A perinatal social nutrition approach to improve breastfeeding in a culturally diverse group of low-income women.

Alima, Perinatal Social Nutrition Centre, is an established community organization that adopts a perinatal social nutrition approach to provide multidimensional support to women living in vulnerable conditions, particularly those with a precarious migratory status. This study aims to (i) determine which maternal characteristics, pregnancy-related variables, and structural features of the Alima intervention are associated with breastfeeding; and (ii) examine whether the association between attending breastfeeding workshops and breastfeeding characteristics differ according to maternal factors. The Alima digital database was used to analyze data from women who received the perinatal intervention between 2013 and 2020. Infant feeding data were retrieved at 2 weeks postpartum (T0, n = 2925), 2 months postpartum (T2, n = 1475), and 4 months postpartum (T4, n = 890). Logistic regressions were used to estimate the odds of overall and exclusive breastfeeding depending on sociodemographic characteristics, pregnancy-related variables, and features of the intervention. The prevalence of overall and exclusive breastfeeding was, respectively, 96.1% and 60.7% at T0; 93.0% and 58.5% at T2; 83.0% and 48.4% at T4. Higher education, previous breastfeeding experience, and recent immigration were associated with a higher likelihood of breastfeeding at each time point. Breastfeeding workshop attendance was associated with a greater likelihood of overall and exclusive breastfeeding at T2 and T4, with a stronger effect among women aged 35 or less, those with lower education, and those with excessive gestational weight gain. In conclusion, the Alima intervention is associated with positive breastfeeding outcomes, especially among vulnerable women living with precarious migratory status in Canada.

Evaluation of the Olo Prenatal Nutrition Follow-up Care for Vulnerable Pregnant Women.

Olo nutritional follow-up care offers vulnerable pregnant women food vouchers, multivitamin supplements, tools, and nutritional counselling to support healthy pregnancy outcomes.Purpose: To evaluate the contribution of Olo follow-up care to nutritional intakes and eating practices, as well as to assess the programme-related experience of participants.Methods: Participants (n = 30) responded to questionnaires and web-based 24-hour dietary recalls and participated in a semi-structured interview (n = 10).Results: Olo follow-up care reduced the proportion of participants below the recommended intake for groups for many micronutrients, with the greatest reduction for folate (by 96.7%), vitamin D (by 93.3%), iron (by 70.0%), calcium (by 50.0%), and zinc (by 30.0%), mainly due to the prenatal multivitamin supplements. Most participants (96.7%) did not follow Olo's typical recommendations but, if they had, hypothetically they would have consumed an average of 746 additional calories per day and be above the recommendations for excessive intakes of folic acid and iron (100% and 33.3%, respectively). More than half of the participants were moderately to severely food insecure. Olo contributed to reducing the impact of isolation and increased food accessibility and budget flexibility among participants.Conclusion: Olo follow-up care helped reduce the proportion of women below the recommended intake for micronutrients, but revising the food offered and strategies to address food insecurity may be necessary.

Understanding the challenges related to breastfeeding education and barriers to curricular change: a systems perspective for transforming health professions education.

Objectives: A majority of women and families wish that their babies be breastfed. However, too many still receive insufficient or inappropriate initial care from health professionals (HPs) who have limited breastfeeding (BF) competencies. We investigated barriers and potential solutions to improve the undergraduate training programs for various HPs. Methods: Focus groups were carried out in three universities in Quebec and one in Ontario (Canada), with 30 faculty and program directors from medicine, midwifery, nursing, nutrition, and pharmacy. Discussions were subjected to thematic content analysis, before being validated in a strategic planning workshop with 48 participants from the same disciplines, plus dentistry and chiropractic. Findings: Substantive improvements of undergraduate training programs for BF could be obtained by addressing challenges related to the insufficient, or lack of, (i) interactions among various HPs, (ii) opportunities for practical learning, (iii) specific standards to guide course content, (iv) real-life experience with counselling, and (v) understanding of the influence of attitudes on professional practice. Several potential solutions were proposed and validated. The re-interpretation of the results in light of various literature led to an emerging framework that takes a systems perspective for enhancing the education of HPs on BF. Conclusions: To improve the education of HPs so as to enable them to provide relevant support for future mothers, mothers and their families, solutions need to be carried out to address challenges in the health system, the education system as well as regarding the curricular change process.

Objectifs: La majorité des femmes et des familles souhaitent que leur bébé soit allaité. Toutefois, plusieurs ne reçoivent pas un soutien adéquat de la part de professionnels de la santé (PS) qui ont des compétences limitées en allaitement. Nous avons étudié les barrières et les solutions potentielles en vue de rehausser la formation initiale de divers PS. Méthodes: Des groupes de discussion ont été organisés dans trois universités du Québec et une en Ontario (Canada) avec 30 directeurs de programmes et membres du corps professoral en médecine, pratique sage-femme, sciences infirmières, nutrition et pharmacie. Les discussions ont fait l'objet d'une analyse de contenu thématique laquelle fut ensuite validée dans un atelier de planification stratégique avec 48 participants des mêmes disciplines auxquelles se sont ajoutées dentisterie et chiropratique. Résultats: Des améliorations substantielles des compétences en allaitement dans les programmes de formation initiale pourraient être obtenues en travaillant sur les défis associés à l'insuffisance, ou à l'absence de, (i) interactions entre les divers PS, (ii) opportunités d'apprentissages pratiques, (iii) normes spécifiques pour guider les contenus de cours, (iv) expériences réelles avec le counseling, et (v) compréhension de l'influence des attitudes sur la pratique professionnelle. La ré-interprétation des résultats à la lumière de la littérature a fait émerger un cadre conceptuel avec une perspective systémique pour guider le rehaussement de la formation en allaitement des divers PS. Conclusions: Afin d'améliorer la formation des PS pour qu'ils/elles puissent fournir un soutien pertinent aux futures mères, aux mères et à leurs familles, des solutions visant à la fois les défis dans le système de santé, dans le système d'éducation et dans le processus de changement curriculaire doivent être mises en œuvre.

A Community Prenatal Intervention in Social Nutrition: Evaluating the Impact on Pregnancy and Birthweight Outcomes.

This study aims to assess the associations between structural features of the Montreal Diet Dispensary's social nutrition intervention and pregnancy (i.e., anemia, gestational diabetes mellitus (GDM), gestational weight gain (GWG), hypertension) and birthweight outcomes (i.e., small- or large-for-gestational-age) among pregnant women, most of them recent immigrants. The study consists of a secondary analysis of the digital client database of the Montreal Diet Dispensary (n = 2925). Logistic regressions were used to estimate the odds of pregnancy and birthweight outcomes, depending on structural features of the intervention. Pregnant women who attended a welcoming group session presented lower odds of GDM and anemia compared to those who did not attend. A longer duration of intervention was also associated with lower odds of GDM and anemia. Each additional appointment with a dietitian was associated with higher odds of excessive GWG and lower odds of insufficient GWG only among women with a pre-pregnancy BMI lower than 25 kg/m2. This study emphasizes the importance of providing nutritional services early in pregnancy to reduce the risk of GDM and anemia. It also stresses the importance of using appropriate nutritional guidelines to avoid increasing the risk of excessive GWG.

Knowledge, attitude and practice of physicians regarding periconceptional folic acid for women at low risk of a neural tube defect affected pregnancy.

Canadian expert guidelines recommend low-risk women to consume a daily multivitamin supplement containing 400 µg of folic acid (FA) to prevent neural tube defects. Mandatory food fortification coupled with intake of prenatal vitamin/mineral supplements (PVS), most of which contain ≥ 1000 µg-FA, has resulted in an unprecedented shift in Canadian pregnant women folate status. This study assessed the knowledge, attitude and practice (KAP) of physicians regarding periconceptional FA recommendations, intake and health related outcomes, since they play an essential role in promoting appropriate FA intake. Seventy-seven physicians answered the self-administered KAP survey. Only half of physicians knew the correct dose and duration of FA for low-risk women. Approximately 70% were unsure of, or unfamiliar with the most recent guidelines and 60% of physicians most often recommend a ≥ 1000 µg-FA supplement. Knowledge score 1 (KS1), which related to low-risk women, was associated with physicians' attitude toward believing that most PVS contain the recommended amount of FA (p = 0.004). Significant correlations were also found between KS1 and the total practice score (TPS) (r = 0.45, p < 0.0001) as well as between the total knowledge score and TPS (r = 0.38, p = 0.0007). Our findings show that physicians lacking knowledge regarding periconceptional FA is associated with their attitude and practice. Despite a vast majority of physicians being unsure or uncomfortable recommending PVS that are not in line with recommendations, a lack of knowledge and a widely accessible 400 µg-FA PVS, enables a contradictory practice in reality.

Energy expenditure during pregnancy: a systematic review.

CONTEXT: Contrary to nutritional guidelines, accumulating evidence shows that pregnant women's energy intakes remain stable throughout trimesters. Although pregnant women may eat below their needs or underreport their energy intakes, it is also relevant to question how energy requirements - estimated through measurements of energy expenditure (EE) - change throughout pregnancy. OBJECTIVE: This review examined prospective studies that measured EE during pregnancy, following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. DATA SOURCES: PubMed/MEDLINE, Web of Science, Embase, and CINAHL databases were searched to identify relevant publications up to November 14, 2019. STUDY SELECTION: All studies that measured EE prospectively and objectively during pregnancy were included in this systematic review. Two authors independently screened 4852 references. A total of 32 studies were included in the final analysis. DATA EXTRACTION: One author extracted data and assessed the risk of bias and a second author did so for a random sample of studies (n = 7; 22%). DATA ANALYSIS: Increases in resting EE ranged from 0.5% to 18.3% (8-239 kcal), from 3.0% to 24.1% (45-327 kcal), and from 6.4% to 29.6% (93-416 kcal) between early and mid-, mid- and late, and early and late pregnancy, respectively. Increases in total EE ranged from 4.0% to 17.7% (84-363 kcal), from 0.2% to 30.2% (5-694 kcal), and from 7.9% to 33.2% (179-682 kcal) between early and mid-, mid- and late, and early and late pregnancy, respectively. Participants were mainly of normal weight, although many studies did not report important covariates such as prepregnancy body mass index and gestational weight gain adequacy. CONCLUSIONS: Additional high-quality longitudinal studies (ie, with multiple objective measurements of EE in all periods of pregnancy while considering important confounding variables, like gestational weight gain) are required.

Tracking of Dietary Intake and Diet Quality from Late Pregnancy to the Postpartum Period.

The present study aimed to characterize dietary intake and diet quality from late pregnancy to six months postpartum. Participants (n = 28) completed 2-3 Web-based 24 h recalls at three distinct periods: (1) during the third trimester of pregnancy; (2) three months and (3) six months after delivery. Energy, macro-and micronutrient intakes (from foods and supplements), as well as the Canadian healthy eating index (C-HEI) were derived from the dietary recalls. No significant variation in energy and macronutrient intakes was observed between time points. The proportion of women taking at least one supplement decreased over time (p = 0.003). The total intake of several micronutrients (vitamins A, C, D, group B vitamins, iron, magnesium, zinc, calcium, phosphorus, manganese, and copper) decreased significantly over time (p < 0.05 for all micronutrients). The total C-HEI score and its components did not change, except for the total vegetables and fruit subscore, which decreased over time (8.2 ± 2.0 in the 3rd trimester, 7.1 ± 2.2 at three months postpartum, 6.9 ± 2.4 at 6 months postpartum, p = 0.04). In conclusion, we observed a general stability in diet quality, energy, and macronutrient intakes from the third trimester of pregnancy to six months postpartum. However, several micronutrient intakes decreased over time, mostly due to changes in supplement use.

Investigating Gene-Gene and Gene-Environment Interactions in the Association Between Overnutrition and Obesity-Related Phenotypes.

Introduction: Animal studies suggested that NFKB1, IKBKB, and SOCS3 genes could be involved in the association between overnutrition and obesity. This study aims to investigate interactions involving these genes and macronutrient intakes affecting obesity-related phenotypes. Methods: We used a traditional statistical method, logistic regression, and compared it to alternative statistical method, multifactor dimensionality reduction (MDR) and penalized logistic regression (PLR), to better detect genes/environment interactions in the Toronto Nutrigenomics and Health Study (n = 1639) using dichotomized body mass index (BMI) and waist circumference as obesity-related phenotypes. Exposure variables included genotype on 54 single nucleotide polymorphisms (NFKB1: 18, IKBKB: 9, SOCS3: 27), macronutrient (carbohydrates, protein, fat) and alcohol intakes and ethno-cultural background. Results: After correction for multiple testing, no interaction was found using logistic regression. MDR identified interactions between SOCS3 rs6501199 and rs4969172, and IKBKB rs3747811 affecting BMI in the Caucasian population; SOCS3 rs6501199 and NFKB1 rs1609798 affecting WC in the Caucasian population; and SOCS3 rs4436839 and IKBKB rs3747811 affecting WC in the South Asian population. PLR found a main effect of SOCS3 rs12944581 on BMI among the South Asian population. Conclusion: While MDR and PLR had discordant results, some models support results from previous studies. These results emphasize the need to use alternative statistical methods to investigate high-order interactions and suggest that variants in the nutrient-responsive hypothalamic IKKB/NF-kB signaling pathway may be involved in obesity pathogenesis.

The Association between Plasma Omega-6/Omega-3 Ratio and Anthropometric Traits Differs by Racial/Ethnic Groups and NFKB1 Genotypes in Healthy Young Adults.

Evidence for a relationship between omega-6/omega-3 (n-6/n-3) polyunsaturated fatty acid (PUFA) ratio and obesity in humans is inconsistent, perhaps due to differences in dietary intake or metabolism of PUFAs between different subsets of the population. Since chronic inflammation is central to obesity and inflammatory pathways are regulated by PUFAs, the objective of this study was to examine whether variants in the NFKB1 gene, an upstream regulator of the inflammatory response, modify the association between the n-6/n-3 ratio (from diet and plasma) and anthropometric traits in a multiethnic/multiracial population of young adults. Participants' (n = 898) dietary PUFA intake was assessed using a food frequency questionnaire and plasma PUFA concentrations by gas chromatography. Nine tag single nucleotide polymorphisms (SNP) in NFKB1 were genotyped. Significant interactions were found between racial/ethnic groups and plasma n-6/n-3 ratio for body mass index (BMI) (p = 0.02) and waist circumference (WC) (p = 0.007). Significant interactions were also observed between racial/ethnic groups and three NFKB1 genotypes (rs11722146, rs1609798, and rs230511) for BMI and WC (all p ≤ 0.04). Significant interactions were found between two NFKB1 genotypes and plasma n-6/n-3 ratio for BMI and WC (rs4648090 p = 0.02 and 0.03; rs4648022 p = 0.06 and 0.04, respectively). Our findings suggest that anthropometric traits may be influenced by a unique combination of n-6/n-3 ratio, racial/ethnic background, and NFKB1 genotypes.

Correction: Savard et al. Trimester-Specific Dietary Intakes in a Sample of French-Canadian Pregnant Women in Comparison with National Nutritional Guidelines. Nutrients 2018, 10, 768.

The authors wish to make the following changes to their paper (Savard et al., 2018 [1]) [...].

Periconceptional intake of folic acid among low-risk women in Canada: summary of a workshop aiming to align prenatal folic acid supplement composition with current expert guidelines.

The Government of Canada and the Society of Obstetricians and Gynaecologists of Canada both recommend a daily multivitamin supplement containing 400 µg folic acid (FA) for the primary prevention of neural tube defects among low-risk women from before conception and throughout lactation. Prenatal supplements marketed and prescribed in Canada typically exceed the recommended dose, usually providing ≥1000 µg FA/d. This high daily dose, coupled with staple-food FA fortification, has resulted in the observation of very high blood folate concentrations among reproductive-aged women consuming FA-containing supplements. The long-term consequences of high folate status on fetal development are unknown; however, evidence from animal studies and some human epidemiologic data suggest potential adverse consequences. To address this issue, a workshop was convened with the overall goal to identify challenges and solutions to aligning supplemental FA intakes with current evidence-based recommendations. Thirty-eight stakeholders from academia, industry, government, and health professional groups participated. Group discussions facilitated the identification and prioritization of 5 key challenges for which solutions and implementation strategies were proposed. The 5 themes encompassed clarity and harmonization of evidence-based guidelines, reformulation or relabeling of FA-containing supplements, access to FA for all women, knowledge dissemination strategies and education of the public and health care professionals, and attitude change to overcome the perception of "more is better." A combination of the proposed implementation strategies involving all key stakeholders and directed to health care professionals and the public may enable a sustainable change to align FA intake during the periconceptional period with evidence-based recommendations.

Adequacy of nutritional intake during pregnancy in relation to prepregnancy BMI: results from the 3D Cohort Study.

Our study compares adequacy of nutritional intakes among pregnant women with different prepregnancy BMI and explores associations between nutritional intakes during pregnancy and both prepregnancy BMI and gestational weight gain (GWG). We collected dietary information from a large cohort of pregnant Canadian women (n 861) using a 3-d food record. We estimated usual dietary intakes of energy (E), macronutrients and micronutrients using the National Cancer Institute method. We also performed Pearson's correlations between nutritional intakes and both prepregnancy BMI and GWG. In all BMI categories, intakes considered suboptimal (by comparison with estimated average requirements) were noted for Fe, vitamin D, folate, vitamin B6, Mg, Zn, Ca and vitamin A. Total fat intakes were above the acceptable macronutrient distribution range (AMDR) for 36 % of the women. A higher proportion of obese women had carbohydrate intakes (as %E) below the AMDR (v. normal-weight and overweight women; 19 v. 9 %) and Na intakes above the tolerable upper intake level (v. other BMI categories; 90 v. 77-78 %). In all BMI categories, median intakes of K and fibre were below adequate intake. Intakes of several nutrients (adjusted for energy) were correlated with BMI. Correlations were detected between energy-adjusted nutrient intakes and total GWG and were, for the most part, specific to certain BMI categories. Overweight and obese pregnant women appear to be the most nutritionally vulnerable. Nutrition interventions are needed to guide pregnant women toward their optimal GWG while also meeting their nutritional requirements.

Trimester-Specific Dietary Intakes in a Sample of French-Canadian Pregnant Women in Comparison with National Nutritional Guidelines.

Diet during pregnancy greatly impacts health outcomes. This study aims to measure changes in dietary intakes throughout trimesters and to assess pregnant women’s dietary intakes in comparison with current Canadian nutritional recommendations. Seventy-nine pregnant women were recruited and completed, within each trimester, three Web-based 24-h dietary recalls and one Web questionnaire on supplement use. Dietary intakes from food, with and without supplements, were compared to nutritional recommendations throughout pregnancy. Energy and macronutrient intakes remained stable throughout pregnancy. A majority of women exceeded their energy and protein requirements in the first trimester, and fat intakes as a percentage of energy intakes were above recommendations for more than half of the women in all trimesters. Supplement use increased dietary intakes of most vitamins and minerals, but 20% of women still had inadequate total vitamin D intakes and most women had excessive folic acid intakes. This study showed that pregnant women did not increase their energy intakes throughout pregnancy as recommended. Furthermore, although prenatal supplementation reduces the risk of inadequate intake for most micronutrients, there is still a risk of excessive folic acid and insufficient vitamin D intake, which needs further investigation.

A crucial role for maternal dietary methyl donor intake in epigenetic programming and fetal growth outcomes.

The fetal origins of health and disease framework has identified extremes in fetal growth and birth weight as factors associated with the lifelong generation of chronic diseases such as obesity, diabetes, cardiovascular disease, and hypertension. Maternal nutrition plays a critical role in fetal and placental development, in part by providing the methyl groups required to establish the fetus's genome structure and function, notably through DNA methylation. The goal of this narrative review is to describe the role of maternal dietary methyl donor (methionine, folate, and choline) and cofactor (zinc and vitamins B2, B6, and B12) intake in one-carbon metabolism and DNA methylation in the fetus and placenta, as well as their impacts on fetal growth and lifelong health outcomes, with specific examples in animals and humans. Based on the available evidence, it is concluded that intake of different amounts of dietary methyl donors and cofactors during pregnancy may alter fetal growth and development, thus establishing a major link between early environmental exposure and disease development in the offspring later in life.

Adequacy of nutritional intake from food and supplements in a cohort of pregnant women in Québec, Canada: the 3D Cohort Study (Design, Develop, Discover).

Background: Assessments of the dietary intakes in various populations suggest that pregnant women have difficulty meeting all their nutritional requirements through diet alone. Few large-scale studies have considered both food sources and supplements in assessing the adequacy of nutritional intakes during pregnancy.Objective: Our study aimed to assess nutritional intakes during pregnancy by examining dietary sources and supplements. It then compared these findings with Dietary Reference Intakes.Design: We conducted a nutrition study in a large pregnancy cohort using a 3-d food record during the second trimester of pregnancy. Detailed information about supplement consumption was obtained by interview at each prenatal visit. We estimated the distribution of total usual intakes for energy, macronutrients, and micronutrients for 1533 pregnant women.Results: A third of the participants had total fat intakes that exceeded the Acceptable Micronutrient Distribution Range. A majority of women (85%) had sodium intakes above the Tolerable Upper Intake Level (UL). Median intakes for fiber and potassium were lower than Adequate Intakes. Dietary intakes of vitamin B-6, magnesium, and zinc were below the Estimated Average Requirements (EARs) for 10-15% of the women. A majority of the women had dietary intakes below the EARs for iron (97%), vitamin D (96%), and folate (70%). When we considered micronutrient intakes from both food and supplements, we found that the prevalence of inadequate intake was <10% for all nutrients except vitamin D (18%) and iron (15%), whereas 32% and 87% of the women had total intakes above the ULs for iron and folic acid, respectively.Conclusions: The level of intake of some nutrients from food alone remains low in the diets of pregnant women. Supplement use reduces the risk of inadequate intake for many micronutrients, but diet-related issues during pregnancy remain and deserve to be addressed in public health interventions. This trial was registered at clinicaltrials.gov as NCT03113331.

Dietary Intake at 9 Years and Subsequent Body Mass Index in Adolescent Boys and Girls: A Study of Monozygotic Twin Pairs.

There is a lack of evidence pointing to specific dietary elements related to weight gain and obesity prevention in childhood and adulthood. Dietary intake and obesity are both inherited and culturally transmitted, but most prospective studies on the association between diet and weight status do not take genetics into consideration. The objective of this study was to document the association between dietary intake at 9 years and subsequent Body Mass Index (BMI) in adolescent monozygotic boy and girl twin pairs. This research used data from 152 twin pairs. Dietary data were collected from two 24-hour-recall interviews with a parent and the child aged 9 years. Height and weight were obtained when the twins were aged 9, 12, 13, and 14 years. Intrapair variability analysis was performed to identify dietary elements related to BMI changes in subsequent years. BMI-discordant monozygotic twin pairs were also identified to analyze the dietary constituents that may have generated the discordance. After eliminating potential confounding genetic factors, pre-adolescent boys who ate fewer grain products and fruit and consumed more high-fat meat and milk had higher BMIs during adolescence; pre-adolescent girls who consumed more grain products and high-fat meat and milk had higher BMIs during adolescence. Energy intake (EI) at 9 years was not related to BMI in subsequent years. Our study suggests that messages and interventions directed at obesity prevention could take advantage of sex-specific designs and' eventually' genetic information.

Effect of folic acid on human trophoblast health and function in vitro.

INTRODUCTION: The combined intake of folic acid (FA) from prenatal multivitamin supplements and fortified foods can result in FA intake values that exceed the tolerable upper intake level (UL). It is unclear what impact FA intake above the UL may have on the feto-placental unit. Our objective was to determine the effects of increasing concentrations of FA on trophoblast health and function in vitro. METHODS: Two human placental cell lines [HTR-8/SVneo (n = 5 experiments) and BeWo (n = 5 experiments)] and human placenta tissue explants (n = 6 experiments) were exposed to increasing concentrations of FA (2-2000 ng/mL) for 48-h. Intracellular total folate concentration, trophoblast proliferation, viability, apoptosis, placenta cell invasion and ß-hCG hormone release were assessed. RESULTS: Exposure to increasing FA concentrations resulted in higher intracellular total folate in placental cell lines and tissue explants (p < 0.05); yet, only minimal effects of excess folic acid were observed on the primary indicators of placental health and function studied. Specifically, treatment with excess folic acid (2000 ng/mL) resulted in reduced cellular viability in the villous trophoblast BeWo cell line and increased rates of proliferation in the HT8-8/SVneo extravillous trophoblast cell line (p < 0.05). Further, deficient concentrations of folic acid (2 ng/mL) resulted in decreased cell viability and invasive capabilities of the HTR-8/SVneo extravillous trophoblast cell line (p < 0.05). DISCUSSION: Our results demonstrate that placental health and function may be compromised in conditions of folate deficiency, and not necessarily in conditions of excess FA. This finding supports the recommendation of prenatal folic acid supplementation in the North American population. Further work aimed at clarifying the therapeutic window of FA intake in the obstetrical population is warranted.

A Comparison of Statistical Methods for the Discovery of Genetic Risk Factors Using Longitudinal Family Study Designs.

The etiology of immune-related diseases or traits is often complex, involving many genetic and environmental factors and their interactions. While methodological approaches focusing on an outcome measured at one time point have succeeded in identifying genetic factors involved in immune-related traits, they fail to capture complex disease mechanisms that fluctuate over time. It is increasingly recognized that longitudinal studies, where an outcome is measured at multiple time points, have great potential to shed light on complex disease mechanisms involving genetic factors. However, longitudinal data require specialized statistical methods, especially in family studies where multiple sources of correlation in the data must be modeled. Using simulated data with known genetic effects, we examined the performance of different analytical methods for investigating associations between genetic factors and longitudinal phenotypes in twin data. The simulations were modeled on data from the Québec Newborn Twin Study, an ongoing population-based longitudinal study of twin births with multiple phenotypes, such as cortisol levels and body mass index, collected multiple times in infancy and early childhood and with sequencing data on immune-related genes and pathways. We compared approaches that we classify as (1) family-based methods applied to summaries of the observations over time, (2) longitudinal-based methods with simplifications of the familial correlation, and (3) Bayesian family-based method with simplifications of the temporal correlation. We found that for estimation of the genetic main and interaction effects, all methods gave estimates close to the true values and had similar power. If heritability estimation is desired, approaches of type (1) also provide heritability estimates close to the true value. Our work shows that the simpler approaches are likely adequate to detect genetic effects; however, interpretation of these effects is more challenging.

Melanin-concentrating hormone receptor 1 polymorphisms are associated with components of energy balance in the Complex Diseases in the Newfoundland Population: Environment and Genetics (CODING) study.

BACKGROUND: The melanin-concentrating hormone receptor 1 (MCHR1) is a G protein-coupled receptor that regulates energy balance and body composition in animal models. Inconsistent effects of MCHR1 polymorphisms on energy homeostasis in humans may partly be attributable to environmental factors. OBJECTIVES: We examined the effect of 4 single nucleotide polymorphisms (rs133073, rs133074, rs9611386, and rs882111) in the MCHR1 gene on body composition as well as energy-related lifestyle factors (diet and physical activity). We also examined the effect of gene-lifestyle interactions on body composition. DESIGN: A total of 1153 participants (248 men and 905 women) from the cross-sectional Complex Diseases in the Newfoundland Population: Environment and Genetics (CODING) study were genotyped by using probe-based chemistry validated assays. Diet and physical activity were estimated by using validated frequency questionnaires, and body composition was assessed by using dual-energy X-ray absorptiometry. RESULTS: Three polymorphisms (rs9611386, rs882111, and rs133073) were associated with differences in body-composition measurements (all P < 0.05). There was an interaction between rs9611386 and carbohydrate intake on total mass and waist circumference (both P ≤ 0.01). There was also an interaction between rs9611386 and body mass index categories (normal weight, overweight, and obese) on energy intakes (P = 0.02). A similar interaction was shown with rs882111 (P = 0.02). Interactions were also observed between each of these polymorphisms (rs9611386, rs882111, and rs133073) and physical activity score on body-composition measurements (all P < 0.05). CONCLUSION: These findings suggest that polymorphisms in the MCHR1 gene are associated with differences in body composition and interact with physiologic and energy-related lifestyle factors.