-demographic and perinatal confounding factors. CONCLUSIONS/INTERPRETATION: Our findings suggest that an early age at introduction of fruits and berries and roots associates independently with beta cell autoimmunity, contradicting earlier findings from smaller birth cohort studies.

Validity and reproducibility of a food frequency questionnaire for pregnant Finnish women.

The authors developed a self-administered 181-item food frequency questionnaire (FFQ) to assess dietary intake during pregnancy for Finnish women from August 1995 to July 1996. In the validation study (n = 113), the data that were collected by using two 5-day food records completed during the eighth month of pregnancy were compared with FFQ data. The intake of foods and nutrients was higher as determined by FFQ than that assessed using food records. Pearson correlation coefficients for nutrients, after adjustment for energy, ranged from 0.19 (vitamin E) to 0.70 (thiamin) and, for foods, from 0.03 (high-fat milk) to 0.84 (low-fat milk). Energy adjustment improved the correlations for nutrients. Correction for attenuation improved correlations for both foods and nutrients. On average, 70% of the foods and 69% of the nutrients fell into the same or adjacent quintiles, according to the FFQ and the food record. In the reproducibility study, 111 women completed the FFQs twice at a 1-month interval. The intraclass correlation coefficients for nutrients ranged from 0.42 (ethanol) to 0.72 (sucrose, riboflavin, and calcium), and for foods, they ranged from 0.44 (ice cream) to 0.91 (coffee). The authors conclude that the FFQ has an acceptable reproducibility and represents a useful tool for categorizing pregnant women according to their dietary intake.

Short-term exclusive breastfeeding predisposes young children with increased genetic risk of Type I diabetes to progressive beta-cell autoimmunity.

AIMS/HYPOTHESIS: This study aimed to establish the relation between early infant nutrition and signs of beta-cell autoimmunity in young children. METHODS: We identified and observed from birth 2949 infants with increased genetic risk of Type I (insulin-dependent) diabetes mellitus (HLA DQB1*02/ *0302 or DQB1*0302/x, x = other than *02, *0301 or *0602) and monitored them for islet cell antibodies at 3 to 6 month intervals. If an infant seroconverted to islet cell antibody positivity, all of his or her samples were also analysed for autoantibodies to insulin, GAD65 (GADA) and to the protein tyrosine phosphatase related IA-2 molecule (IA-2A). Our case-control study comprises the first 65 children who seroconverted to islet cell antibody positivity before the age of 4 years and 390 control children who were islet cell antibody-negative (six control children/ case). We monitored the duration of exclusive and total breastfeeding and the age at which cows' milk was introduced. RESULTS: Infants who had been breastfed exclusively for at least 4 months had lower risk of seroconversion to positivity for IA-2A or all four autoantibodies [odds ratio (OR) 0.24; 95 % CI 0.06-0.94 and OR 0.17; 95 % CI 0.03-0.86, respectively] than those infants who had been breastfed exclusively for less than 2 months. The risk of seroconversion to positivity for IA-2A or all four autoantibodies was higher in those younger than 2 months (OR 4.37; 95 % CI 1.33-14.42 and OR 5.02; 95 % CI 1.27-19.89) or aged 2 to 3.9 months (OR 5.50; 95 % CI 1.21-25.04 and 6.19; 95% CI 1.10-34.84) when they first received cows' milk than in those aged 4 months or older. CONCLUSIONS/INTERPRETATION: These observations suggest that short-term breastfeeding and the early introduction of cows' milk-based infant formula predispose young children who are genetically susceptible to Type I diabetes to progressive signs of beta-cell autoimmunity.