OBJECTIVES:To assess the associations of birthweight, contemporary body mass index and height with insulin resistance in children.DESIGN:Cross-sectional study.PARTICIPANTS:From Estonia (n = 1174) and Denmark (n = 1018), 2192 school children aged 9 and 15 years were randomly selected.MAIN OUTCOMES:Insulin resistance (homeostasis model assessment), triglyceride levels, high-density lipoprotein cholesterol and systolic blood pressure.RESULTS:There was an inverse association between birthweight and insulin resistance and a positive association between contemporary body mass index and insulin resistance. With adjustment for maternal and paternal educational level, income, smoking and body mass index, an increase of one unit of sex, age and country standardized body mass index z-score was associated with a 5% (95% CI: 2, 7%) increase in homeostasis model assessment (HOMA) score and a one-unit z-score increase in birthweight with a 2% (95% CI: 0, 5%) decrease in HOMA score. In the 9-year-old age group, height was positively associated with insulin resistance [for a one-unit increase in height z-score HOMA score increased by 30% (95% CI: 14, 50%)], but in the 15-year-old age group there was no association between height and insulin resistance (4% (95% CI: -5, 14%), P for interaction with age group = 0.001). For both ages, those in the lowest third of the birthweight distribution and highest third of the body mass index distribution were most insulin resistant and, among 9-year olds, those in the lowest third of the birthweight distribution and highest third of the height distribution were most insulin resistant. Birthweight was only inversely associated with systolic blood pressure when adjustment was made for either contemporary body mass index or height and there was no association between birthweight and high-density lipoprotein or triglyceride concentrations.CONCLUSIONS:Taken together, these results suggest that a slow intrauterine growth trajectory and/or a fast post-natal growth trajectory is associated with greater insulin resistance in childhood.

Background: Elevated plasma total homocysteine (tHcy) predisposes to vascular disease and results from interactions between genetic and nutritional factors. MTHFR C677T increases tHcy in association with low folate. CBS 844ins68 lowers tHcy and negates the raising effect of MTHFR C677T in healthy subjects, but it is unclear if this is the case in subjects at high risk of vascular disease. This study examines the effect on plasma tHcy of interactions between these polymorphisms in an at-risk group. Methods: Blood samples were collected from 376 subjects at increased risk of coronary artery disease. Plasma tHcy and vitamin B6 were measured by HPLC and red cell folate and serum vitamin B12 were measured by immuno-luminometric assay. MTHFR C677T and CBS 844ins68 status was established by standard PCR techniques. Results: MTHFR TT predisposed to hyperhomocysteinaemia; this was increased in the presence of low folate (P<0.05) and vitamin B12 (P<0.01). An inverse relationship was found between tHcy and folate (r= -0.42, P<0.0001), vitamin B12 (r= -0.26, P<0.0005) and vitamin B6 (r= -0.25, P<0.01). There was no interaction between plasma tHcy, vitamins or MTHFR C677T and CBS 844ins68. Discussion: In this population at high risk of coronary artery disease, plasma tHcy was determined by vitamin status. This was exacerbated by the MTHFR C677T mutation. CBS 844ins68 did not influence tHcy and did not negate the tHcy-raising effect of MTHFR C677T.

AIMS:To assess the associations of type and duration of infant feeding with components of the metabolic syndrome in children aged 9 and 15.METHODS:A total of 2192 randomly selected schoolchildren aged 9 and 15 years from Estonia (n = 1174) and Denmark (n = 1018) were studied. Insulin resistance (homoeostasis model assessment), triglyceride levels, high density lipoprotein cholesterol, and systolic blood pressure were measured.RESULTS:Children who had ever been exclusively breast fed had lower systolic blood pressures than those who were not. With full adjustment for age, sex, country, birth weight, pubertal stage, body mass index, height, maternal and paternal education, income, smoking, and body mass index the mean systolic blood pressure of children who had ever been breast fed was 1.7 mm Hg (95% CI -3.0 to -0.5) lower than those who had never been exclusively breast fed. There was a dose-response in this association with decreasing mean systolic blood pressure across categories from never exclusively breast fed to breast fed for more than six months. Exclusive breast feeding was not associated with other components of the metabolic syndrome. Results were similar when examined separately in each country.CONCLUSIONS:The magnitude of the association, its independence of important confounding factors, and the dose-response suggest that exclusive breast feeding is causally associated with reduced systolic blood pressure. The magnitude of the effect we found with blood pressure is comparable to the published effects of salt restriction and physical activity on blood pressure in adult populations, suggesting that it is of public health importance.

OBJECTIVES:To examine the association between socioeconomic position and insulin resistance in children from three countries in northern Europe (Denmark), eastern Europe (Estonia), and southern Europe (Portugal) that have different physical, economic, and cultural environments.DESIGN:Cross sectional study.PARTICIPANTS:3189 randomly selected schoolchildren aged 9 and 15 years from Denmark (n = 933), Estonia (n = 1103), and Portugal (n = 1153).MAIN OUTCOME MEASURE:Insulin resistance (homoeostasis model assessment).RESULTS:Family income and parental education were inversely associated with insulin resistance in Danish children but were positively associated with insulin resistance in Estonian and Portuguese children. Among Danish children, insulin resistance was 24% lower (95% confidence interval -38% to -10%) in those whose fathers had the most education compared with those with the least education. The equivalent results were 15% (2% to 28%) higher for Estonia and 19% (2% to 36%) higher for Portugal. These associations remained after adjustment for a range of covariates: -20% (-36% to -5%) for Denmark, 10% (-4% to 24%) for Estonia, and 18% (-1% to 31%) for Portugal. Strong statistical evidence supported differences between the associations in Denmark and those in the other two countries in both unadjusted and adjusted models (all P < 0.03).CONCLUSIONS:Among Danish children, those with the most educated and highest earning parents had least insulin resistance, whereas the opposite was true for children from Estonia and Portugal.

Homocystinuria is an autosomal recessive disorder usually caused by deficiency of cystathionine β-synthase, leading to grossly increased plasma and urine concentrations of homocysteine. There is considerable evidence that early detection and treatment can prevent the clinical consequences of the enzyme deficiency (1)(2); therefore, screening for the disorder has been advocated (1). Many cases of homocystinuria have secondary hypermethioninemia. Neonatal screening for homocystinuria by measurement of increased methionine concentrations in dried blood spots (DBS) has been performed in some centers but has poor sensitivity. Approximately 20% of cases are missed, partly because of low methionine concentrations in breast milk and some infant formulas (3). The measurement of homocysteine in DBS has not been used as a screen for homocystinuria, partly because of uncertainty about the suitability of DBS samples. Homocysteine concentrations are unstable in whole blood stored at room temperature and increase by ∼1.0 μmol/L per hour (4). This is attributable to in vitro erythrocyte transmethylation reactions that lead to continuous production and release of homocysteine (5). It is not known whether homocysteine is released from erythrocytes in blood that has been spotted on filter paper and dried, either during the spotting and drying process or during storage at room temperature. A recent report assessed stability in screening cards that were stored at 4 °C, which does not reflect routine practice (6). Another investigated the stability of DBS samples, using whole blood to which large concentrations of aqueous homocysteine calibrator had been added, thus potentially masking any increase in homocysteine attributable to release from erythrocytes (7). The lack of information on the stability …

Increased plasma homocysteine is now well established as a risk factor for cardiac, cerebral, and peripheral vascular disease (1). Despite this, the test is not widely available. This is partly because of practical difficulties in sample collection. The homocysteine concentration increases in whole blood by up to 10% per hour unless samples are kept on ice and separated within 60 min. The introduction of containers with 3-deazaadenosine (3-dad; DS30 Homocysteine Blood Collection Tubes; Drew Scientific Ltd.), described in a recent report (2) in the Journal, may solve the problem, but they are not in widespread …

Healthy middle-aged men (n = 1,470) from eight general practices across Britain were examined for plasma total homocysteine levels and genotyped for the A222V polymorphism in the methylene-tetrahydrofolate (MTHFR) gene, the 68 bp insertion polymorphism in exon 8 of the cystathionine b synthase (CBS) gene and the D919G polymorphism in the methionine synthase (MS) gene. The median value for plasma homocysteine was 11.90 micromol/l (25-75% Interquartile range 10.10-14.20) for the whole sample. Smokers had significantly higher homocysteine levels than non-smokers (12.90 vs 11.70 micromol/l and p < 0.00005) and levels significantly differed according to folate (p-value < 0.00005), with men in the lowest quartile of folate having the highest median homocysteine levels. Genotype at all three loci was associated with differences in plasma homocysteine level. Individuals homozygous for the MTHFR V222 allele had 1.6 micromol/l higher median homocysteine levels when compared to the other two genotypes (p < 0.00005), while for the CBS and MS genes, individuals carrying one or more of the rare alleles had lower median homocysteine than individuals homozygous for the common allele (0.80 micromol/l, p < 0.03, and 0.70 micromol/l, p < 0.04 respectively). The raising effect associated with homozygosity for the V222 allele was greater in men in the lowest quartile of folate (interaction between folate and genotype p = 0.02), but none of the genotype effects was significantly modulated by B12 levels. While the raising effects of V222 and MS D919 homozygosity on homocysteine level were essentially additive, the homocysteine lowering effect associated with the CBS 68bp allele was seen most strongly in men homozygous for the V222 allele (MTHFR-CBS genotype interaction p = 0.03) and the D919 allele (MS-CBS interaction p = 0.09). Age, folate, B12 and smoking explained 13.48% of the variance while the three genotypes combined and with interaction terms explained only an additional 2.63%. This interaction between CBS genotype and MTHFR and MS genotype points to a key role of the CBS transulphuration pathway in the metabolism of homocysteine that may be particularly important as a compensatory mechanism in subjects with low dietary folate.

Elevated plasma total homocysteine concentrations are a marker of vitamin deficiency and a risk factor for cardiovascular disease. It is possible that vitamin supplementation with folic acid and other B vitamins, which lower plasma homocysteine concentrations, may reduce the risk of cardiovascular disease. Large-scale clinical trials are currently underway to assess the homocysteine hypothesis of cardiovascular disease. Pending the outcome of such trials, measurement of plasma homocysteine concentrations in people at high risk of cardiovascular disease may help to identify patients who could benefit from more intensive treatment of classical cardiovascular risk factors. The introduction of immunoassays for homocysteine determination has made assessment of homocysteine status accessible to most routine hospital laboratories, and this review summarizes the evidence on why and how to assess homocysteine as a risk factor for cardiovascular disease in clinical practice.

Increased numbers of requests for serological investigation of coeliac disease, and a local trend to request both anti-gliadin antibodies (AGA) and anti-endomysium antibodies (AEA) simultaneously, resulted in cost pressures that prompted a review of our practice. Serology results from all patients (771 children, 511 adults) investigated for coeliac disease over a 3-year period were compared with small intestine histology where available. IgG AGA and IgA AGA were measured by enzyme-linked immunosorbent assay (in-house), IgA AEA by immunofluorescence (send-away contract). Overall diagnostic performance was as follows: AGA sensitivity 84%, specificity 88%, positive predictive value (PPV) 24%, negative predictive value (NPV) 99%; AEA sensitivity 88%, specificity 97%, PPV 65%, NPV 99%. Results showed AGA, with its high NPV, to be a suitable first-line test to exclude coeliac disease. The high specificity of AEA makes it a suitable confirmatory test when AGA is positive. Introduction of this step-wise approach to coeliac disease investigation resulted in cost savings of at least £5000 per year without detriment to the clinical service.

Conference Abstract| February 01 1999 Effect of Homocysteine on Human Umbilical Vein Endothelial Cell Nitric Oxide Synthase Activity A Day; A Day 1Department of Chemical Pathology, Bristol Royal Infirmary, Marlborough Street, Bristol BS2 8HW, UK Search for other works by this author on: This Site PubMed Google Scholar M Ariseanu; M Ariseanu 1Department of Chemical Pathology, Bristol Royal Infirmary, Marlborough Street, Bristol BS2 8HW, UK Search for other works by this author on: This Site PubMed Google Scholar D Stansbie D Stansbie 1Department of Chemical Pathology, Bristol Royal Infirmary, Marlborough Street, Bristol BS2 8HW, UK Search for other works by this author on: This Site PubMed Google Scholar Clin Sci (Lond) (1999) 96 (s40): 9P–10P. https://doi.org/10.1042/cs096009Pc Views Icon Views Article contents Figures & tables Video Audio Supplementary Data Peer Review Share Icon Share Facebook Twitter LinkedIn MailTo Cite Icon Cite Get Permissions Citation A Day, M Ariseanu, D Stansbie; Effect of Homocysteine on Human Umbilical Vein Endothelial Cell Nitric Oxide Synthase Activity. Clin Sci (Lond) 1 February 1999; 96 (s40): 9P–10P. doi: https://doi.org/10.1042/cs096009Pc Download citation file: Ris (Zotero) Reference Manager EasyBib Bookends Mendeley Papers EndNote RefWorks BibTex toolbar search Search Dropdown Menu toolbar search search input Search input auto suggest filter your search All ContentAll JournalsClinical Science Search Advanced Search This content is only available as a PDF. © 1999 The Biochemical Society and the Medical Research Society1999 Article PDF first page preview Close Modal You do not currently have access to this content.

We recently described 1 the stabilization of homocysteine in blood by 3-deazaadenosine, which inhibits S-adenosylhomocysteine hydrolase, thereby preventing homocysteine release from the erythrocyte S-adenosylhomocysteine (SAH). It thereby prevents the increase in plasma homocysteine which occurs unless blood is separated rapidly, and we have used this technique successfully with a high-performance liquid chromatography assay method for homocysteine. Abbott (Abbott Diagnostics, Maidenhead, UK) have recently introduced a method for homocysteine analysis on the IMx analyser. This depends upon conversion of homocysteine to SAH by SAH-hydrolase followed by measurement of SAH by competitive fluorescence polarization immunoassay.i 3-deazaadenosine, a competitive inhibitor of SAH-hydrolase, could potentially interfere with the Abbott IMx assay. In order to test this hypothesis we collected blood from healthy laboratory staff (six women, five men) into tubes with and without 3deazaadenosine at a final concentration of 100/lmol/L. Samples were separated and plasma total homocysteine concentration was measured using the Abbott IMx method. Mean homocysteine concentration measured by the Abbott IMx was lower in samples containing 3-deazaadenosine (5·8/lmol/L) than in controls (6'4/lmol/L; P = 0·0005. 3-deazaadenosine resulted in a mean reduction of 8·8% (range 4,9-12,3%) in apparent homocysteine concentration. Addition of 3-deazaadenosine to a representative blood sample to produce final concentrations of 0, lO, SO, 100 and 1000/lmol/L resulted in a progressive decrease in apparent plasma homocysteine concentration measured by the Abbott IMx assay (Fig. I). This is consistent with competitive inhibition of SAH hydrolase by Letters 533

Conference Abstract| February 01 1998 Alcohol, Uric Acid & Predisposition to Coronary Heart Disease D Stansbie; D Stansbie 1Chemical Pathology, Bristol Royal Infirmary, Bristol BS2 8HW Search for other works by this author on: This Site PubMed Google Scholar A P Day; A P Day 1Chemical Pathology, Bristol Royal Infirmary, Bristol BS2 8HW Search for other works by this author on: This Site PubMed Google Scholar A Bowron; A Bowron 1Chemical Pathology, Bristol Royal Infirmary, Bristol BS2 8HW Search for other works by this author on: This Site PubMed Google Scholar J Scott; J Scott 1Chemical Pathology, Bristol Royal Infirmary, Bristol BS2 8HW Search for other works by this author on: This Site PubMed Google Scholar V Nicaud; V Nicaud 1 INSERM U258, 96, rue Didot, 75674 Paris cedex 14 Search for other works by this author on: This Site PubMed Google Scholar L Tiret L Tiret 1 INSERM U258, 96, rue Didot, 75674 Paris cedex 14 Search for other works by this author on: This Site PubMed Google Scholar Author and article information Publisher: Portland Press Ltd Online ISSN: 1470-8736 Print ISSN: 0143-5221 © 1998 The Biochemical Society and the Medical Research Society1998 Clin Sci (Lond) (1998) 94 (s38): 13P. https://doi.org/10.1042/cs094013P Views Icon Views Article contents Figures & tables Video Audio Supplementary Data Peer Review Share Icon Share Facebook Twitter LinkedIn Email Cite Icon Cite Get Permissions Citation D Stansbie, A P Day, A Bowron, J Scott, V Nicaud, L Tiret; Alcohol, Uric Acid & Predisposition to Coronary Heart Disease. Clin Sci (Lond) 1 February 1998; 94 (s38): 13P. doi: https://doi.org/10.1042/cs094013P Download citation file: Ris (Zotero) Reference Manager EasyBib Bookends Mendeley Papers EndNote RefWorks BibTex toolbar search Search Dropdown Menu toolbar search search input Search input auto suggest filter your search All ContentAll JournalsClinical Science Search Advanced Search This content is only available as a PDF. © 1998 The Biochemical Society and the Medical Research Society1998 Article PDF first page preview Close Modal You do not currently have access to this content.

The link between homocysteine and the vascular pathology of arteriosclerosis was first described almost 30 years ago.' However, it is only recently that hyperhomocysteinaemia has achieved widespread recognition as an indepen­ dent risk factor for vascular disease, including coronary heart disease, stroke and peripheral vascular disease.' This renewed interest has stimulated laboratories to re-examine meth­ ods for the estimation of homocysteine in plasma. The major problem that bedevils epidemiolo­ gical and clinical studies of homocysteine is the increase in plasma homocysteine concentration that occurs if blood is not centrifuged immedi­ ately after collection. Plasma total homocysteine concentration rises by up to 10% per hour in blood kept at room temperature, largely as a result of the conversion of S-adenosylmethionine and S-adenosylhomocysteine to homocysteine within erythrocytes.' Since this laboratory receives blood samples for epidemiological studies by post, our aim was to identify an additive to blood which would stabilize homo­ cysteine levels for up to 72 h, thereby avoiding the need to centrifuge samples immediately after collection.

Cystathionine beta synthase (CBS) is a key enzyme in homocysteine metabolism We have examined four apparently non-functional polymorphisms in the CBS gene and have determined their frequency, degree of linkage disequilibrium and association with plasma homocysteine levels. The polymorphisms are a 68 bp insertion in exon 8, C699T in exon 8, C1080T in exon 11 and C1985T in the 3' untranslated region. 785 individuals participating in the European Atherosclerosis Research Study II (EARSII), from 11 countries across Europe were genotyped for these polymorphisms. The 68bp insertion had the highest frequency in the UK and in the Middle region, with a lower frequency in the Baltic and the South (p = 0.01), and the exon 11. polymorphism had the highest frequencies of the rare allele in the Baltic (p < 0.05). There was a high degree of linkage disequilibrium between the polymorphisms (p < 0.001 overall). except between C699T and the C1985T, with three common haplotypes accounting for nearly 80% of chromosomes. Examination of the association between these polymorphisms and plasma homocysteine levels revealed that the carriers of the rare alleles of the C699T, C1080T and C1985T polymorphisms had lower plasma homocysteine concentrations than those homozygous for the common alleles; although these differences were not statistically significant. The thermolabile valine variant caused by a substitution of a C for a T at nucleotide 677 in the methylenetetrahydrofolate reductase (MTHFR) has previously been shown to have profound effects on plasma levels of homocysteine in this sample. but the homocysteine-raising effect associated with this thermolabile variant was not seen in carriers of the 68 bp insertion, with this interaction being statistically significant (p < 0.001). These data demonstrate that variation in the CBS gene as detected with these four polymorphisms, had no statistically significant effect on plasma homocysteine levels in these healthy young men. However, the presence of the 68 bp insertion, which is found in approximately 7.5% of individuals in the populations of Europe sampled, abolishes the raising effect of thermolabile MTHFR Val/Val genotype, and may be of importance in the situation of high homocysteine.

A common polymorphism has been described in the methylenetetrahydrofolate reductase (MTHFR) gene, substituting an alanine (A) for a valine (V), where the V allele results in a thermolabile enzyme with reduced activity. This polymorphism is easily detectable by PCR amplification and digestion with HinfI restriction enzyme. We describe the use of the MADGE high throughput genotyping system for rapid typing of this polymorphism. Seven hundred and eighty five individuals participating in the European Atherosclerosis Research Study II (EARS II), aged 22–25 from 14 universities in 12 countries across Europe were genotyped for this polymorphism. The frequency of the V allele was 0.32 overall (95% CI; 0.30–0.35), but was significantly lower in the Baltic countries (0.23; 95% CI; 0.19–0.28) compared with the other regions of Europe (0.37; 95% CI; 0.32–0.38) (P<0.001). Individuals homozygous for the V allele had statistically significant (P<0.001) higher plasma homocysteine (16.5 μmol/l) compared with those heterozygous for an A allele (10.4 μmol/l) or homozygous for an A allele (10.0 μmol/l). This effect was seen in all countries and regions of Europe. Mean plasma homocysteine levels were significantly higher in the South compared to the Baltic, UK and Middle regions (P=0.001), but this difference was not explained by the difference in the frequency of the V allele in the samples. This polymorphism explained 12.3% of the total sample variance in plasma homocysteine, other measured factors (smoking, alcohol consumption, systolic blood pressure, physical activity) explained 0.7%. This study demonstrates the large and consistent impact of the thermolabile MTHFR variant on plasma homocysteine levels in different European populations, and shows a regional difference in the levels of homocysteine that must be explained by other genetic or environmental factors.