Cynthia K. Colapinto

Folate status of the population in the Canadian Health Measures Survey

Background Low folate concentrations are inversely associated with birth defects, including neural tube defects, congenital heart disease and oral clefts. Conversely, high folate concentrations may be associated with adverse outcomes, including increased risk of colorectal cancer among those with pre-existing neoplasms. The purpose of our study was to investigate the folate status of a nationally representative sample of Canadians, including a subset of women of childbearing age. Methods We examined red blood cell folate concentrations among members of the general population aged 6–79 years (n = 5248) and separately among women of childbearing age (15–45 yr, n = 1162), as recorded by the Canadian Health Measures Survey and measured by immunologic assay. We assessed the data for significant differences by age, sex and socioeconomic status. Results Less than 1% of Canadians showed folate deficiency (red blood cell folate < 305 nmol/L) and 40% showed high folate concentrations (> 1360 nmol/L). Among women of childbearing age, 22% showed concentrations below those considered optimal for maximal neural tube defect-risk reduction (< 906 nmol/L). Significant differences by age and socio-economic status, but not sex, were evident in median red blood cell folate concentrations, although concentrations in all groups exceeded recommended levels. No differences by age or income were found among women of child-bearing age. Interpretation Folate deficiency is virtually nonexistent in the Canadian population, although high folate concentrations are evident. Additional research is needed to better understand the determinants of red blood cell folate among women of childbearing age who have concentrations below levels that are maximally protective against neural tube defects. Ongoing monitoring of the folate status of Canadians and the relationship between red blood cell folate and health outcomes is warranted.

Folic acid supplement use is the most significant predictor of folate concentrations in Canadian women of childbearing age.

One-fifth of Canadian women of childbearing age (WCBA) have red blood cell (RBC) folate concentrations below those considered optimal for neural tube defect risk reduction (≥906 nmol·L(-1)). Determinants of optimal concentrations have not been examined in a nationally representative sample of Canadian WCBA since food fortification with folic acid was implemented. This study explored correlates of optimal RBC folate concentrations and characteristics of folic acid supplement users in a sample of Canadian WCBA. RBC folate concentrations from the 2007-2009 Canadian Health Measures Survey were assessed in women aged 15 to 45 years (n = 1162). Sociodemographic, behavioural, and clinical determinants of RBC folate ≥906 nmol·L(-1) were examined using univariate and separate multiple logistic regression models that controlled for age and household income. t tests were used to study differences between folic acid supplement users and nonusers. WCBA not taking folic acid supplements were less likely to achieve a RBC folate concentration ≥906 nmol·L(-1) compared with folic acid supplement users (odds ratio, 0.47; 95% confidence interval, 0.24, 0.92). Twenty-five percent of WCBA reported folic acid supplement use, and there was a higher percentage of folic acid supplement users in the highest income group. Folic acid supplement users were also more frequent consumers of supplemental vitamin B(12) and of fruit and vegetables (>3 times per day). Folic acid supplement use was the most significant predictor of WCBA achieving optimal RBC folate concentrations. These results indicate a need for targeted strategies to improve compliance with folic acid supplement recommendations among WCBA.

Obesity, lifestyle and socio-economic determinants of vitamin D intake: a population-based study of Canadian children.

ObjectiveVitamin D intake in childhood is primarily for the prevention of rickets. Inconsistent evidence has associated adequate blood concentrations with a decreased risk of certain health conditions. Further, obese individuals may have lower vitamin D status. The estimated average requirement (EAR) for children recently doubled to 400 IU/day. Our aim was to examine dietary intake of vitamin D in different body mass index (BMI) categories, in addition to assessing determinants.MethodsData from two provincial surveys of grade 5 children, including a food frequency questionnaire and measured BMI, were used. Rao-Scott chi-square statistic tested the bivariate association between provinces and adequate dietary vitamin D intake. Key correlates were examined using multilevel logistic regression.ResultsThose below the EAR differed between Alberta (78%) and Nova Scotia (81 %). Those drinking <2 glasses of milk/day had 0.02 times the odds of meeting the EAR (95% CI: 0.01 -0.02) compared to those drinking more. No significant difference was observed for BMI, though those consuming <1 glass of milk/day were more likely to be obese than those consuming >-2 glasses/day. Income and physical activity were negatively correlated with meeting the EAR.ConclusionMany children did not meet the EAR for vitamin D from dietary sources and milk consumption was an important determinant. Given trends towards a more sedentary lifestyle and limited sun exposure, we recommend prioritizing public health efforts to support dietary vitamin D intake alongside interventions to increase physical activity and reduce sedentary behaviour. Further investigation is required to determine the need for targeted strategies for obese children.RésuméObjectifL’apport en vitamine D durant l’enfance sert principalement à prévenir le rachitisme. Bien que les données probantes divergent, des études associent des concentrations sanguines adéquates à un moindre risque de contracter certains troubles médicaux. De plus, les personnes obèses pourraient avoir un statut plus faible en vitamine D. Le besoin moyen estimatif (BME) en vitamine D des enfants a récemment été doublé à 400 Ul/jour. Notre but était d’examiner l’apport alimentaire en vitamine D dans différentes catégories de l’indice de masse corporelle (IMC), en plus d’en évaluer les déterminants.MéthodeNous avons utilisé les données de deux enquêtes provinciales auprès d’élèves de 5e année comportant un questionnaire sur la fréquence de consommation des produits alimentaires et des mesures de l’IMC des élèves. Le test du khi-carré de Rao-Scott a analysé l’association bivariée entre les deux provinces et la suffisance de l’apport alimentaire en vitamine D. Les principaux corrélats ont été examinés par régression logistique multiniveau.RésultatsLa proportion d’enfants dont l’apport est en-deçà du BME était différente en Alberta (78 %) et en Nouvelle-Écosse (81 %). Les enfants qui buvaient <2 verres de lait/jour avaient 0,02 fois la probabilité d’avoir un apport supérieur ou égal au BME (IC de 95 %: 0,01 -0,02) que ceux qui en buvaient plus. Aucun écart significatif n’a été observé pour l’IMC, mais les enfants qui consommaient <1 verre de lait/jour étaient plus susceptibles d’être obèses que ceux qui en consommaient >-2 verres/jour. Le revenu et l’activité physique présentaient des corrélations négatives avec le statut par rapport au BME.ConclusionDe nombreux enfants avaient un apport en vitamine D de sources alimentaires en-deçà du BME, et la consommation de lait en était un important déterminant. Étant donné la tendance à la sédentarisation des modes de vie et l’exposition limitée au soleil, nous recommandons de privilégier les efforts de santé publique qui appuient l’apport alimentaire en vitamine D en plus des interventions pour accroître l’activité physique et réduire les comportements sédentaires. Il est nécessaire de pousser la recherche pour déterminer s’il faudrait des stratégies ciblant les enfants obèses.

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.

Examining the Folate Status of Canadians: An Analysis of the Canadian Health Measures Survey to Assess and Guide Folate Policies

Canada fortifies certain products with folic acid and has periconceptional supplementation guidelines [Formula: see text] policies designed to improve folate status and reduce the incidence of poor birth outcomes. Though optimal folate concentrations have been linked to health benefits, concerns have been raised regarding potential associations with adverse health outcomes. Direct biochemical assessment of the folate status of Canadians based on a nationally representative sample has not been done in more than 40 years. The overall purpose of this research was to investigate the folate status of the Canadian population. All analyses used the nationally representative 2007-2009 Canadian Health Measures Survey (CHMS). Red blood cell (RBC) folate was measured by Immulite 2000 immunoassay. Key findings indicate that folate deficiency (<305 nmol/L) was virtually nonexistent in the Canadian population (6-79 years old). Still, one-fifth of women of childbearing age (WCBA; 15-45 years old) had suboptimal concentrations for the prevention of neural tube defects (<906 nmol/L). Folic acid supplement intake was a primary determinant of WCBA, achieving a RBC folate concentration of ≥906 nmol/L. A distinct shift towards elevated RBC folate concentrations emerged. Three hypothetical cut-offs (1450 nmol/L, 1800 nmol/L and 2150 nmol/L) were examined to create a dialogue since a universal definition of high RBC folate concentration does not exist. Females, participants aged 60-79 years, and those who were overweight or obese had the greatest prevalence of having high RBC folate at each cut-off. We conducted the first national-level comparison of RBC folate concentrations between the United States and Canada. Two different folate assay methods [Formula: see text] microbiologic assay (NHANES) and Immulite 2000 immunoassay (CHMS) [Formula: see text] necessitated the application of a conversion equation. Median Canadian RBC folate concentrations (adjusted to microbiologic assay) were lower than those of Americans but unadjusted Canadian median RBC folate values were higher. Canadian WCBA were less likely than American WCBA to have RBC folate ≥906 nmol/L, though Canadian WCBA with unadjusted RBC folate values were more likely to achieve this cut-off. These results indicate a need for strategies targeting WCBA to improve compliance with folic acid supplement recommendations. The strength and necessity of supplements for the general population should be re-assessed. Further, harmonization of folate measurement procedures in future surveillance efforts would support comparisons and inform policy directions.

Is there a relationship between tea intake and maternal whole blood heavy metal concentrations

The aim of this analysis was to examine the association between tea intake during pregnancy and maternal and infant metal exposures. Data from the Maternal-Infant Research on Environmental Chemicals (MIREC) Study, a pan-Canadian pregnancy cohort, were used. All participants with a gestational age of ⩾20 weeks (n=1954) with available biomarkers were included. Geometric means (GMs) for lead, arsenic, mercury, cadmium and manganese in maternal (first and third trimesters) and cord blood, as well as speciated arsenic in maternal urine in the first trimester, were calculated for participants who drank regular, green or herbal tea and for those who did not. Differences between groups were examined using chi-square tests. Adjusted least squares geometric means (LSGMs) were estimated by tea intake, controlling for factors such as country of birth, coffee intake and maternal smoking. Concentrations of all metals were above the limits of detection in most participants in the first trimester: lead (GM): 0.62 μg/dl), mercury (GM: 2.99 nmol/l); cadmium (GM 1.93 nmol/l), arsenic (GM 9.75 nmol/l) and manganese (GM 160.1 nmol/l). Adjusted LSGMs for lead in the first trimester were higher for tea drinkers than for those who were non-tea drinkers (LSGM 0.65 μg/dl, 95%CI: 0.62, 0.69 and 0.61 μg/dl, 95%CI: 0.59, 0.62), and there was evidence of a dose–response relationship for green and herbal tea. Those who consumed herbal tea in the third trimester had significantly higher third trimester maternal and cord blood lead concentrations than non-herbal tea drinkers. This study provides evidence of an association between blood lead concentrations and green or herbal tea consumption. However, the GM blood lead concentrations of the highest tea consumers were still less than 1 μg/dl and within the normal range of blood lead concentrations in the Canadian population.

Prevalence and correlates of high red blood cell folate concentrations in the Canadian population using 3 proposed cut-offs.

A distinct shift towards higher folate concentrations has emerged in Canada. These higher concentrations have known benefits, including prevention of neural tube defects, but concerns have been raised regarding potential associations with adverse health outcomes. The aim of this research was to propose cut-offs for high red blood cell (RBC) folate concentrations and identify their correlates. RBC folate was measured in a nationally representative cross-sectional sample of Canadians (N = 5248) aged 6 to 79 years. RBC folate concentrations were adjusted from the IMMULITE 2000 immunoassay to a microbiologic assay. The population was characterized at 3 RBC folate cut-offs: 1450 nmol/L, 1800 nmol/L, and 2150 nmol/L. We used t tests to examine differences by age, sex, income, and body mass index (BMI) at each cut-off and logistic regression to explore associations with folic acid supplement intake. The prevalence of high RBC folate was 16%, 6%, and 2% at thresholds of 1450 nmol/L, 1800 nmol/L, and 2150 nmol/L, respectively. Females, those aged 60 to 79 years, and overweight or obese participants had the greatest prevalence of having high RBC folate at each cut-off. Folic acid supplement users were more likely than non-users to have high RBC folate concentrations. Older age, higher BMI, and folic acid supplement use were identified as correlates of high folate status. A high RBC folate concentration cut-off will advance the field towards consistent measurement and reporting of high folate status. This may facilitate future investigation of associations between RBC folate concentrations at the upper end of the distribution and health outcomes.

Systematic review of adverse health outcomes associated with high serum or red blood cell folate concentrations.

BACKGROUND To examine the relationship between reported high serum or red blood cell (RBC) folate status and adverse health outcomes. METHODS We systematically searched PubMed/Medline and EMBASE (to May 2013), with no limits by study type, country or population, to identify studies reporting high folate concentrations in association with adverse health outcomes. Two reviewers screened studies and extracted data. Study quality was assessed. RESULTS We included 51 articles, representing 46 studies and 71 847 participants. Quantiles were used by 96% of studies to identify high folate concentrations. Eighty-three percent of serum folate and 50% of RBC folate studies reported a high folate cutoff that corresponded with a clinically normal concentration. Increasing values of reported high folate concentration did not demonstrate a consistent association with risk of adverse health outcomes. Overall, reported high folate concentrations appeared to be associated with a decreased risk of adverse health outcomes, though substantial methodological heterogeneity precluded complex analyses. CONCLUSIONS Our interpretation was complicated by methodological variability. High folate cutoffs varied and often corresponded with normal or desirable blood concentrations. In general, a negative association appeared to exist between reported high folate status and adverse health outcomes. Consistent methods and definitions are needed to examine high folate status and ultimately inform public health interventions.