No association between long-chain n-3 fatty acid intake during pregnancy and risk of type 1 diabetes in offspring in two large Scandinavian pregnancy cohorts.

AIMS/HYPOTHESIS: The aim of this study was to investigate whether higher dietary intake of marine n-3 fatty acids during pregnancy is associated with a lower risk of type 1 diabetes in children. METHODS: The Danish National Birth Cohort (DNBC) and the Norwegian Mother, Father and Child Cohort Study (MoBa) together include 153,843 mother-child pairs with prospectively collected data on eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) intake during pregnancy from validated food frequency questionnaires. Type 1 diabetes diagnosis in children (n=634) was ascertained from national diabetes registries. RESULTS: There was no association between the sum of EPA and DHA intake during pregnancy and risk of type 1 diabetes in offspring (pooled HR per g/day of intake: 1.00, 95% CI 0.88, 1.14), with consistent results for both the MoBa and the DNBC. Robustness analyses gave very similar results. CONCLUSIONS/INTERPRETATION: Initiation of a trial of EPA and DHA during pregnancy to prevent type 1 diabetes in offspring should not be prioritised.

An SMS chatbot digital educational program to increase healthy eating behaviors in adolescence: A multifactorial randomized controlled trial among 7,890 participants in the Danish National Birth Cohort.

BACKGROUND: Few cost-effective strategies to shift dietary habits of populations in a healthier direction have been identified. We examined if participating in a chatbot health education program transmitted by Short Messages Service ("SMS-program") could improve adolescent dietary behaviors and body weight trajectories. We also explored possible added effects of maternal or peer involvement. METHODS AND FINDINGS: We conducted a randomized controlled trial (RCT) among adolescents from the Danish National Birth Cohort (DNBC). Eligible were adolescents who during 2015 to 2016 at age 14 years had completed a questionnaire assessing height, weight, and dietary habits. Two thirds were offered participation in an SMS-program, whereas 1/3 ("non-SMS group") received no offer. The SMS program aimed to improve 3 key dietary intake behaviors: sugar-sweetened beverages (SSBs), fruit and vegetables (FV), and fish. The offered programs had 3 factorially randomized schemes; the aims of these were to test effect of asking the mother or a friend to also participate in the health promotion program, and to test the effect of a 4-week individually tailored SMS program against the full 12-week SMS program targeting all 3 dietary factors. Height and weight and intakes of SSB, FV, and fish were assessed twice by a smartphone-based abbreviated dietary questionnaire completed at 6 months (m) and 18 m follow-up. Main outcome measures were (1) body mass index (BMI) z-score; and (2) an abbreviated Healthy Eating Index (mini-HEI, 1 m window, as mean of z-scores for SSB, FV, and fish). Among the 7,890 randomized adolescents, 5,260 were assigned to any SMS program; 63% (3,338) joined the offered program. Among the 7,890 randomized, 74% (5,853) and 68% (5,370) responded to follow-ups at 6 m and 18 m, respectively. Effects were estimated by intention-to-treat (ITT) analyses and inverse probability weighted per-protocol (IPW-PP) analyses excluding adolescents who did not join the program. Mean (standard deviation (SD)) mini-HEI at baseline, 6 m and 18 m was -0.01 (0.64), 0.01 (0.59), and -0.01 (0.59), respectively. In ITT-analyses, no effects were observed, at any time point, in those who had received any SMS program compared to the non-SMS group, on BMI z-score (6 m: -0.010 [95% confidence interval (CI) -0.035, 0.015]; p = 0.442, 18 m: 0.002 [95% CI -0.029, 0.033]; p = 0.901) or mini-HEI (6 m: 0.016 [95% CI -0.011, 0.043]; p = 0.253, 18m: -0.016 [95% CI -0.045, 0.013]; p = 0.286). In IPW-PP analyses, at 6 m, a small decrease in BMI z-score (-0.030 [95% CI -0.057, -0.003]; p = 0.032) was observed, whereas no significant effect was observed in mini-HEI (0.027 [95% CI -0.002, 0.056]; p = 0.072), among those who had received any SMS program compared to the non-SMS group. At 18 m, no associations were observed (BMI z-score: -0.006 [95% CI -0.039, 0.027]; p = 0.724, and mini-HEI: -0.005 [95% CI -0.036, 0.026]; p = 0.755). The main limitations of the study were that DNBC participants, though derived from the general population, tend to have higher socioeconomic status than average, and that outcome measures were self-reported. CONCLUSIONS: In this study, a chatbot health education program delivered through an SMS program had no effect on dietary habits or weight trajectories in ITT analyses. However, IPW-PP-analyses, based on those 63% who had joined the offered SMS program, suggested modest improvements in weight development at 6 m, which had faded at 18 m. Future research should focus on developing gender-specific messaging programs including "booster" messages to obtain sustained engagement. CLINICAL TRIAL REGISTRATION: ClinicalTrials.gov Identifier: NCT02809196 https://clinicaltrials.gov/study/NCT02809196.

Association of common maternal infections with birth outcomes: a multinational cohort study.

PURPOSE: It is unclear whether common maternal infections during pregnancy are risk factors for adverse birth outcomes. We assessed the association between self-reported infections during pregnancy with preterm birth and small-for-gestational-age (SGA) in an international cohort consortium. METHODS: Data on 120,507 pregnant women were obtained from six population-based birth cohorts in Australia, Denmark, Israel, Norway, the UK and the USA. Self-reported common infections during pregnancy included influenza-like illness, common cold, any respiratory tract infection, vaginal thrush, vaginal infections, cystitis, urinary tract infection, and the symptoms fever and diarrhoea. Birth outcomes included preterm birth, low birth weight and SGA. Associations between maternal infections and birth outcomes were first assessed using Poisson regression in each cohort and then pooled using random-effect meta-analysis. Risk ratios (RR) and 95% confidence intervals (CI) were calculated, adjusted for potential confounders. RESULTS: Vaginal infections (pooled RR, 1.10; 95% CI, 1.02-1.20) and urinary tract infections (pooled RR, 1.17; 95% CI, 1.09-1.26) during pregnancy were associated with higher risk of preterm birth. Similar associations with low birth weight were also observed for these two infections. Fever during pregnancy was associated with higher risk of SGA (pooled RR, 1.07; 95% CI, 1.02-1.12). No other significant associations were observed between maternal infections/symptoms and birth outcomes. CONCLUSION: Vaginal infections and urinary infections during pregnancy were associated with a small increased risk of preterm birth and low birth weight, whereas fever was associated with SGA. These findings require confirmation in future studies with laboratory-confirmed infection diagnosis.

Adherence to different forms of plant-based diets and pregnancy outcomes in the Danish National Birth Cohort: A prospective observational study.

INTRODUCTION: The number of people adhering to plant-based diets has been increasing dramatically in recent years, fueled by both environmental and animal welfare concerns. Beneficial or possible adverse consequences of such diets, particularly the most restrictive forms during pregnancy, have been minimally explored. The aim of this prospective observational study was to examine associations between different forms of plant-based diets during pregnancy with birth outcomes and pregnancy complications. MATERIAL AND METHODS: The Danish National Birth Cohort included 100 413 pregnancies to 91 381 women in 1996-2002. The population consisted of 66 738 pregnancies, about which sufficient dietary data were available and included in the study. Dietary and supplemental intake was assessed by Food Frequency Questionnaire in gestational week 25 and women were characterized as fish/poultry-vegetarians, lacto/ovo-vegetarians, vegans or omnivorous, based on their self-report in gestational week 30. Main outcome measures were pregnancy and birth complications, birthweight and small for gestational age. RESULTS: A total of 98.7% (n = 65 872) of participants were defined as omnivorous, whereas 1.0% (n = 666), 0.3% (n = 183) and 0.03% (n = 18) identified themselves as fish/poultry vegetarians, lacto/ovo-vegetarians or vegans, respectively. Protein intake was lower among lacto/ovo-vegetarians (13.3%) and vegans (10.4%) than among omnivorous participants (15.4%). Intake of micronutrients was also considerably lower among vegans, but when dietary supplements were taken into consideration, no major differences were observed. Compared with omnivorous mothers, vegans had a higher prevalence of preeclampsia and their offspring had on average -240 g (95% confidence interval -450 to -30) lower birthweight. CONCLUSIONS: The women reporting that they adhered to vegan diets during pregnancy had offspring with lower mean birthweight and higher risk of preeclampsia compared with omnivorous mothers. Low protein intake might be one plausible explanation for the observed association with birthweight.

Maternal intake of folate and folic acid during pregnancy and pubertal timing in girls and boys: A population-based cohort study.

BACKGROUND: Folate is essential for normal foetal development as it plays an important role for gene expression during different periods of foetal development. Thus, prenatal exposure to folate may have a programming effect on pubertal timing. OBJECTIVES: To study the association between maternal intake of folate during pregnancy and pubertal timing in girls and boys. METHODS: We studied 6585 girls and 6326 boys from a Danish population-based Puberty Cohort, 2000-2021. Information on maternal intake of folate from diet and folic acid from supplements was obtained from a food-frequency questionnaire in mid-pregnancy, and total folate was calculated as dietary folate equivalents. Information on age at menarche in girls, age at first ejaculation and voice break in boys, and Tanner stages, acne and axillary hair in both girls and boys was obtained every 6 months throughout puberty. We estimated mean monthly differences according to exposure groups for each pubertal milestone in addition to a combined estimate for the average age at attaining all pubertal milestones using multivariable interval-censored regression models. Total folate was analysed in quintiles, continuous and as restricted cubic splines. RESULTS: Maternal intake of total folate in mid-pregnancy was not associated with pubertal timing in girls (combined estimate for overall pubertal timing per standard deviation (SD 325 µg/day) decrease in maternal intake of total folate: -0.14 months (95% confidence interval [CI] -0.51, 0.22)). Boys had slightly later overall pubertal timing per standard deviation (SD 325 µg/day) decrease in maternal intake of total folate (combined estimate: 0.40 months, 95% CI 0.01, 0.72). Spline plots supported these findings. CONCLUSIONS: Prenatal exposure to low maternal intake of total folate in mid-pregnancy was not associated with pubertal timing in girls but associated with slightly later pubertal timing in boys. This minor delay is likely not of clinical importance.

Comprehensive Evaluation of Blood Plasma and Serum Sample Preparations for HRMS-Based Chemical Exposomics: Overlaps and Specificities.

Sample preparation of biological samples can have a substantial impact on the coverage of small molecules detectable using liquid chromatography-high-resolution mass spectrometry (LC-HRMS). This initial step is particularly critical for the detection of externally derived chemicals and their metabolites (internal chemical exposome) generally present at trace levels. Hence, our objective was to investigate how blood sample preparation methods affect the detection of low-abundant chemicals and to propose alternative methods to improve the coverage of the internal chemical exposome. We performed a comprehensive evaluation of 12 sample preparation methods (SPM) using phospholipid and protein removal plates (PLR), solid phase extraction plates (SPE), supported liquid extraction cartridge (SLE), and conventionally used protein precipitation (PPT). We implemented new quantitative and qualitative criteria for nontargeted analyses (detection frequency, recoveries, repeatability, matrix effect, low-level spiking significance, method detection limits, throughput, and ease of use) to amply characterize these SPM in a step-by-step-type approach. As a final step, PPT and one PLR plate were applied to cohort plasma and serum samples injected in triplicate to monitor batch repeatability, and annotation was performed on the related data sets to compare the respective impacts of these SPM. We demonstrate that sample preparation significantly affects both the range of observable compounds and the level at which they can be observed (only 43%-54% of total features are overlapping between the two SPM). We propose to use PPT and PLR on the same samples by implementing a simple analytical workflow as their complementarity would allow the broadening of the visible chemical space.

Parental occupational exposure to pesticides, animals and organic dust and risk of childhood leukemia and central nervous system tumors: Findings from the International Childhood Cancer Cohort Consortium (I4C).

Parental occupational exposures to pesticides, animals and organic dust have been associated with an increased risk of childhood cancer based mostly on case-control studies. We prospectively evaluated parental occupational exposures and risk of childhood leukemia and central nervous system (CNS) tumors in the International Childhood Cancer Cohort Consortium. We pooled data on 329,658 participants from birth cohorts in five countries (Australia, Denmark, Israel, Norway and United Kingdom). Parental occupational exposures during pregnancy were estimated by linking International Standard Classification of Occupations-1988 job codes to the ALOHA+ job exposure matrix. Risk of childhood (<15 years) acute lymphoblastic leukemia (ALL; n = 129), acute myeloid leukemia (AML; n = 31) and CNS tumors (n = 158) was estimated using Cox proportional hazards models to generate hazard ratios (HR) and 95% confidence intervals (CI). Paternal exposures to pesticides and animals were associated with increased risk of childhood AML (herbicides HR = 3.22, 95% CI = 0.97-10.68; insecticides HR = 2.86, 95% CI = 0.99-8.23; animals HR = 3.89, 95% CI = 1.18-12.90), but not ALL or CNS tumors. Paternal exposure to organic dust was positively associated with AML (HR = 2.38 95% CI = 1.12-5.07), inversely associated with ALL (HR = 0.55, 95% CI = 0.31-0.99) and not associated with CNS tumors. Low exposure prevalence precluded evaluation of maternal pesticide and animal exposures; we observed no significant associations with organic dust exposure. This first prospective analysis of pooled birth cohorts and parental occupational exposures provides evidence for paternal agricultural exposures as childhood AML risk factors. The different risks for childhood ALL associated with maternal and paternal organic dust exposures should be investigated further.

Maternal Infection in Pregnancy and Childhood Leukemia: A Systematic Review and Meta-analysis.

OBJECTIVE: To summarize the published evidence regarding the association between maternal infection during pregnancy and childhood leukemia. STUDY DESIGN: In this systematic review and meta-analysis (PROSPERO number, CRD42018087289), we searched PubMed and Embase to identify relevant studies. We included human studies that reported associations of at least one measure of maternal infection during pregnancy with acute lymphoblastic leukemia (ALL) or all childhood leukemias in the offspring. One reviewer extracted the data first using a standardized form, and the second reviewer independently checked the data for accuracy. Two reviewers used the Newcastle-Ottawa Scale to assess the quality of included studies. We conducted random effects meta-analyses to pool the ORs of specific type of infection on ALL and childhood leukemia. RESULTS: This review included 20 studies (ALL, n = 15; childhood leukemia, n = 14) reported in 32 articles. Most (>65%) included studies reported a positive association between infection variables and ALL or childhood leukemia. Among specific types of infection, we found that influenza during pregnancy was associated with higher risk of ALL (pooled OR, 3.64; 95% CI, 1.34-9.90) and childhood leukemia (pooled OR, 1.77; 95% CI, 1.01-3.11). Varicella (pooled OR, 10.19; 95% CI, 1.98-52.39) and rubella (pooled OR, 2.79; 95% CI, 1.16-6.71) infections were also associated with higher childhood leukemia risk. CONCLUSIONS: Our findings suggest that maternal infection during pregnancy may be associated with a higher risk of childhood leukemia.

Sodium Intake during Pregnancy, but Not Other Diet Recommendations Aimed at Preventing Cardiovascular Disease, Is Positively Related to Risk of Hypertensive Disorders of Pregnancy.

BACKGROUND: The role of diet on hypertensive disorders of pregnancy (HDPs), including preeclampsia and gestational hypertension (GHTN), remains unclear. OBJECTIVES: We evaluated whether adherence during pregnancy to dietary recommendations that reduce cardiovascular disease (CVD) in the general population is related to the risk of HDPs. METHODS: We followed 66,651 singleton pregnancies from 62,774 women participating in the Danish National Birth Cohort. Diet was assessed during week of gestation 25 with an FFQ from which we created 2 dietary pattern scores: 1) AHA, based on the diet recommendations from the AHA 2020 Strategic Impact Goals; and 2) the Dietary Approaches to Stop Hypertension (DASH) diet. Cases of HDPs were identified through linkage with the Danish National Patient Registry. RRs and 95% CIs of HDPs were estimated by increasing quintiles of adherence to the AHA and DASH scores using log-Poisson regression models with generalized estimating equations-to account for repeated pregnancies per woman-while adjusting for potential confounders. RESULTS: We identified 1809 cases of HDPs: n = 1310 preeclampsia (n = 300 severe preeclampsia) and n = 499 cases of GHTN. Greater adherence to AHA or DASH scores was not related to the risk of HDPs. However, when each component of the scores was separately evaluated, there were positive linear relations of sodium intake with HDPs (P-linearity < 0.01). Women with the highest sodium intake [median 3.70 g/d (range: 3.52, 7.52 g/d)] had 54% (95% CI:16%, 104%) higher risk of GHTN and 20% (95% CI:1%, 42%) higher risk of preeclampsia than women with the lowest intake [median 2.60 g/d (range: 0.83, 2.79 g/d)]. In addition, intake of whole grains was positively related to the risk of GHTN but not to preeclampsia ( P-heterogeneity = 0.002). CONCLUSION: Sodium intake during pregnancy, but no other diet recommendations to prevent CVD among nonpregnant adults, is positively related to the occurrence of HDPs among pregnant Danish women.

Nut Consumption and Renal Function Among Women With a History of Gestational Diabetes.

OBJECTIVE: Nut intake has been associated with reduced cardiometabolic risk, but few studies have examined its association with renal function. We examined associations between nut intake and renal function among women with previous gestational diabetes mellitus (GDM), a population with an increased risk for renal dysfunction. DESIGN AND METHODS: This study included 607 women with a history of GDM who participated in the Diabetes & Women's Health Study (2012-2014) follow-up clinical examination in Denmark. At the clinic, biospecimens were collected, and habitual intake of nuts (9 types) in the past year was assessed using a food frequency questionnaire. A total of 330 women free of major chronic diseases were included in the analysis. Total nut intake was classified as none (≤1 serving/month), monthly (2-3 servings/month), weekly (1-6 servings/week), and daily (≥1 serving/day). One serving was defined as 28 g. Renal function markers included estimated glomerular rate (eGFR) and urinary albumin-to-creatinine ratio (UACR), calculated based on plasma creatinine (mg/dL), and urinary albumin (mg/L), and creatinine (mg/dL) measurements, respectively. We estimated percent differences with 95% confidence intervals for each outcome by nut intake, adjusted for current body mass index, age, physical activity, energy intake, alcohol consumption, and vegetables intake. RESULTS: We observed a nonlinear association between total nut intake and UACR with lowest UACR values among women with weekly intake. Compared to women with weekly intake (n = 222), the adjusted UACR values were higher by 86% [95% confidence interval: 15%, 202%], 24% [-1%, 54%], and 117% [22%, 288%] among women with no (n = 13), monthly (n = 86), and daily (n = 9) intake, respectively. Compared to weekly consumers, daily nut consumers also had 9% [0%, 19%] significantly higher eGFR values, but eGFR values were similar among women with no and monthly intake. CONCLUSION: Moderate nut consumption may be beneficial to kidney health among women with prior GDM.

The association between birth order and childhood leukemia may be modified by paternal age and birth weight. Pooled results from the International Childhood Cancer Cohort Consortium (I4C).

The "delayed infection hypothesis" states that a paucity of infections in early childhood may lead to higher risks of childhood leukemia (CL), especially acute lymphoblastic leukemia (ALL). Using prospectively collected data from six population-based birth cohorts we studied the association between birth order (a proxy for pathogen exposure) and CL. We explored whether other birth or parental characteristics modify this association. With 2.2 × 106 person-years of follow-up, 185 CL and 136 ALL cases were ascertained. In Cox proportional hazards models, increasing birth order (continuous) was inversely associated with CL and ALL; hazard ratios (HR) = 0.88, 95% confidence interval (CI): (0.77-0.99) and 0.85: (0.73-0.99), respectively. Being later-born was associated with similarly reduced hazards of CL and ALL compared to being first-born; HRs = 0.78: 95% CI: 0.58-1.05 and 0.73: 0.52-1.03, respectively. Successive birth orders were associated with decreased CL and ALL risks (P for trend 0.047 and 0.055, respectively). Multivariable adjustment somewhat attenuated the associations. We found statistically significant and borderline interactions between birth weight (p = 0.024) and paternal age (p = 0.067), respectively, in associations between being later-born and CL, with the lowest risk observed for children born at <3 kg with fathers aged 35+ (HR = 0.18, 95% CI: 0.06-0.50). Our study strengthens the theory that increasing birth order confers protection against CL and ALL risks, but suggests that this association may be modified among subsets of children with different characteristics, notably advanced paternal age and lower birth weight. It is unclear whether these findings can be explained solely by infectious exposures.

Correction: Mother's dietary quality during pregnancy and offspring's dietary quality in adolescence: Follow-up from a national birth cohort study of 19,582 mother-offspring pairs.

[This corrects the article DOI: 10.1371/journal.pmed.1002911.].

Mother's dietary quality during pregnancy and offspring's dietary quality in adolescence: Follow-up from a national birth cohort study of 19,582 mother-offspring pairs.

BACKGROUND: The Developmental Origins of Health and Disease (DOHaD) hypothesis postulates that exposures during early life, such as maternal dietary intake during pregnancy, may have a lifelong impact on the individual's susceptibility to diseases. The individual's own lifestyle habits are obviously an additional factor, but we have only limited knowledge regarding how it may interact with prenatal exposures in determining later disease. To gain further insight into these potentially complex relationships, we examined the longitudinal association between maternal diet quality during pregnancy and diet quality in early adolescence in a contemporary cohort. METHODS AND FINDINGS: From 1996 to 2003, the Danish National Birth Cohort (DNBC) was established. Women from across the country were enrolled, and dietary intake in midpregnancy was assessed concurrently with a 360-item food frequency questionnaire (FFQ) (https://www.dnbc.dk/-/media/arkiv/projekt-sites/dnbc/kodeboeger/dnbc-food-frequency-questionnaire/dnbc-food-frequency-questionnaire-pdf.pdf?la=en). During 2013-2018, dietary intake was assessed at age 14 years with a 150-item FFQ (https://www.dnbc.dk/-/media/arkiv/projekt-sites/dnbc/kodeboeger/ffq-14/dnbc-ffq-14-english-translation.pdf?la=en) in the DNBC children. Among the 19,582 mother-offspring pairs included in the analyses, the mean age (±standard deviation [SD]) was 30.7 (±4.1) years and 14.0 (±0.0) years for mothers and offspring, respectively. The majority of both mothers (67%) and offspring (76%) were classified as normal weight. For both questionnaires, a Healthy Eating Index (HEI) was developed as an indicator for diet quality based on current Danish Food-Based Dietary Guidelines (FBDG) including eight components: fruits and vegetables, fish, dietary fibres, red meat, saturated fatty acids (SFAs), sodium, sugar-sweetened beverages (SSBs), and added sugar. The HEI score was divided into quartiles; individuals in the highest quartile represented those with the most optimal diet. The maternal HEI score was correlated positively with offspring HEI score (Pearson r = 0.22, p < 0.001). A log-linear binomial model was used to estimate the relative risk of the offspring being in the highest quartile of HEI at age 14 years if the mother was ranked in quartile 4 during pregnancy. Results showed that offspring born to mothers who were in the highest HEI quartile during pregnancy were more likely themselves to be located in the highest HEI quartile at age 14 years (risk ratio [RR]: 2.1, 95% confidence interval [CI]: 2.0, 2.3, p < 0.001). Adjusting for maternal prepregnancy body mass index (BMI), parity, education, alcohol intake, physical activity, smoking, and breastfeeding, as well as offspring total energy intake and sex, did not influence the effect estimates. The limitations of our study include that some attrition bias towards more healthy participants was observed when comparing participants with nonparticipants. Bias in the FFQ method may also have resulted in underrepresentation of adolescents with poorer diet quality. CONCLUSIONS: In this study using data from a large national birth cohort, we observed that maternal diet quality during pregnancy was associated with diet quality of the offspring at age 14 years. These findings indicate the importance of separating early dietary exposures from later dietary exposures when studying dietary aetiologies of diseases postulated to have developmental origins such as, for instance, obesity or asthma in observational settings.

Fish Oil-Derived Fatty Acids in Pregnancy and Wheeze and Asthma in Offspring.

BACKGROUND: Reduced intake of n-3 long-chain polyunsaturated fatty acids (LCPUFAs) may be a contributing factor to the increasing prevalence of wheezing disorders. We assessed the effect of supplementation with n-3 LCPUFAs in pregnant women on the risk of persistent wheeze and asthma in their offspring. METHODS: We randomly assigned 736 pregnant women at 24 weeks of gestation to receive 2.4 g of n-3 LCPUFA (fish oil) or placebo (olive oil) per day. Their children formed the Copenhagen Prospective Studies on Asthma in Childhood2010 (COPSAC2010) cohort and were followed prospectively with extensive clinical phenotyping. Neither the investigators nor the participants were aware of group assignments during follow-up for the first 3 years of the children's lives, after which there was a 2-year follow-up period during which only the investigators were unaware of group assignments. The primary end point was persistent wheeze or asthma, and the secondary end points included lower respiratory tract infections, asthma exacerbations, eczema, and allergic sensitization. RESULTS: A total of 695 children were included in the trial, and 95.5% completed the 3-year, double-blind follow-up period. The risk of persistent wheeze or asthma in the treatment group was 16.9%, versus 23.7% in the control group (hazard ratio, 0.69; 95% confidence interval [CI], 0.49 to 0.97; P=0.035), corresponding to a relative reduction of 30.7%. Prespecified subgroup analyses suggested that the effect was strongest in the children of women whose blood levels of eicosapentaenoic acid and docosahexaenoic acid were in the lowest third of the trial population at randomization: 17.5% versus 34.1% (hazard ratio, 0.46; 95% CI, 0.25 to 0.83; P=0.011). Analyses of secondary end points showed that supplementation with n-3 LCPUFA was associated with a reduced risk of infections of the lower respiratory tract (31.7% vs. 39.1%; hazard ratio, 0.75; 95% CI, 0.58 to 0.98; P=0.033), but there was no statistically significant association between supplementation and asthma exacerbations, eczema, or allergic sensitization. CONCLUSIONS: Supplementation with n-3 LCPUFA in the third trimester of pregnancy reduced the absolute risk of persistent wheeze or asthma and infections of the lower respiratory tract in offspring by approximately 7 percentage points, or one third. (Funded by the Lundbeck Foundation and others; ClinicalTrials.gov number, NCT00798226 .).

Examining the Effect of Fish Oil Supplementation in Chinese Pregnant Women on Gestation Duration and Risk of Preterm Delivery.

BACKGROUND: Intervention studies have shown that long-chain (LC) n-3 PUFA intake can prolong gestation but the dose-time-effect relations remain unresolved. OBJECTIVES: We examined the effect on gestation duration of 2 doses of supplemental LC n-3 PUFAs. METHODS: We undertook a 3-group parallel randomized controlled trial in areas of China with low (median: 2.1 g/d) and higher (14.3 g/d) fish intake. Unselected women (median: age, 26.2 y; BMI, 20. kg/m2) were randomly assigned at midgestation to take four 0.72-g identical gelatin capsules per day until the last day of the preterm period (<259 days of gestation), when they were asked to stop. Capsules contained fish oil [high fish oil (HFO) group (60% w/w LC n-3 PUFAs)], a 1:3 mixture of fish oil to olive oil [low fish oil (LFO) group (20%)], or olive oil [control (CON) group (0%)], providing 2.0, 0.5, and 0 g/d of LC n-3 PUFAs, respectively. Habitual fish intake was recorded at baseline. Hazard rate ratios (HRRs) for spontaneous delivery <259 days of gestation and <273 days of gestation across groups were estimated by Cox regression. RESULTS: Among 5531 women randomly assigned, 92.5% were included in analyses (1706/1825, 1695/1851, and 1717/1855, respectively). The groups were similar with respect to hazard rates <259 days of gestation [HRR: 1.04 (95% CI: 0.70, 1.53) for LFO compared with CON and 0.90 (95% CI: 0.60, 1.35) for HFO compared with CON], hazard rates <273 days of gestation [HRR: 1.00 (95% CI: 0.86, 1.18) and 0.91 (95% CI: 0.77, 1.07), respectively], and mean gestation durations [differences: 0.2 d (95% CI: -0.5, 0.8) and 0.6 d (95% CI: -0.06, 1.2), respectively]. Inspection of pregnancy survival curves suggested that LC n-3 PUFAs delayed delivery in low fish consumers by 5-10 d and that this effect ceased rapidly after stopping taking the capsules. CONCLUSION: This trial could not substantiate that fish oil prevents preterm birth in Chinese women, possibly because statistical power was too low. This trial was registered at clinicaltrials.gov as NCT02770456.

Telomere length is reduced in 9- to 16-year-old girls exposed to gestational diabetes in utero.

AIMS/HYPOTHESIS: Shortened telomere length is a marker of cell damage and is associated with oxidative stress, chronic inflammation and metabolic disease. We hypothesised that the offspring of women with gestational diabetes mellitus (GDM) with increased risk of cardiovascular and metabolic diseases might exhibit shorter telomere length. METHODS: We investigated telomere length in 439 GDM and 469 control group offspring, aged between 9 and 16 years, recruited from the Danish National Birth Cohort. Relative telomere length was measured in peripheral blood DNA (n = 908) using a quantitative PCR approach. Multivariate regression analysis was used to investigate the association between mothers' GDM status and telomere length in the offspring. RESULTS: Female offspring had longer telomeres than males. Offspring of mothers with GDM had significantly shorter telomere length than control offspring, but this difference was observed only in girls. There was a negative association between telomere length and GDM exposure among the female offspring (14% shorter telomeres, p = 0.003) following adjustment for the age of the offspring. Telomere length in female offspring was negatively associated with fasting insulin levels and HOMA-IR (p = 0.03). Maternal age, smoking, gestational age, birthweight and the offspring's anthropometric characteristics were not associated with telomere length (p ≥ 0.1). CONCLUSIONS/INTERPRETATION: The 9- to 16-year-old girls of mothers with GDM had shorter telomeres than those from the control population. Further studies are needed to understand the extent to which shortened telomere length predicts and/or contributes to the increased risk of disease later in life among the offspring of women with GDM.

Genetic variants of gestational diabetes mellitus: a study of 112 SNPs among 8722 women in two independent populations.

AIMS/HYPOTHESIS: Gestational diabetes mellitus (GDM) is a common complication of pregnancy that has substantial short- and long-term adverse health implications for women and their children. However, large-scale studies on genetic risk loci for GDM remain sparse. METHODS: We conducted a case-control study among 2636 women with GDM and 6086 non-GDM control women from the Nurses' Health Study II and the Danish National Birth Cohort. A total of 112 susceptibility genetic variants confirmed by genome-wide association studies for type 2 diabetes were selected and measured. A weighted genetic risk score (GRS) was created based on variants that were significantly associated with risk of GDM after correcting for the false discovery rate. RESULTS: For the first time, we identified eight variants associated with GDM, namely rs7957197 (HNF1A), rs10814916 (GLIS3), rs3802177 (SLC30A8), rs9379084 (RREB1), rs34872471 (TCF7L2), rs7903146 (TCF7L2), rs11787792 (GPSM1) and rs7041847 (GLIS3). In addition, we confirmed three variants, rs10830963 (MTNR1B), rs1387153 (MTNR1B) and rs4506565 (TCF7L2), that had previously been significantly associated with GDM risk. Furthermore, compared with participants in the first (lowest) quartile of weighted GRS based on these 11 SNPs, the ORs for GDM were 1.07 (95% CI 0.93, 1.22), 1.23 (95% CI 1.07, 1.41) and 1.53 (95% CI 1.34, 1.74) for participants in the second, third and fourth (highest) quartiles, respectively. The significant positive associations between the weighted GRS and risk of GDM persisted across most of the strata of major risk factors for GDM, including family history of type 2 diabetes, smoking status, BMI and age. CONCLUSIONS/INTERPRETATION: In this large-scale case-control study with women from two independent populations, eight novel GDM SNPs were identified. These findings offer the potential to improve our understanding of the aetiology of GDM, and particularly of biological mechanisms related to beta cell function.

Lack of Association Between Maternal or Neonatal Vitamin D Status and Risk of Childhood Type 1 Diabetes: A Scandinavian Case-Cohort Study.

Studies on vitamin D status during pregnancy and risk of type 1 diabetes mellitus (T1D) lack consistency and are limited by small sample sizes or single measures of 25-hydroxyvitamin D (25(OH)D). We investigated whether average maternal 25(OH)D plasma concentrations during pregnancy are associated with risk of childhood T1D. In a case-cohort design, we identified 459 children with T1D and a random sample (n = 1,561) from the Danish National Birth Cohort (n = 97,127) and Norwegian Mother and Child Cohort Study (n = 113,053). Participants were born between 1996 and 2009. The primary exposure was the estimated average 25(OH)D concentration, based on serial samples from the first trimester until delivery and on umbilical cord plasma. We estimated hazard ratios using weighted Cox regression adjusting for multiple confounders. The adjusted hazard ratio for T1D per 10-nmol/L increase in the estimated average 25(OH)D concentration was 1.00 (95% confidence interval: 0.90, 1.10). Results were consistent in both cohorts, in multiple sensitivity analyses, and when we analyzed mid-pregnancy or cord blood separately. In conclusion, our large study demonstrated that normal variation in maternal or neonatal 25(OH)D is unlikely to have a clinically important effect on risk of childhood T1D.

Parental Smoking and Risk of Childhood-onset Type 1 Diabetes.

BACKGROUND: A few prospective studies suggest an association between maternal smoking during pregnancy and lower risk of type 1 diabetes. However, the role of unmeasured confounding and misclassification remains unclear. METHODS: We comprehensively evaluated whether maternal smoking in pregnancy predicts lower risk of childhood-onset type 1 diabetes in two Scandinavian pregnancy cohorts (185,076 children; 689 cases) and a Norwegian register-based cohort (434,627 children; 692 cases). We measured cord blood cotinine as an objective marker of nicotine exposure during late pregnancy in 154 cases and 476 controls. We also examined paternal smoking during pregnancy, in addition to environmental tobacco smoke exposure the first 6 months of life, to clarify the role of characteristics of smokers in general. RESULTS: In the pregnancy cohorts, maternal smoking beyond gestational week 12 was inversely associated with type 1 diabetes, pooled adjusted hazard ratio (aHR) 0.66 (95% CI = 0.51, 0.85). Similarly, in the Norwegian register-based cohort, children of mothers who still smoked at the end of pregnancy had lower risk of type 1 diabetes, aHR 0.65 (95% CI = 0.47, 0.89). Cord blood cotinine ≥30 nmol/L was also associated with reduced risk of type 1 diabetes, adjusted odds ratio 0.42 (95% CI = 0.17, 1.0). We observed no associations of paternal smoking during pregnancy, or environmental tobacco smoke exposure, with childhood-onset type 1 diabetes. CONCLUSION: Maternal sustained smoking during pregnancy is associated with lower risk of type 1 diabetes in children. This sheds new light on the potential intrauterine environmental origins of the disease.

The International Childhood Cancer Cohort Consortium (I4C): A research platform of prospective cohorts for studying the aetiology of childhood cancers.

BACKGROUND: Childhood cancer is a rare but leading cause of morbidity and mortality. Established risk factors, accounting for <10% of incidence, have been identified primarily from case-control studies. However, recall, selection and other potential biases impact interpretations particularly, for modest associations. A consortium of pregnancy and birth cohorts (I4C) was established to utilise prospective, pre-diagnostic exposure assessments and biological samples. METHODS: Eligibility criteria, follow-up methods and identification of paediatric cancer cases are described for cohorts currently participating or planning future participation. Also described are exposure assessments, harmonisation methods, biological samples potentially available for I4C research, the role of the I4C data and biospecimen coordinating centres and statistical approaches used in the pooled analyses. RESULTS: Currently, six cohorts recruited over six decades (1950s-2000s) contribute data on 388 120 mother-child pairs. Nine new cohorts from seven countries are anticipated to contribute data on 627 500 additional projected mother-child pairs within 5 years. Harmonised data currently includes over 20 "core" variables, with notable variability in mother/child characteristics within and across cohorts, reflecting in part, secular changes in pregnancy and birth characteristics over the decades. CONCLUSIONS: The I4C is the first cohort consortium to have published findings on paediatric cancer using harmonised variables across six pregnancy/birth cohorts. Projected increases in sample size, expanding sources of exposure data (eg, linkages to environmental and administrative databases), incorporation of biological measures to clarify exposures and underlying molecular mechanisms and forthcoming joint efforts to complement case-control studies offer the potential for breakthroughs in paediatric cancer aetiologic research.