Intake of B vitamins and the risk of developing islet autoimmunity and type 1 diabetes in the TEDDY study.

PURPOSE: The aim was to study the association between dietary intake of B vitamins in childhood and the risk of islet autoimmunity (IA) and progression to type 1 diabetes (T1D) by the age of 10 years. METHODS: We followed 8500 T1D-susceptible children born in the U.S., Finland, Sweden, and Germany in 2004 -2010 from the Environmental Determinants of Diabetes in the Young (TEDDY) study, which is a prospective observational birth cohort. Dietary intake of seven B vitamins was calculated from foods and dietary supplements based on 24-h recall at 3 months and 3-day food records collected regularly from 6 months to 10 years of age. Cox proportional hazard models were adjusted for energy, HLA-genotype, first-degree relative with T1D, sex, and country. RESULTS: A total of 778 (9.2) children developed at least one autoantibody (any IA), and 335 (3.9%) developed multiple autoantibodies. 280 (3.3%) children had IAA and 319 (3.8%) GADA as the first autoantibody. 344 (44%) children with IA progressed to T1D. We observed that higher intake of niacin was associated with a decreased risk of developing multiple autoantibodies (HR 0.95; 95% CI 0.92, 0.98) per 1 mg/1000 kcal in niacin intake. Higher intake of pyridoxine (HR 0.66; 95% CI 0.46, 0.96) and vitamin B12 (HR 0.87; 95% CI 0.77, 0.97) was associated with a decreased risk of IAA-first autoimmunity. Higher intake of riboflavin (HR 1.38; 95% CI 1.05, 1.80) was associated with an increased risk of GADA-first autoimmunity. There were no associations between any of the B vitamins and the outcomes "any IA" and progression from IA to T1D.  CONCLUSION: In this multinational, prospective birth cohort of children with genetic susceptibility to T1D, we observed some direct and inverse associations between different B vitamins and risk of IA.

Incidence of Pediatric Celiac Disease Varies by Region.

INTRODUCTION: The Environmental Determinants of Diabetes in the Young study follows an HLA risk selected birth cohort for celiac disease (CD) development using a uniform protocol. Children under investigation come from 6 different regions within Europe and the United States. Our aim was to identify regional differences in CD autoimmunity and CD cumulative incidence for children born between 2004 and 2010. METHODS: Children (n = 6,628) with DQ2.5 and/or DQ8.1 were enrolled prospectively from birth in Georgia, Washington, Colorado, Finland, Germany, and Sweden. Children underwent periodic study screening for tissue transglutaminase antibodies and then CD evaluation per clinical care. Population-specific estimates were calculated by weighting the study-specific cumulative incidence with the population-specific haplogenotype frequencies obtained from large stem cell registries from each site. RESULTS: Individual haplogenotype risks for CD autoimmunity and CD varied by region and affected the cumulative incidence within that region. The CD incidence by age 10 years was highest in Swedish children at 3%. Within the United States, the incidence by age 10 years in Colorado was 2.4%. In the model adjusted for HLA, sex, and family history, Colorado children had a 2.5-fold higher risk of CD compared to Washington. Likewise, Swedish children had a 1.4-fold and 1.8-fold higher risk of CD compared with those in Finland and Germany, respectively. DISCUSSION: There is high regional variability in cumulative incidence of CD, which suggests differential environmental, genetic, and epigenetic influences even within the United States. The overall high incidence warrants a low threshold for screening and further research on region-specific CD triggers.

Dietary Intake and Body Mass Index Influence the Risk of Islet Autoimmunity in Genetically At-Risk Children: A Mediation Analysis Using the TEDDY Cohort.

Background/Objective: Growth and obesity have been associated with increased risk of islet autoimmunity (IA) and progression to type 1 diabetes. We aimed to estimate the effect of energy-yielding macronutrient intake on the development of IA through BMI. Research Design and Methods: Genetically at-risk children (n = 5,084) in Finland, Germany, Sweden, and the USA, who were autoantibody negative at 2 years of age, were followed to the age of 8 years, with anthropometric measurements and 3-day food records collected biannually. Of these, 495 (9.7%) children developed IA. Mediation analysis for time-varying covariates (BMI z-score) and exposure (energy intake) was conducted. Cox proportional hazard method was used in sensitivity analysis. Results: We found an indirect effect of total energy intake (estimates: indirect effect 0.13 [0.05, 0.21]) and energy from protein (estimates: indirect effect 0.06 [0.02, 0.11]), fat (estimates: indirect effect 0.03 [0.01, 0.05]), and carbohydrates (estimates: indirect effect 0.02 [0.00, 0.04]) (kcal/day) on the development of IA. A direct effect was found for protein, expressed both as kcal/day (estimates: direct effect 1.09 [0.35, 1.56]) and energy percentage (estimates: direct effect 72.8 [3.0, 98.0]) and the development of GAD autoantibodies (GADA). In the sensitivity analysis, energy from protein (kcal/day) was associated with increased risk for GADA, hazard ratio 1.24 (95% CI: 1.09, 1.53), p = 0.042. Conclusions: This study confirms that higher total energy intake is associated with higher BMI, which leads to higher risk of the development of IA. A diet with larger proportion of energy from protein has a direct effect on the development of GADA.

Is staff consistency important to parents' satisfaction in a longitudinal study of children at risk for type 1 diabetes: the TEDDY study.

BACKGROUND: Participants' study satisfaction is important for both compliance with study protocols and retention, but research on parent study satisfaction is rare. This study sought to identify factors associated with parent study satisfaction in The Environmental Determinants of Diabetes in the Young (TEDDY) study, a longitudinal, multinational (US, Finland, Germany, Sweden) study of children at risk for type 1 diabetes. The role of staff consistency to parent study satisfaction was a particular focus. METHODS: Parent study satisfaction was measured by questionnaire at child-age 15 months (5579 mothers, 4942 fathers) and child-age four years (4010 mothers, 3411 fathers). Multiple linear regression analyses were used to identify sociodemographic factors, parental characteristics, and study variables associated with parent study satisfaction at both time points. RESULTS: Parent study satisfaction was highest in Sweden and the US, compared to Finland. Parents who had an accurate perception of their child's type 1 diabetes risk and those who believed they can do something to prevent type 1 diabetes were more satisfied. More educated parents and those with higher depression scores had lower study satisfaction scores. After adjusting for these factors, greater study staff change frequency was associated with lower study satisfaction in European parents (mothers at child-age 15 months: - 0.30,95% Cl - 0.36, - 0.24, p < 0.001; mothers at child-age four years: -0.41, 95% Cl - 0.53, - 0.29, p < 0.001; fathers at child-age 15 months: -0.28, 95% Cl - 0.34, - 0.21, p < 0.001; fathers at child-age four years: -0.35, 95% Cl - 0.48, - 0.21, p < 0.001). Staff consistency was not associated with parent study satisfaction in the US. However, the number of staff changes was markedly higher in the US compared to Europe. CONCLUSIONS: Sociodemographic factors, parental characteristics, and study-related variables were all related to parent study satisfaction. Those that are potentially modifiable are of particular interest as possible targets of future efforts to improve parent study satisfaction. Three such factors were identified: parent accuracy about the child's type 1 diabetes risk, parent beliefs that something can be done to reduce the child's risk, and study staff consistency. However, staff consistency was important only for European parents. TRIAL REGISTRATION: NCT00279318 .

Maternal food consumption during late pregnancy and offspring risk of islet autoimmunity and type 1 diabetes.

AIMS/HYPOTHESIS: We aimed to investigate the association between maternal consumption of gluten-containing foods and other selected foods during late pregnancy and offspring risk of islet autoimmunity (IA) and type 1 diabetes in The Environmental Determinants of Diabetes in the Young (TEDDY) study. METHODS: The TEDDY study recruited children at high genetic risk for type 1 diabetes at birth, and prospectively follows them for the development of IA and type 1 diabetes (n = 8556). A questionnaire on the mother's diet in late pregnancy was completed by 3-4 months postpartum. The maternal daily intake was estimated from a food frequency questionnaire for eight food groups: gluten-containing foods, non-gluten cereals, fresh milk, sour milk, cheese products, soy products, lean/medium-fat fish and fatty fish. For each food, we described the distribution of maternal intake among the four participating countries in the TEDDY study and tested the association of tertile of maternal food consumption with risk of IA and type 1 diabetes using forward selection time-to-event Cox regression. RESULTS: By 28 February 2019, 791 cases of IA and 328 cases of type 1 diabetes developed in TEDDY. There was no association between maternal late-pregnancy consumption of gluten-containing foods or any of the other selected foods and risk of IA, type 1 diabetes, insulin autoantibody-first IA or GAD autoantibody-first IA (all p ≥ 0.01). Maternal gluten-containing food consumption in late pregnancy was higher in Sweden (242 g/day), Germany (247 g/day) and Finland (221 g/day) than in the USA (199 g/day) (pairwise p < 0.05). CONCLUSIONS/INTERPRETATION: Maternal food consumption during late pregnancy was not associated with offspring risk for IA or type 1 diabetes. TRIAL REGISTRATION: ClinicalTrials.gov NCT00279318.

Plasma ascorbic acid and the risk of islet autoimmunity and type 1 diabetes: the TEDDY study.

AIMS/HYPOTHESIS: We studied the association of plasma ascorbic acid with the risk of developing islet autoimmunity and type 1 diabetes and examined whether SNPs in vitamin C transport genes modify these associations. Furthermore, we aimed to determine whether the SNPs themselves are associated with the risk of islet autoimmunity or type 1 diabetes. METHODS: We used a risk set sampled nested case-control design within an ongoing international multicentre observational study: The Environmental Determinants of Diabetes in the Young (TEDDY). The TEDDY study followed children with increased genetic risk from birth to endpoints of islet autoantibodies (350 cases, 974 controls) and type 1 diabetes (102 cases, 282 controls) in six clinical centres. Control participants were matched for family history of type 1 diabetes, clinical centre and sex. Plasma ascorbic acid concentration was measured at ages 6 and 12 months and then annually up to age 6 years. SNPs in vitamin C transport genes were genotyped using the ImmunoChip custom microarray. Comparisons were adjusted for HLA genotypes and for background population stratification. RESULTS: Childhood plasma ascorbic acid (mean ± SD 10.76 ± 3.54 mg/l in controls) was inversely associated with islet autoimmunity risk (adjusted OR 0.96 [95% CI 0.92, 0.99] per +1 mg/l), particularly islet autoimmunity, starting with insulin autoantibodies (OR 0.94 [95% CI 0.88, 0.99]), but not with type 1 diabetes risk (OR 0.93 [95% Cl 0.86, 1.02]). The SLC2A2 rs5400 SNP was associated with increased risk of type 1 diabetes (OR 1.77 [95% CI 1.12, 2.80]), independent of plasma ascorbic acid (OR 0.92 [95% CI 0.84, 1.00]). CONCLUSIONS/INTERPRETATION: Higher plasma ascorbic acid levels may protect against islet autoimmunity in children genetically at risk for type 1 diabetes. Further studies are warranted to confirm these findings. DATA AVAILABILITY: The datasets generated and analysed during the current study will be made available in the NIDDK Central Repository at https://www.niddkrepository.org/studies/teddy.

Parental anxiety after 5 years of participation in a longitudinal study of children at high risk of type 1 diabetes.

AIM: Parents of children participating in screening studies may experience increased levels of anxiety. The aim of this study was to assess parental anxiety levels after 5 years of participation in the Diabetes Prediction in Skåne study. Associations between parental anxiety about their child developing type 1 diabetes and clinical, demographic, and immunological factors were analyzed. METHOD: Mothers and fathers of participating 5-year-old children answered a questionnaire regarding parental anxiety associated with their child's increased risk of type 1 diabetes. Anxiety levels were assessed using the State Anxiety Inventory scale. Data were analyzed using logistic and multinomial regression. RESULTS: Parents of 2088 5-year-old children participated. Both parents answered the questionnaire for 91.2% (n = 1904) of children. In 67.1% of families, neither parent reported being anxious that their child had an increased risk of developing type 1 diabetes. Anxiety was higher in mothers of children positive for autoantibodies (OR 2.21 95% CI 1.41, 3.48, P < .001) and those perceiving their child had a higher risk for type 1 diabetes (2.01; 1.29, 3.13, P = .002). Frequency of worry was associated with parental anxiety (mothers 5.33; 3.48, 8.17, P < .001, fathers 5.27; 3.51, 7.92, P < .001). Having a family member with type 1 diabetes and having lower education level were also associated with increased anxiety. CONCLUSIONS: Diabetes in the family, the child's autoantibody status, education level, frequency of worry and risk perception where associated with higher parental anxiety. These findings add to our understanding of the impact of screening for type 1 diabetes in children on parental anxiety.

Maternal dietary supplement use and development of islet autoimmunity in the offspring: TEDDY study.

OBJECTIVE: We investigated the association between maternal use of vitamin D and omega-3 fatty acids (n-3 FAs) supplements during pregnancy and risk of islet autoimmunity (IA) in the offspring. METHODS: The Environmental Determinants of Diabetes in the Young (TEDDY) Study is prospectively following 8676 children with increased genetic risk for type 1 diabetes in Finland, Germany, Sweden, and the United States. Blood samples were collected every 3 months between 3 and 48 months of age then every 6 months thereafter to determine persistent IA. Duration, frequency, and supplement dose during pregnancy were recalled by mothers at 3 to 4 months postpartum. Cumulative intakes of supplemental vitamin D and n-3 FAs were analyzed as continuous or binary variables. We applied time-to-event analysis to study the association between maternal supplement use and IA, adjusting for country, human leukocyte antigen-DR-DQ genotype, family history of type 1 diabetes and sex. Secondary outcomes included insulin autoantibodies (IAA) or glutamic acid decarboxylase (GADA) as the first appearing autoantibody. RESULTS: As of February 2018, there were 747 (9.0%) children with IA. Vitamin D supplement intake during pregnancy (any vs none) was not associated with risk for IA (hazard ratio [HR] 1.11; 95% confidence interval [CI] 0.94, 1.31); neither was cumulative vitamin D supplement intake. Supplemental n-3 FA intake was similarly not associated with IA risk (HR: 1.19, 95% CI 0.98, 1.45). Similar lack of association was observed for either IAA or GADA as the first appearing autoantibody. CONCLUSIONS: The TEDDY cohort showed no evidence of benefit regarding IA risk for vitamin D or n-3 FA supplementation during pregnancy.

Association of Gluten Intake During the First 5 Years of Life With Incidence of Celiac Disease Autoimmunity and Celiac Disease Among Children at Increased Risk.

Importance: High gluten intake during childhood may confer risk of celiac disease. Objectives: To investigate if the amount of gluten intake is associated with celiac disease autoimmunity and celiac disease in genetically at-risk children. Design, Setting, and Participants: The participants in The Environmental Determinants of Diabetes in the Young (TEDDY), a prospective observational birth cohort study designed to identify environmental triggers of type 1 diabetes and celiac disease, were followed up at 6 clinical centers in Finland, Germany, Sweden, and the United States. Between 2004 and 2010, 8676 newborns carrying HLA antigen genotypes associated with type 1 diabetes and celiac disease were enrolled. Screening for celiac disease with tissue transglutaminase autoantibodies was performed annually in 6757 children from the age of 2 years. Data on gluten intake were available in 6605 children (98%) by September 30, 2017. Exposures: Gluten intake was estimated from 3-day food records collected at ages 6, 9, and 12 months and biannually thereafter until the age of 5 years. Main Outcomes and Measures: The primary outcome was celiac disease autoimmunity, defined as positive tissue transglutaminase autoantibodies found in 2 consecutive serum samples. The secondary outcome was celiac disease confirmed by intestinal biopsy or persistently high tissue transglutaminase autoantibody levels. Results: Of the 6605 children (49% females; median follow-up: 9.0 years [interquartile range, 8.0-10.0 years]), 1216 (18%) developed celiac disease autoimmunity and 447 (7%) developed celiac disease. The incidence for both outcomes peaked at the age of 2 to 3 years. Daily gluten intake was associated with higher risk of celiac disease autoimmunity for every 1-g/d increase in gluten consumption (hazard ratio [HR], 1.30 [95% CI, 1.22-1.38]; absolute risk by the age of 3 years if the reference amount of gluten was consumed, 28.1%; absolute risk if gluten intake was 1-g/d higher than the reference amount, 34.2%; absolute risk difference, 6.1% [95% CI, 4.5%-7.7%]). Daily gluten intake was associated with higher risk of celiac disease for every 1-g/d increase in gluten consumption (HR, 1.50 [95% CI, 1.35-1.66]; absolute risk by age of 3 years if the reference amount of gluten was consumed, 20.7%; absolute risk if gluten intake was 1-g/d higher than the reference amount, 27.9%; absolute risk difference, 7.2% [95% CI, 6.1%-8.3%]). Conclusions and Relevance: Higher gluten intake during the first 5 years of life was associated with increased risk of celiac disease autoimmunity and celiac disease among genetically predisposed children.

Cesarean Section on the Risk of Celiac Disease in the Offspring: The Teddy Study.

OBJECTIVE: Cesarean section (C-section) is associated with various immune-mediated diseases in the offspring. We investigated the relationship between mode of delivery and celiac disease (CD) and CD autoimmunity (CDA) in a multinational birth cohort. METHODS: From 2004 to 2010, infants from the general population who tested positive for HLA DR3-DQ2 or DR4-DQ8 were enrolled in The Environmental Determinants for Diabetes in the Young (TEDDY) study. Children were annually screened for transglutaminase autoantibodies, if positive, they are retested after 3 to 6 months and those persistently positive defined as CDA. Associations of C-section with maternal (age, education level, parity, pre-pregnancy weight, diabetes, smoking, weight gain during pregnancy) and child characteristics (gestational age, birth weight) were examined by Fisher exact test or Wilcoxon rank-sum test. Hazard ratios (HRs) for CDA or CD were calculated by Cox proportional hazard regression models. RESULTS: Of 6087 analyzed singletons, 1600 (26%) were born by C-section (Germany 38%, United States 37%, Finland 18%, Sweden 16%), and the remaining were born vaginally without instrumental support; 979 (16%) had developed CDA and 343 (6%) developed CD. C-section was associated with lower risk for CDA (hazard ratio [HR] = 0.85; 95% confidence interval [CI] 0.73, 0.99 P = 0.032) and CD (HR = 0.75; 95% CI 0.58, 0.98; P = 0.034). After adjusting for country, sex, HLA-genotype, CD in family, maternal education, and breast-feeding duration, significance was lost for CDA (HR = 0.91; 95% CI 0.78, 1.06; P = 0.20) and CD (HR = 0.85; 95% CI 0.65, 1.11; P = 0.24). Presurgical ruptured membranes had no influence on CDA or CD development. CONCLUSION: C-section is not associated with increased risk for CDA or CD in the offspring.

Milk feeding and first complementary foods during the first year of life in the TEDDY study.

The aim was to describe milk feeding patterns and first weaning foods during the first year of life in a large prospective birth cohort of infants with increased genetic risk for Type 1 diabetes (T1D) recruited in 4 different countries: the United States, Finland, Germany, and Sweden. All enrolled children with dietary information (n = 8,673) were included in the analyses; 1,307 (15%) children who dropped out before the first birthday were excluded from some analyses. Supplementary milk feeding in the first 3 days of life was common in all the four countries, although the type of the supplementary milk differed by country and by maternal T1D. Donated human milk was commonly used only in Finland. In all the countries, the most common first supplementary food was cow's milk-based infant formula, especially among offspring of mothers with T1D. The use of specific types of infant formulas differed notably by country: Extensively hydrolysed formulas were most used in Finland, partially hydrolysed ones in the United States and in Germany, and soy formulas only in the United States. Infant formulas commonly included probiotics, prebiotics, and starches. During the first year of life, most of the infants received conventional cow's milk. Overall, milk feeding during the first 3 days of life and thereafter until the first birthday differed markedly by maternal T1D status and across countries. These descriptive data may be useful in understanding early infant feeding practices and in planning potential interventions, which affect infant feeding.

Risk of pediatric celiac disease according to HLA haplotype and country.

BACKGROUND: The presence of HLA haplotype DR3-DQ2 or DR4-DQ8 is associated with an increased risk of celiac disease. In addition, nearly all children with celiac disease have serum antibodies against tissue transglutaminase (tTG). METHODS: We studied 6403 children with HLA haplotype DR3-DQ2 or DR4-DQ8 prospectively from birth in the United States, Finland, Germany, and Sweden. The primary end point was the development of celiac disease autoimmunity, which was defined as the presence of tTG antibodies on two consecutive tests at least 3 months apart. The secondary end point was the development of celiac disease, which was defined for the purpose of this study as either a diagnosis on biopsy or persistently high levels of tTG antibodies. RESULTS: The median follow-up was 60 months (interquartile range, 46 to 77). Celiac disease autoimmunity developed in 786 children (12%). Of the 350 children who underwent biopsy, 291 had confirmed celiac disease; an additional 21 children who did not undergo biopsy had persistently high levels of tTG antibodies. The risks of celiac disease autoimmunity and celiac disease by the age of 5 years were 11% and 3%, respectively, among children with a single DR3-DQ2 haplotype, and 26% and 11%, respectively, among those with two copies (DR3-DQ2 homozygosity). In the adjusted model, the hazard ratios for celiac disease autoimmunity were 2.09 (95% confidence interval [CI], 1.70 to 2.56) among heterozygotes and 5.70 (95% CI, 4.66 to 6.97) among homozygotes, as compared with children who had the lowest-risk genotypes (DR4-DQ8 heterozygotes or homozygotes). Residence in Sweden was also independently associated with an increased risk of celiac disease autoimmunity (hazard ratio, 1.90; 95% CI, 1.61 to 2.25). CONCLUSIONS: Children with the HLA haplotype DR3-DQ2, especially homozygotes, were found to be at high risk for celiac disease autoimmunity and celiac disease early in childhood. The higher risk in Sweden than in other countries highlights the importance of studying environmental factors associated with celiac disease. (Funded by the National Institute of Diabetes and Digestive and Kidney Diseases and others.).

Maternal use of dietary supplements during pregnancy is not associated with coeliac disease in the offspring: The Environmental Determinants of Diabetes in the Young (TEDDY) study.

Perinatal exposure to nutrients and dietary components may affect the risk for coeliac disease (CD). We investigated the association between maternal use of vitamin D, n-3 fatty acids (FA) and Fe supplements during pregnancy and risk for CD autoimmunity (CDA) and CD in the offspring. Children at increased genetic risk were prospectively followed from birth in The Environmental Determinants of Diabetes in the Young (TEDDY) study. CDA was defined as having persistently positive tissue transglutaminase autoantibodies (tTGA). Diagnosis of CD was either biopsy-confirmed or considered likely if having persistently elevated levels of tTGA>100 AU. Of 6627 enrolled children, 1136 developed CDA at a median 3·1 years of age (range 0·9-10) and 409 developed CD at a median 3·9 years of age (range 1·2-11). Use of supplements containing vitamin D, n-3 FA and Fe was recalled by 66, 17 and 94 % of mothers, respectively, at 3-4 months postpartum. The mean cumulative intake over the entire pregnancy was 2014 µg vitamin D (sd 2045 µg), 111 g n-3 FA (sd 303 g) and 8806 mg Fe (sd 7017 mg). After adjusting for country, child's human leucocyte antigen genotype, sex, family history of CD, any breast-feeding duration and household crowding, Cox's proportional hazard ratios did not suggest a statistically significant association between the intake of vitamin D, n-3 FA or Fe, and risk for CDA or CD. Dietary supplementation during pregnancy may help boost nutrient intake, but it is not likely to modify the risk for the disease in the offspring.

Effects of Gluten Intake on Risk of Celiac Disease: A Case-Control Study on a Swedish Birth Cohort.

BACKGROUND & AIMS: Early nutrition may affect the risk of celiac disease. We investigated whether amount of gluten in diet until 2 years of age increases risk for celiac disease. METHODS: We performed a 1-to-3 nested case-control study of 146 cases, resulting in 436 case-control pairs matched for sex, birth year, and HLA genotype generated from Swedish children at genetic risk for celiac disease. Newborns were annually screened for tissue transglutaminase autoantibodies (tTGA). If tested tTGA positive, time point of seroconversion was determined from frozen serum samples taken every 3 months. Celiac disease was confirmed by intestinal biopsies. Gluten intake was calculated from 3-day food records collected at ages 9, 12, 18 and 24 months. Odds ratios (OR) were calculated through conditional logistic regression. RESULTS: Breastfeeding duration (median, 32 wk) and age at first introduction to gluten (median, 22 wk) did not differ between cases and tTGA-negative controls. At the visit before tTGA seroconversion, cases reported a larger intake of gluten than controls (OR, 1.28; 95% confidence interval [CI], 1.13-1.46; P = .0002). More cases than controls were found in the upper third tertile (ie, >5.0 g/d) before they tested positive for tTGA seroconversion than controls (OR, 2.65; 95% CI, 1.70-4.13; P < .0001). This finding was similar in children homozygous for DR3-DQ2 (OR, 3.19; 95% CI, 1.61-6.30; P = .001), heterozygous for DR3-DQ2 (OR, 2.24; 95% CI, 1.08-4.62; P = .030), and for children not carrying DR3-DQ2 (OR, 2.43; 95% CI, 0.90-6.54; P = .079). CONCLUSIONS: The amount of gluten consumed until 2 years of age increases the risk of celiac disease at least 2-fold in genetically susceptible children. These findings may be taken into account for future infant feeding recommendations.

Factors associated with longitudinal food record compliance in a paediatric cohort study.

OBJECTIVE: Non-compliance with food record submission can induce bias in nutritional epidemiological analysis and make it difficult to draw inference from study findings. We examined the impact of demographic, lifestyle and psychosocial factors on such non-compliance during the first 3 years of participation in a multidisciplinary prospective paediatric study. DESIGN: The Environmental Determinants of Diabetes in the Young (TEDDY) study collects a 3 d food record quarterly during the first year of life and semi-annually thereafter. High compliance with food record completion was defined as the participating families submitting one or more days of food record at every scheduled clinic visit. SETTING: Three centres in the USA (Colorado, Georgia/Florida and Washington) and three in Europe (Finland, Germany and Sweden). SUBJECTS: Families who finished the first 3 years of TEDDY participation (n 8096). RESULTS: High compliance was associated with having a single child, older maternal age, higher maternal education and father responding to study questionnaires. Families showing poor compliance were more likely to be living far from the study centres, from ethnic minority groups, living in a crowded household and not attending clinic visits regularly. Postpartum depression, maternal smoking behaviour and mother working outside the home were also independently associated with poor compliance. CONCLUSIONS: These findings identified specific groups for targeted strategies to encourage completion of food records, thereby reducing potential bias in multidisciplinary collaborative research.

Age at first introduction to complementary foods is associated with sociodemographic factors in children with increased genetic risk of developing type 1 diabetes.

Infant's age at introduction to certain complementary foods (CF) has in previous studies been associated with islet autoimmunity, which is an early marker for type 1 diabetes (T1D). Various maternal sociodemographic factors have been found to be associated with early introduction to CF. The aims of this study were to describe early infant feeding and identify sociodemographic factors associated with early introduction to CF in a multinational cohort of infants with an increased genetic risk for T1D. The Environmental Determinants of Diabetes in the Young study is a prospective longitudinal birth cohort study. Infants (N = 6404) screened for T1D high risk human leucocyte antigen-DQ genotypes (DR3/4, DR4/4, DR4/8, DR3/3, DR4/4, DR4/1, DR4/13, DR4/9 and DR3/9) were followed for 2 years at six clinical research centres: three in the United States (Colorado, Georgia/Florida, Washington) and three in Europe (Sweden, Finland, Germany). Age at first introduction to any food was reported at clinical visits every third month from the age of 3 months. Maternal sociodemographic data were self-reported through questionnaires. Age at first introduction to CF was primarily associated with country of residence. Root vegetables and fruits were usually the first CF introduced in Finland and Sweden and cereals were usually the first CF introduced in the United States. Between 15% and 20% of the infants were introduced to solid foods before the age of 4 months. Young maternal age (<25 years), low educational level (<12 years) and smoking during pregnancy were significant predictors of early introduction to CF in this cohort. Infants with a relative with T1D were more likely to be introduced to CF later.

Infant feeding patterns in families with a diabetes history - observations from The Environmental Determinants of Diabetes in the Young (TEDDY) birth cohort study.

OBJECTIVE: To assess the association between diabetes family history and infant feeding patterns. DESIGN: Data on breast-feeding duration and age at first introduction of cow's milk and gluten-containing cereals were collected in 3-month intervals during the first 24 months of life. SETTING: Data from the multicentre TEDDY (The Environmental Determinants of Diabetes in the Young) study, including centres in the USA, Sweden, Finland and Germany. SUBJECTS: A total of 7026 children, including children with a mother with type 1 diabetes (T1D; n 292), gestational diabetes mellitus (GDM; n 404) or without diabetes but with a father and/or sibling with T1D (n 464) and children without diabetes family history (n 5866). RESULTS: While exclusive breast-feeding ended earlier and cow's milk was introduced earlier in offspring of mothers with T1D and GDM, offspring of non-diabetic mothers but a father and/or sibling with T1D were exclusively breast-fed longer and introduced to cow's milk later compared with infants without diabetes family history. The association between maternal diabetes and shorter exclusive breast-feeding duration was attenuated after adjusting for clinical variables (delivery mode, gestational age, Apgar score and birth weight). Country-specific analyses revealed differences in these associations, with Sweden showing the strongest and Finland showing no association between maternal diabetes and breast-feeding duration. CONCLUSIONS: Family history of diabetes is associated with infant feeding patterns; however, the associations clearly differ by country, indicating that cultural differences are important determinants of infant feeding behaviour. These findings need to be considered when developing strategies to improve feeding patterns in infants with a diabetes family history.

Coeliac disease: what can we learn from prospective studies about disease risk?

Paediatric prospective studies of coeliac disease with longitudinal collection of biological samples and clinical data offer a unique perspective on disease risk. This Review highlights the information now available from international paediatric prospective studies on genetic and environmental risk factors for coeliac disease. In addition, recent omics studies have made it possible to study complex interactions between genetic and environmental factors and thereby further our insight into the causes of the disease. In the future, paediatric prospective studies will be able to provide more detailed risk prediction models combining genes, the environment, and biological corroboration from multiomics. Such studies could also contribute to biomarker development and an improved understanding of disease pathogenesis.

Detecting potential outliers in longitudinal data with time-dependent covariates.

BACKGROUND: Outliers can influence regression model parameters and change the direction of the estimated effect, over-estimating or under-estimating the strength of the association between a response variable and an exposure of interest. Identifying visit-level outliers from longitudinal data with continuous time-dependent covariates is important when the distribution of such variable is highly skewed. OBJECTIVES: The primary objective was to identify potential outliers at follow-up visits using interquartile range (IQR) statistic and assess their influence on estimated Cox regression parameters. METHODS: Study was motivated by a large TEDDY dietary longitudinal and time-to-event data with a continuous time-varying vitamin B12 intake as the exposure of interest and development of Islet Autoimmunity (IA) as the response variable. An IQR algorithm was applied to the TEDDY dataset to detect potential outliers at each visit. To assess the impact of detected outliers, data were analyzed using the extended time-dependent Cox model with robust sandwich estimator. Partial residual diagnostic plots were examined for highly influential outliers. RESULTS: Extreme vitamin B12 observations that were cases of IA had a stronger influence on the Cox regression model than non-cases. Identified outliers changed the direction of hazard ratios, standard errors, or the strength of association with the risk of developing IA. CONCLUSION: At the exploratory data analysis stage, the IQR algorithm can be used as a data quality control tool to identify potential outliers at the visit level, which can be further investigated.

Use of dietary supplements in pregnant women in relation to sociodemographic factors - a report from The Environmental Determinants of Diabetes in the Young (TEDDY) study.

OBJECTIVES: The aim of the present study was to examine the prevalence and associated factors of dietary supplement use, particularly supplements containing vitamin D and fatty acids, in pregnant women enrolled in a multi-national study. DESIGN: The Environmental Determinants of Diabetes in the Young (TEDDY) study is a prospective longitudinal cohort study. Maternal dietary supplement use was self-reported through questionnaires at month 3 to 4 postpartum. SETTING: Six clinical research centres; three in the USA (Colorado, Georgia/Florida and Washington) and three in Europe (Sweden, Finland and Germany). SUBJECTS: Mothers (n 7326) to infants screened for high-risk HLA-DQ genotypes of type 1 diabetes. RESULTS: Ninety-two per cent of the 7326 women used one or more types of supplement during pregnancy. Vitamin D supplements were taken by 65% of the women, with the highest proportion of users in the USA (80.5 %). Overall, 16% of the women reported taking fatty acid supplements and a growing trend was seen in all countries between 2004 and 2010 (P,0.0001). The use was more common in Germany (32 %) and the USA (24 %) compared with Finland (8.5%) and Sweden (7.0 %). Being pregnant with the first child was a strong predictor for any supplement use in all countries. Low maternal age (<25 years), higher education, BMI<=25.0 kg/m2 and smoking during pregnancy were factors associated with supplement use in some but not all countries. CONCLUSIONS: The majority of the women used dietary supplements during pregnancy. The use was associated with sociodemographic and behavioural factors, such as parity, maternal age, education, BMI and maternal smoking.