Rationale and design of South Asian Birth Cohort (START): a Canada-India collaborative study

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.

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.

Cross-cultural food practices and nutrition seeking behaviors among pregnant and postpartum Indian women living in Australia

No research has explored the experiences of Indian women who become pregnant after they migrate to Australia, and how their existing traditions mix with their new environment and subsequently impact eating patterns. Semi-structured interviews were conducted with eleven women of Indian heritage who were living in Australia, and data were thematically analyzed. The researchers identified two main themes were identified (a) foods to eat and which to avoid, and (b) support networks and sources of health information during pregnancy. Women get advice and information from a range of sources and have diverse attitudes and beliefs about cultural food practices. that are both rigid and flexible, as well as traditional and contemporary.

Psychosocial and sociodemographic factors associated with gestational blood glucose levels in women attending public hospitals: Results from baseline of MAASTHI cohort

BACKGROUND

Understanding psychosocial environment is important for improving maternal and fetal health outcomes during pregnancy. We aimed to identify the association between gestational blood glucose levels and psychosocial and demographic factors in pregnant women.

METHODS

In the MAASTHI pregnancy cohort in Bengaluru, we assessed depressive symptoms, and social support using validated scales at baseline in first trimester. A 2-hour 75 g oral glucose tolerance test (OGTT) was administered between 24-36 weeks of gestation. We examined the relation between psychosocial factors assessed at baseline and gestational blood glucose levels in second/third trimester using multivariate linear regression and explored association between serum cortisol and gestational blood glucose levels in subgroup samples.

RESULTS

We found that 9% of pregnant women had depressive symptoms and 14.3% had Gestational Diabetes Mellitus (GDM). Psychosocial factors, including depressive symptoms, have a significant correlation with gestational fasting(β = 0.12, p-value<0.05) and postprandial blood sugar level(β = 0.23, p-value<0.05) and poor social support were found to have a significant association with gestational fasting blood glucose levels(β = 1.45, p-value <0.05) and postprandial blood sugar levels(β = 2.60, p-value <0.05). The sociodemographic factors such as respondent education, occupation, social and economic status were associated with gestational blood sugar after adjusting for potential confounder variables.

CONCLUSION

Depressive symptoms and poor social support earlier in pregnancy were significantly associated with increased gestational blood glucose levels. Early detection and recognition of modifiable psychosocial risk factors can reduce glucose intolerance during pregnancy. Evaluating the benefits of screening for psychosocial factors and timely management of gestational diabetes mellitus can be helpful in India.

Integrative multiomics analysis of infant gut microbiome and serum metabolome reveals key molecular biomarkers of early onset childhood obesity

Evidence supports a complex interplay of gut microbiome and host metabolism as regulators of obesity. The metabolic phenotype and microbial metabolism of host diet may also contribute to greater obesity risk in children early in life. This study aimed to identify features that discriminated overweight/obese from normal weight infants by integrating gut microbiome and serum metabolome profiles. This prospective analysis included 50 South Asian children living in Canada, selected from the SouTh Asian biRth cohorT (START). Serum metabolites were measured by multisegment injection-capillary electrophoresis-mass spectrometry and the relative abundance of bacterial 16S rRNA gene amplicon sequence variant was evaluated at 1 year. Cumulative body mass index (BMI_AUC) and skinfold thickness (SSF_AUC) scores were calculated from birth to 3 years as the total area under the growth curve (AUC). BMI_AUC and/or SSF_AUC >85th percentile was used to define overweight/obesity. Data Integration Analysis for Biomarker discovery using Latent cOmponent (DIABLO) was used to identify discriminant features associated with childhood overweight/obesity. The associations between identified features and anthropometric measures were examined using logistic regression. Circulating metabolites including glutamic acid, acetylcarnitine, carnitine, and threonine were positively, whereas γ-aminobutyric acid (GABA), symmetric dimethylarginine (SDMA), and asymmetric dimethylarginine (ADMA) were negatively associated with childhood overweight/obesity. The abundance of the Pseudobutyrivibrio and Lactobacillus genera were positively, and Clostridium sensu stricto 1 and Akkermansia were negatively associated with childhood overweight/obesity. Integrative analysis revealed that Akkermansia was positively whereas Lactobacillus was inversely correlated with GABA and SDMA, and Pseudobutyrivibrio was inversely correlated with GABA. This study provides insights into metabolic and microbial signatures which may regulate satiety, energy metabolism, inflammatory processes, and/or gut barrier function, and therefore, obesity trajectories in childhood. Understanding the functional capacity of these molecular features and potentially modifiable risk factors such as dietary exposures early in life may offer a novel approach for preventing childhood obesity.

A culturally tailored personaliseD nutrition intErvention in South ASIan women at risk of Gestational Diabetes Mellitus (DESI-GDM): a randomised controlled trial protocol

INTRODUCTION

South Asians are more likely to develop gestational diabetes mellitus (GDM) than white Europeans. Diet and lifestyle modifications may prevent GDM and reduce undesirable outcomes in both the mother and offspring. Our study seeks to evaluate the effectiveness and participant acceptability of a culturally tailored, personalised nutrition intervention on the glucose area under the curve (AUC) after a 2-hour 75 g oral glucose tolerance test (OGTT) in pregnant women of South Asian ancestry with GDM risk factors.

METHODS AND ANALYSIS

A total of 190 South Asian pregnant women with at least 2 of the following GDM risk factors-prepregnancy body mass index>23, age>29, poor-quality diet, family history of type 2 diabetes in a first-degree relative or GDM in a previous pregnancy will be enrolled during gestational weeks 12-18, and randomly assigned in a 1:1 ratio to: (1) usual care, plus weekly text messages to encourage walking and paper handouts or (2) a personalised nutrition plan developed and delivered by a culturally congruent dietitian and health coach; and FitBit to track steps. The intervention lasts 6-16 weeks, depending on week of recruitment. The primary outcome is the glucose AUC from a three-sample 75 g OGTT 24-28 weeks' gestation. The secondary outcome is GDM diagnosis, based on Born-in-Bradford criteria (fasting glucose>5.2 mmol/L or 2 hours post load>7.2 mmol/L).

ETHICS AND DISSEMINATION

The study has been approved by the Hamilton Integrated Research Ethics Board (HiREB #10942). Findings will be disseminated among academics and policy-makers through scientific publications along with community-orientated strategies.

TRIAL REGISTRATION NUMBER

NCT03607799.

The association of maternal sugary beverage consumption during pregnancy and the early years with childhood sugary beverage consumption

OBJECTIVES

A woman's food choices during pregnancy may be associated with her offspring's food choices. Several studies support an association between childhood sugary beverage (SB) consumption and poor cardiometabolic health. This study aimed to assess the association of maternal SB consumption during pregnancy and later, with her offspring's SB consumption in early infancy and childhood.

METHODS

A total of 1945 women and 1595 children participating in 3 Canadian studies reported SB consumption during pregnancy, at 2 years of age, and/or at school age (5 to 8 years old). Mother and offspring SB intakes were self-reported by mothers. Multivariable linear regression analyses were conducted within each cohort and cohort data were combined using fixed effect meta-analyses.

RESULTS

Maternal SB consumption during pregnancy was associated with higher offspring SB consumption at 2 years of age (standardized β = 0.19 predicted change in the number of standard deviations of offspring SB intake for an increase of 1 standard deviation in maternal serving [95% CI: 0.16 to 0.22]). Concurrent maternal SB consumption was associated with higher offspring SB intake when children were aged 5 to 8 years (standardized β= 0.25 [95% CI: 0.10 to 0.40]).

CONCLUSION

Maternal SB consumption during pregnancy is associated with a marginally higher SB intake among their offspring at age 2, and concurrent maternal consumption is associated with a higher SB intake among school-aged offspring (5 to 8 years old). Future interventions tailored for pregnancy and early childrearing years to reduce SB intakes of mothers may reduce young children's SB intake.

Associations Between ADHD Symptoms and Maternal and Birth Outcomes: An Exploratory Analysis in a Multi-Country Cohort of Expectant Mothers

OBJECTIVE

ADHD symptoms can adversely impact functioning in a range of domains relevant for maternal well-being and fetal development; however, there has been almost no research examining their impact during pregnancy. We aimed to address this gap.

METHOD

We used data (n = 1,204) from a longitudinal birth cohort study spanning eight countries to address this gap.

RESULTS

ADHD symptoms in the third trimester of pregnancy were associated with lower social support from family (b = -0.16, p = .031), friends (b = -0.16, p = .024), and significant others (b = -0.09, p = .001); higher stress (b = 0.34, p < .001) and depressive symptoms (b = 0.31, p < .001), and increased likelihood of an unwanted pregnancy (b = 0.30, p = .009). Significant associations with tobacco use (b = 0.36, p = .023) and premature birth (b = 0.35, p = .007) did not survive correction for multiple comparisons and there were no significant associations with alcohol use, low birth weight, or unplanned pregnancy.

CONCLUSION

Results suggest that women with ADHD symptoms could benefit from earlier, more regular screening for mental health difficulties and greater mental health support during pregnancy.

The genetic risk of gestational diabetes in South Asian women

South Asian women are at increased risk of developing gestational diabetes mellitus (GDM). Few studies have investigated the genetic contributions to GDM risk. We investigated the association of a type 2 diabetes (T2D) polygenic risk score (PRS), on its own, and with GDM risk factors, on GDM-related traits using data from two birth cohorts in which South Asian women were enrolled during pregnancy. 837 and 4372 pregnant South Asian women from the SouTh Asian BiRth CohorT (START) and Born in Bradford (BiB) cohort studies underwent a 75-g glucose tolerance test. PRSs were derived using genome-wide association study results from an independent multi-ethnic study (~18% South Asians). Associations with fasting plasma glucose (FPG); 2 hr post-load glucose (2hG); area under the curve glucose; and GDM were tested using linear and logistic regressions. The population attributable fraction (PAF) of the PRS was calculated. Every 1 SD increase in the PRS was associated with a 0.085 mmol/L increase in FPG ([95% confidence interval, CI=0.07-0.10], p=2.85×10^-20); 0.21 mmol/L increase in 2hG ([95% CI=0.16-0.26], p=5.49×10^-16); and a 45% increase in the risk of GDM ([95% CI=32-60%], p=2.27×10^-14), independent of parental history of diabetes and other GDM risk factors. PRS tertile 3 accounted for 12.5% of the population's GDM alone, and 21.7% when combined with family history. A few weak PRS and GDM risk factors interactions modulating FPG and GDM were observed. Taken together, these results show that a T2D PRS and family history of diabetes are strongly and independently associated with multiple GDM-related traits in women of South Asian descent, an effect that could be modulated by other environmental factors.

Cohort profile: maternal antecedents of adiposity and studying the transgenerational role of hyperglycaemia and insulin (MAASTHI)

PURPOSE

The Maternal Antecedents of Adiposity and Studying the transgenerational role of Hyperglycaemia and Insulin cohort in Bengaluru, South India, aims to understand the transgenerational role of increased circulating glucose levels or hyperglycaemia and other nutrients and psychosocial environment, on the risk of childhood obesity, as an early marker of chronic diseases.

PARTICIPANTS

Through this paper, we describe the baseline characteristics of the cohort participants and their children, along with plans and challenges. A total of 5694 pregnant women were screened, with 4862 (85.4%) eligible pregnant women recruited at baseline. We assessed anthropometry, Haemoglobin status, Oral Glucose Tolerance Test (OGTT), dietary practices, depressive symptoms using the Edinburgh Postnatal Depression Scale and social support in all women. Follow-up visits involved assessing anthropometry and the health profile of mothers and children.

FINDINGS TO DATE

Among 4862 eligible participants recruited, 3260 (67%) underwent OGTT, while 2962 participants completed OGTT (90.9%). During the pregnancy, 9.7% of women were obese (>90th percentile of skinfold thickness), and 14.3% had gestational diabetesmellitus. Moreover, 6.2% and 16.8% of women had symptoms suggestive of depression during pregnancy and the immediate postnatal period, respectively. We found that 3.3% of children were small for gestational age, 10.8% were large for gestational age and 9.7% of children were obese at birth.

FUTURE PLANS

We have completed recruitment and baseline data collection in 2019, and are conducting annual follow-ups until age 4 of the participant's children. For delineating causal pathways of childhood obesity, blood aliquots are stored in the biorepository. The study will inform policy formulation and community awareness in the prevention and control of non-communicable diseases and health promotion.

Sources of Variation in Food-Related Metabolites during Pregnancy

The extent to which variation in food-related metabolites are attributable to non-dietary factors remains unclear, which may explain inconsistent food-metabolite associations observed in population studies. This study examined the association between non-dietary factors and the serum concentrations of food-related biomarkers and quantified the amount of variability in metabolite concentrations explained by non-dietary factors. Pregnant women (n = 600) from two Canadian birth cohorts completed a validated semi-quantitative food frequency questionnaire, and serum metabolites were measured by multisegment injection-capillary electrophoresis-mass spectrometry. Hierarchical linear modelling and principal component partial R-square (PC-PR2) were used for data analysis. For proline betaine and DHA (mainly exogenous), citrus foods and fish/fish oil intake, respectively, explained the highest proportion of variability relative to non-dietary factors. The unique contribution of dietary factors was similar (15:0, 17:0, hippuric acid, TMAO) or lower (14:0, tryptophan betaine, 3-methylhistidine, carnitine) compared to non-dietary factors (i.e., ethnicity, maternal age, gestational age, pre-pregnancy BMI, physical activity, and smoking) for metabolites that can either be produced endogenously, biotransformed by gut microbiota, and/or derived from multiple food sources. The results emphasize the importance of adjusting for non-dietary factors in future analyses to improve the accuracy and precision of the measures of food intake and their associations with health and disease.

Gene-environment interactions related to maternal exposure to environmental and lifestyle-related chemicals during pregnancy and the resulting adverse fetal growth: a review

Background

There are only limited numbers of reviews on the association of maternal-child genetic polymorphisms and environmental and lifestyle-related chemical exposure during pregnancy with adverse fetal growth. Thus, this article aims to review: (1) the effect of associations between the above highlighted factors on adverse fetal growth and (2) recent birth cohort studies regarding environmental health risks.

Methods

Based on a search of the PubMed database through August 2021, 68 epidemiological studies on gene-environment interactions, focusing on the association between environmental and lifestyle-related chemical exposure and adverse fetal growth was identified. Moreover, we also reviewed recent worldwide birth cohort studies regarding environmental health risks.

Results

Thirty studies examined gene-smoking associations with adverse fetal growth. Sixteen maternal genes significantly modified the association between maternal smoking and adverse fetal growth. Two genes significantly related with this association were detected in infants. Moreover, the maternal genes that significantly interacted with maternal smoking during pregnancy were cytochrome P450 1A1 (CYP1A1), X-ray repair cross-complementing protein 3 (XRCC3), interleukin 6 (IL6), interleukin 1 beta (IL1B), human leukocyte antigen (HLA) DQ alpha 1 (HLA-DQA1), HLA DQ beta 1 (HLA-DQB1), and nicotinic acetylcholine receptor. Fetal genes that had significant interactions with maternal smoking during pregnancy were glutathione S-transferase theta 1 (GSTT1) and fat mass and obesity-associated protein (FTO). Thirty-eight studies examined the association between chemical exposures and adverse fetal growth. In 62 of the 68 epidemiological studies (91.2%), a significant association was found with adverse fetal growth. Across the studies, there was a wide variation in the analytical methods used, especially with respect to the genetic polymorphisms of interest, environmental and lifestyle-related chemicals examined, and the study design used to estimate the gene-environment interactions. It was also found that a consistently increasing number of European and worldwide large-scale birth cohort studies on environmental health risks have been conducted since approximately 1996.

Conclusion

There is some evidence to suggest the importance of gene-environment interactions on adverse fetal growth. The current knowledge on gene-environment interactions will help guide future studies on the combined effects of maternal-child genetic polymorphisms and exposure to environmental and lifestyle-related chemicals during pregnancy.

Supplementary information

The online version contains supplementary material available at https://doi.org/10.1265/ehpm.21-00033.

Serum metabolomic signatures of gestational diabetes in South Asian and white European women

INTRODUCTION

This study aimed to identify serum metabolomic signatures associated with gestational diabetes mellitus (GDM), and to examine if ethnic-specific differences exist between South Asian and white European women.

RESEARCH DESIGN AND METHODS

Prospective cohort study with a nested case-control analysis of 600 pregnant women from two Canadian birth cohorts; using an untargeted approach, 63 fasting serum metabolites were measured and analyzed using multisegment injection-capillary electrophoresis-mass spectrometry. Multivariate logistic regression modeling was conducted overall and by cohort.

RESULTS

The proportion of women with GDM was higher in South Asians (27.1%) compared with white Europeans (17.9%). Several amino acid, carbohydrate, and lipid pathways related to GDM were common to South Asian and white European women. Elevated circulating concentrations of glutamic acid, propionylcarnitine, tryptophan, arginine, 2-hydroxybutyric acid, 3-hydroxybutyric acid, and 3-methyl-2-oxovaleric acid were associated with higher odds of GDM, while higher glutamine, ornithine, oxoproline, cystine, glycine with lower odds of GDM. Per SD increase in glucose concentration, the odds of GDM increased (OR=2.07, 95% CI 1.58 to 2.71), similarly for metabolite ratios: glucose to glutamine (OR=2.15, 95% CI 1.65 to 2.80), glucose to creatinine (OR=1.79, 95% CI 1.39 to 2.32), and glutamic acid to glutamine (OR=1.46, 95% CI 1.16 to 1.83). South Asians had higher circulating ratios of glucose to glutamine, glucose to creatinine, arginine to ornithine, and citrulline to ornithine, compared with white Europeans.

CONCLUSIONS

We identified a panel of serum metabolites implicated in GDM pathophysiology, consistent in South Asian and white European women. The metabolic alterations leading to larger ratios of glucose to glutamine, glucose to creatinine, arginine to ornithine, and citrulline to ornithine in South Asians likely reflect the greater burden of GDM among South Asians compared with white Europeans.

DNA methylation changes in cord blood and the developmental origins of health and disease – a systematic review and replication study

Background

Environmental exposures in utero which modify DNA methylation may have a long-lasting impact on health and disease in offspring. We aimed to identify and replicate previously published genomic loci where DNA methylation changes are attributable to in utero exposures in the NutriGen birth cohort studies Alliance.

Methods

We reviewed the literature to identify differentially methylated sites of newborn DNA which are associated with the following five traits of interest maternal diabetes, pre-pregnancy body mass index (BMI), diet during pregnancy, smoking, and gestational age. We then attempted to replicate these published associations in the Canadian Healthy Infant Longitudinal Development (CHILD) and the South Asian birth cohort (START) cord blood epigenome-wide data.

Results

We screened 68 full-text articles and identified a total of 17 cord blood epigenome-wide association studies (EWAS) of the traits of interest. Out of the 290 CpG sites reported, 19 were identified in more than one study; all of them associated with maternal smoking. In CHILD and START EWAS, thousands of sites associated with gestational age were identified and maintained significance after correction for multiple testing. In CHILD, there was differential methylation observed for 8 of the published maternal smoking sites. No other traits tested (i.e., folate levels, gestational diabetes, birthweight) replicated in the CHILD or START cohorts.

Conclusions

Maternal smoking during pregnancy and gestational age are strongly associated with differential methylation in offspring cord blood, as assessed in the EWAS literature and our birth cohorts. There are a limited number of reported methylation sites associated in more than two independent studies related to pregnancy. Additional large studies of diverse populations with fine phenotyping are needed to produce robust epigenome-wide data in order to further elucidate the effect of intrauterine exposures on the infants’ methylome.

Feasibility of a birth-cohort in Pakistan: evidence for better lives study

Background

Evidence for Better Lives Study Foundational Research (EBLS-FR) is a preliminary endeavor to establish the feasibility of a global birth cohort, and within this feasibility study, piloting the research instrument, with participants from eight lower middle-income countries across the globe. It aims to investigate mediators and moderators of child development and wellbeing; it envisages informing policy and practice change to promote child health and wellbeing globally. Pakistan is one of the resource poor lower middle-income country (LMIC) taking part in this global birth cohort; we report the feasibility of establishing such a birth cohort in Pakistan.

Method

From March 2019 to July 2019, 153 third trimester pregnant women were identified, using community health worker registers, and approached for baseline demographics and a number of maternal wellbeing, mental health, support-related information, and stress-related biomarkers from bio-samples in a peri-urban area of Islamabad Capital Territory. One hundred fifty of these women gave consent and participated in the study. From October 2019 to December 2019, we re-contacted and were able to follow 121 of these women in the 8–24 weeks postnatal period. All interviews were done after obtaining informed consent and data were collected electronically.

Results

One hundred fifty (98.0%) third trimester pregnant women consented and were successfully interviewed, 111 (74.0%) provided bio-samples and 121 (80.6%) were followed up postnatally. Their mean age and years of schooling was 27.29 (SD = 5.18) and 7.77 (SD = 4.79) respectively. A majority (82.3%) of the participants were housewives. Nearly a tenth were first time mothers. Ninety-two (61.3%) of the women reported current pregnancy to have been unplanned. Overall wellbeing and mental health were reported to be poor (WHO-5 mean scores 49.41 (SD = 32.20) and PHQ-9 mean scores 8.23 (SD = 7.0)). Thirty-eight (21.8%) of the women reported four or more adverse childhood experiences; 46 (31.3%) reported intimate partner violence during their current pregnancy. During the postnatal follow up visits, 72 (58.0%) of the women reported breastfeeding their infants.

Conclusion

The foundational research demonstrated that Pakistan site could identify, approach, interview, and follow up women and children postnatally, with a high response rates for both the follow up visits and bio-samples. Therefore, a future larger-scale pregnancy birth cohort study in Pakistan is feasible.

Studies to Improve Perinatal Health through Diet and Lifestyle among South Asian Women Living in Canada: A Brief History and Future Research Directions

South Asians (i.e., people who originate from India, Pakistan, Sri Lanka, Nepal, and Bangladesh) have higher cardiovascular disease rates than other populations, and these differences persist in their offspring. Nutrition is a critical lifestyle-related factor that influences fetal development, and infant and child health in early life. In high-income countries such as Canada, nutrition-related health risks arise primarily from overnutrition, most strikingly for obesity and associated non-communicable diseases. Evidence for developmental programming during fetal life underscores the critical influence of maternal diet on fetal growth and development, backed by several birth cohort studies including the Pune Maternal Nutrition Study, the South Asian Birth Cohort Study, and the Born in Bradford Study. Gestational diabetes mellitus is a strong risk factor for type 2 diabetes, future atherosclerosis and cardiovascular disease in the mother and increases the risk of type 2 diabetes in her offspring. Non-pharmacological trials to prevent gestational diabetes are few, often not randomized, and are heterogeneous with respect to design, and outcomes have not converged upon a single optimal prevention strategy. The aim of this review is to provide an understanding of the current knowledge around perinatal nutrition and gestational diabetes among the high-risk South Asian population as well as summarize our research activities investigating the role of culturally-tailored nutrition advice to South Asian women living in high-income settings such as Canada. In this paper, we describe these qualitative and quantitative studies, both completed and underway. We conclude with a description of the design of a randomized trial of a culturally tailored personalized nutrition intervention to reduce gestational glycaemia in South Asian women living in Canada and its implications.

The maternal serum metabolome by multisegment injection-capillary electrophoresis-mass spectrometry: a high-throughput platform and standardized data workflow for large-scale epidemiological studies

A standardized data workflow is described for large-scale serum metabolomic studies using multisegment injection-capillary electrophoresis-mass spectrometry. Multiplexed separations increase throughput (<4 min/sample) for quantitative determination of 66 polar/ionic metabolites in serum filtrates consistently detected (coefficient of variance (CV) <30%) with high frequency (>75%) from a multi-ethnic cohort of pregnant women (n = 1,004). We outline a validated protocol implemented in four batches over a 7-month period that includes details on preventive maintenance, sample workup, data preprocessing and metabolite authentication. We achieve stringent quality control (QC) and robust batch correction of long-term signal drift with good mutual agreement for a wide range of metabolites, including serum glucose as compared to a clinical chemistry analyzer (mean bias = 11%, n = 668). Control charts for a recovery standard (mean CV = 12%, n = 2,412) and serum metabolites in QC samples (median CV = 13%, n = 202) demonstrate acceptable intermediate precision with a median intraclass coefficient of 0.87. We also report reference intervals for 53 serum metabolites from a diverse population of women in their second trimester of pregnancy.

Determinants of Breastfeeding Practices and Its Association With Infant Anthropometry: Results From a Prospective Cohort Study in South India

Introduction

Despite national efforts for promoting exclusive breastfeeding (EBF) during the first 6 months of the infants' life, breastfeeding rates are low in India. Evidence on the interference of supplementary food on optimal nourishment and growth of the infant has also been well-established. Our study was undertaken to assess the effect of breastfeeding practices on infant anthropometry and determine the various factors affecting breastfeeding practices.

Methods

A prospective cohort study - Maternal antecedents of adiposity and studying the transgenerational role of hyperglycemia and insulin (MAASTHI) was conducted at a tertiary care public hospital in Bengaluru, South India. From the consenting women, data such as obstetric history, infant feeding practices, anthropometry of mother and child, the psychosocial status of the women using the Edinburgh Postnatal Depression Scale (EPDS), was collected at baseline and subsequent follow-up: post-delivery and 14 weeks after birth. In this study, we analyzed data collected from April 2016 to April 2018, with descriptive statistics presented in mean and standard deviation, and logistic regression adjusting for confounders.

Results

Among the 240 women enrolled in the study, 33% (n= 80) were using supplementary food for their infants at 14 weeks of infants age. Infants who received supplementary feeding at age 14 weeks had nearly 2.5 times higher odds of being wasted (OR: 2.449, p-value: 0.002) as compared to exclusively breastfed infants.

Conclusion

Infants between 14 to 16 weeks of age who received supplementary feeding were at risk of wasting as compared to exclusively breastfed infants. Despite strong evidence in support of the benefits of exclusive breastfeeding, awareness in urban women in India is low. Increased focus on promoting exclusive breastfeeding is necessary to ensure proper nutritional intake and healthy growth of infants.

Evidence for Better Lives Study: a comparative birth-cohort study on child exposure to violence and other adversities in eight low- and middle-income countries - foundational research (study protocol)

INTRODUCTION

Violence against children is a health, human rights and social problem affecting approximately half of the world's children. Its effects begin at prenatal stages with long-lasting impacts on later health and well-being. The Evidence for Better Lives Study (EBLS) aims to produce high-quality longitudinal data from cities in eight low- and middle-income countries-Ghana, Jamaica, Pakistan, the Philippines, Romania, South Africa, Sri Lanka and Vietnam-to support effective intervention to reduce violence against children. EBLS-Foundational Research (EBLS-FR) tests critical aspects of the planned EBLS, including participant recruitment and retention, data collection and analysis. Alongside epidemiological estimates of levels and predictors of exposure to violence and adversity during pregnancy, we plan to explore mechanisms that may link exposure to violence to mothers' biological stress markers and subjective well-being.

METHODS AND ANALYSES

EBLS-FR is a short longitudinal study with a sample of 1200 pregnant women. Data are collected during the last trimester of pregnancy and 2 to 6 months after birth. The questionnaire for participating women has been translated into nine languages. Measures obtained from mothers will include, among others, mental and physical health, attitudes to corporal punishment, adverse childhood experiences, prenatal intimate partner violence, substance use and social/community support. Hair and dry blood spot samples are collected from the pregnant women to measure stress markers. To explore research participation among fathers, EBLS-FR is recruiting 300 fathers in the Philippines and Sri Lanka.

ETHICS AND DISSEMINATION

The study received ethical approvals at all recruiting sites and universities in the project. Results will be disseminated through journal publications, conferences and seminar presentations involving local communities, health services and other stakeholders. Findings from this work will help to adjust the subsequent stages of the EBLS project.

Maternal Diet and the Serum Metabolome in Pregnancy: Robust Dietary Biomarkers Generalizable to a Multiethnic Birth Cohort

BACKGROUND

Advances in metabolomics are anticipated to decipher associations between dietary exposures and health. Replication biomarker studies in different populations are critical to demonstrate generalizability.

OBJECTIVES

To identify and validate robust serum metabolites associated with diet quality and specific foods in a multiethnic cohort of pregnant women.

DESIGN

In this cross-sectional analysis of 3 multiethnic Canadian birth cohorts, we collected semiquantitative FFQ and serum data from 900 women at the second trimester of pregnancy. We calculated a diet quality score (DQS), defined as daily servings of "healthy" minus "unhealthy" foods. Serum metabolomics was performed by multisegment injection-capillary electrophoresis-mass spectrometry, and specific serum metabolites associated with maternal DQSs were identified. We combined the results across all 3 cohorts using meta-analysis to classify robust dietary biomarkers (r > ± 0.1; P < 0.05).

RESULTS

Diet quality was higher in the South Asian birth cohort (mean DQS = 7.1) than the 2 white Caucasian birth cohorts (mean DQS <3.2). Sixty-six metabolites were detected with high frequency (>75%) and adequate precision (CV <30%), and 47 were common to all cohorts. Hippuric acid was positively associated with healthy diet score in all cohorts, and with the overall DQS only in the primarily white Caucasian cohorts. We observed robust correlations between: 1) proline betaine-citrus foods; 2) 3-methylhistidine-red meat, chicken, and eggs; 3) hippuric acid-fruits and vegetables; 4) trimethylamine N-oxide (TMAO)-seafood, meat, and eggs; and 5) tryptophan betaine-nuts/legumes.

CONCLUSIONS

Specific serum metabolites reflect intake of citrus fruit/juice, vegetables, animal foods, and nuts/legumes in pregnant women independent of ethnicity, fasting status, and delays to storage across multiple collection centers. Robust biomarkers of overall diet quality varied by cohort. Proline betaine, 3-methylhistidine, hippuric acid, TMAO, and tryptophan betaine were robust dietary biomarkers for investigations of maternal nutrition in diverse populations.

A scientometric analysis of birth cohorts in South Asia: Way forward for Pakistan

The present study aims to: a) systematically map the of birth cohort studies from the South Asian region b) examine the major research foci and landmark contributions from these cohorts using reproducible scientometric techniques and c) offer recommendations on establishing new birth cohorts in Pakistan, building upon the strengths, weaknesses and gaps of previous cohorts. Bibliographic records for a total of 260 articles, published during through December 2018, were retrieved from the Web of Science (core database). All data were analysed using Microsoft Excel (2013), Web of Science platform and CiteSpace. A series of network analysis were then run for each time-period using the link reduction method and pathfinder network scaling. The co-cited articles were clustered into their homogeneous research clusters. The clusters were named using the Latent Semantic Indexing (LSI) method that utilized author keywords as source of names for these clusters. The scientometric analyses of original research output from these birth cohorts also paint a pessimistic landscape in Pakistan- where Pakistani sites for birth cohorts contributed only 31 publications; a majority of these utilized the MAL-ED birth cohort data. A majority of original studies were published from birth cohorts in India (156), Bangladesh (63), and Nepal (15). Out of these contributions, 31 studies reported data from multiple countries. The three major birth cohorts include prospective and multi-country MAL-ED birth cohort and The Pakistan Early Childhood Development Scale Up Trial, and a retrospective Maternal and infant nutrition intervention cohort. In addition to these, a few small-scale birth cohorts reported findings pertaining to neonatal sepsis, intrauterine growth retardation and its effects on linear growth of children and environmental enteropathy.

Fine-tuning of Genome-Wide Polygenic Risk Scores and Prediction of Gestational Diabetes in South Asian Women

Gestational diabetes Mellitus (GDM) affects 1 in 7 births and is associated with numerous adverse health outcomes for both mother and child. GDM is suspected to share a large common genetic background with type 2 diabetes (T2D). The aim of our study was to characterize different GDM polygenic risk scores (PRSs) and test their association with GDM using data from the South Asian Birth Cohort (START). PRSs were derived for 832 South Asian women from START using the pruning and thresholding (P + T), LDpred, and GraBLD methods. Weights were derived from a multi-ethnic and a white Caucasian study of the DIAGRAM consortium. GDM status was defined using South Asian-specific glucose values in response to an oral glucose tolerance test. Association with GDM was tested using logistic regression. Results were replicated in South Asian women from the UK Biobank (UKB) study. The top ranking P + T, LDpred and GraBLD PRSs were all based on DIAGRAM's multi-ethnic study. The best PRS was highly associated with GDM in START (AUC = 0.62, OR = 1.60 [95% CI = 1.44-1.69]), and in South Asian women from UKB (AUC = 0.65, OR = 1.69 [95% CI = 1.28-2.24]). Our results highlight the importance of combining genome-wide genotypes and summary statistics from large multi-ethnic studies to optimize PRSs in South Asians.

Ethnic differences in maternal diet in pregnancy and infant eczema

BACKGROUND

The global prevalence of childhood eczema has increased over the last few decades, with a marked increase in high-income countries. Differences in prevalence of childhood eczema between countries and ethnicities suggest that genetic and early modifiable environmental factors, such as dietary intake, may underlie this observation. To investigate the association between pregnancy diet and infant eczema in a consortium of prospective Canadian birth cohorts predominantly comprised of white Europeans and South Asians.

METHODS

We evaluated the association of maternal dietary patterns reported during pregnancy (assessed at 24-28 weeks gestation using a semi-quantitiative food-frequency questionnaire) with parent-reported physician-diagnosed infant eczema at 1-year from 2,160 mother-infant pairs. Using three dietary patterns ("Western", "plant-based", and "Balanced") previously derived in this cohort using principal component analysis, we used multivariable logistic regression to determine the association of these dietary patterns with infant eczema, adjusted for potential confounders.

RESULTS

We observed a lower odds of eczema in the full sample combining white Europeans and South Asians with greater adherence to a plant-based (OR = 0.65; 95% CI: 0.55, 0.76; <0.001) and Western dietary pattern (OR = 0.73; 95% CI: 0.60, 0.89; P<0.01), after adjusting for other known predictors of eczema, including ethnicity, which was not significant. No associations were observed for the balanced diet. An interaction between the Western diet and ethnicity was observed (P<0.001). Following stratification by ethnicity, a protective association between the plant-based diet and infant eczema was confirmed in both white Europeans (OR = 0.59; 95% CI: 0.47, 0.74; P<0.001) and South Asians (OR = 0.77; 95% CI: 0.61, 0.97; P = 0.025). In white Europeans only, a Western diet was associated with a lower odds of infant eczema (OR = 0.69; 95% CI: 0.56, 0.87; P = 0.001) while a balanced diet increased the odds of infant eczema (OR = 1.23; 95% CI: 1.02, 1.49; P = 0.03). Beyond a plant-based diet, no significant associations with other dietary patterns were observed in South Asians.

CONCLUSION

A plant-based diet during pregnancy is associated with a lowered odds of infant eczema at 1 year in all participants. Future studies of the components of plant-based diet which underlie the lower risk of eczema are needed.

Small for gestational age babies and depressive symptoms of mothers during pregnancy: Results from a birth cohort in India

Background: Annually, more than a million low birthweight (LBW) is born in India, often afflicting disadvantaged families. Several studies have undertaken the association of poverty, nutritional status, and obstetric factors with LBW. Through our study, we aimed to examine the possibility of any relation between the Edinburgh Postnatal Depression Scale (EPDS) score measured during pregnancy with the incidence of babies born Small for Gestational Age (SGA). Methods: Pregnant women attending the antenatal clinic at a public hospital between 14 to 32 weeks were recruited from April 2016 to Oct 2017. The EPDS was administered to assess depression through face-to-face interviews. Newborn anthropometry was performed post-delivery. For analysis, birth weight <10 percentile was classified as SGA. Results: Prevalence of depressive symptoms (EPDS score >11) was 16.5% (n=108/654) in antenatal mothers. These women delivered a higher proportion of SGA babies (21.3 v/s 15.8) compared to women with no symptoms. The odds of women giving birth to a child with SGA were twice as high for women with EPDS scores >11 (adjusted OR = 2.03; 95% CI = 1.12 - 3.70) compared to the women with EPDS scores of ≤11, The EPDS 12 (Adjusted OR = 1.96; 95% CI = 1.04 - 3.69) and EPDS 13 (Adjusted OR = 2.42; 95% CI = 1.24 - 4.70) cut-off categories also proved to be a risk factor for SGA with significant p-value (0.0006 and 0.0003) and the individuals with more than 13 EPDS score is found to have the highest odds of SGA. Conclusions: We found a strong association of antenatal depressive symptoms during pregnancy with SGA measured by EPDS. Thus, we recommend the implementation of timely and effective screening, diagnostic services, and evidence-based antenatal mental health services to combat SGA and further associated-metabolic syndromes.

A qualitative investigation of optimal perinatal health: the perspectives of south Asian grandmothers living in southern Ontario, Canada

Background

Perinatal health-seeking behaviours are influenced by various factors, including personal beliefs. South Asian women, who often live within a wide kinship system, can be influenced by the advice and guidance of their mothers and/or mothers-in-law.

Methods

To explore the cultural health perceptions of South Asian grandmothers within this context, we used constructivist grounded theory to sample and interview 17 South Asian grandmothers who reside in Southern Ontario, Canada. Interviews were audio-recorded, transcribed verbatim, and coded/analyzed by three independent coders.

Results

Many grandmothers emphasized that the preconception phase should focus on building healthy habits around nutrition, physical activity, and mental wellness; the pregnancy period should encompass an enriched environment (positive relationships, healthy routines, nutritional enhancement); and the postpartum phase should emphasize healing and restoration for both the mother and newborn (self-care, bonding, rebuilding healthy habits). Many of the grandmothers conceptualized these stages as a cyclical relationship where healing and restoration transitions gradually to re-establishing healthy habits before having a subsequent child. They also expressed responsibility in supporting their daughters and/or daughters-in-law with their family units and encouraging the transfer of perinatal health information.

Conclusions

South Asian grandmothers are involved in supporting the family units of their children and involving them in perinatal health programming can be an effective way to translate health knowledge to South Asian women.

Small for gestational age babies and depressive symptoms of mothers during pregnancy: Results from a birth cohort in India

Background: Annually, more than a million low birthweight (LBW) is born in India, often afflicting disadvantaged families. Several studies have undertaken the association of poverty, nutritional status, and obstetric factors with LBW. Through our study, we aimed to examine the possibility of any relation between the Edinburgh Postnatal Depression Scale (EPDS) score measured during pregnancy with the incidence of babies born Small for Gestational Age (SGA). Methods: Pregnant women attending the antenatal clinic at a public hospital between 14 to 32 weeks were recruited from April 2016 to Oct 2017. The EPDS was administered to assess depression through face-to-face interviews. Newborn anthropometry was performed post-delivery. For analysis, birth weight <10 percentile was classified as SGA. Results: Prevalence of depressive symptoms (EPDS score >11) was 16.5% (n=108/654) in antenatal mothers. These women delivered a higher proportion of SGA babies (21.3 v/s 15.8) compared to women with no symptoms. The odds of women giving birth to a child with SGA were twice as high for women with EPDS scores >11 (adjusted OR = 2.03; 95% CI = 1.12 - 3.70) compared to the women with EPDS scores of ≤11, The EPDS 12 (Adjusted OR = 1.96; 95% CI = 1.04 - 3.69) and EPDS 13 (Adjusted OR = 2.42; 95% CI = 1.24 - 4.70) cut-off categories also proved to be a risk factor for SGA with significant p-value (0.0006 and 0.0003) and the individuals with more than 13 EPDS score is found to have the highest odds of SGA. Conclusions: We found a strong association of antenatal depressive symptoms during pregnancy with SGA measured by EPDS. Thus, we recommend the implementation of timely and effective screening, diagnostic services, and evidence-based antenatal mental health services to combat SGA and further associated-metabolic syndromes.

Small for gestational age babies and depressive symptoms of mothers during pregnancy: Results from a birth cohort in India

Background: Annually, more than a million low birthweight (LBW) is born in India, often afflicting disadvantaged families. Several studies have undertaken the association of poverty, nutritional status, and obstetric factors with LBW. Through our study, we aimed to examine the possibility of any relation between the Edinburgh Postnatal Depression Scale (EPDS) score measured during pregnancy with the incidence of babies born Small for Gestational Age (SGA).

Methods: Pregnant women attending the antenatal clinic at a public hospital between 14 to 32 weeks were recruited from April 2016 to Oct 2017. The EPDS was administered to assess depression through face-to-face interviews. Newborn anthropometry was performed post-delivery. For analysis, birth weight <10 percentile was classified as SGA.

Results: Prevalence of depressive symptoms (EPDS score >11) was 16.5% (n=108/654) in antenatal mothers. These women delivered a higher proportion of SGA babies (21.3 v/s 15.8) compared to women with no symptoms. The odds of women giving birth to a child with SGA were twice as high for women with EPDS scores >11 (adjusted OR = 2.03; 95% CI = 1.12 – 3.70) compared to the women with EPDS scores of ≤11, The EPDS 12 (Adjusted OR = 1.96; 95% CI = 1.04 – 3.69) and EPDS 13 (Adjusted OR = 2.42; 95% CI = 1.24 – 4.70) cut-off categories also proved to be a risk factor for SGA with significant p-value (0.0006 and 0.0003) and the individuals with more than 13 EPDS score is found to have the highest odds of SGA.

Conclusions: We found a strong association of antenatal depressive symptoms during pregnancy with SGA measured by EPDS. Thus, we recommend the implementation of timely and effective screening, diagnostic services, and evidence-based antenatal mental health services to combat SGA and further associated-metabolic syndromes.

The influence of maternal and infant nutrition on cardiometabolic traits: novel findings and future research directions from four Canadian birth cohort studies

A mother's nutritional choices while pregnant may have a great influence on her baby's development in the womb and during infancy. There is evidence that what a mother eats during pregnancy interacts with her genes to affect her child's susceptibility to poor health outcomes including childhood obesity, pre-diabetes, allergy and asthma. Furthermore, after what an infant eats can change his or her intestinal bacteria, which can further influence the development of these poor outcomes. In the present paper, we review the importance of birth cohorts, the formation and early findings from a multi-ethnic birth cohort alliance in Canada and summarise our future research directions for this birth cohort alliance. We summarise a method for harmonising collection and analysis of self-reported dietary data across multiple cohorts and provide examples of how this birth cohort alliance has contributed to our understanding of gestational diabetes risk; ethnic and diet-influences differences in the healthy infant microbiome; and the interplay between diet, ethnicity and birth weight. Ongoing work in this birth cohort alliance will focus on the use of metabolomic profiling to measure dietary intake, discovery of unique diet-gene and diet-epigenome interactions, and qualitative interviews with families of children at risk of metabolic syndrome. Our findings to-date and future areas of research will advance the evidence base that informs dietary guidelines in pregnancy, infancy and childhood, and will be relevant to diverse and high-risk populations of Canada and other high-income countries.

Socio-economic, environmental and nutritional characteristics of urban and rural South Indian women in early pregnancy: findings from the South Asian Birth Cohort (START)

Objective

High frequency of low birth weight (LBW) is observed in rural compared with urban Indian women. Since maternal BMI is known to be associated with pregnancy outcomes, the present study aimed to investigate factors associated with BMI in early pregnancy of urban and rural South Indian women.

Design

Prospective observational cohort.

Setting

A hospital-based study conducted at an urban and a rural health centre in Karnataka State.

Subjects

Pregnant women (n 843) aged 18–40 years recruited in early pregnancy from whom detailed sociodemographic, environmental, anthropometric and dietary intake information was collected.

Results

A high proportion of low BMI (32 v. 26 %, P<0·000) and anaemia (48 v. 23 %, P<0·000) was observed in the rural v. the urban cohort. Rural women were younger, had lower body weight, tended to be shorter and less educated. They lived in poor housing conditions, had less access to piped water and good sanitation, used unrefined fuel for cooking and had lower standard of living score. The age (β=0·21, 95 % CI 0·14, 0·29), education level of their spouse (β=1·36, 95 % CI 0·71, 2·71) and fat intake (β=1·24, 95 % CI 0·20, 2·28) were positively associated with BMI in urban women.

Conclusions

Our findings indicate that risk factors associated with BMI in early pregnancy are different in rural and urban settings. It is important to study population-specific risk factors in relation to perinatal health.

Does the impact of a plant-based diet during pregnancy on birth weight differ by ethnicity? A dietary pattern analysis from a prospective Canadian birth cohort alliance

OBJECTIVE

Birth weight is an indicator of newborn health and a strong predictor of health outcomes in later life. Significant variation in diet during pregnancy between ethnic groups in high-income countries provides an ideal opportunity to investigate the influence of maternal diet on birth weight.

SETTING

Four multiethnic birth cohorts based in Canada (the NutriGen Alliance).

PARTICIPANTS

3997 full-term mother-infant pairs of diverse ethnic groups who had principal component analysis-derived diet pattern scores-plant-based, Western and health-conscious-and birth weight data.

RESULTS

No associations were identified between the Western and health-conscious diet patterns and birth weight; however, the plant-based dietary pattern was inversely associated with birth weight (β=-67.6 g per 1-unit increase; P<0.001), and an interaction with non-white ethnicity and birth weight was observed. Ethnically stratified analyses demonstrated that among white Europeans, maternal consumption of a plant-based diet associated with lower birth weight (β=-65.9 g per 1-unit increase; P<0.001), increased risk of small-for-gestational age (SGA; OR=1.46; 95% CI 1.08 to 1.54;P=0.005) and reduced risk of large-for-gestational age (LGA; OR=0.71; 95% CI 0.53 to 0.95;P=0.02). Among South Asians, maternal consumption of a plant-based diet associated with a higher birth weight (β=+40.5 g per 1-unit increase; P=0.01), partially explained by cooked vegetable consumption.

CONCLUSIONS

Maternal consumption of a plant-based diet during pregnancy is associated with birth weight. Among white Europeans, a plant-based diet is associated with lower birth weight, reduced odds of an infant born LGA and increased odds of SGA, whereas among South Asians living in Canada, a plant-based diet is associated with increased birth weight.

Causes and consequences of gestational diabetes in South Asians living in Canada: results from a prospective cohort study

BACKGROUND

The reasons for the increased risk of gestational diabetes among South Asian women are not well understood. We sought to identify the determinants of gestational diabetes and its impact on newborn health in a prospective birth cohort of South Asian women and their babies.

METHODS

As part of the South Asian Birth Cohort (START) prospective birth cohort study in Ontario, we recruited 1012 South Asian women with singleton pregnancies in the second trimester of pregnancy between July 11, 2011, and Nov. 10, 2015. We collected health information and physical measurements and administered an oral glucose tolerance test. Birth weight and skinfold thickness measurements were obtained from their newborns, and cord blood glucose and insulin levels were measured.

RESULTS

The incidence of gestational diabetes was 36.3% (95% confidence interval [CI] 33.3%-39.3%); the age-standardized rate was 40.7%. Factors associated with gestational diabetes included maternal age (odds ratio [OR] 1.08 [95% CI 1.04-1.12]), family history of diabetes (OR 1.65 [95% CI 1.26-2.17]), prepregnancy weight (OR 1.025 [95% CI 1.01-1.04]) and low diet quality (OR 1.57 [95% CI 1.16-2.12]). Maternal height was protective against gestational diabetes (OR 0.97 [95% CI 0.95-0.99]). The population attributable risk due to prepregnancy body mass index and low diet quality was 37.3%. Compared to newborns of women without gestational diabetes, those of women with gestational diabetes had a significantly higher birth weight (3267 [standard error (SE) 23] g v. 3181 [SE 17] g, p = 0.005), greater skinfold thickness (11.7 [SE 0.1] mm v. 11.2 [SE 0.1] mm, p = 0.007) and lower insulin sensitivity (glucose/insulin ratio 0.092 [SE 0.009] mmol/pmol v. 0.129 [SE 0.006] mmol/pmol, p = 0.001).

INTERPRETATION

The modifiable risk factors of prepregnancy weight and low diet quality accounted for 37% of the population attributable risk of gestational diabetes in our cohort. Intervention studies to lower prepregnancy weight and to prevent gestational diabetes among South Asian women in high-income countries are needed.

Recruitment and Retention of South Asian Ethnic Minority Populations in Behavioral Interventions to Improve Type 2 Diabetes Outcomes

PURPOSE OF REVIEW

South Asian (SA) immigrants have a higher burden of type 2 diabetes, report poor self-management, and remain a hard-to-engage group in behavioral interventions. The purpose of this review was to characterize recruitment and retention of SAs in behavioral interventions.

RECENT FINDINGS

We identified 14 studies with limited information regarding recruitment and retention. Overall recruitment rates were low: 12 studies had a mean recruitment rate of 44% among those screened, and 9 studies with complete information on eligibility had a mean recruitment rate of 65.8% among those eligible. Mean retention rate was 79.4% across all 14 studies. Although unstandardized and inconsistent reporting limited our ability to draw any conclusions regarding the best strategies to maximize recruitment and retention, we were able to highlight some novel and effective strategies. There is a need for consistent and standardized reporting of recruitment and retention-related information to encourage meaningful research and guide researchers in efficient allocation of resources and a successful conclusion of future interventions.

Ethnic and diet-related differences in the healthy infant microbiome

Background

The infant gut is rapidly colonized by microorganisms soon after birth, and the composition of the microbiota is dynamic in the first year of life. Although a stable microbiome may not be established until 1 to 3 years after birth, the infant gut microbiota appears to be an important predictor of health outcomes in later life.

Methods

We obtained stool at one year of age from 173 white Caucasian and 182 South Asian infants from two Canadian birth cohorts to gain insight into how maternal and early infancy exposures influence the development of the gut microbiota. We investigated whether the infant gut microbiota differed by ethnicity (referring to groups of people who have certain racial, cultural, religious, or other traits in common) and by breastfeeding status, while accounting for variations in maternal and infant exposures (such as maternal antibiotic use, gestational diabetes, vegetarianism, infant milk diet, time of introduction of solid food, infant birth weight, and weight gain in the first year).

Results

We demonstrate that ethnicity and infant feeding practices independently influence the infant gut microbiome at 1 year, and that ethnic differences can be mapped to alpha diversity as well as a higher abundance of lactic acid bacteria in South Asians and a higher abundance of genera within the order Clostridiales in white Caucasians.

Conclusions

The infant gut microbiome is influenced by ethnicity and breastfeeding in the first year of life. Ethnic differences in the gut microbiome may reflect maternal/infant dietary differences and whether these differences are associated with future cardiometabolic outcomes can only be determined after prospective follow-up.

Electronic supplementary material

The online version of this article (doi:10.1186/s13073-017-0421-5) contains supplementary material, which is available to authorized users.

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.

Ambient Air Pollution and Newborn Size and Adiposity at Birth: Differences by Maternal Ethnicity (the Born in Bradford Study Cohort)

BACKGROUND

Exposure to ambient air pollution has been associated with reduced size of newborns; however, the modifying effect of maternal ethnicity remains little explored among South Asians.

OBJECTIVES

We investigated ethnic differences in the association between ambient air pollution and newborn's size.

METHOD

Pregnant women were recruited between 2007 and 2010 for the Born in Bradford cohort study, in England. Exposures to particulate matter (≤ 10 μm, PM10; ≤ 2.5 μm, PM2.5), PM2.5 absorbance, and nitrogen oxides (NOx, NO2) were estimated using land-use regressions models. Using multivariate linear regression models, we evaluated effect modification by maternal ethnicity ("white British" or "Pakistani origin," self-reported) on the associations of air pollution and birth weight, head circumference, and triceps and subscapular skinfold thickness.

RESULTS

A 5-μg/m3 increase in mean third trimester PM2.5 was associated with significantly lower birth weight and smaller head circumference in children of white British mothers (-43 g; 95% CI: -76, -10 and -0.28 cm; 95% CI: -0.39, -0.17, respectively), but not in children of Pakistani origin (9 g; 95% CI: -17, 35 and -0.08 cm; 95% CI: -0.17, 0.01, respectively) (p(int) = 0.03 and < 0.001). In contrast, PM2.5 was associated with significantly larger triceps and subscapular skinfold thicknesses in children of Pakistani origin (0.17 mm; 95% CI: 0.08, 0.25 and 0.21 mm; 95% CI: 0.12, 0.29, respectively), but not in white British children (-0.02 mm; 95% CI: -0.14, 0.01 and 0.06 mm; 95% CI: -0.06, 0.18, respectively) (p(int) = 0.06 and 0.11). Patterns of associations for PM10 and PM2.5 absorbance according to ethnicity were similar to those for PM2.5, but associations of the outcomes with NO2 and NOx were mostly nonsignificant in both ethnic groups.

CONCLUSIONS

Our results suggest that associations of ambient PM exposures with newborn size and adiposity differ between white British and Pakistani origin infants.

CITATION

Schembari A, de Hoogh K, Pedersen M, Dadvand P, Martinez D, Hoek G, Petherick ES, Wright J, Nieuwenhuijsen MJ. 2015. Ambient air pollution and newborn size and adiposity at birth: differences by maternal ethnicity (the Born in Bradford study cohort). Environ Health Perspect 123:1208-1215; http://dx.doi.org/10.1289/ehp.1408675.

What accounts for ethnic differences in newborn skinfold thickness comparing South Asians and White Caucasians? Findings from the START and FAMILY Birth Cohorts

Objective:

South Asians are a high-risk group for type 2 diabetes and coronary heart disease. We sought to determine ethnic differences in newborn adiposity comparing South Asians (SA) to White Caucasians (Whites).

Methods:

Seven hundred ninety pregnant women (401 SA, 389 Whites) and their full-term offspring from two birth cohorts in Canada were analyzed. Pregnant women completed a health assessment including a 75-g oral glucose tolerance test to assess for dysglycemia. Birthweight, length, waist and hip circumference, and triceps and subscapular skinfold thickness (a surrogate measure of body adiposity) were measured in all newborns. Multivariate regression was used to identify maternal factors associated with newborn skinfold measurements.

Results:

South Asian women were younger (30.1 vs 31.8 years, P<0.001), their prepregnancy body mass index was lower (23.7 vs 26.2, P<0.0001) and gestational diabetes was substantially higher (21% vs 13%, P=0.005) compared with Whites. Among full-term newborns, South Asians had lower birthweight (3283 vs 3517 g, P=0.0001), had greater skinfold thickness (11.7 vs 10.6 mm; P=0.0001) and higher waist circumference (31.1 vs 29.9 cm, P=0.0001) compared with Whites. Risk factors for newborn skinfold thickness included South Asian ethnicity (standardized estimate (s.e.): 0.24; P<0.0001), maternal glucose (s.e.: 0.079; P=0.04) and maternal body fat (s.e.: 0.14; P=0.0002).

Conclusions:

South Asian newborns are lower birthweight and have greater skinfold thickness, compared with White newborns, and this is influenced by maternal body fat and glucose. Interventions aimed at reducing body fat prior to pregnancy and gestational diabetes during pregnancy in South Asians may favorably alter newborn body composition and require evaluation.

The ethnoepidemiology of obesity

The prevalence of overweight and obesity varies significantly across ethnic groups and among aboriginal people in Canada and appears to be increasing overall in children and youth, which will have significant health consequences in the future. Individual health behaviours, genetic predisposition, and community-level factors all contribute to the high burden of overweight and obesity across communities in Canada. Preliminary studies indicate that individuals who live in neighbourhoods in Canada with increased walkability, fewer fast food outlets, and higher socioeconomic status have lower rates of overweight/obesity when compared with other neighbourhoods. However, more research is required to understand the impact of community level factors on overweight/obesity trends in Canadian ethnic groups, including children and youth, and aboriginal people.

Cardiovascular risk among South Asians living in Canada: a systematic review and meta-analysis

BACKGROUND

South Asians represent about 3% of the Canadian population and have a higher burden of certain cardiovascular risk factors and cardiovascular disease (CVD) compared with white people. The objective of this study was to review the literature to compare cardiovascular risk factors and disease management practices among adult South Asian and white Canadians.

METHODS

We searched MEDLINE, Embase, Cochrane and Cumulative Index to Nursing and Allied Health Literature databases from their inception through Feb. 17, 2014 and the reference lists of the selected articles. English-language studies of interventions and observational studies of biological mechanisms underlying CVD risk in South Asians conducted in Canada were eligible for inclusion. Where appropriate, we used random-effects meta-analyses to integrate results comparing the CVD risk profiles of South Asian and white Canadians.

RESULTS

We included 50 articles (n = 5 805 313 individuals) in this review. Compared with white Canadians, South Asian Canadians had a higher prevalence and incidence of CVD, an increased prevalence of diabetes (odds ratio [OR] 2.25, 95% confidence interval [CI] 1.81 to 2.80, p < 0.001) and hypertension (OR 1.11, 95% CI 1.02 to 1.22, p = 0.02), lower high-density lipoprotein cholesterol levels (mean difference -0.19 mmol/L, 95% CI -0.25 to -0.13 mmol/L, p < 0.001) and a higher percentage of body fat (men: absolute mean difference 3.23%, 95% CI 0.83% to 5.62%, p = 0.008; women: absolute mean difference 4.09%, 95% CI 3.46% to 4.72%, p < 0.001). South Asian people are also more sedentary, consume higher levels of carbohydrates and are less likely to smoke tobacco (OR 0.38, 95% CI 0.24 to 0.60, p < 0.001]) than white Canadians. No differences in access to diagnostic tests, outcomes following cardiovascular surgery or use of cardiac rehabilitation programs were apparent.

INTERPRETATION

Compared with white people, South Asian people living in Canada have a higher prevalence and incidence of CVD and possess a unique cardiovascular risk profile.

Aboriginal birth cohort (ABC): a prospective cohort study of early life determinants of adiposity and associated risk factors among Aboriginal people in Canada

BACKGROUND

Aboriginal people living in Canada have a high prevalence of obesity, type 2 diabetes, and cardiovascular disease (CVD). To better understand the pre and postnatal influences on the development of adiposity and related cardio-metabolic factors in adult Aboriginal people, we will recruit and follow prospectively Aboriginal pregnant mothers and their children - the Aboriginal Birth Cohort (ABC) study.

METHODS/DESIGN

We aim to recruit 300 Aboriginal pregnant mothers and their newborns from the Six Nations Reserve, and follow them prospectively to age 3 years. Key details of environment and health including maternal nutrition, glucose tolerance, physical activity, and weight gain will be collected. At birth, cord blood and placenta samples will be collected, as well as newborn anthropometric measurements. Mothers and offspring will be followed annually with serial measurements of diet and physical activity, growth trajectory, and adiposity.

DISCUSSION

There is an urgent need to understand maternal and child factors that underlie the early development of adiposity and type 2 diabetes in Aboriginal people. The information generated from this cohort will assist the Six Nations community in developing interventions to prevent early adiposity in Aboriginal children.

Race/Ethnicity, Obesity, and Related Cardio-Metabolic Risk Factors: A Life-Course Perspective

The adoption of health behaviors characterized by minimal energy expenditure and overconsumption of energy has led to cardiometabolic risk factors in pregnancy, childhood, and youth, all of which increase the prevalence of cardiovascular disease in adulthood. The propensity to develop abdominal obesity and cardiometabolic risk factors appears to disproportionally affect non-white ethnic groups. While the majority of observational research has been conducted in populations of European origin, studies in non-white ethnic groups across the life-course are underway and there is evidence that unique ethnic-specific differences exist. This review will focus on the life-course determinants of obesity and its related cardio-metabolic risk factors among diverse ethnic groups including people of Afro-Caribbean origin, South Asian, East Asian, and indigenous ancestry.