Maternal serum unmetabolized folic acid concentration following multivitamin and mineral supplementation with or without folic acid after 12 weeks gestation: A randomized controlled trial.

Pregnant women are advised to take folic acid (FA) supplements before conception and during the first trimester of pregnancy. Many women continue FA supplementation throughout pregnancy, and concerns have been raised about associations between excessive FA intake and adverse maternal and child health outcomes. Unmetabolized folic acid (UMFA) is found in serum after high FA intakes and is proposed as a biomarker for excessive FA intake. We aimed to determine if removing FA from prenatal micronutrient supplements after 12 weeks of pregnancy reduces serum UMFA concentrations at 36 weeks gestation. In this double-blind, randomized controlled trial conducted in South Australia, 103 women with a singleton pregnancy were randomly assigned at 12-16 weeks gestation to take a micronutrient supplement containing no FA or 800 µg/day FA from enrollment until 36 weeks gestation. Ninety women (0 µg/day FA n = 46; 800 µg/day FA n = 44) completed the study. Mean, UMFA concentration was lower in the women randomized to the 0 µg/day group compared to the 800 µg/day FA group, 0.6 ± 0.7 and 1.4 ± 2.7 nmol/L, respectively. The adjusted mean difference (95% CI) in UMFA between the groups was [-0.85 (-1.62, -0.08) nmol/L, p = 0.03]. Maternal serum and red blood cell folate concentrations were lower in the 0 µg/day FA group than in the 800 µg/day group (median 23.2 vs. 49.3 and 1335 vs. 1914 nmol/L, respectively; p < 0.001). Removing FA at 12-16 weeks gestation from prenatal micronutrient supplements reduced the concentration of UMFA at 36 weeks gestation.

The association between dietary intake and cardiometabolic risk factors among obese adolescents in Indonesia.

BACKGROUND AND OBJECTIVE: Poor diets, characterized by excess fat, sugar and sodium intakes, are considered to be one of the most important modifiable risk factors for cardiovascular disease. Diet patterns and intakes during adolescence may persist into adulthood and impact on risk for chronic disease later in life. We aimed to evaluate the dietary intake of obese adolescents and its relationship to cardiometabolic health including lipid status and glycemic control. METHODS AND STUDY DESIGN: This was a cross-sectional study of obese children aged 15 to < 18 years in Yogyakarta, Indonesia. All children had a medical history performed including a physical examination and fasting blood sample. Dietary intake was assessed using a semi-quantitative recall food frequency questionnaire. Multivariable linear regression model was performed to determine the relationship between dietary intakes and cardiovascular disease risks and to adjust for potential confounders. RESULTS: Of 179 adolescents, 101 (57.4%) were male and median age was 16.4 (15.0-17.9) years. The majority of adolescents (98%) had inadequate intake of fibre and exceeded intakes of total fat (65%) and total sugar (36%). There was statistically significant correlation found in the multivariable linear regression analysis between fibre intake and HDL cholesterol after adjusting for potential confounders (ß = 0.165; p = 0.033). CONCLUSIONS: This study demonstrates that there is a high proportion of obese Indonesian adolescents with poor dietary intakes. There was relationship observed between intake of nutrients of concern (fibre) and cardiometabolic risk factor among this sample of obese adolescents. Future research should examine overall dietary patterns in more detail among this population to elucidate the role of poor diet intakes in development of cardiovascular disease risk factors in young people transitioning into adulthood.

Maternal Late-Pregnancy Serum Unmetabolized Folic Acid Concentrations Are Not Associated with Infant Allergic Disease: A Prospective Cohort Study.

BACKGROUND: The increase in childhood allergic disease in recent decades has coincided with increased folic acid intakes during pregnancy. Circulating unmetabolized folic acid (UMFA) has been proposed as a biomarker of excessive folic acid intake. OBJECTIVE: We aimed to determine if late-pregnancy serum UMFA and total folate concentrations were associated with allergic disease risk in the offspring at 1 y of age in a population at high risk of allergy. METHODS: The cohort consisted of 561 mother-infant pairs from Western Australia. To be eligible the infant had to have a first-degree relative (mother, father, or sibling) with a history of medically diagnosed allergic disease. Maternal venous blood was collected between 36 and 40 wk of gestation. Serum UMFA was measured by LC-tandem MS. Serum total folate was determined using a microbiological method with chloramphenicol-resistant Lactobacillus rhamnosus as the test organism, and was collected between 36 and 40 wk of gestation. UMFA concentrations were measured by tandem MS using stable isotope dilution; folate concentrations were determined using the microbiological method with standardized kits. Infant allergic disease outcomes of medically diagnosed eczema, steroid-treated eczema, atopic eczema, IgE-mediated food allergy, allergen sensitization, and medically diagnosed wheeze were assessed at 1 y of age. RESULTS: Median (IQR) concentrations for UMFA and serum folate were 1.6 (0.6-4.7) and 53.2 (32.6-74.5) nmol/L, respectively. Of the infants, 34.6% had medically diagnosed eczema, 26.4% allergen sensitization, and 14.9% had an IgE-mediated food allergy. In both adjusted and unadjusted models there was little evidence of association between UMFA or serum folate and any of the infant allergy outcomes. CONCLUSIONS: In this cohort of children at high risk of allergic disease there was no association between maternal UMFA or serum folate concentrations measured in late pregnancy and allergic disease outcomes at 1 y of age.

The Inclusion of Folic Acid in Weekly Iron-Folic Acid Supplements Confers no Additional Benefit on Anemia Reduction in Nonpregnant Women: A Randomized Controlled Trial in Malaysia.

BACKGROUND: Weekly iron-folic acid (IFA) supplements are recommended for all menstruating women in countries where anemia prevalence is ≥20%; however, it is unknown whether the inclusion of folic acid in weekly IFA supplements reduces anemia. OBJECTIVES: We examined whether the inclusion of folic acid in weekly IFA supplements conferred any benefit on hemoglobin (Hb) concentration, anemia reduction, or iron status [ferritin and soluble transferrin receptor (sTfR)], over iron alone. METHODS: In this secondary analysis of a randomized controlled trial in Malaysia, n = 311 nonpregnant women (18-45 y old) received 60 mg Fe with either 0, 0.4, or 2.8 mg folic acid once-weekly for 16 wk. Fasting blood was collected at baseline and 16 wk. A generalized linear model (normal distribution with identity link) was used to assess Hb concentration at 16 wk (primary outcome). RESULTS: At baseline, 84% of women had low folate status (plasma folate < 14 nmol/L). At 16 wk, marginal mean (95% CI) Hb was 131 (130, 133), 131 (129, 132), and 132 (130, 133) g/L; ferritin was 58.2 (53.9, 62.5), 56.5 (52.2, 60.9), and 58.0 (53.7, 62.3) µg/L; and sTfR was 5.8 (5.5, 6.1), 5.8 (5.5, 6.1), and 5.9 (5.6, 6.2) mg/L in the 0, 0.4, and 2.8 mg/wk groups, respectively, with no differences between groups (P > 0.05). Baseline plasma folate concentration did not modify the effect of treatment on Hb concentration at 16 wk. Among all women, the risks of anemia [risk ratio (RR): 0.65; 95% CI: 0.45, 0.96; P = 0.03] and iron deficiency based on ferritin (RR: 0.30; 95% CI: 0.20, 0.44; P < 0.001) were lower at 16 wk than at baseline. CONCLUSIONS: Despite the low folate status among these nonpregnant Malaysian women, the inclusion of folic acid in weekly IFA supplements did not reduce anemia or improve iron status, over iron alone. However, the benefits of folic acid for neural tube defect prevention still warrant its retention in weekly IFA supplements.This trial was registered at www.anzctr.org.au as ACTRN12619000818134.

Prenatal alcohol exposure alters methyl metabolism and programs serotonin transporter and glucocorticoid receptor expression in brain.

Prenatal alcohol exposure (PAE) programs the fetal hypothalamic-pituitary-adrenal (HPA) axis, resulting in HPA dysregulation and hyperresponsiveness to stressors in adulthood. Molecular mechanisms mediating these alterations are not fully understood. Disturbances in one-carbon metabolism, a source of methyl donors for epigenetic processes, contributes to alcoholic liver disease. We assessed whether PAE affects one-carbon metabolism (including Mtr, Mat2a, Mthfr, and Cbs mRNA) and programming of HPA function genes (Nr3c1, Nr3c2, and Slc6a4) in offspring from ethanol-fed (E), pair-fed (PF), and ad libitum-fed control (C) dams. At gestation day 21, plasma total homocysteine and methionine concentrations were higher in E compared with C dams, and E fetuses had higher plasma methionine concentrations and lower whole brain Mtr and Mat2a mRNA compared with C fetuses. In adulthood (55 days), hippocampal Mtr and Cbs mRNA was lower in E compared with C males, whereas Mtr, Mat2a, Mthfr, and Cbs mRNA were higher in E compared with C females. We found lower Nr3c1 mRNA and lower nerve growth factor inducible protein A (NGFI-A) protein in the hippocampus of E compared with PF females, whereas hippocampal Slc6a4 mRNA was higher in E than C males. By contrast, hypothalamic Slc6a4 mRNA was lower in E males and females compared with C offspring. This was accompanied by higher hypothalamic Slc6a4 mean promoter methylation in E compared with PF females. These findings demonstrate that PAE is associated with alterations in one-carbon metabolism and has long-term and region-specific effects on gene expression in the brain. These findings advance our understanding of mechanisms of HPA dysregulation associated with PAE.

Total and high molecular weight adiponectin and ethnic-specific differences in adiposity and insulin resistance: a cross-sectional study.

BACKGROUND: Ethnic-specific differences in insulin resistance (IR) are well described but the underlying mechanisms are unknown. Adiponectin is an insulin sensitizing adipocytokine that circulates as multiple isoforms, with high molecular weight (HMW) adiponectin associated with greatest insulin sensitivity. The objective of this study is to determine if plasma total and HMW adiponectin concentrations underlie ethnic-specific differences in IR. METHODS: Healthy Canadian Aboriginal, Chinese, European, and South Asian adults (N = 634) were assessed for sociodemographics; lifestyle; fasting plasma insulin, glucose, and total and HMW adiponectin; and adiposity measures [BMI, waist circumference, waist-to-hip ratio, percent body fat, and subcutaneous and visceral adipose tissue (quantified by computed tomography)]. The homeostasis model assessment-insulin resistance (HOMA-IR) assessed IR. RESULTS: South Asians had the greatest HOMA-IR, followed by Aboriginals, Chinese, and Europeans (P < 0.001). Plasma total and HMW adiponectin concentrations were lower in Chinese and South Asians than Aboriginal and Europeans (P < 0.05). Total and HMW adiponectin were inversely associated with HOMA-IR (P < 0.001). Ethnicity modified the relationship between HMW adiponectin and HOMA-IR with stronger effects observed in Aboriginals (P = 0.001), Chinese (P = 0.002), and South Asians (P = 0.040) compared to Europeans. This was not observed for total adiponectin (P = 0.431). At mean total adiponectin concentrations South Asians had higher HOMA-IR than Europeans (P < 0.001). CONCLUSIONS: For each given decrease in HMW adiponectin concentrations a greater increase in HOMA-IR is observed in Aboriginals, Chinese, and South Asians than Europeans. Ethnic-specific differences in HMW adiponectin may account for differences in IR.

Altered glutathione homeostasis in heart augments cardiac lipotoxicity associated with diet-induced obesity in mice.

Obesity-related cardiac lipid accumulation is associated with increased myocardial oxidative stress. The role of the antioxidant glutathione in cardiac lipotoxicity is unclear. Cystathionine ß-synthase (Cbs) catalyzes the first step in the trans-sulfuration of homocysteine to cysteine, which is estimated to provide ∼50% of cysteine for hepatic glutathione biosynthesis. As cardiac glutathione is a reflection of the liver glutathione pool, we hypothesize that mice heterozygous for targeted disruption of Cbs (Cbs(+/-)) are more susceptible to obesity-related cardiolipotoxicity because of impaired liver glutathione synthesis. Cbs(+/+) and Cbs(+/-) mice were fed a high fat diet (60% energy) from weaning for 13 weeks to induce obesity and had similar increases in body weight and body fat. This was accompanied by increased hepatic triglyceride but no differences in hepatic glutathione levels compared with mice fed chow. However, Cbs(+/-) mice with diet-induced obesity had greater glucose intolerance and lower total and reduced glutathione levels in the heart, accompanied by lower plasma cysteine levels compared with Cbs(+/+) mice. Higher triglyceride concentrations, increased oxidative stress, and increased markers of apoptosis were also observed in heart from Cbs(+/-) mice with diet-induced obesity compared with Cbs(+/+) mice. This study suggests a novel role for Cbs in maintaining the cardiac glutathione pool and protecting against cardiac lipid accumulation and oxidative stress during diet-induced obesity in mice.

Estimated Choline Intakes and Dietary Sources of Choline in Pregnant Australian Women.

(1) Background: Despite the postulated importance of choline during pregnancy, little is known about the choline intake of Australians during pregnancy. In this study, we estimated dietary intakes of choline in early and late pregnancy, compared those intakes to recommendations, and investigated food sources of choline in a group of pregnant women in Australia. (2) Methods: 103 pregnant women enrolled in a randomized controlled trial. In early pregnancy (12−16 weeks gestation) and late pregnancy (36 weeks gestation), women completed a food frequency questionnaire designed to assess dietary intake over the previous month. (3) Results: Choline intakes and sources were similar in early and late pregnancy. Median choline intake in early pregnancy was 362 mg/day. Of the women, 39% and 25% had choline intakes above the Australian National Health and Medical Research Council (NHMRC) adequate intake (AI) of >440 mg/day and the European Food Safety Authority (EFSA) AI of >480 mg/day for choline in pregnancy, respectively. Eggs, red meat, nuts, legumes, and dairy accounted for 50% of choline intake, with eggs being the most significant contributor at 17%. (4) Conclusions: Few pregnant women in our study met the AI recommended by the NHMRC and EFSA. In Australia, choline intake in pregnancy may need to be improved, but further work to define choline requirements in pregnancy is required.

Associations of the FTO rs9939609 variant with discrete body fat depots and dietary intake in a multi-ethnic cohort.

The fat mass and obesity associated (FTO) gene has been implicated with obesity and dietary intake predominantly in European populations. We assessed the association between the FTO rs9939609 variant with body fat distribution and dietary intake in a multi-ethnic population. Aboriginal, Chinese, European and South Asian participants living in Canada (n = 706) were assessed for body fat and inner-abdominal fat using imaging techniques, dietary intake and genotyped for the FTO rs9939609 variant. Linear regression was used to study the associations between the minor allele of the variant and measures of adiposity and dietary intake. Minor allele frequencies were: Aboriginals (17%), Chinese (17%), Europeans (39%) and South Asians (31%). The rs9939609 variant was associated with intake of dietary macronutrients in Aboriginals and Europeans only. In the total population, there were positive associations between the rs9939609 minor allele and greater fat mass (0.94 ± 0.56 kg, P = 0.045), per cent body fat (0.7 ± 0.4%, P = 0.031), relative greater subcutaneous abdominal adipose tissue (4.9 ± 2.8%, P = 0.039) and percent daily calories from fat (0.4 ± 0.2%, P = 0.064). Our findings suggest that the FTO rs9939609 minor allele may be associated with dietary intake in adults and is positively associated with regional fat deposition.

Sex differences in the association of vitamin D and metabolic risk factors with carotid intima-media thickness in obese adolescents.

BACKGROUND: It has been shown that vitamin D is associated with obesity and the development of atherosclerosis. Less is known about this association among adolescents with obesity. OBJECTIVES: To determine the association of vitamin D level and metabolic risk factors with carotid intima-media thickness (CIMT) among obese adolescents. METHODS: We conducted a cross-sectional study among obese children aged 15 to 17 years in Yogyakarta, Indonesia. The association of vitamin D and other metabolic risk factors (triglyceride, low-density lipoprotein cholesterol (LDL-C) and high-density lipoprotein cholesterol (HDL-C), and insulin resistance using homeostasis model assessment of insulin resistance (HOMA-IR)) with CIMT was explored by multivariable linear regression models. RESULTS: Out of 156 obese adolescents, 55.8% were boys. Compared to girls, boys had higher BMI z-score, waist circumference, and HDL-cholesterol. After adjustment for age, sex and second-hand smoke exposure, high HOMA-IR, total cholesterol, LDL-cholesterol and triglyceride levels were associated with higher odds of elevated CIMT. In analyses stratified by sex, a similar trend was observed in boys, while none of the risk factors were associated with CIMT in girls. We observed no association between vitamin D and CIMT. CONCLUSIONS: Hyperinsulinemia, higher total cholesterol and LDL cholesterol were associated with greater odds of elevated CIMT among obese adolescent boys.

Risk of metabolic syndrome and early vascular markers for atherosclerosis in obese Indonesian adolescents.

Background: The prevalence of childhood obesity has increased in low- and middle-income countries, including Indonesia. It is important to identify risk factors for cardiovascular disease in obese adolescents in this region.Aim: To assess the risk of metabolic syndrome and early vascular markers for atherosclerosis in obese Indonesian adolescentsMethods: A cross-sectional study was undertaken in obese high school students aged 15-<18 years in Yogyakarta, Indonesia. All eligible adolescents were interviewed about their medical history, were physically examined and had a fasting blood sample taken. Arterial stiffness was measured during systole and diastole blood pressure, endothelial dysfunction was estimated using flow-mediated dilation (FMD) and arterial wall thickness using carotid artery intima-media thickness (CIMT).Results: A total of 4268 students were screened, 298 (7%) of whom were classified as obese. Of those, 229 had blood samples taken, 173 had FMD performed and 156 had CIMT examination. Adolescents with a higher body mass index or BMI Z-score (>3.0) had a significantly poorer lipid profile, insulin level and homeostasis model assessment of insulin resistance (HOMA-IR) than those with a lower BMI Z-score. There were no significant differences for early vasculature markers for atherosclerosis between these two groups.Conclusion: The prevalence of risks of cardiovascular disease in obese adolescents was significant. The higher the BMI Z-score, the higher the risks of cardiovascular disease. Interventions to reduce obesity and its cardiovascular disease morbidities are urgently needed in low- and middle-income countries.Abbreviations: BMI; body mass index; CIMT, carotid artery intima-media thickness; CDC, Centers for Disease Control and Prevention; FMD flow-mediated dilation; HDL high-density lipoprotein cholesterol; HbA1c haemoglobin A1c; HOMA-IR, homeostasis model assessment of insulin resistance; IOTF, International Obesity Task Force; LDL, low-density lipoprotein cholesterol; WHO, World Health Organization.

Weekly iron-folic acid supplements containing 2.8 mg folic acid are associated with a lower risk of neural tube defects than the current practice of 0.4 mg: a randomised controlled trial in Malaysia.

INTRODUCTION: Weekly iron-folic acid (IFA) supplements are recommended for all menstruating women in countries where anaemia prevalence is >20%. Anaemia caused by folate deficiency is low worldwide, and the need to include folic acid is in question. Including folic acid might reduce the risk of a neural tube defect (NTD) should a woman become pregnant. Most weekly supplements contain 0.4 mg folic acid; however, WHO recommends 2.8 mg because it is seven times the daily dose effective in reducing NTDs. There is a reluctance to switch to supplements containing 2.8 mg of folic acid because of a lack of evidence that this dose would prevent NTDs. Our aim was to investigate the effect of two doses of folic acid, compared with placebo, on red blood cell (RBC) folate, a biomarker of NTD risk. METHODS: We conducted a three-arm double-blind efficacy trial in Malaysia. Non-pregnant women (n=331) were randomised to receive 60 mg iron and either 0, 0.4, or 2.8 mg folic acid once weekly for 16 weeks. RESULTS: At 16 weeks, women receiving 0.4 mg and 2.8 mg folic acid per week had a higher mean RBC folate than those receiving 0 mg (mean difference (95% CI) 84 (54 to 113) and 355 (316 to 394) nmol/L, respectively). Women receiving 2.8 mg folic acid had a 271 (234 to 309) nmol/L greater mean RBC folate than those receiving 0.4 mg. Moreover, women in the 2.8 mg group were seven times (RR 7.3, 95% CI 3.9 to 13.7; p<0.0001) more likely to achieve an RBC folate >748 nmol/L, a concentration associated with a low risk of NTD, compared with the 0.4 mg group. CONCLUSION: Weekly IFA supplements containing 2.8 mg folic acid increases RBC folate more than those containing 0.4 mg. Increased availability and access to the 2.8 mg formulation is needed. TRAIL REGISTRATION NUMBER: This trial is registered with the Australian New Zealand Clinical Trial Registry (ACTRN12619000818134).

Effect of once weekly folic acid supplementation on erythrocyte folate concentrations in women to determine potential to prevent neural tube defects: a randomised controlled dose-finding trial in Malaysia.

INTRODUCTION: Folic acid (0.4 mg) taken prior to and during early pregnancy reduces the risk of neural tube defects (NTDs). Because these birth defects occur early in pregnancy, before women may know they are pregnant, many countries have mandated the addition of folic acid to food staples. In countries where fortification is not possible, and weekly iron folic acid programmes exist to reduce anaemia, the WHO recommends that 2.8 mg (7×0.4 mg) folic acid be given instead of the current weekly practice of 0.4 mg. Currently, there is a lack of evidence to support if the 2.8 mg folic acid per week dose is sufficient to raise erythrocyte folate concentrations to a level associated with a reduced risk of a NTD-affected pregnancy. We aim to conduct a three-arm randomised controlled trial to determine the effect of weekly folic acid with iron on erythrocyte folate, a biomarker of NTD risk. METHODS AND ANALYSIS: We will recruit non-pregnant women (n=300; 18-45 years) from Selangor, Malaysia. Women will be randomised to receive either 2.8, 0.4 or 0.0 (placebo) mg folic acid with 60 mg iron weekly for 16 weeks, followed by a 4-week washout period. The primary outcome will be erythrocyte folate concentration at 16 weeks and the mean concentration will be compared between randomised treatment groups (intention-to-treat) using a linear regression model adjusting for the baseline measure. ETHICS AND DISSEMINATION: Ethical approval was obtained from the University of British Columbia (H18-00768) and Universiti Putra Malaysia (JKEUPM-2018-255). The results of this trial will be presented at scientific conferences and published in peer-reviewed journals. TRIAL REGISTRATION NUMBERS: ACTRN12619000818134 and NMRR-19-119-45736.

Estimated Resting Metabolic Rate and Body Composition Measures Are Strongly Associated With Diabetic Retinopathy in Indonesian Adults With Type 2 Diabetes.

OBJECTIVE: To investigate the associations of estimated resting metabolic rate (RMR), body fat (BF), subcutaneous fat (SCF), visceral fat (VF), fat-free mass (FFM) percentage, BMI, and waist circumference (WC) with diabetic retinopathy (DR) in Indonesian adults with type 2 diabetes. RESEARCH DESIGN AND METHODS: This was a community-based cross-sectional study of 1,184 subjects with type 2 diabetes. DR was assessed from fundus photography and categorized as mild, moderate nonproliferative DR (NPDR), and vision-threatening DR (VTDR). RMR and body composition parameters were measured using automated body composition scan. Logistic regression with semipartial correlation analysis was used. RESULTS: DR and VTDR were present in 43.1 and 26.3% of participants, respectively. After adjustment for age, sex, diabetes duration, fasting glucose, systolic blood pressure, smoking, diabetic ulcer, and use of combined diabetes treatment, per SD increase in RMR (odds ratio [OR] 2.60 [95% CI 2.19-3.07]; P < 0.001) was associated with DR, while per SD increases in BF (0.66 [95% CI 0.56-0.78]; P < 0.001), FFM (0.69 [0.57-0.84]; P < 0.001), VF (0.77 [0.67-0.88]; P < 0.001), BMI (0.83 [0.73-0.94]; P = 0.004), and WC (0.81 [0.73-0.91]; P < 0.001) were inversely associated with presence of DR. Similar associations were found for VTDR. Among all variables, RMR had the largest contribution to the variance in the DR model (39%). CONCLUSIONS: In this study, RMR and body composition measures were strongly associated with and contributed considerably to the presence and severity of DR. These findings, if confirmed, suggest that RMR and body composition may be strong markers that represent actual metabolic state in the pathophysiology of DR.

Association of vitamin D deficiency with cardiovascular disease risk in children: implications for the Asia Pacific Region.

BACKGROUND AND OBJECTIVES: Vitamin D deficiency significantly affects cardiovascular disease risk. Cardiovascular disease is epidemic in nature. Because the prevalence of cardiovascular disease has been increasing in children, it has been changing from an adulthood disease to a childhood disease. Therefore, formulating an effective prevention strategy against cardiovascular disease development in children is crucial. METHODS AND STUDY DESIGN: From PubMed, we identified and reviewed studies evaluating the association of vitamin D deficiency with cardiovascular disease risk in children. RESULTS: The mechanism through which vitamin D protects against cardiovascular disease has yet to be fully elucidated. Vitamin D deficiency may be associated with various risk factors for cardiovascular disease that are already manifested in childhood, including obesity, hypertension, dyslipidaemia, insulin resistance, and metabolic syndrome. Vitamin D deficiency has been associated with cardiovascular disease because it promotes vascular stiffness and calcification, leading to atherosclerosis. However, studies investigating the effectiveness of vitamin D in preventing cardiovascular disease risk by using an ideal study design are scant. CONCLUSIONS: Vitamin D deficiency in children may increase cardiovascular disease risk, which tends to manifest in childhood. Because data on the association of vitamin D deficiency with cardiovascular disease risk among children are limited and inconclusive, additional studies are required to investigate this association in children in general and in a setting with naturally abundant sun exposure.

Adiposity and the relationship between vitamin D and blood pressure.

OBJECTIVE: Circulating vitamin D (25OHD) concentrations are negatively associated with blood pressure (BP) but little is known about the mechanisms for this relationship. Adiposity is positively associated with BP and inversely with circulating 25OHD concentrations but no studies have assessed the relationship between plasma 25OHD and adiposity on BP. The goal of this study is to investigate if the association between plasma 25OHD and BP is mediated by adiposity. MATERIALS/METHODS: The relationship between plasma 25OHD, systolic and diastolic BP, and adiposity [BMI, waist circumference, visceral adipose tissue (VAT)] was assessed in a multi-ethnic cross-sectional study of Aboriginal (n=151), Chinese (n=190), European (n=170), and South Asian (n=176) participants by linear regression models. RESULTS: Plasma 25OHD concentrations were negatively associated with systolic (standardized B=-0.191, P<0.001) and diastolic BP (standardized B=-0.196, P<0.001) in models adjusted for age, sex, ethnicity, family history of CVD, smoking status, alcohol consumption, and physical activity. The negative relationship between plasma 25OHD concentrations and systolic and diastolic BP was attenuated after the addition of BMI, waist circumference, and VAT to the models, but the relationship remained significant. Plasma 25OHD concentrations accounted for 0.7% and 0.8% of the variance in systolic and diastolic BP, respectively. CONCLUSION: These findings suggest that the relationship between vitamin D and BP is independent of adiposity. Further studies are required to determine the mechanisms by which vitamin D affects BP.

Tissue-specific relationship of S-adenosylhomocysteine with allele-specific H19/Igf2 methylation and imprinting in mice with hyperhomocysteinemia.

DNA methylation is linked to homocysteine metabolism through the generation of S-adenosylmethionine (AdoMet) and S-Adenosylhomocysteine (AdoHcy). The ratio of AdoMet/AdoHcy is often considered an indicator of tissue methylation capacity. The goal of this study is to determine the relationship of tissue AdoMet and AdoHcy concentrations to allele-specific methylation and expression of genomically imprinted H19/Igf2. Expression of H19/Igf2 is regulated by a differentially methylated domain (DMD), with H19 paternally imprinted and Igf2 maternally imprinted. F1 hybrid C57BL/6J x Castaneous/EiJ (Cast) mice with (+/-), and without (+/+), heterozygous disruption of cystathionine-ß-synthase (Cbs) were fed a control diet or a diet (called HH) to induce hyperhomocysteinemia and changes in tissue AdoMet and AdoHcy. F1 Cast x Cbs+/- mice fed the HH diet had significantly higher plasma total homocysteine concentrations, higher liver AdoHcy, and lower AdoMet/AdoHcy ratios and this was accompanied by lower liver maternal H19 DMD allele methylation, lower liver Igf2 mRNA levels, and loss of Igf2 maternal imprinting. In contrast, we found no significant differences in AdoMet and AdoHcy in brain between the diet groups but F1 Cast x Cbs+/- mice fed the HH diet had higher maternal H19 DMD methylation and lower H19 mRNA levels in brain. A significant negative relationship between AdoHcy and maternal H19 DMD allele methylation was found in liver but not in brain. These findings suggest the relationship of AdoMet and AdoHcy to gene-specific DNA methylation is tissue-specific and that changes in DNA methylation can occur without changes in AdoMet and AdoHcy.

Epigenetic regulation of glucocorticoid receptor expression in aorta from mice with hyperhomocysteinemia.

Hyperhomocysteinemia (HHcy) is a risk factor for vascular disease but its underlying molecular pathology is not understood. Homocysteine is metabolically linked to the epigenetic process of DNA methylation. Tissue-specific changes in DNA methylation have been observed in HHcy but little is known about vascular tissue. The objective of this study was to determine if changes in the epigenetic regulation of glucocorticoid receptor (GR) expression (encoded by Nr3c1) in aorta are associated with HHcy. C57BL/6 mice heterozygous for disruption of the cystathionine-ß-synthase gene (Cbs+/-) and controls (Cbs+/+) were fed a control or high methionine/low folate (HH) diet to induce HHcy. Cbs+/- and Cbs+/+ fed the HH diet had higher plasma total homocysteine levels (19.9 ± 3.2 and 7.0 ± 0.9 µM, respectively) than Cbs+/+ mice fed the control diet (2.7 ± 0.2 µM), and this was accompanied by lower Nr3c1 mRNA and lower GR protein in aorta. The Nr3c1 gene contains multiple first exons producing heterogeneous RNA transcripts expressed in a tissue-specific manner. We identified expression of two transcripts in aorta. Bisulfite pyrosequencing found increased methylation of the promoter regions for these transcripts at sites corresponding to Sp1 and Nrf1 binding sites. Chromatin immunoprecipitation found lower binding of Nrf1 to the Nr3c1 promoter but higher expression of Nrf1 protein in aorta from mice with HHcy. These findings show methylation and silencing of vascular Nr3c1 expression and suggest a role for epigenetic regulation of gene expression in HHcy.

Ethnic-specific differences in vitamin D status is associated with adiposity.

BACKGROUND: Low circulating 25 hydroxyvitamin D [25(OH)D] concentrations are common in obesity (BMI ≥30 kg/m(2)) and a negative relationship with body fat distribution has recently been reported. Ethnic-specific differences in body fat distribution have been described with South Asians are reported to have greater visceral adipose tissue (VAT), which could influence circulating 25(OH)D concentrations. The objective of this study is to investigate the relationship between plasma 25(OH)D, adiposity, and body fat distribution in Europeans and South Asians. METHODS/PRINCIPAL FINDINGS: 187 Europeans and 192 South Asians were assessed for demographics, anthropometrics, and plasma 25(OH)D concentrations. Subcutaneous adipose tissue (SAT) and VAT were quantified by CT scan, and percent body fat by DEXA. Data were assessed by general linear models. South Asians had lower (P<0.001) plasma 25(OH)D concentrations and higher VAT (P = 0.04) than Europeans. Plasma 25(OH)D concentrations were negatively (P<0.05) associated with BMI, waist circumference, percent body fat, total adipose tissue, VAT, and SAT in unadjusted models and negatively (P<0.05) associated with VAT, SAT, and percent body fat after adjusting for BMI, ethnicity, age, and season of blood collection in males and females. When percent body fat, VAT, and SAT were included in the same model, only VAT remained negatively (P<0.05) associated with plasma 25(OH)D concentrations. Ethnicity remained significant in all models (P<0.001). CONCLUSION: Compared to other adipose tissue compartments, VAT may have a distinct role in determining plasma 25(OH)D concentrations, which may account for the lower levels in South Asians.