Dietary supplements contribute to the total nutrient intake in pregnant women. It has been reported that among women using supplements containing vitamin D, more than 50 % of the total vitamin D intake is provided by the supplement(Reference Haugen, Brantsæter and Alexander1, Reference Dror, King and Durand2) and that vitamin D and fatty acids from food and supplements are significantly correlated with maternal and cord blood serum levels(Reference Dror, King and Durand2, Reference Brantsæter, Haugen and Hagve3). Further, high intake of vitamin D and n-3 fatty acids from both foods and dietary supplements during pregnancy has been reported to be associated with reduced risk of islet autoimmunity and development of type 1 diabetes (T1D) in the offspring(Reference Stene, Ulriksen and Magnus4, Reference Fronczak, Baron and Chase5). It is hypothesized that the immune-regulatory properties of vitamin D and the anti-inflammatory properties of the long-chain n-3 fatty acids may inhibit the pathogenesis of T1D(Reference Hewison6, Reference Calder7).
Pregnant women are encouraged to enhance their diet during pregnancy to meet increased needs for most nutrients. There are no explicit recommendations regarding consumption of dietary supplements, but women with poor diets, iron-deficiency anaemia, vegans, smokers and women carrying two or more fetuses are recommended to enhance their diet with a prenatal dietary supplement(Reference Kaiser and Allen8). The prevalence of supplement use during pregnancy has been reported to be as high as 80 %(Reference Haugen, Brantsæter and Alexander1, Reference Dror, King and Durand2, Reference Arkkola, Uusitalo and Pietikäinen9). However, there are few such studies, especially in the USA(Reference Picciano and McGuire10). The National Health and Nutrition Examination Survey (NHANES) has monitored the use of dietary supplements in the US population since the 1970s, but the sample size of pregnant women is too small to draw conclusions regarding dietary supplement use during pregnancy among US women(Reference Bailey, Gahche and Lentino11). Supplement use is also reported to be related to sociodemographic variables(Reference Picciano and McGuire10, Reference Rock12). NHANES showed that dietary supplement use in the adult population varied by education level, weight status and ethnicity(Reference Bailey, Gahche and Lentino11). Supplement use during pregnancy appears to vary among ethnic and socio-economic groups and interact with factors such as supplement use before pregnancy and smoking(Reference Picciano and McGuire10). Supplement use during pregnancy has been reported to be related to age, education, smoking and BMI in the Nordic countries(Reference Haugen, Brantsæter and Alexander1, Reference Arkkola, Uusitalo and Pietikäinen9, Reference Brekke and Ludvigsson13, Reference Marjamäki, Niinistö and Kenward14).
The primary aim of the present study was to describe the prevalence of dietary supplement use, and particularly the use of supplements containing vitamin D and fatty acids, in pregnant women whose children were at increased genetic risk of T1D. We also wanted to identify sociodemographic and behavioural factors associated with supplement use.
Materials and methods
Participants
The Environmental Determinants of Diabetes in the Young (TEDDY) is a prospective study designed to examine dietary and environmental exposures on islet autoimmunity and the development of T1D among children with high-risk HLA-DQ genotypes in the USA, Finland, Germany and Sweden(15). Infants are followed from birth until T1D is diagnosed or until the child is 15 years old. A total of 424 788 newborns were screened between September 2004 and February 2010, and 8677 HLA eligible infants were enrolled in the study(Reference Hagopian, Erlich and Lernmark16). Ongoing monitoring for diet, infectious agents, other environmental exposures and autoimmunity status are completed with interviews, questionnaires, food records and laboratory tests. Detailed study design and methods have been previously published(17).
Information on dietary supplement consumption was asked at month 3 to 4 postpartum from 8677 women. The following women were excluded: (i) mothers of 850 children (9·8 %) who had not completed the 9-month clinic visit, where all sociodemographic data were collected; (ii) mothers of sixty-six children (0·8 %) with missing supplement use data; (iii) mothers of 178 children (2·1 %) due to missing or extreme anthropometric measures (BMI < 16·0 or >50·0 kg/m2); and (iv) mothers of 257 children (3·0 %) with incomplete or missing sociodemographic data, resulting in a total of 7326 mothers with complete data. Written informed consents were obtained for all study participants from a parent or primary caregiver, separately, for genetic screening and participation in prospective follow-up. The study was approved by local Institutional Review Boards (six clinical centres in four countries) and is monitored by an External Advisory Board formed by the National Institutes of Health.
Questionnaires
A questionnaire containing questions on illnesses, medications, smoking habits, alcohol intake, diet and dietary supplement use during pregnancy was mailed to the women of enrolled children and was completed at month 3 to 4 postpartum. Dietary supplements were defined as supplements that contain one or any combination of the following substances: a vitamin, mineral, herb or other botanical substance, and amino acids, in accordance with the US Dietary Supplement Health and Education Act of 1994. Homeopathic and protein supplements were not coded as dietary supplements in TEDDY(18). Dietary supplements taken due to medical condition or illness were also included. The women reported product name, frequency per week and duration of usage during pregnancy. Supplements were classified into twenty-seven single supplements and ten multivitamin/mineral subgroups based on their nutrient profiles (Appendix 2)(Reference Moyers, Richesson and Krischer19). A dietary supplement user was defined as anyone who reported taking at least one supplement at least once during the pregnancy.
Maternal education was recorded on a ten-category scale to accommodate for different education systems in each country, which was then aggregated into two categories, basic primary education (primary school through trade school) and higher education (completed trade school or higher), to achieve comparability across countries. Maternal age was defined as the woman's age at time of delivery and was treated as both a continuous and a categorical variable (<25·0 years, 25·0–29·9 years, 30·0–34·9 years and ≥35·0 years). Pre-pregnancy BMI was calculated by using mother's self-reported weight (in kilograms) before pregnancy divided by the square of height (in metres) and was categorized based on the WHO classification(20). Smoking and alcohol consumption during pregnancy were defined as ‘yes’ if reported, regardless of frequency and duration. Birth order of the TEDDY child (first-born v. others) was determined by the question ‘Is this your first child?’ Maternal diabetes status during pregnancy was self-reported and was grouped into four groups: ‘no diabetes’, ‘type 1 diabetes’, ‘gestational diabetes and type 2 diabetes’ and ‘unknown’. Race/ethnicity was analysed only in the US women and was categorized in five groups (non-Hispanic white, African Americans, Hispanics, all other races and unknown).
Statistical analyses
Data were analysed using the SAS® statistical software package version 9·2. Categorical variables were analysed using the Pearson χ 2 test or Fisher's exact test and continuous variables were analysed using ANOVA. Multiple logistic regression analysis was used to determine the independent factors associated with maternal use of supplements containing vitamin D and fatty acids. All models were assessed overall and separately by country.
Results
The distribution of characteristics of the study population across the four countries is provided in Table 1. Germany had the highest maternal age (mean 31·6 years) followed by Sweden, the USA and Finland (P < 0·0001). Pre-pregnancy BMI was higher among US women compared with the European women (P < 0·0001). Finland had the highest proportion of women with higher education followed by Germany, the USA and Sweden (P < 0·0001). A greater proportion of German women reported smoking and drinking during pregnancy than women from the other countries (P < 0·0001). The use of dietary supplements during pregnancy was common among women in all countries (Table 2). The highest percentage of users was in the USA (96·4 %) while the lowest was in Finland (87·1 %) Users tended to be older women (≥35·0 years), to be pregnant with their first child and to have a higher educational level compared with non-users. In both the USA and Finland, drinking alcohol during pregnancy was more common among supplement users than non-users, although these differences were not seen in Germany and Sweden. Smoking was more often reported among the non-users in all four countries. A higher percentage of women with BMI ≥ 25·0 kg/m2 was seen among non-users in Germany (P = 0·0003) and Sweden (P < 0·0001) but not in the USA and Finland.
Table 1 Cohort characteristics by country (n 7326): The Environmental Determinants of Diabetes in the Young (TEDDY) study
T1D, type 1 diabetes; T2D, type 2 diabetes; FDR, first-degree relative (mother, father and/or siblings).
a,b,cMean values within a row with unlike superscript letters were significantly different (P < 0·05).
*US mothers only.
Table 2 Distribution and description of non-users and any supplement users, by respondent characteristics: The Environmental Determinants of Diabetes in the Young (TEDDY) study
T1D, type 1 diabetes; T2D, type 2 diabetes.
Predictors of any dietary supplement use during pregnancy
Results of the multivariable analysis demonstrated that in all countries, women who were pregnant with their first child were more likely to use supplements (Table 3). Younger women (<25·0 years) were less likely to use supplements compared with older women. Women with higher education in the USA and Sweden, but not in Finland and Germany, were more likely to use dietary supplements. Women who smoked during pregnancy were less likely to use dietary supplements in Finland and Sweden, but not in the USA and Germany. In Finland, women were more likely to be supplement users if the child had a first-degree relative diagnosed with T1D or if they reported alcohol consumption during pregnancy. Women in Sweden and Germany with a pre-pregnancy BMI ≥ 25·0 kg/m2 were less likely to use any dietary supplement during pregnancy. Race/ethnicity among US women did not predict dietary supplement use.
Table 3 Adjusted sociodemographic predictors for any dietary supplement use during pregnancy, by country: The Environmental Determinants of Diabetes in the Young (TEDDY) study
T1D, type 1 diabetes; FDR, first-degree relative (mother, father and/or siblings).
Separate multivariate models, including the variables listed above, were run for each country.
*US mothers only.
Use of supplements containing vitamin D or fatty acids
The overall proportion of women using supplemental vitamin D from either single or multivitamin preparations was 65 % (4768/7326) and of those, 62 % (2972/4768) used vitamin D supplements throughout the entire pregnancy. The remaining women (38 %) were using supplements on average for 24·7 (sd 10·2) weeks during pregnancy. In the USA, 81 % of the women reported using vitamin D-containing supplements while the proportion of women using supplements was lower in the European countries, with 71 % in Finland, 48 % in Sweden and 33 % in Germany (Table 4). For dietary supplements containing fatty acids, the overall proportion of users was 16 % (1161/7326) and of those, 53 % (616/1161) used the fatty acid supplements throughout the entire pregnancy. The mean duration for the remaining 47 % was 21·3 (sd 9·9) weeks. The highest proportion of fatty acid supplement users was found in Germany (32 %). In the USA, 24 % of the women used such supplements compared with less than 10 % in Finland and Sweden (Table 5).
Table 4 Adjusted sociodemographic predictors for use of supplements containing vitamin D during pregnancy, by country: The Environmental Determinants of Diabetes in the Young (TEDDY) study
MVM, multivitamin/mineral.
Separate multivariate models, including the variables listed above, were run for each country.
*US mothers only.
Table 5 Adjusted sociodemographic predictors for use of supplements containing fatty acids during pregnancy, by country: The Environmental Determinants of Diabetes in the Young (TEDDY) study
MVM, multivitamin/mineral.
Separate multivariate models, including the variables listed above, were run for each country.
*US mothers only.
The prevalence of vitamin D supplement use during pregnancy was relatively stable through the study screening years (2004–2010), except that it increased from 63 % to 79 % in Finland (P < 0·0001; Fig. 1). Meanwhile, consumption of fatty acid supplements grew in all countries during this 5-year period (P < 0·0001). The greatest change was seen in the USA and Germany, with an increase in supplement use by 60 %.
Fig. 1 Trends in reported intake of dietary supplements containing vitamin D (
$$$$
) and fatty acids (
$$$$
) during pregnancy between 2004 and 2010, by country: The Environmental Determinants of Diabetes in the Young (TEDDY) study
Predictors of supplements containing vitamin D during pregnancy
Being pregnant with the first child was a common predictor for use of vitamin D-containing supplements in all TEDDY countries (Table 4). Higher education in the USA and Sweden, but not in Finland and Germany, was a predictor for vitamin D use. Higher maternal age (≥30·0 years) was also a predictor for vitamin D supplement use in the USA and Sweden, but not in Germany; and was a predictor of less use in Finland (≥35·0 years). Women in Sweden with a pre-pregnancy BMI ≥ 25·0 kg/m2 were less likely to use vitamin D supplements. Women in the USA, Finland and Germany who smoked during pregnancy were less likely to use vitamin D supplements, while alcohol consumption during pregnancy was not associated with the use of vitamin D supplements. In the USA, women with race/ethnicity other than non-Hispanic white were less likely to use vitamin D supplements.
Predictors of supplements containing fatty acids during pregnancy
Older maternal age, ≥30·0 years in the USA and Germany and ≥35·0 years in Sweden, was associated with using supplements containing fatty acids (Table 5). Higher maternal education was associated with fatty acid supplements use in the USA only. Women pregnant with the first child or with higher maternal age were more likely to use dietary supplements containing fatty acids, except in Finland. Smoking was a predictor of less use in the USA and Germany but not in Finland and Sweden. Women with BMI ≥ 25·0 kg/m2 in the USA and Finland were less likely to use fatty acid supplements. Birth year of the child was associated with a growing prevalence of fatty acid supplement use in all countries. There was no difference in use by race/ethnicity among the US women.
Discussion
To the best of our knowledge, the current study is the first international prospective cohort study presenting data on maternal dietary supplement use from four countries. High prevalence of any dietary supplement use, ranging from 87 % in Finland to 96 % in the USA, was observed in pregnant women participating in the TEDDY study. Women who were pregnant with their first child were more likely to take supplements. In both the USA and Sweden, supplement users were more likely to have a higher education. Younger women (<25·0 years) were less likely to use any supplements during their pregnancy in all countries except in Germany. The association between demographic and lifestyle factors and dietary supplement use during pregnancy observed in the TEDDY population was consistent with the literature(Reference Haugen, Brantsæter and Alexander1, Reference Arkkola, Uusitalo and Pietikäinen9, Reference Brekke and Ludvigsson13, Reference Marjamäki, Niinistö and Kenward14).
In the present study, supplement use was self-reported by mothers at months 3 to 4 postpartum. The questionnaires were checked by trained study personnel for completeness during the first clinic visit. Self-reported supplement use may be associated with both over- or under-reporting, but studies on dietary supplement use during pregnancy have reported a high correlation between biomarker concentrations and intake estimated by self-reported methods(Reference Dror, King and Durand2, Reference Brantsæter, Haugen and Hagve3, Reference Burton, Wilson and Gillies21).
A healthy pre-pregnancy BMI has often been associated with maternal supplement use, but we did not see a clear association across countries in our analysis. One reason may be due to different cut-off points. We used the current WHO classification without differentiating between overweight and obesity(20). Other studies have used different cut-off points, often in four levels, that define underweight and normal weight slightly differently and separate overweight (BMI = 25·0–30·0 kg/m2) from obese (BMI > 30·0 kg/m2)(Reference Haugen, Brantsæter and Alexander1, Reference Arkkola, Uusitalo and Pietikäinen9, Reference Marjamäki, Niinistö and Kenward14, Reference Brustad, Braaten and Lund22). Our results showed that overweight women in Sweden and Germany were less likely to use dietary supplements and overweight women in the USA and Finland were less likely to use supplements containing fatty acids.
One of the few recent studies on maternal supplement use and sociodemographic factors from the USA reports that iron supplementation is associated with ethnicity(Reference Cogswell, Kettel-Khan and Ramakrishnan23). We did not observe differences regarding race/ethnicity when looking at any supplement use. This may be due to the definition of supplement use, although most of the prenatal multivitamins contain iron. Our description of any dietary supplement use is very broad, it may contain supplement use for health-seeking reasons (enhance the diet) and for medical reasons (e.g. anaemia). We do not have information about the reason why women use dietary supplements and are therefore not able to separate these behaviours. However, when looking at vitamin D-containing supplements, women with race/ethnicity other than non-Hispanic white were less likely to use these supplements.
The variable maternal education only affected women in the USA and Sweden. It has been implied that a higher education level gives a greater awareness of the role of nutrition in good health(Reference Foote, Murphy and Wilkens24, Reference Conner, Kirk and Cade25). Factors such as being pregnant with the first child and higher maternal age may also indicate higher awareness regarding possible mechanisms in diet-related health. In our study, the use of supplements containing fatty acids may give a better picture of a health-seeking behaviour during pregnancy. An adequate intake of DHA in pregnant women is critical to development of the fetal brain in the third trimester(Reference Zeisel26), and has also been linked to reduced risk of T1D in the offspring(Reference Stene, Ulriksen and Magnus4). The recommended DHA intake should preferably come from consumption of one or two fish meals per week or a dietary supplement(Reference Koletzko, Cetin and Brenna27). However, despite higher needs during pregnancy, women often decrease fish consumption due to warnings about contaminants such as methyl mercury and dioxins. Reduced or altered fish consumption together with low frequency of fatty acid supplementation may lead to insufficient exposure to long-chain n-3 fatty acids in utero (Reference Koletzko, Cetin and Brenna27). The use of fatty acid supplementation during pregnancy was not common in the TEDDY population, with less than 10 % in Finland and Sweden but higher in the USA (24 %) and Germany (32 %). In Norway, a Nordic country with a long-standing tradition of cod-liver oil use, the prevalence of fatty acid supplement use was 59 % among pregnant women(Reference Haugen, Brantsæter and Alexander1). The lower prevalence in TEDDY could be compared with another Nordic country, Denmark, where only 4 % of women reported use of fish oil formulations during pregnancy(Reference Olsen, Mikkelsen and Knudsen28). The use of fatty acid supplementation has increased in all TEDDY countries. Birth year of the child was a factor that was significant across all countries. The later the child was born during the TEDDY screening period, the more likely it was that the mother used fatty acid supplements. This could reflect different trends in the prenatal supplement markets, but could also be due to revised national recommendations.
There are very few studies on prevalence of supplement use during pregnancy in the USA, but in a study on pregnant women in California during 2006–2008, 89 % of the women reported using dietary supplements(Reference Dror, King and Durand2). More studies from Europe have presented data on maternal supplement use. In the DIPP study in 1998–2000, 85 % of the women reported taking dietary supplements(Reference Arkkola, Uusitalo and Pietikäinen9). In the All Babies in Southeast Sweden (ABIS) study in Sweden, 56 % of the women took some type of dietary supplement during pregnancy in 1997–1999(Reference Brekke and Ludvigsson13); this can be compared with, almost 10 years later, the 89 % of Swedish women in TEDDY who reported any supplement use. The high prevalence of supplement use in all TEDDY countries may be attributed to the recommendations on supplementation during pregnancy. The folic acid recommendation of 400 μg/d before getting pregnant and for the first trimester is given in all countries. Most countries recommend iron supplementation if the status is too low, often during the second half of the pregnancy. In the USA, health-care providers recommend women to use a standard prenatal multivitamin/multimineral supplement throughout pregnancy and even before becoming pregnant(Reference Kaiser and Allen8). In Europe, there are variations in additional supplement recommendations and they have changed during the TEDDY study period. In Germany, prenatal iodine supplementation is recommended(29). Since 2008, both Germany and Sweden have clarified the benefits of eating fish during pregnancy(29, 30) in their national recommendations. Women who do not eat fish are recommended to eat 200 mg DHA/d during pregnancy. In Finland, pregnant women are currently recommended to take 10 μg of supplemental vitamin D daily throughout the year; before 2011, vitamin D supplements were recommended to be used only during winter months(31). Table 6 summarizes the country-specific recommendations regarding dietary supplementation during pregnancy. Country-specific recommendations on vitamin D and fatty acids were reflected in our data. Countries with vitamin D recommendations had higher prevalence of supplement use than countries without specific recommendations.
Table 6 Country-specific dietary supplement recommendations for pregnant women (TEDDY screening period 2004–2010)
TEDDY, The Environmental Determinants of Diabetes in the Young.
*A prenatal multivitamin/multimineral supplement is recommended for women with iron-deficiency anaemia, poor-quality diets, vegans, vegetarians, smokers and women carrying two or more fetuses.
Our findings may not be readily generalized to the general population due to our selection criterion of high-risk HLA genotypes representing approximately 5 % of the population, but the results are important and comparable with other longitudinal studies.
Conclusion
The present study captured a high prevalence of supplement use during pregnancy in the USA, Sweden, Finland and Germany. Being pregnant with the first child was a strong predictor for any supplement use in all countries. Higher education, low maternal age, BMI ≥ 25·0 kg/m2 and smoking during pregnancy were additional predictors but not consistently across all countries. The use of vitamin D-containing supplements was more common in countries with pertinent national recommendations.
Acknowledgements
Sources of funding: The TEDDY study was funded by grant numbers DK 63829, 63861, 63821, 63865, 63863, 63836, 63790 and UC4DK095300 and contract number HHSN267200700014C from the National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK), the National Institute of Allergy and Infectious Diseases (NIAID), the National Institute of Child Health and Human Development (NICHD), the National Institute of Environmental Health Sciences (NIEHS), the Juvenile Diabetes Research Foundation (JDRF) and the Centers for Disease Control and Prevention (CDC). Conflicts of interest: The authors declare no conflict of interest. Authors’ contributions: C.A.A. wrote the manuscript and analysed the data; K.V. did the statistical analysis; J.Y. and U.U. assisted with drafting the manuscript and critically reviewed the manuscript; K.H., G.J. and A.R. critically reviewed the manuscript; L.B. was responsible for data handling; and S.V. and J.N. designed the study and critically reviewed the manuscript; J.M.N. and S.M.V. share last authorship. Acknowledgements: The participation of all families in the TEDDY study is gratefully acknowledged.
The TEDDY Study Group
Colorado Clinical Center
Marian Rewers, MD, PhD, Principal Investigator1,4,6,10,11; Katherine Barriga12; Kimberly Bautista12; Judith Baxter9,12,15; George Eisenbarth, MD, PhD; Nicole Frank2; Patricia Gesualdo2,6,12,14,15; Michelle Hoffman12,13,14; Lisa Ide; Rachel Karban12; Edwin Liu, MD13; Jill Norris, PhD2,12; Kathleen Waugh7,12,15; Adela Samper-Imaz; Andrea Steck, MD (University of Colorado, Anschutz Medical Campus, Barbara Davis Center for Childhood Diabetes).
Georgia/Florida Clinical Center
Jin-Xiong She, PhD, Principal Investigatora,1,3,4,11; Desmond Schatz, MDb,4,5,7,8; Diane Hopkinsa,12; Leigh Steeda,12,13,14,15; Jamie Thomasb,6,12; Katherine Silvisa,2; Michael Haller, MDb,14; Meena Shankarb,2; Kim Englisha; Richard McIndoe, PhDa; Haitao Liu, MDc; John Nechtmanc; Ashok Sharmaa; Joshua Williamsa; Gabriela Foghisa; Stephen W. Anderson, MDd (aGeorgia Health Sciences University; bUniversity of Florida; cJinfiniti Biosciences LLC, Augusta, GA; dPediatric Endocrine Associates, Atlanta, GA).
Germany Clinical Center
Anette G. Ziegler MD, Principal Investigatora,1,3,4,11; Alexandra Achenbach, PhDb,12; Andreas Beyerlein, PhDa,2; Ezio Bonifacio, PhDb,5; Nadine Bruckmeiera; Melanie Bunka; Vanessa Dietricha; Anna Huppert, MDa; Minna Harsunen, MDa; Lydia Hennebergera,2,12; Michael Hummel, MDa,13; Sandra Hummel, PhDa,2; Gesa Joslowskic,2; Mathilde Kersting, PhDc,2; Annette Knopffa,7; Nadja Kochera; Sibylle Koletzko, MDd,13; Miriam Krasmann, MDa; Stephanie Krausea; Lorenz Lachmanna; Claudia Matzkea; Claudia Peplowb,12; Maren Pflüger, PhDa,6; Claudia Rammingera; Christiane Rieda; Roswith Roth, PhDa,9; Julia Schenkela; Marlon Scholza; Joanna Stocka; Elisabeth Straussa; Alexandra Thalmeiera; Katja Voita; Katharina Warncke, MDa,14; Christiane Winkler, PhDa,2,12,15; Anja Woscha (aForschergruppe Diabetes eV at Helmholtz Zentrum München; bCenter for Regenerative Therapies, TU Dresden; cResearch Institute for Child Nutrition, Dortmund; dDr. von Hauner Children's Hospital, Department of Gastroenterology, Ludwig Maximillians University Munich).
Finland Clinical Center
Olli G. Simell, MD, PhD, Principal Investigatora,b,1,4,11,13; Heikki Hyöty, MD, PhDc,d,6; Jorma Ilonen, MD, PhDa,e,3; Mikael Knip, MD, PhDc,d; Maria Lonnrot, MD, PhDc,d,6; Elina Mantymakia,b; Juha Mykkänen, PhDa,b,3; Kirsti Nanto-Salonen, MD, PhDa,b,12; Tiina Niininenc,d; Mia Nyblomc,d; Anne Riikonenc,d,2; Minna Romoa,b; Barbara Simella,b,12,15; Tuula Simell, PhDa,b,9,12; Ville Simella,b,13; Maija Sjöberga,b,12,14; Aino Steniusf,g; Eeva Varjonena,b; Riitta Veijola, MD, PhDf,g; Suvi M. Virtanen, MD, PhDc,d,h,2 (aUniversity of Turku; bTurku University Hospital; cUniversity of Tampere; dTampere University Hospital; eUniversity of Kuopio; fUniversity of Oulu; gOulu University Hospital; hNational Institute for Health and Welfare, Finland).
Sweden Clinical Center
Åke Lernmark, PhD, Principal Investigator1,3,4,8,10,11,15; Daniel Agardh, MD, PhD13; Peter Almgren; Eva Andersson; Carin Andrén-Aronsson2,13; Maria Ask; Ulla-Marie Karlsson; Corrado Cilio, MD, PhD5; Jenny Bremer; Emilie Ericson-Hallström; Thomas Gard; Joanna Gerardsson; Gertie Hansson12,14; Monica Hansen; Susanne Hyberg; Rasmus Håkansson; Fredrik Johansen; Linda Jonsson; Helena Larsson, MD, PhD14; Barbro Lernmark, PhD9,12; Maria Markan; Theodosia Massadakis; Jessica Melin; Maria Månsson-Martinez; Anita Nilsson; Kobra Rahmati; Monica Sedig Järvirova; Sara Sibthorpe; Birgitta Sjöberg; Carina Törn, PhD3,15; Anne Wallin; Åsa Wimar; Sofie Åberg (Lund University).
Washington Clinical Center
William A. Hagopian, MD, PhD, Principal Investigator1,3,4,5,6,7,11,13,14; Xiang Yan, MD; Michael Killian6,7,12,13; Claire Cowen Crouch12,14,15; Kristen M. Hay2; Stephen Ayres; Carissa Adams; Brandi Bratrude; David Coughlin; Greer Fowler; Czarina Franco; Carla Hammar; Diana Heaney; Patrick Marcus; Arlene Meyer; Denise Mulenga; Elizabeth Scott; Jennifer Skidmore; Joshua Stabbert; Viktoria Stepitova; Nancy Williams (Pacific Northwest Diabetes Research Institute).
Pennsylvania Satellite Center
Dorothy Becker, MD; Margaret Franciscus12; MaryEllen Dalmagro-Elias2; Ashi Daftary, MD (Children's Hospital of Pittsburgh, University of Pittsburgh Medical Center).
Data Coordinating Center
Jeffrey P. Krischer, PhD, Principal Investigator1,4,5,10,11; Michael Abbondondolo; Lori Ballard3,9,14,15; Rasheedah Brown12,15; Brant Burkhardt, PhD5,6; David Cuthbertson; Christopher Eberhard; Steven Fiske; Veena Gowda; David Hadley, PhD3,13; Hye-Seung Lee, PhD3,6,13,15; Shu Liu; Kristian Lynch, PhD9; Jamie Malloy; Cristina McCarthy12,15; Wendy McLeod2,5,6,13,15; Laura Smith, PhD9; Susan Smith12,15; Ulla Uusitalo, PhD2,15; Kendra Vehik, PhD4,5,9,14,15; Earnest Washington; Jimin Yang, PhD, RD2,15 (University of South Florida).
Project Scientist
Beena Akolkar, PhD1,3,4,5,7,10,11 (National Institutes of Diabetes and Digestive and Kidney Diseases).
Other contributors
Kasia Bourcier, PhDa,5; Thomas Briese, PhDb,6,15; Henry Erlich, PhDc,3; Suzanne Bennett Johnson, PhDd,9,12; Steve Oberste, PhDe,6 (aNational Institutes of Allergy and Infectious Diseases; bColumbia University; cChildren's Hospital Oakland Research Institute; dFlorida State University; eCenters for Disease Control and Prevention).
Committees
1Ancillary Studies; 2Diet; 3Genetics; 4Human Subjects/Publicity/Publications; 5Immune Markers; 6Infectious Agents; 7Laboratory Implementation; 8Maternal Studies; 9Psychosocial; 10Quality Assurance; 11Steering; 12Study Coordinators; 13Celiac Disease; 14Clinical Implementation; 15Quality Assurance Subcommittee on Data Quality.
Coding of dietary supplements in The Environmental Determinants of Diabetes in the Young (TEDDY) study
Single vitamins and minerals
• Vitamin D
• Vitamin C
• Probiotic
• Single fatty acid (e.g. DHA, EPA, γ-linolenic acid, dihomo-γ-linolenic acid, arachidonic acid)
• Calcium
• Vitamin B6
• Vitamin B12
• Folic acid
• Vitamin A
• Vitamin E
• Iron
• Niacin
• Zinc
• Magnesium
• Potassium
• Choline
• Vitamin B1
• Vitamin B2
• Biotin
• Pantothenic acid
• Selenium
• Chromium
• Fluorine
• β-Carotene
• Iodine
• Copper
• Antioxidants (non-vitamin/mineral; e.g. lycopene, coenzyme Q10)
Multivitamins/minerals
• Multivitamins/minerals with probiotic (no vitamin D, no fish oil/fatty acids)
• Multivitamins/minerals containing vitamin D (no probiotic, no fish oil/fatty acids)
• Multivitamins/minerals (no vitamin D, no probiotic, no fish oil/fatty acids)
• Multivitamins/minerals with fish oil/fatty acids (no vitamin D, no probiotic)
• Multivitamins/minerals with fish oil/fatty acids containing vitamin D (no probiotic)
• Multivitamins/minerals with probiotic and fish oil/fatty acids and containing vitamin D
• Multivitamins/minerals with probiotic containing vitamin D (no fish oil/fatty acids)
• Multivitamins/minerals with probiotic and fish oil/fatty acids (no vitamin D)
• Antioxidants (products with several non-vitamin/mineral antioxidants, e.g. combination of lycopene, coenzyme Q10, etc.)
• Mixture of fatty acids without vitamin/mineral (no probiotic, no vitamin D)
