Spina bifida, folate metabolism, and dietary folate intake in a Northern Canadian aboriginal population

Measurement of diet quality among First Nations peoples in Canada and associations with health: a scoping review

BACKGROUND

Given the increasing number and the diversity of dietary quality indices used for research, and the differences between settings, there is a need to identify valid indices of dietary quality in different contexts and populations and to identify their associations with health-related outcomes.

OBJECTIVES

The primary objective of this scoping review is to identify the tools used in determining dietary quality among First Nations and to describe the changes in diet. The second objective is to describe the associations identified in studies that have measured the relationship between health and dietary quality among First Nations; and the third objective is to identify factors associated with diet quality.

METHODS

PubMed, Embase, CINAHL, Global Health, and Web of Science were searched from inception to June 2021 and updated in February 2022. Articles were included if the research subjects were First Nations, or if articles reported disaggregated subset data for First Nations. Eligible studies focused on nutrition and diet and were published in English or French.

RESULTS

A total of 151 articles were included in the analysis. Studies used several indicators to measure if individuals adhered to dietary guidelines. Traditional food consumption was frequently used as an indicator of diet quality (n = 96). The consumption of store-bought foods was used as an indicator in 28 studies. Some studies used other diet quality indicators such as the Healthy Eating Index (n = 5) and ultra-processed food "NOVA" classification (n = 6). A trend for decreasing traditional food intake over time was apparent, alongside an increase in store-bought food intake. This trend was accompanied with declining health status, including the increased prevalence of overweight and obesity, diabetes, metabolic diseases, and dental caries.

CONCLUSION

This scoping review showed that diet quality among First Nations is improved when traditional foods are consumed. Reduced diet quality was associated with increased risk of noncommunicable diseases.

Food insecurity and its consequences in indigenous children and youth in Canada

Food insecurity (FI) is at a crisis level in some Indigenous communities and impacts many of the half million First Nations Inuit and Métis (FNIM) children across Canada, particularly in isolated northern communities. This can lead to malnutrition and can have significant impacts on the physical, intellectual, emotional and social development of a child, often with lasting effects across the life course. This is a narrative review article with extensive search of the medical literature with input from the FNIM National organizations. The primary cause of FI is an imbalance between the high price of food relative to household income, where poverty is a driving factor. The cost and lack of availability to healthy foods has resulted in a transition to unhealthy market foods. Food security programs need to be prioritized, multi-faceted and multi-tiered within a framework of food sovereignty. Translational science, research, to practice is also important. The use of successful Indigenous based models of FI, towards food sovereignty using self-determination, Indigenous Knowledge, strength-based models, and ancestral sustainability are critical. Continued community-based evaluation of FI towards sustainable healthy food programs are important for communities to initiate track, evaluate, and grow robust community-based programs to counter-balance FI. Continued scientific research in the fields of FI, food sovereignty, and their relationship to co-occurring conditions related to healthy eating and beverage consumption are vastly important to the health of Indigenous Peoples. These are all part of many Indigenous connection to the earth, through food source, the maintenance of health through ancestral ways of living, set in the premise of looking forward multiple generations towards the continued resiliency through food, diet, relationship, and sovereignty. Food Security is a human right and needs to be urgently addressed for Indigenous children in Canada.

Maternal biomarkers for early prediction of the neural tube defects pregnancies

BACKGROUND

Neural tube defects (NTD) are one of the most common congenital birth defects. The reason for the NTD cause is still not completely known, but it is believed that some genetic and environmental factors might play a role in its etiology. Among the genetic factors the polymorphism in the folate gene pathway is crucial. Numerous studies have suggested the possible role of maternal higher plasma concentration of homocysteine and low concentration of folate and cobalamin in the development of NTD but some negative studies are also published.

AIM

Aim of the present was to find out the exact relation between NTD and maternal biomarkers like folate, cobalamin and homocysteine by conducting a meta-analysis.

METHOD

Different electronic databases were searched for the eligible studies. Standardized mean difference (SMD) with 95% confidence interval (CI) was used to determine association between maternal markers as risk for NTD pregnancy. The p value <0.05 was considered statistically significant in all tests. All the statistical analyses were done in the Open Meta-Analyst program.

RESULTS

The homocysteine is significantly associated with the increased risk of NTD (SMD = 0.57; 95% CI: 0.35-0.80, p = <0.001; I2 = 93.01%), s-folate showed protective role in NTD (SMD = -0.48; 95% CI: -0.77 to -0.19, p = 0.001; I2 = 95.73%), similarly cobalamin is also having protective role (SMD = -0.28; 95% CI: -0.43 to -0.13, p = <0.001; I2 = 80.40%).

CONCLUSION

In conclusion this study suggest that different maternal biomarkers may be used for the early prediction of the NTDs.

Red blood cell folate levels in Canadian Inuit women of childbearing years: influence of food security, body mass index, smoking, education, and vitamin use

Background

The benefits of folic acid for prevention of congenital anomalies are well known. For the Inuit of Canada, where vitamin use is low and access to folate-rich foods limited, fortification is likely a major source of intake. We sought to determine whether red blood cell folate (RBCF) levels of Inuit women reached accepted target levels.

Methods

The Inuit Health Survey, 2007–2008, included evaluation of RBCF levels among 249 randomly selected non-pregnant women of reproductive age. Using descriptive statistics and linear regression analyses, RBCF levels were assessed and compared across several socio-demographic variables to evaluate the characteristics associated with RBCF status.

Results

Mean (SD) RBCF levels of 935.5 nmol/L (± 192) reached proposed target levels (> 906 nmol/L); however, 47% of women had lower than target levels. In bivariate analysis, non-smoking, higher education, higher income, food security, increased body mass index, and vitamin use were each significantly associated with higher RBCF. Increased levels of smoking had a negative association with RBCF levels (− 5.8 nmol/L per cigarette smoked per day (p = 0.001)). A total of 6.8% of women reported taking vitamin supplements, resulting in a 226 nmol/L higher RBCF level on average compared to non-users (p < 0.001).

Conclusion

While mean levels of folate reached target levels, this was largely driven by the small number of women taking vitamin supplements. Our results suggest that folate status is often too low in Inuit women of childbearing years. Initiatives to improve food security, culturally relevant education on folate-rich traditional foods, vitamin supplements, and smoking cessation/reduction programs may benefit Inuit women and improve birth outcomes.

Assessing the association between the methylenetetrahydrofolate reductase (MTHFR) 677C>T polymorphism and blood folate concentrations: a systematic review and meta-analysis of trials and observational studies

BACKGROUND

The methylenetetrahydrofolate reductase (MTHFR) 677C>T polymorphism is a risk factor for neural tube defects. The T allele produces an enzyme with reduced folate-processing capacity, which has been associated with lower blood folate concentrations.

OBJECTIVE

We assessed the association between MTHFR C677T genotypes and blood folate concentrations among healthy women aged 12-49 y.

DESIGN

We conducted a systematic review of the literature published from January 1992 to March 2014 to identify trials and observational studies that reported serum, plasma, or red blood cell (RBC) folate concentrations and MTHFR C677T genotype. We conducted a meta-analysis for estimates of percentage differences in blood folate concentrations between genotypes.

RESULTS

Forty studies met the inclusion criteria. Of the 6 studies that used the microbiologic assay (MA) to measure serum or plasma (S/P) and RBC folate concentrations, the percentage difference between genotypes showed a clear pattern of CC > CT > TT. The percentage difference was greatest for CC > TT [S/P: 13%; 95% credible interval (CrI): 7%, 18%; RBC: 16%; 95% CrI: 12%, 20%] followed by CC > CT (S/P: 7%; 95% CrI: 1%, 12%; RBC: 8%; 95% CrI: 4%, 12%) and CT > TT (S/P: 6%; 95% CrI: 1%, 11%; RBC: 9%; 95% CrI: 5%, 13%). S/P folate concentrations measured by using protein-binding assays (PBAs) also showed this pattern but to a greater extent (e.g., CC > TT: 20%; 95% CrI: 17%, 22%). In contrast, RBC folate concentrations measured by using PBAs did not show the same pattern and are presented in the Supplemental Material only.

CONCLUSIONS

Meta-analysis results (limited to the MA, the recommended population assessment method) indicated a consistent percentage difference in S/P and RBC folate concentrations across MTHFR C677T genotypes. Lower blood folate concentrations associated with this polymorphism could have implications for a population-level risk of neural tube defects.

Association between MTHFR C677T polymorphism and neural tube defect risks: A comprehensive evaluation in three groups of NTD patients, mothers, and fathers

BACKGROUND

The C677T polymorphism in the methylenetetrahydrofolate reductase gene (MTHFR) gene has been reported to play a critical role in the pathogenesis of neural tube defects (NTDs). The association of the C677T polymorphism in the MTHFR gene and NTD susceptibility has been widely demonstrated, but the results are inconclusive. In this study, we performed a meta-analysis in three groups to investigate the association between the MTHFR C677T polymorphism and NTD risk.

METHODS

A computer retrieval of PubMed, Cochrane Library, CBM, and Embase for papers on the MTHFR C677T polymorphism and NTD risk was performed. All data were analyzed with STATA (Version 13.0). Odds ratios (ORs) with 95% confidence intervals (CIs) were estimated to assess the association. A test for heterogeneity, a sensitivity analysis, and an assessment of publication bias were performed in our meta-analysis.

RESULTS

Forty articles were included in this meta-analysis: 13 studies for Group A: 1329 NTD patients versus 2965 healthy controls; 34 studies for Group B: 3018 mothers with NTD progeny versus 8746 healthy controls; three studies for Group C: 157 fathers with NTD progeny versus 705 healthy controls. The analysis results show: allele contrast in NTD patients: OR = 1.445, 95% CI [1.186, 1.760]; allele contrast in mothers: OR = 1.342, 95% CI [1.166, 1.544]; allele contrast in fathers: OR = 1.062, 95% CI [0.821, 1.374].

CONCLUSION

We found no association between any of the fathers' genotypes and NTDs, whereas a significant correlation between MTHFR C677T polymorphism and NTD risk was found in NTD patients and in their mother.

Quantitative assessment of maternal biomarkers related to one-carbon metabolism and neural tube defects

Periconceptional supplementation with folic acid reduces the occurrence of neural tube defects (NTDs). The association between maternal abnormalities in homocysteine metabolism (e.g., hyperhomocysteinaemia, folate deficiency and low vitamin B12) and the risk of NTDs-affected pregnancies has been widely evaluated in recent years, although the results are conflicting. To investigate this inconsistency, we performed a meta-analysis of 32 studies, involving 1,890 NTD-affected mothers and 3,995 control mothers, to develop an understanding of the relationship between maternal biomarkers related to one-carbon metabolism and NTD. A random-effects model was used to calculate the ratio of means (RoM) between the cases and controls, along with the 95% confidence intervals (CIs). A significant increase in homocysteine levels was observed in NTD-affected mothers compared with controls (RoM: 1.16, 95% CI: 1.09-1.23, P = 1.8 × 10(-6)). The pooled analysis also revealed that NTD-affected mothers had significantly lower levels of folate (RoM: 0.93, 95% CI: 0.88-0.97, P = 0.002), vitamin B12 (RoM: 0.91, 95% CI: 0.87-0.95, P = 3.6 × 10(-5)) and red blood cell folate (RoM: 0.92, 95% CI: 0.86-0.98, P = 0.01). Therefore, altered plasma levels of biomarkers related to one-carbon metabolism are associated with NTD-affected pregnancies.

"Polymorphisms in folate metabolism genes as maternal risk factor for neural tube defects: an updated meta-analysis"

Epidemiological studies have evaluated the association between maternal methylenetetrahydrofolate reductase (MTHFR) C677T, A1298C and methionine synthase reductase (MTRR) A66G polymorphisms and risk of neural tube defects (NTDs) in offspring. However, the results from the published studies on the association between these three polymorphisms and NTD risk are conflicting. To derive a clearer picture of association between these three maternal polymorphisms and risk of NTD, we performed meta-analysis. A comprehensive search was conducted to identify all case-control studies of maternal MTHFR and MTRR polymorphisms and NTD risk. We used odds ratios (ORs) with 95% confidence intervals (CIs) to assess the strength of the association. Overall, we found that maternal MTHFR C677T polymorphism (OR(TvsC) =1.20; 95% CI = 1.13-1.28) and MTRR A66G polymorphism (OR(GvsA) = 1.21; 95% CI = 0.98-1.49) were risk factors for producing offspring with NTD but maternal MTHFR A1298C polymorphism (OR(CvsA) = 0.91; 95% CI = 0.78-1.07) was not associated with NTD risk. However, in stratified analysis by geographical regions, we found that the maternal C677T polymorphism was significantly associated with the risk of NTD in Asian (OR(TvsC) = 1.43; 95% CI: 1.05-1.94), European (OR(TvsC) = 1.13; 95% CI: 1.04-1.24) and American (OR(TvsC) = 1.26; 95% CI: 1.13-1.41) populations. In conclusion, present meta-analysis supports that the maternal MTHFR C677T and MTRR A66G are polymorphisms contributory to risk for NTD.

Association of the maternal MTHFR C677T polymorphism with susceptibility to neural tube defects in offsprings: evidence from 25 case-control studies

Background

Methylenetetrahydrofolate reductase (MTHFR) is a critical enzyme in folate metabolism and is involved in DNA methylation, DNA synthesis, and DNA repair. In addition, it is a possible risk factor in neural tube defects (NTDs). The association of the C677T polymorphism in the MTHFR gene and NTD susceptibility has been widely demonstrated, but the results remain inconclusive. In this study, we performed a meta-analysis with 2429 cases and 3570 controls to investigate the effect of the MTHFR C677T polymorphism on NTDs.

Methods

An electronic search of PubMed and Embase database for papers on the MTHFR C677T polymorphism and NTD risk was performed. All data were analysed with STATA (version 11). Odds ratios (ORs) with 95% confidence intervals (CIs) were estimated to assess the association. Sensitivity analysis, test of heterogeneity, cumulative meta-analysis, and assessment of bias were performed in our meta-analysis.

Results

A significant association between the MTHFR C677T polymorphism and NTD susceptibility was revealed in our meta-analysis ( TT versus CC: OR  = 2.022, 95% CI: 1.508, 2.712; CT+TT versus CC: OR  = 1.303, 95% CI: 1.089, 1.558; TT versus CC+CT: OR  = 1.716, 95% CI: 1.448, 2.033; 2TT+CT versus 2CC+CT: OR  = 1.330, 95% CI: 1.160, 1.525). Moreover, an increased NTD risk was found after stratification of the MTHFR C677T variant data by ethnicity and source of controls.

Conclusion

The results suggested the maternal MTHFR C677T polymorphism is a genetic risk factor for NTDs. Further functional studies to investigate folate-related gene polymorphisms, periconceptional multivitamin supplements, complex interactions, and the development of NTDs are warranted.

DNA on loan: issues to consider when carrying out genetic research with aboriginal families and communities

In the current research milieu where genetic etiology is considered a critical component in the discovery of pathogenesis, aboriginal families and communities affected with genetic conditions may be considered as research participants. However, because of concerns about the impact of genetic information and historical harmful research practices, some aboriginal communities have considerable unease when faced with this prospect. Therefore, in the circumstance that genetics is considered an important part of research inquiry by aboriginal families and communities, there needs to be assurance that the research will be carried out according to mutual expectations. A research relationship that respects aboriginal individuals and communities within their culture and is in keeping with their values is essential. This respect extends to the use of biological samples, considering the DNA to be 'on loan' to the researcher for the purpose of the research for which consent was obtained. This paper will explore practical ways of maintaining a respectful research relationship when genetics research with aboriginal people is undertaken.

Heart defects and other malformations in the Inuit in Canada: a baseline study

OBJECTIVES

Birth defects occur in all ethnic groups, remaining an important world-wide cause of perinatal and infant morbidity. This contributes greatly to an excess of health care dollars allocated to the care and repair of those affected. This is especially true when those affected live in remote geographical locations.

STUDY DESIGN

A chart review of 2567 live births of children of Inuit parents residing in Arctic Quebec (Nunavik) and on Baffin Island (Nunavut) between 1989 and 1994 (five years) was carried out compared to rates of anomalies of the Alberta Congenital Anomalies Surveillance System (ACASS).

RESULTS

Birth defects were higher in the Inuit sample in nearly every major ICD-9 category with the exception of neural tube defects, eye anomalies and chromosome abnormalities. (Total: 99.7/1000 Vs 51.5/1000; OR 1.93 95% CI 1.7-2.3). Congenital heart defects were significantly increased 22.9/1000 Vs 5.6/1000, with an OR of 4.18 (95% CI 3.2-5.4) in the ICD-9 category 745. In particular, ventricular septal defects (VSDs) and atrial septal defects (ASDs) (OR 4.9 CI 3.5-6.9 and 4.6 CI 2.9-7.2) were frequent.

CONCLUSIONS

A high rate of heart defects was an important contributor to the nearly two times rate of total birth defects in the Inuit compared to the ACASS. Further study should be carried out to determine the contributing factors. Genetic predisposition to specific heart defects, and a diet low in folate and vitamin A are considerations. The use of alcohol may exacerbate vitamin status in pregnancy. Optimizing vitamin status in the periconceptional period may reduce the rate of birth defects.

Maternal ethnicity and risk of neural tube defects: a population-based study

BACKGROUND

Maternal body mass and the presence of diabetes mellitus are probable risk factors for neural tube defects (NTDs). The association between maternal ethnicity and the risk of NTDs remains poorly understood, however.

METHODS

We performed a retrospective population-based study and included all women in Ontario who underwent antenatal maternal screening (MSS) at 15 to 20 weeks' gestation between 1994 and late 2000. Self-declared maternal date of birth, ethnicity and weight and the presence of pregestational diabetes mellitus were recorded in a standardized fashion on the MSS requisition sheet. NTDs were detected antenatally by ultrasonography or fetal autopsy and postnatally by considering all live and stillborn affected infants beyond 20 weeks' gestation. The risk of open NTD was evaluated across the 5 broad ethnic groups used for MSS, with white ethnicity as the referent.

RESULTS

Compared with white women (n = 290 799), women of First Nations origin (n = 1551) were at increased associated risk of an NTD-affected pregnancy (adjusted odds ratio [OR] 5.2, 95% confidence interval [CI] 2.1-12.9). Women of other ethnic origins were not at increased associated risk compared with white women (women of Asian origin [n = 75 590]: adjusted OR 0.9, 95% CI 0.6-1.3; black women [n = 25 966]: adjusted OR 0.6, 95% CI 0.3-1.1; women of "other" ethnic origin [n = 10 009]: adjusted OR 0.1, 95% CI 0.02-0.9).

INTERPRETATION

The associated risk of NTD-affected pregnancies was higher among women of First Nations origin than among women of other ethnic origins. The mechanisms for this discrepancy should be explored.