Early sex-dependent differences in metabolic profiles of overweight and adiposity in young children: a cross-sectional analysis.

BACKGROUND: Childhood obesity is a global health concern and can lead to lifetime cardiometabolic disease. New advances in metabolomics can provide biochemical insights into the early development of obesity, so we aimed to characterize serum metabolites associated with overweight and adiposity in early childhood and to stratify associations by sex. METHODS: Nontargeted metabolite profiling was conducted in the Canadian CHILD birth cohort (discovery cohort) at age 5 years (n = 900) by multisegment injection-capillary electrophoresis-mass spectrometry. Clinical outcome was defined using novel combined measures of overweight (WHO-standardized body mass index ≥ 85th percentile) and/or adiposity (waist circumference ≥ 90th percentile). Associations between circulating metabolites and child overweight/adiposity (binary and continuous outcomes) were determined by multivariable linear and logistic regression, adjusting for covariates and false discovery rate, and by subsequent sex-stratified analysis. Replication was assessed in an independent replication cohort called FAMILY at age 5 years (n = 456). RESULTS: In the discovery cohort, each standard deviation (SD) increment of branched-chain and aromatic amino acids, glutamic acid, threonine, and oxoproline was associated with 20-28% increased odds of overweight/adiposity, whereas each SD increment of the glutamine/glutamic acid ratio was associated with 20% decreased odds. All associations were significant in females but not in males in sex-stratified analyses, except for oxoproline that was not significant in either subgroup. Similar outcomes were confirmed in the replication cohort, where associations of aromatic amino acids, leucine, glutamic acid, and the glutamine/glutamic acid ratio with childhood overweight/adiposity were independently replicated. CONCLUSIONS: Our findings show the utility of combining measures of both overweight and adiposity in young children. Childhood overweight/adiposity at age 5 years has a specific serum metabolic phenotype, with the profile being more prominent in females compared to males.

Dynamic Metabolic Signatures of Choline and Carnitine across Healthy Pregnancy and in Cord Blood: Association with Maternal Dietary Protein.

BACKGROUND: In pregnancy, choline is deemed an essential nutrient and carnitine needs are increased, but amounts remain undefined. OBJECTIVES: We aimed to measure choline and total dietary protein and dairy protein intake from food and supplements across pregnancy and the response to intake by profiling choline and carnitine metabolites across pregnancy and in cord blood. METHODS: An exploratory analysis of choline and protein intake from 3-d diet records and measures of 36 serum choline and carnitine metabolites in early (12-17 wk) and late (36-38 wk) pregnancy was conducted in participants from the Be Healthy in Pregnancy study randomized to high dairy protein+walking exercise or usual care. Metabolites were measured in fasted maternal and cord serum using multisegment injection-capillary electrophoresis-mass spectrometry. Mixed ANOVA adjusted for body mass index was performed for comparison of metabolites across pregnancy and between intervention and control. RESULTS: In 104 participants, the median (Q1, Q3) total choline intake was 347 (263, 427) mg/d in early and 322 (270, 437) mg/d in late pregnancy. Only ∼20% of participants achieved the recommended adequate intake (450 mg/d) and ∼10% consumed supplemental choline (8-200 mg/d). Serum-free choline (µmol/L) was higher in late compared with early pregnancy [12.9 (11.4, 15.1) compared with 9.68 (8.25, 10.61), P < 0.001], but choline downstream metabolites were similar across pregnancy. Serum carnitine [10.3 (9.01, 12.2) compared with 15.9 (14.1, 17.9) µmol/L, P < 0.001] and acetylcarnitine [2.35 (1.92, 2.68) compared with 3.0 (2.56, 3.59), P < 0.001] were significantly lower in late pregnancy. High cord:maternal serum metabolite ratios were found in most measured metabolites. CONCLUSIONS: Despite inadequate choline intake, serum-free choline was elevated in late pregnancy and enriched in cord blood compared with maternal serum. Serum carnitine declined in late pregnancy despite a high protein diet. The higher cord:maternal concentrations in choline and carnitine metabolites suggest active uptake in late pregnancy, reflecting the importance of these circulating metabolites in fetal development. This trial was registered at clinicaltrials.gov as NCT01689961.

How Do Health Schemas Inform Healthy Behaviours During Pregnancy? Qualitative Findings from the Be Healthy in Pregnancy (BHIP) Study.

OBJECTIVE: Excess gestational weight gain (GWG) is associated with adverse long and short-term outcomes for both woman and child, yet evidence demonstrates pregnant women are frequently not engaging in healthy behaviours linked to appropriate weight gain. The purpose of the current study was to explore women's values and beliefs related to weight, nutrition and physical activity during pregnancy and to describe how these beliefs influence their behaviours. METHODS: As part of a larger randomized controlled trial, we conducted 20 focus groups with 66 pregnant women between 16 and 24-weeks gestation using a semi-structured interview guide. Focus groups were recorded and transcribed verbatim and analyzed using a grounded theory approach. RESULTS: Three personal health schemas emerged from the findings which illustrated women's diverging beliefs about their health behaviours in pregnancy. 'Interconnected health' described beliefs regarding the impact their health had on that of their growing baby and awareness of risks associated with inappropriate weight gain. 'Gestational weight gain as an indicator of health' illustrated perceptions regarding how GWG impacted health and the utility of guidelines. Finally, 'Control in pregnancy' described the sense of agency over one's body and health. CONCLUSIONS FOR PRACTICE: Our results showed that health-related behaviours in pregnancy are driven by personal health schemas which are often discordant with clinical evidence. Interventions and health care provider advice aimed at behaviour modification would benefit from first understanding and addressing these schemas. Tackling the conflict between beliefs and behaviour may improve health outcomes associated with appropriate weight gain in pregnancy.

Metabolite profiles and the risk of metabolic syndrome in early childhood: a case-control study.

BACKGROUND: Defining the metabolic syndrome (MetS) in children remains challenging. Furthermore, a dichotomous MetS diagnosis can limit the power to study associations. We sought to characterize the serum metabolite signature of the MetS in early childhood using high-throughput metabolomic technologies that allow comprehensive profiling of metabolic status from a biospecimen. METHODS: In the Family Atherosclerosis Monitoring In earLY life (FAMILY) prospective birth cohort study, we selected 228 cases of MetS and 228 matched controls among children age 5 years. In addition, a continuous MetS risk score was calculated for all 456 participants. Comprehensive metabolite profiling was performed on fasting serum samples using multisegment injection-capillary electrophoresis-mass spectrometry. Multivariable regression models were applied to test metabolite associations with MetS adjusting for covariates of screen time, diet quality, physical activity, night sleep, socioeconomic status, age, and sex. RESULTS: Compared to controls, thirteen serum metabolites were identified in MetS cases when using multivariable regression models, and using the quantitative MetS score, an additional eight metabolites were identified. These included metabolites associated with gluconeogenesis (glucose (odds ratio (OR) 1.55 [95% CI 1.25-1.93]) and glutamine/glutamate ratio (OR 0.82 [95% CI 0.67-1.00])) and the alanine-glucose cycle (alanine (OR 1.41 [95% CI 1.16-1.73])), amino acids metabolism (tyrosine (OR 1.33 [95% CI 1.10-1.63]), threonine (OR 1.24 [95% CI 1.02-1.51]), monomethylarginine (OR 1.33 [95% CI 1.09-1.64]) and lysine (OR 1.23 [95% CI 1.01-1.50])), tryptophan metabolism (tryptophan (OR 0.78 [95% CI 0.64-0.95])), and fatty acids metabolism (carnitine (OR 1.24 [95% CI 1.02-1.51])). The quantitative MetS risk score was more powerful than the dichotomous outcome in consistently detecting this metabolite signature. CONCLUSIONS: A distinct metabolite signature of pediatric MetS is detectable in children as young as 5 years old and may improve risk assessment at early stages of development.

Investigating the normalization and normative views of gestational weight gain: Balancing recommendations with the promotion and support of healthy pregnancy diets.

OBJECTIVES: Gestational weight gain (GWG) is increasingly monitored in the United States and Canada. While promoting healthy GWG offers benefits, there may be costs with over-surveillance. We aimed to explore these costs/benefits. METHODS: Quantitative data from 350 pregnant survey respondents and qualitative focus group data from 43 pregnant/post-partum and care-provider participants were collected in the Mothers to Babies (M2B) study in Hamilton, Canada. We report descriptive statistics and discussion themes on GWG trajectories, advice, knowledge, perceptions, and pregnancy diet. Relationships between GWG monitoring/normalization and worry, knowledge, diet quality, and sociodemographics-namely low-income and racialization-were assessed using χ2 tests and a linear regression model and contextualized with focus group data. RESULTS: Most survey respondents reported GWG outside recommended ranges but rejected the mid-20th century cultural norm of "eating for two"; many worried about gaining excessively. Conversely, respondents living in very low-income households were more likely to be gaining less than recommended GWG and to worry about gaining too little. A majority had received advice about GWG, yet half were unable to identify the range recommended for their prepregnancy BMI. This proportion was even lower for racialized respondents. Pregnancy diet quality was associated with household income, but not with receipt or understanding of GWG guidance. Care-providers encouraged normalized GWG, while worrying about the consequences of pathologizing "abnormal" GWG. CONCLUSIONS: Translation of GWG recommendations should be done with a critical understanding of GWG biological normalcy. Supportive GWG monitoring and counseling should consider clinical, socioeconomic, and community contexts.

Be Healthy in Pregnancy: Exploring factors that impact pregnant women's nutrition and exercise behaviours.

Excess gestational weight gain is associated with short- and long-term pregnancy complications. Although a healthy diet and physical activity during pregnancy are recommended and shown to reduce the risk of complications and improve outcomes, adherence to these recommendations is low. The aims of this study were to explore women's view of nutrition and physical activity during pregnancy and to describe barriers and facilitators experienced in implementing physical activity and nutrition recommendations. In a substudy of the Be Healthy in Pregnancy randomized trial, 20 semistructured focus groups were conducted with 66 women randomized to the control group when they were between 16 and 24 weeks gestation. Focus groups were recorded, transcribed verbatim, coded and thematically analysed. The results indicate that women felt motivated to be healthy for their baby, but competing priorities may take precedence. Participants described limited knowledge and access to information on safe physical activity in pregnancy and lacked the skills needed to operationalize both physical activity and dietary recommendations. Women's behaviours regarding diet and physical activity in pregnancy were highly influenced by their own and their peers' beliefs and values regarding how weight gain impacted their health during pregnancy. Pregnancy symptoms beyond women's control such as fatigue and nausea made physical activity and healthy eating more challenging. Counselling from care providers about nutrition and physical activity was perceived as minimal and ineffective. Future interventions should address improving counselling strategies and address individual's beliefs around nutrition and activity in pregnancy.

Summer Season and Recommended Vitamin D Intake Support Adequate Vitamin D Status throughout Pregnancy in Healthy Canadian Women and Their Newborns.

BACKGROUND: Vitamin D deficiency in pregnancy is reported as a prevalent public health problem. OBJECTIVES: We aimed to evaluate, in pregnant Canadian women, 1) vitamin D intake, 2) maternal and cord serum 25-hydroxycholecalciferol [25(OH)D] and maternal 1,25-dihydroxycholecalciferol [1,25(OH)2D], and 3) factors associated with maternal serum 25(OH)D. METHODS: Women (n = 187; mean prepregnancy BMI 24.4 kg/m2, mean age 31 y) recruited to the Be Healthy in Pregnancy study provided fasting blood samples and nutrient intake at 12-17 (early) and 36-38 (late) weeks of gestation, and cord blood. Vitamin D intakes (Nutritionist Pro™) and serum 25(OH)D and 1,25(OH)2D concentrations (LC-tandem MS) were measured. RESULTS: Vitamin D intake was comparable in early and late pregnancy [median (IQR) = 586 (459, 859) compared with 689 (544, 974) IU/d; P = 0.83], with 71% consumed as supplements. Serum 25(OH)D was significantly higher in late pregnancy (mean ± SD: 103.1 ± 29.3 nmol/L) than in early pregnancy (82.5 ± 22.5 nmol/L; P < 0.001) and no vitamin D deficiency (<30 nmol/L) occurred. Serum 1,25(OH)2D concentrations were significantly higher in late pregnancy (101.1 ± 26.9 pmol/L) than in early pregnancy (82.2 ± 19.2 pmol/L, P < 0.001, n = 84). Cord serum 25(OH)D concentrations averaged 55% of maternal concentrations. In adjusted multivariate analyses, maternal vitamin D status in early pregnancy was positively associated with summer season (est.ß: 13.07; 95% CI: 5.46, 20.69; P < 0.001) and supplement intake (est.ß: 0.01; 95% CI: 0.00, 0.01; P < 0.001); and in late pregnancy with summer season (est.ß: 24.4; 95% CI: 15.6, 33.2; P < 0.001), nonmilk dairy intake (est.ß: 0.17; 95% CI: 0.02, 0.32; P = 0.029), and supplement intake (est.ß: 0.01; 95% CI: 0.00, 0.01; P = 0.04). CONCLUSIONS: Summer season and recommended vitamin D intakes supported adequate vitamin D status throughout pregnancy and in cord blood at >50 nmol/L in healthy Canadian pregnant women. This trial was registered at clinicaltrials.gov as NCT01693510.

Diet in Early Pregnancy: Focus on Folate, Vitamin B12, Vitamin D, and Choline.

Purpose: Prenatal multivitamins are recommended in pregnancy. This study assessed food and supplement intakes of folate, vitamin B12 (B12), vitamin D, and choline in pregnant women living in Southern Ontario in comparison with current recommendations. Methods: Women recruited to the Be Healthy in Pregnancy RCT (NCT01693510) completed 3-day diet/supplement records at 12-17 weeks gestation. Intakes of folate, B12, vitamin D, and choline were quantified and compared with recommendations for pregnant women. Results: Folate intake (median (min, max)) was 1963 µg/day dietary folate equivalents (153, 10 846); 90% of women met the Estimated Average Requirement (EAR) but 77% exceeded the Tolerable Upper Intake Level (UL) (n = 232). B12 intake was 12.1 µg/day (0.3, 2336); 96% of women met the EAR with 7% exceeding the EAR 100-fold (n = 232). Vitamin D intake was 564 IU/day (0.0, 11 062); 83% met the EAR, whereas 1.7% exceeded the UL (n = 232). Choline intake was 338 mg/day (120, 1016); only 18% met the Adequate Intake and none exceeded the UL (n = 158). Conclusion: To meet the nutrient requirements of pregnancy many women rely on prenatal vitamins. Reformulating prenatal multivitamin supplements to provide doses of vitamins within recommendations to complement a balanced healthy diet would ensure appropriate micronutrient intakes for pregnant women.

Knowledge about the Developmental Origins of Health and Disease is independently associated with variation in diet quality during pregnancy.

Environmental factors affecting development through embryogenesis, pregnancy, and infancy impact health through all subsequent stages of life. Known as the Developmental Origins of Health and Disease (DOHaD) hypothesis, this concept is widely accepted among health and social scientists. However, it is unclear whether DOHaD-based ideas are reaching the general public and/or influencing behaviour. This study thus investigated whether and under what circumstances pregnant people in Canada are familiar with DOHaD, and if DOHaD familiarity relates to eating behaviour. Survey responses from pregnant people from Hamilton, Canada, were used to assess respondents' knowledge of DOHaD (hereafter, DOHaDKNOWLEDGE ) compared with their knowledge of more general pregnancy health recommendations (Pregnancy GuidelineKNOWLEDGE ). The survey also characterized respondents' pregnancy diet quality and sociodemographic profiles. We fit two multiple, linear, mixed regression models to the data, one with DOHaDKNOWLEDGE score as the dependent variable and the other with diet quality score as the dependent. In both models, responses were clustered by respondents' neighbourhoods. Complete, internally consistent responses were available for 330 study-eligible respondents. Relative to Pregnancy GuidelineKNOWLEDGE , respondents had lower, more variable DOHaDKNOWLEDGE scores. Additionally, higher DOHaDKNOWLEDGE was associated with higher socio-economic position, older age, and lower parity, independent of Pregnancy GuidelineKNOWLEDGE . Diet quality during pregnancy was positively associated with DOHaDKNOWLEDGE , adjusting for sociodemographic factors. A subset of relatively high socio-economic position respondents was familiar with DOHaD. Greater familiarity with DOHaD was associated with better pregnancy diet quality, hinting that translating DOHaD knowledge to pregnant people may motivate improved pregnancy nutrition and thus later-life health for developing babies.

Experiences regarding nutrition and exercise among women during early postpartum: a qualitative grounded theory study.

BACKGROUND: Excess gestational weight gain has long- and short-term implications for women and children, and postpartum weight retention is associated with an increased risk of long-term obesity. Despite the existence of dietary and exercise guidelines, many women struggle to return to pre-pregnancy weight. Experiences of women in tackling postpartum weight loss are poorly understood. We undertook this study to explore experiences related to nutrition, exercise and weight in the postpartum in women in Ontario, Canada. METHODS: This was a nested qualitative study within The Be Healthy in Pregnancy Study, a randomized controlled trial. Women randomized to the control group were invited to participate. Semi-structured focus groups were conducted at 4-6 months postpartum. Focus groups were audio recorded, transcribed verbatim, coded and analyzed thematically using a constructivist grounded theory approach. RESULTS: Women experienced a complex relationship with their body image, due to unrealistic expectations related to their postpartum body. Participants identified barriers and enablers to healthy habits during pregnancy and postpartum. Gestational weight gain guidelines were regarded as unhelpful and unrealistic. A lack of guidance and information about weight management, healthy eating, and exercise in the postpartum period was highlighted. CONCLUSION: Strategies for weight management that target the unique characteristics of the postpartum period have been neglected in research and in patient counselling. Postpartum women may begin preparing for their next pregnancy and support during this period could improve their health for subsequent pregnancies. TRIAL REGISTRATION: NCT01689961 registered September 21, 2012.

Harmonization of Food-Frequency Questionnaires and Dietary Pattern Analysis in 4 Ethnically Diverse Birth Cohorts.

BACKGROUND: Canada is an ethnically diverse nation, which introduces challenges for health care providers tasked with providing evidence-based dietary advice. OBJECTIVES: We aimed to harmonize food-frequency questionnaires (FFQs) across 4 birth cohorts of ethnically diverse pregnant women to derive robust dietary patterns to investigate maternal and newborn outcomes. METHODS: The NutriGen Alliance comprises 4 prospective birth cohorts and includes 4880 Canadian mother-infant pairs of predominantly white European [CHILD (Canadian Healthy Infant Longitudinal Development) and FAMILY (Family Atherosclerosis Monitoring In earLY life)], South Asian [START (SouTh Asian birth cohoRT)-Canada], or Aboriginal [ABC (Aboriginal Birth Cohort)] origins. CHILD used a multiethnic FFQ based on a previously validated instrument designed by the Fred Hutchinson Cancer Research Center, whereas FAMILY, START, and ABC used questionnaires specifically designed for use in white European, South Asian, and Aboriginal people, respectively. The serving sizes and consumption frequencies of individual food items within the 4 FFQs were harmonized and aggregated into 36 common food groups. Principal components analysis was used to identify dietary patterns that were internally validated against self-reported vegetarian status and externally validated against a modified Alternative Healthy Eating Index (mAHEI). RESULTS: Three maternal dietary patterns were identified-"plant-based," "Western," and "health-conscious"-which collectively explained 29% of the total variability in eating habits observed in the NutriGen Alliance. These patterns were strongly associated with self-reported vegetarian status (OR: 3.85; 95% CI: 3.47, 4.29; r2 = 0.30, P < 0.001; for a plant-based diet), and average adherence to the plant-based diet was higher in participants in the fourth quartile of the mAHEI than in the first quartile (mean difference: 46.1%; r2 = 0.81, P < 0.001). CONCLUSION: Dietary data collected by using FFQs from ethnically diverse pregnant women can be harmonized to identify common dietary patterns to investigate associations between maternal dietary intake and health outcomes.

Protein Needs of Physically Active Children.

Current Dietary Reference Intakes (DRI) for protein for children and youth require revision as they were derived primarily on nitrogen balance data in young children or extrapolated from adult values; did not account for the possible influence of above average physical activity; and did not set an upper tolerable level of intake. Revision of the protein DRIs requires new research that investigates: 1) long-term dose-response to identify protein and essential amino acid requirements of both sexes at various pubertal stages and under differing conditions of physical activity; 2) the acute protein needs (quantity and timing) following a single bout of exercise; 3) the potential adverse effects of chronic high intakes of protein; and 4) new measurement techniques (i.e., IAAO or stable isotope methodologies) to improve accuracy of protein needs. While active individuals may require protein in excess of current DRIs, most active Canadian children and youth have habitual protein intakes that exceed current recommendations.

Validation of a Food Frequency Questionnaire for Bone Nutrients in Pregnant Women.

PURPOSE: The aim was to validate a food frequency questionnaire (FFQ) against a 3-day food record (3DFR) for pregnant women with a focus on nutrients important for bone health from food and supplements. METHODS: The FFQ and 3DFR were administered to pregnant women (n = 42) aged 18-45 years in their third trimester of pregnancy in Hamilton, Ontario. Nutrient analysis of intakes was conducted using an FFQ calculator and Nutritionist-Pro software. The average daily serving consumption of Milk and alternatives group and Vegetable subgroup from Canada's Food Guide were also compared. RESULTS: There was a high positive correlation between methods for total dietary vitamin D (r = 0.83). Low positive associations were observed for total protein (r = 0.37), calcium (r = 0.36), vitamin K (r = 0.41), and servings of Milk and alternatives (r = 0.36). A cross-classification analysis using participants' intake quartiles revealed no major misclassifications. Bland-Altman analysis showed that the FFQ mildly underestimated the intake for protein, whereas it grossly overestimated the intake of vitamin K, and daily servings of Milk and alternatives and Vegetable. CONCLUSIONS: This FFQ can serve as a useful tool in clinical and research settings to assess key bone nutrients from foods and supplement sources in pregnant women.

Effects of Short-Term Exercise Training With and Without Milk Intake on Cardiometabolic and Inflammatory Adaptations in Obese Adolescents.

There is some evidence that a combination of factors can reduce inflammation and associated metabolic risk factors. We studied the early cardiometabolic and inflammatory adaptations to a short-term exercise intervention with and without milk in obese adolescents. Fifty-four adolescents were randomized to consume milk post exercise (MILK) or a carbohydrate beverage (CONT) during one-week of daily exercise. Insulin levels were not different between the groups post training. Glucose was reduced over time in both groups (-9 ± 13 mg/ dl MILK and -6 ± 14 mg/dl CONT, p < .05) but not different between groups. There was a greater decrease in mean arterial pressure (MAP) in the MILK group (-3 ± 6 mmHg MILK vs. 2 ± 7 mmHg CONT, p < .04). Milk provided postexercise did not affect C-reactive protein (CRP), tumor necrosis factor-α (TNF-α) or interleukin-6 (IL-6). The exercise intervention led to an increase in TNF-α in both groups (0.27 ± 0.7 pg/ml MILK and 0.48 ± 0.6 pg/ml CONT, p < .001). The early adaptations to a short-term exercise intervention in obese adolescents include a reduction in MAP and an increase in some inflammatory markers.

Exploring the benefits and challenges of establishing a DRI-like process for bioactives.

Bioactives can be defined as: "Constituents in foods or dietary supplements, other than those needed to meet basic human nutritional needs, which are responsible for changes in health status" (Office of Disease Prevention and Health Promotion, Office of Public Health and Science, Department of Health and Human Services in Fed Reg 69:55821-55822, 2004). Although traditional nutrients, such as vitamins, minerals, protein, essential fatty acids and essential amino acids, have dietary reference intake (DRI) values, there is no such evaluative process for bioactives. For certain classes of bioactives, substantial scientific evidence exists to validate a relationship between their intake and enhanced health conditions or reduced risk of disease. In addition, the study of bioactives and their relationship to disease risk is a growing area of research supported by government, academic institutions, and food and supplement manufacturers. Importantly, consumers are purchasing foods containing bioactives, yet there is no evaluative process in place to let the public know how strong the science is behind the benefits or the quantitative amounts needed to achieve these beneficial health effects. This conference, Bioactives: Qualitative Nutrient Reference Values for Life-stage Groups?, explored why it is important to have a DRI-like process for bioactives and challenges for establishing such a process.

The association of red and processed meat with gestational diabetes mellitus: Results from 2 Canadian birth cohort studies.

OBJECTIVE: Red and processed meat is considered risk factors of gestational diabetes mellitus (GDM), but the evidence is inconclusive. We aimed to examine the association between red and processed meat intake and odds of GDM among South Asian and White European women living in Canada. METHODS: This is a cross-sectional analysis of pregnant women from two birth cohorts: SouTh Asian biRth cohorT (START; n = 976) and Family Atherosclerosis Monitoring In earLY life (FAMILY; n = 581). Dietary intake was assessed using a validated 169-item semi-quantitative food-frequency questionnaire (FFQ). Multivariate logistic regression models were used to examine the associations between gestational diabetes and: 1) total red and processed meat; 2) unprocessed red meat; 3) processed meat and GDM after adjustment for potential confounders. RESULTS: There were 241 GDM cases in START and 91 in FAMILY. The median total red and processed meat intake were 1.5 g/d (START) and 52.8 g/d (FAMILY). In START, the multivariable-adjusted odds ratio (OR) showed neither lower nor higher intakes of unprocessed red meat (p-trend = 0.68), processed meat (p-trend = 0.90), or total red and processed meat (p-trend = 0.44), were associated with increased odds of GDM, when compared with medium intake. Similar results were observed in FAMILY except for processed meat intake [OR = 0.94 (95% CI 0.47-1.91), for medium versus low and OR = 1.51 (95% CI 0.77-2.29) for medium versus high; p-trend = 0.18] after adjusting for additional dietary factors such as the diet quality score, total fiber, saturated fat and glycemic load. CONCLUSION: Medium compared with low or high red and processed meat intake is not associated with GDM in White Europeans and South Asians living in Canada.

Consistent cord blood DNA methylation signatures of gestational age between South Asian and white European cohorts.

BACKGROUND: Epigenetic modifications, particularly DNA methylation (DNAm) in cord blood, are an important biological marker of how external exposures during gestation can influence the in-utero environment and subsequent offspring development. Despite the recognized importance of DNAm during gestation, comparative studies to determine the consistency of these epigenetic signals across different ethnic groups are largely absent. To address this gap, we first performed epigenome-wide association studies (EWAS) of gestational age (GA) using newborn cord blood DNAm comparatively in a white European (n = 342) and a South Asian (n = 490) birth cohort living in Canada. Then, we capitalized on established cord blood epigenetic GA clocks to examine the associations between maternal exposures, offspring characteristics and epigenetic GA, as well as GA acceleration, defined as the residual difference between epigenetic and chronological GA at birth. RESULTS: Individual EWASs confirmed 1,211 and 1,543 differentially methylated CpGs previously reported to be associated with GA, in white European and South Asian cohorts, respectively, with a similar distribution of effects. We confirmed that Bohlin's cord blood GA clock was robustly correlated with GA in white Europeans (r = 0.71; p = 6.0 × 10-54) and South Asians (r = 0.66; p = 6.9 × 10-64). In both cohorts, Bohlin's clock was positively associated with newborn weight and length and negatively associated with parity, newborn female sex, and gestational diabetes. Exclusive to South Asians, the GA clock was positively associated with the newborn ponderal index, while pre-pregnancy weight and gestational weight gain were strongly predictive of increased epigenetic GA in white Europeans. Important predictors of GA acceleration included gestational diabetes mellitus, newborn sex, and parity in both cohorts. CONCLUSIONS: These results demonstrate the consistent DNAm signatures of GA and the utility of Bohlin's GA clock across the two populations. Although the overall pattern of DNAm is similar, its connections with the mother's environment and the baby's anthropometrics can differ between the two groups. Further research is needed to understand these unique relationships.

Maternal smoking DNA methylation risk score associated with health outcomes in offspring of European and South Asian ancestry.

Background: Maternal smoking has been linked to adverse health outcomes in newborns but the extent to which it impacts newborn health has not been quantified through an aggregated cord blood DNA methylation (DNAm) score. Here, we examine the feasibility of using cord blood DNAm scores leveraging large external studies as discovery samples to capture the epigenetic signature of maternal smoking and its influence on newborns in White European and South Asian populations. Methods: We first examined the association between individual CpGs and cigarette smoking during pregnancy, and smoking exposure in two White European birth cohorts (n=744). Leveraging established CpGs for maternal smoking, we constructed a cord blood epigenetic score of maternal smoking that was validated in one of the European-origin cohorts (n=347). This score was then tested for association with smoking status, secondary smoking exposure during pregnancy, and health outcomes in offspring measured after birth in an independent White European (n=397) and a South Asian birth cohort (n=504). Results: Several previously reported genes for maternal smoking were supported, with the strongest and most consistent association signal from the GFI1 gene (6 CpGs with p<5 × 10-5). The epigenetic maternal smoking score was strongly associated with smoking status during pregnancy (OR = 1.09 [1.07, 1.10], p=5.5 × 10-33) and more hours of self-reported smoking exposure per week (1.93 [1.27, 2.58], p=7.8 × 10-9) in White Europeans. However, it was not associated with self-reported exposure (p>0.05) among South Asians, likely due to a lack of smoking in this group. The same score was consistently associated with a smaller birth size (-0.37±0.12 cm, p=0.0023) in the South Asian cohort and a lower birth weight (-0.043±0.013 kg, p=0.0011) in the combined cohorts. Conclusions: This cord blood epigenetic score can help identify babies exposed to maternal smoking and assess its long-term impact on growth. Notably, these results indicate a consistent association between the DNAm signature of maternal smoking and a small body size and low birth weight in newborns, in both White European mothers who exhibited some amount of smoking and in South Asian mothers who themselves were not active smokers. Funding: This study was funded by the Canadian Institutes of Health Research Metabolomics Team Grant: MWG-146332.

Changes in trabecular bone microarchitecture in postmenopausal women with and without type 2 diabetes: a two year longitudinal study.

BACKGROUND: The risk of experiencing an osteoporotic fracture is greater for adults with type 2 diabetes despite higher than normal bone mineral density (BMD). In addition to BMD, trabecular bone microarchitecture contributes to bone strength, but is not assessed using conventional BMD measurement by dual x-ray absorptiometry (DXA). The aim of this study was to compare two year changes in trabecular bone microarchitecture in women with and without type 2 diabetes. METHODS: We used a 1 Tesla magnetic resonance imaging (MRI) scanner to acquire axial images (resolution 195 µm × 195 µm × 1000 µm) of the distal radius. We report the change in the number and size of trabecular bone holes, bone volume fraction (BVTV), trabecular thickness (Tb.Th), number (Tb.N) and separation (Tb.Sp), endosteal area, nodal and branch density for each group. Lumbar spine and proximal femur BMD were measured with DXA (Hologic, Discovery QDR4500A) at baseline and follow-up. Using a multivariable linear regression model, we evaluated whether the percent change in the trabecular bone microarchitecture variables differed between women with and without type 2 diabetes. RESULTS: Of the 54 participants at baseline with valid MRI image sets, 37 participants (baseline mean [SD] age, 70.8 [4.4] years) returned for follow-up assessment after 25.4 [1.9] months. Lumbar spine BMD was greater for women with diabetes compared to without diabetes at both baseline and follow-up. After adjustment for ethnicity, women with diabetes had a higher percent increase in number of trabecular bone holes compared to controls (10[1] % versus -7 [2]%, p=0.010), however results were no longer significant after adjustment for multiple comparisons (p=0.090). There were no differences in the change in other trabecular bone microarchitecture variables between groups. CONCLUSION: There were no differences in percent change in trabecular bone microarchitecture variables over two years in women with type 2 diabetes compared to women without diabetes. This study provides feasibility data, which will inform future trials assessing change in trabecular bone microarchitecture in women with type 2 diabetes. Larger studies using higher resolution imaging modalities that can assess change in trabecular and cortical bone compartments in women with type 2 diabetes are needed.