Maternal and Cord Blood Folate Concentrations Are Inversely Associated with Fetal DNA Hydroxymethylation, but Not DNA Methylation, in a Cohort of Pregnant Canadian Women.

BACKGROUND: Aberrancies in fetal DNA methylation programming may modify disease susceptibility of the offspring. Maternal folate status has potential to alter fetal DNA methylation. OBJECTIVES: We examined the association of maternal and cord blood concentrations of folate and unmetabolized folic acid (UMFA), vitamin B-12, vitamin B-6, and choline with fetal DNA methylation and hydroxymethylation and assessed potential modifying effects of 38 fetal genetic variants in 22 genes. METHODS: Nutrient blood concentrations were measured in 368 pregnant women in early pregnancy (12-16 wk of gestation) and at delivery (37-42 wk of gestation) and in cord blood. DNA methylation and hydroxymethylation in cord blood mononuclear cells were quantified by LC-MS/MS. Pearson partial correlations were used to determine the association between individual nutrients and DNA methylation and hydroxymethylation. RESULTS: Serum and RBC folate and plasma UMFA concentrations (primary outcomes) in early pregnancy, at delivery, and in cord blood were not significantly associated with fetal DNA methylation. In contrast, maternal RBC folate in early pregnancy (r = -0.16, P = 0.04) and cord plasma UMFA (r = -0.23, P = 0.004) were inversely correlated with fetal DNA hydroxymethylation. Neither maternal and cord blood concentrations of other nutrients nor fetal genotypes (secondary outcomes) were significantly associated with fetal DNA methylation or hydroxymethylation. Infants born to mothers with RBC folate concentrations in the highest quartile and serum vitamin B-12 concentrations in the lowest quartile in early pregnancy had significantly lower fetal DNA methylation and higher birth weight compared with those born to mothers with lower RBC folate and higher serum vitamin B-12 concentrations (P = 0.01). CONCLUSIONS: Maternal and cord blood folate concentrations are associated with fetal DNA hydroxymethylation, but not DNA methylation, in a cohort of pregnant Canadian women. The observation that high folate and low vitamin B-12 maternal status in early pregnancy may be associated with decreased fetal DNA methylation and higher birth weight warrants further investigation. This trial was registered at clinicaltrials.gov as NCT02244684.

Formate concentrations in maternal plasma during pregnancy and in cord blood in a cohort of pregnant Canadian women: relations to genetic polymorphisms and plasma metabolites.

BACKGROUND: One-carbon metabolism, responsible for purine and thymidylate synthesis and transmethylation reactions, plays a critical role in embryonic and fetal development. Formate is a key player in one-carbon metabolism. In contrast to other one-carbon metabolites, it is not linked to tetrahydrofolate, is present in plasma at appreciable concentrations, and may therefore be distributed to different tissues. OBJECTIVE: The study was designed to determine the concentration of formate in cord blood in comparison with maternal blood taken earlier in pregnancy and at delivery and to relate formate concentrations to potential precursors and key fetal genotypes. METHODS: Formate and amino acids were measured in plasma during early pregnancy (12-16 wk), at delivery (37-42 wk), and in cord blood samples from 215 mothers, of a prospective cohort study. Three fetal genetic variants in one-carbon metabolism were assessed for their association with cord plasma concentrations of formate. RESULTS: The formate concentration was ∼60% higher in the cord blood samples than in mothers' plasma. The maternal formate concentrations did not differ between the early pregnancy samples and those taken at delivery. Plasma concentrations of 4 formate precursors (serine, glycine, tryptophan, and methionine) were increased in cord blood compared with the maternal samples. Cord blood formate was influenced by fetal genotype, being ∼12% higher in infants harboring the MTHFR A1298C (rs1801131) AC or CC genotypes and 10% lower in infants harboring the MTHFD1 G1958A (rs2236225) GA or AA genotypes. CONCLUSIONS: The increased formate concentrations in cord blood may support the increased activity of one-carbon metabolism in infants. As such, it would support increased rates of purine and thymidylate synthesis and the provision of methionine for methylation reactions.

Profiling Hospital Performance Based on Mortality After Transcatheter Aortic Valve Replacement in Ontario, Canada.

BACKGROUND: Public reporting of hospital-level outcomes is increasingly common as a means to target quality improvement strategies to ensure the delivery of optimal care. Despite the rapid dissemination of transcatheter aortic valve replacement (TAVR), there is a paucity of reliable case-mix adjustment models for hospital profiling in TAVR. Our objective was to develop and evaluate different models for calculating risk-standardized all-cause mortality rates (RSMRs) post-TAVR. METHODS AND RESULTS: In this population-based study in Ontario, Canada, we identified all patients who underwent a TAVR procedure between April 1, 2012, and March 31, 2016. For each hospital, we calculated 30-day and 1-year RSMR, using 2-level hierarchical logistic regression models that accounted for patient-specific demographic and clinical characteristics, as well as the clustering of patients within the same hospital using a hospital-specific random effects. We classified each hospital into one of 3 groups: performing worse than expected, better than expected, or performing as expected, based on whether the 95% CI of the RSMR was above, below, or included the provincial average mortality rate, respectively. Our cohort consisted of 2129 TAVR procedures performed at 10 hospitals. The observed mortality was 7.0% at 30 days and 16.4% at 1 year, with a range of 4% to 10% and 8% to 22%, respectively, across hospitals. We developed case-mix adjustment models using 28 clinically relevant variables. Using 30-day and 1-year RSMR to profile each hospital, we found that all hospitals performed as expected, with 95% CI that included the provincial average. CONCLUSIONS: We found no significant interhospital variation in RSMR among hospitals, suggesting that quality improvement efforts should be directed at aspects other than the variation in observed mortality.

Fetal one-carbon nutrient concentrations may be affected by gestational diabetes.

Both insufficiency and excess of one-carbon nutrients (folate, choline, vitamins B6 and B12) during pregnancy have been associated with gestational diabetes mellitus (GDM). However, the precise nature of this association has not been clearly established. We hypothesized that GDM may affect one-carbon nutrients concentrations in the fetus, thus possibly participating in epigenetic programing of the offspring. Maternal blood was collected at recruitment (12-16 weeks). At delivery (28-42 weeks), both maternal and cord blood were collected. Blood concentrations of one-carbon nutrients and their metabolites were compared between the two groups. A total of 368 women were included in the study, of whom 19 (5.6%) were later diagnosed with GDM. No significant differences were found in maternal blood concentrations of one-carbon nutrients and their metabolites between the GDM and control groups at recruitment or at delivery. In cord blood, however, serum folate (87.7 [IQR 70.4-103.9] vs 66.6 [IQR 45.5-80.3] nmol/L, P = .025) and plasma TMAO (2.82 [IQR 1.3-3.2] vs 1.35 [IQR 1.0-2.0] µmol/L, P = .017) concentrations were higher, while plasma betaine concentrations were lower (17.5 [IQR 16.3-19.4] vs 21.1 [IQR 18.0-24.1] µmol/L, P = .019) in infants born to mothers with GDM compared with control. Our data suggest that while maternal blood concentrations of one-carbon nutrients and their metabolites may not affect the risk of GDM, GDM may alter concentrations of serum folate, plasma betaine and TMAO in cord blood. These alterations in one-carbon nutrient concentrations in fetal circulation may impact epigenetic programing, thereby contributing to physiologic changes and disease susceptibility in adulthood associated with GDM offspring.

Temporal Trends and Clinical Consequences of Wait Times for Transcatheter Aortic Valve Replacement: A Population-Based Study.

BACKGROUND: Transcatheter aortic valve replacement (TAVR) represents a paradigm shift in the therapeutic options for patients with severe aortic stenosis. However, rapid and exponential growth in TAVR demand may overwhelm capacity, translating to inadequate access and prolonged wait times. Our objective was to evaluate temporal trends in TAVR wait times and the associated clinical consequences. METHODS: In this population-based study in Ontario, Canada, we identified all TAVR referrals from April 1, 2010, to March 31, 2016. The primary outcome was the median total wait time from referral to procedure. Piecewise regression analyses were performed to assess temporal trends in TAVR wait times, before and after provincial reimbursement in September 2012. Clinical outcomes included all-cause death and heart failure hospitalizations while on the wait list. RESULTS: The study cohort included 4461 referrals, of which 50% led to a TAVR, 39% were off-listed for other reasons, and 11% remained on the wait list at the conclusion of the study. For patients who underwent a TAVR, the estimated median wait time in the postreimbursement period stabilized at 80 days and has remained unchanged. The cumulative probability of wait-list mortality and heart failure hospitalization at 80 days was ≈2% and 12%, respectively, with a relatively constant increase in events with increased wait times. CONCLUSIONS: Postreimbursement wait time has remained unchanged for patients undergoing a TAVR procedure, suggesting the increase in capacity has kept pace with the increase in demand. The current wait time of almost 3 months is associated with important morbidity and mortality, suggesting a need for greater capacity and access.

Association of Clinical and Economic Outcomes With Permanent Pacemaker Implantation After Transcatheter Aortic Valve Replacement.

Importance: The literature is inconsistent regarding the impact of permanent pacemaker implantation after transcatheter aortic valve replacement. Objective: To evaluate clinical and economic outcomes in patients who required permanent pacemaker implantation during the index hospitalization after transcatheter aortic valve replacement. Design, Setting, and Participants: This retrospective, population-based cohort study using data from a multicenter registry included patients who underwent a transcatheter aortic valve replacement procedure from April 1, 2010, to March 31, 2015, in Ontario, Canada, with follow-up to March 31, 2017. Patients who had a previously implanted permanent pacemaker or who died during the index hospitalization were excluded. Inverse probability of treatment weighting using the propensity score was used to adjust for baseline differences between the pacemaker and nonpacemaker groups. Exposures: Patients received a permanent pacemaker during the index hospitalization after transcatheter aortic valve replacement. Main Outcomes and Measures: All-cause mortality, readmission, readmission for heart failure, emergency department visits, and cumulative 1-year health care costs. Results: The study cohort consisted of 1263 patients (mean [SD] age, 82.3 [7.2] years; 595 [47.1%] female; 137 [10.8%] rural), of whom 186 (14.7%) required permanent pacemaker insertion during the index hospitalization after transcatheter aortic valve replacement. Mean follow-up was 990 days. After propensity score weighting, over the entire follow-up period, pacemaker implantation was associated with significantly higher all-cause mortality (43.9% vs 31.7%; hazard ratio [HR], 1.40; 95% CI, 1.01-1.94; P = .04), all-cause readmission (80.9% vs 70.6%; HR, 1.28; 95% CI, 1.15-1.43; P < .001), and emergency department visits (95.5% vs 87.3%; HR, 1.28; 95% CI, 1.08-1.52; P = .004). Pacemaker implantation was also associated with significantly greater readmission for heart failure (33.9% vs 19.1%; HR, 1.90; 95% CI, 1.53-2.36; P < .001). There were no statistically significant differences between groups in adjusted cumulative health care costs 1 year after discharge. Conclusions and Relevance: New permanent pacemaker implantation after transcatheter aortic valve replacement was associated with significantly greater morbidity and mortality at long-term follow-up. However, this did not translate to a difference in cumulative health care costs after hospital discharge.

Suboptimal maternal and cord plasma pyridoxal 5' phosphate concentrations are uncommon in a cohort of Canadian pregnant women and newborn infants.

Vitamin B6 is important in fetal development, but little is known of the vitamin B6 status of pregnant women and newborns in North America and potential modifying factors. This prospective study determined maternal and cord plasma concentrations of pyridoxal 5' phosphate (PLP; an indicator of vitamin B6 status) in a convenience sample of 368 Canadian pregnant women and their newborns. The association of maternal intake of vitamin B6 and fetal genetic variants with cord plasma PLP and homocysteine concentrations was also examined. Dietary and supplemental intakes of vitamin B6 were assessed in early and mid to late pregnancy. PLP concentrations were measured in maternal plasma in early pregnancy and at delivery, and in cord plasma. Six fetal variants of the MTHFR and CßS genes were assessed for their association with cord plasma PLP and homocysteine concentrations. Geometric mean (95% CI) PLP concentrations were 107 (98, 116) nmol/L in early pregnancy and 58 (53, 62) nmol/L at delivery, respectively, and 296 (275, 319) nmol/L in cord blood (p < .0001). During early pregnancy and at delivery, 3.6% and 5.5% of women had plasma PLP concentrations <20 nmol/L, respectively. Ninety eight percent of the women with supplemental B6 intake of at least the recommended dietary allowance had PLP concentrations >20 nmol/L. Fetal genetic variants were not associated with cord PLP and homocysteine concentrations. Vitamin B6 deficiency is uncommon in a cohort of Canadian pregnant women due largely to prevalent vitamin B6 supplement use.

Variations in Use of Optimal Medical Therapy in Patients With Nonobstructive Coronary Artery Disease: A Population-Based Study.

BACKGROUND: There is a paucity of data on the need for optimal medical therapy (OMT) in nonobstructive coronary artery disease . We sought to understand if there was variation in the use of OMT between hospitals for patients with nonobstructive coronary artery disease, the factors associated with such variation, and its clinical consequences. METHODS AND RESULTS: Using a population-level clinical registry in Ontario, Canada, we identified all patients >66 years undergoing coronary angiography for the indication of stable angina, who had nonobstructive coronary artery disease between November 1, 2010, and October 31, 2013. Hierarchical multivariable logistic models were developed to identify the factors associated with OMT use, with median odds ratio used to quantify the degree of variation between hospitals not explained by the modeled risk factors. Clinical outcomes of interest were all-cause mortality and rehospitalization, with follow-up until March 31, 2015. Our cohort consisted of 5413 patients, of whom 2554 (47.2%) were receiving OMT within 1 year. There was a 2-fold variation in OMT across hospitals (30.4%-61.8%). The variation between hospitals was fully explained by preangiography medication use (median odds ratio of 1.21 in the null model and 1.03 in the full model). There was no difference in risk-adjusted mortality (hazard ratio, 0.94; 95% confidence interval, 0.76-1.16); however, patients receiving OMT had a lower risk of all-cause hospital readmission (hazard ratio, 0.89; 95% confidence interval, 0.84-0.95). CONCLUSIONS: There is wide variation in the use of OMT in patients with nonobstructive coronary artery disease, the major driver of which is differences in baseline medication use.

Economic Impact of Subsequent Depression in Patients With a New Diagnosis of Stable Angina: A Population-Based Study.

BACKGROUND: Depression is strongly linked to increased morbidity and mortality in patients with chronic stable angina; however, its associated healthcare costs have been less well studied. Our objective was to identify the characteristics of chronic stable patients found to have depression and to determine the impact of an occurrence of depression on healthcare costs within 1 year of a diagnosis of stable angina. METHODS AND RESULTS: In this population-based study conducted in Ontario, Canada, we identified patients diagnosed with stable angina based on angiogram between October 1, 2008, and September 30, 2013. Depression was ascertained by physician billing codes and hospital admission diagnostic codes contained within administrative databases. The primary outcome was cumulative mean 1-year healthcare costs following index angiogram. Generalized linear models were developed with a logarithmic link and γ distribution to determine predictors of cost. Our cohort included 22 917 patients with chronic stable angina. Patients with depression had significantly higher mean 1-year healthcare costs ($32 072±$41 963) than patients without depression ($23 021±$25 741). After adjustment for baseline comorbidities, depression was found to be a significant independent predictor of cost, with a cost ratio of 1.33 (95% confidence interval, 1.29-1.37). Higher costs in depressed patients were seen in all healthcare sectors, including acute and ambulatory care. CONCLUSIONS: Depression is an important driver of healthcare costs in patients following a diagnosis of chronic stable angina. Further research is needed to understand whether improvements in the approach to diagnosis and treatment of depression will translate to reduced expenditures in this population.

Low Serum Vitamin B-12 Concentrations Are Prevalent in a Cohort of Pregnant Canadian Women.

BACKGROUND: Among Canadian women of reproductive age, 5% and 20% have serum vitamin B-12 concentrations indicative of deficiency (<148 pmol/L) and marginal status (148-220 pmol/L), respectively. Given the association between suboptimal vitamin B-12 and adverse pregnancy outcomes, an understanding of vitamin B-12 status during pregnancy, and factors that influence it, is required. OBJECTIVE: This prospective analysis from the PREFORM (PREnatal FOlic acid exposuRe on DNA Methylation in the newborn infant) study investigated 1) vitamin B-12 status in a cohort of Canadian pregnant women and their newborns, 2) the association of maternal dietary vitamin B-12 intake with maternal and cord blood concentrations of vitamin B-12 and its biomarkers, and 3) the association of fetal genetic polymorphisms with cord blood concentrations of vitamin B-12 and its biomarkers. METHODS: In pregnant Canadian women (n = 368; mean ± SD age: 32 ± 5 y), vitamin B-12 intakes were assessed in early (0-16 wk) and mid- to late (23-37 wk) pregnancy. Serum vitamin B-12 and plasma total homocysteine (tHcy) and methylmalonic acid (MMA) in maternal blood at 12-16 wk of pregnancy and at delivery (28-42 wk) and in cord blood were measured and compared by using regression analyses. The associations of 28 fetal genetic variants in vitamin B-12 metabolism and cord blood vitamin B-12, tHcy, and MMA concentrations were assessed by using regression analysis, with adjustment for multiple testing. RESULTS: A total of 17% and 38% of women had deficient and 35% and 43% had marginal serum vitamin B-12 concentrations at 12-16 wk of pregnancy and at delivery, respectively. Only 1.9-5.3% had elevated MMA (>271 nmol/L), and no women had elevated tHcy (>13 µmol/L). Maternal dietary vitamin B-12 intake during pregnancy was either weakly associated or not associated with maternal and cord blood vitamin B-12 (r(2) = 0.17-0.24, P < 0.0008), tHcy (P = NS) and MMA (r(2) = 0.05-0.11, P < 0.001). Fetal genetic polymorphisms were not associated with cord blood concentrations of vitamin B-12 and its biomarkers. CONCLUSIONS: Deficient and marginal serum vitamin B-12 concentrations are prevalent in Canadian pregnant women with the use of traditional cutoffs, despite supplement use. Given the growing interest among women to adhere to a vegetarian diet that may be lower in vitamin B-12, and vitamin B-12's importance in pregnancy, the functional ramifications of these observations need to be elucidated. This trial was registered at clinicaltrials.gov as NCT02244684.

High concentrations of folate and unmetabolized folic acid in a cohort of pregnant Canadian women and umbilical cord blood.

BACKGROUND: Mandatory fortification, prevalent supplement use, and public health guidelines recommending periconceptional supplementation have increased folic acid intakes in North American pregnant women. However, the effects of increased folic acid intakes during pregnancy on maternal and cord blood folate concentrations have not been well established. OBJECTIVES: In this prospective study, we determined maternal and cord blood concentrations of folate and unmetabolized folic acid (UMFA) in a cohort of pregnant Canadian women and their newborns and examined the effect of maternal intakes of folate and folic acid and fetal genetic variants in folate metabolism on folate status. DESIGN: Folate and folic acid intakes of 368 Canadian pregnant women were assessed in early (0-16 wk) and late (23-37 wk) pregnancy. Blood concentrations of folate and UMFA were measured with the use of immunoassays and liquid chromatography-mass spectrometry, respectively, in maternal samples in early pregnancy (12-16 wk), at delivery (28-42 wk), and in cord blood. Four fetal genetic variants of the 5,10-methylenetetrahydrofolate reductase (MTHFR) and dihydrofolate reductase (DHFR) genes were assessed for their association with cord blood concentrations of folate and UMFA. RESULTS: Geometric mean (95% CI) maternal red blood cell (RBC) folate concentrations were 2417 nmol/L (2362, 2472 nmol/L ) and 2793 nmol/L (2721, 2867 nmol/L ) in early pregnancy and at delivery, respectively. The mean (95% CI) cord RBC folate concentration was 2689 nmol/L (2614, 2765 nmol/L). UMFA was detectable in >90% of maternal and cord plasma samples. Although 3 fetal MTHFR and DHFR genetic variants had no effect, the fetal MTHFR 677TT genotype was associated with significantly lower cord serum (P = 0.03) and higher cord RBC (P = 0.02) folate concentrations than those of the wild type. CONCLUSIONS: Notwithstanding differences in assays, maternal and cord RBC folate and plasma UMFA concentrations were higher than previously reported values. Functional ramifications of high folate and UMFA concentrations in maternal and fetal circulation warrant additional investigation because an excess folate status may affect long-term health outcomes of the offspring. This study was registered at www.clinicaltrials.gov as NCT02244684.

Pregnant Canadian Women Achieve Recommended Intakes of One-Carbon Nutrients through Prenatal Supplementation but the Supplement Composition, Including Choline, Requires Reconsideration.

BACKGROUND: Folate, vitamin B-6, vitamin B-12, and choline are involved in one-carbon metabolism and play critical roles in pregnancy including prevention of birth defects and promotion of neurodevelopment. However, excessive intakes may adversely affect disease susceptibility in offspring. Intakes of these nutrients during pregnancy are not well characterized. OBJECTIVE: Our aim was to determine dietary and supplemental intakes and major dietary sources of one-carbon nutrients during pregnancy. METHODS: In pregnant women (n = 368) at ≤16 wk postconception, supplement use >30 d before pregnancy was assessed by maternal recall and supplement and dietary intakes in early (0-16 wk) and late pregnancy (23-37 wk) were assessed by food-frequency questionnaire. RESULTS: Preconception, 60.1% (95% CI: 55.8, 64.3) of women used B vitamin-containing supplements. This increased to 92.8% (95% CI: 89.6, 95.2) in early and 89.0% (95% CI: 85.0, 92.3) in late pregnancy. Median supplemental folic acid, vitamin B-12, and vitamin B-6 were 1000 µg/d, 2.6 µg/d, and 1.9 mg/d, respectively. Forty-one percent and 50% of women had dietary intakes of folate and vitamin B-6 less than the estimated average requirement (520 mg/d dietary folate equivalents and 1.6 mg/d, respectively). Eight-seven percent of women had choline intakes less than the Adequate Intake (450 mg/d). Dietary intakes did not change appreciably during pregnancy. Fruits and vegetables and fortified foods contributed ∼57% to total dietary folate intake. Fruits and vegetables contributed ∼32% to total dietary vitamin B-6 intake and dairy and egg products contributed ∼37% to total dietary vitamin B-12 intake. CONCLUSIONS: Vitamin supplements were an important source of one-carbon nutrients during pregnancy in our sample. Without supplements, many women would not have consumed quantities of folate and vitamin B-6 consistent with recommendations. Given the importance of choline in pregnancy, further research to consider inclusion in prenatal supplements is warranted. This trial was registered at clinicaltrials.gov as NCT02244684.

Maternal Choline Status, but Not Fetal Genotype, Influences Cord Plasma Choline Metabolite Concentrations.

BACKGROUND: Choline deficiency during pregnancy can lead to adverse birth outcomes, including impaired neurodevelopment and birth defects. Genetic variants of choline and one-carbon metabolism may also influence birth outcomes by altering plasma choline concentrations. The effects of maternal ad libitum choline intake during pregnancy and fetal genetic variants on maternal and cord concentrations of choline and its metabolites are unknown. OBJECTIVES: This prospective study sought to assess the effect of 1) maternal dietary choline intake on maternal and cord plasma concentrations of choline and its metabolites, and 2) fetal genetic polymorphisms on cord plasma concentrations. METHODS: The dietary choline intake of 368 pregnant Canadian women was assessed in early (0-16 wk) and late (23-37 wk) pregnancy with the use of a food frequency questionnaire. Plasma concentrations of free choline and its metabolites were measured in maternal samples at recruitment and delivery, and in the cord blood. Ten fetal genetic variants in choline and one-carbon metabolism were assessed for their association with cord plasma concentrations of free choline and its metabolites. RESULTS: Mean maternal plasma free choline, dimethylglycine, and trimethylamine N-oxide (TMAO) concentrations increased during pregnancy by 49%, 17%, and 13%, respectively (P < 0.005), whereas betaine concentrations decreased by 21% (P < 0.005). Cord plasma concentrations of free choline, betaine, dimethylglycine, and TMAO were 3.2, 2.0, 1.3, and 0.88 times corresponding maternal concentrations at delivery, respectively (all P < 0.005). Maternal plasma concentrations of betaine, dimethylglycine, and TMAO (r(2) = 0.19-0.51; P < 0.0001) at delivery were moderately strong, whereas maternal concentrations of free choline were not significant (r(2) = 0.12; P = 0.06), predictors of cord plasma concentrations of these metabolites. Neither maternal dietary intake nor fetal genetic variants predicted maternal or cord plasma concentrations of choline and its metabolites. CONCLUSION: These data collectively indicate that maternal choline status, but not fetal genotype, influences cord plasma concentrations of choline metabolites. This trial was registered at clinicaltrials.gov as NCT02244684.