935 resultados para lipoprotein A
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Risperidone is metabolized by polymorphic enzymes, and a large variability in plasma concentration and therapeutic response is observed. Risperidone long-acting injection (RLAI) avoids the first-pass effect, and little is known about the influence of gene polymorphisms involved in its pharmacokinetics. The influence on plasma concentrations of risperidone (RIS), its metabolite 9-hydroxy-risperidone, and on adverse effects were investigated for polymorphisms of cytochrome P450 2D6 (CYP2D6) (*3, *4, *5, *6), CYP3A (CYP3A4*1B, CYP3A4 rs4646437, CYP3A5*3, CYP3A7*1C), ABCB1 (1236C>T, 2677G>T, 3435C>T), NR1/2 coding for pregnane X receptor (rs1523130, rs2472677, rs7643645), and for CYP3A activity measured by a phenotyping test. Forty-two patients with at least 4 consecutive unchanged doses of RLAI were included in a multicenter cross-sectional study. A 55% lower dose-adjusted plasma levels of RIS were observed for CYP2D6 ultrarapid metabolizers (n = 5) as compared with CYP2D6 intermediate metabolizers (P < 0.007). NR1/2 polymorphism (rs7643645A>G) influenced RIS exposure with a 2.8-fold lower active moiety (P = 0.031) in GG compared with the AA genotype. This was confirmed in a second independent cohort (n = 16). Furthermore, high-density lipoprotein cholesterol was positively correlated with CYP3A activity (P = 0.01), and the NR1/2 (rs2472677) polymorphism was associated with different adverse effects including prolactin plasma levels adjusted for age and sex. In conclusion, our results confirmed the influence of CYP2D6 genotype on plasma levels of RIS. This is the first report on the influence of NR1/2 polymorphisms on RLAI exposure and on drug-induced adverse effects. These results should be validated in larger cohorts.
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OBJECTIVES: HIV infection and exposure to certain antiretroviral drugs is associated with dyslipidemia and increased risk for coronary events. Whether this risk is mediated by highly atherogenic lipoproteins is unclear. We investigated the association of highly atherogenic small dense low-density lipoproteins (LDLs) and apolipoprotein B and coronary events in HIV-infected individuals receiving antiretroviral therapy. METHODS: We conducted a case-control study nested into the Swiss HIV Cohort Study to investigate the association of small dense LDL and apolipoprotein B and coronary events in 98 antiretroviral drug-treated patients with a first coronary event (19 fatal and 79 nonfatal coronary events with 53 definite and 15 possible myocardial infarctions, 11 angioplasties or bypasses) and 393 treated controls matched for age, gender, and smoking status. Lipids were measured by ultracentrifugation. RESULTS: In models including cholesterol, triglycerides, high-density lipoprotein cholesterol, blood pressure, central obesity, diabetes, and family history, there was an independent association between small dense LDL and coronary events [odds ratio (OR) for 1 mg/dL increase: 1.06, 95% confidence interval (CI): 1.00 to 1.11] and apolipoprotein B (OR for 10 mg/dL increase: 1.16, 95% CI: 1.02 to 1.32). When adding HIV and antiretroviral therapy-related variables, ORs were 1.04 (95% CI: 0.99 to 1.10) for small dense LDL and 1.13 (95% CI: 0.99 to 1.30) for apolipoprotein B. In both models, blood pressure and HIV viral load was independently associated with the odds for coronary events. CONCLUSIONS: HIV-infected patients receiving antiretroviral therapy with elevate small dense LDL and apolipoprotein B are at increased risk for coronary events as are patients without sustained HIV suppression.
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CONTEXT: The worldwide epidemic of overweight and obesity is setting the scene for a new wave of premature cardiovascular disease. OBJECTIVE: The objective of this study was to define relationships between dyslipidemia and other metabolic abnormalities in overweight subjects. DESIGN: This study included comparison of overweight subjects with and without dyslipidemia. SETTING: The setting was an institutional practice. PATIENTS: Dyslipidemic subjects (n = 715) had plasma triglyceride greater than or equal to the 75th percentile in combination with high-density lipoprotein cholesterol (HDL-C) less than or equal to the 25th percentile. Unrelated, normolipidemic controls (n = 1073) had HDL-C higher than the median and triglyceride lower than the median. It was a requirement for the control subjects to have a body mass index (BMI) greater than 25 kg/m(2). MAIN OUTCOME MEASURES: The main outcome measures included BMI, inflammatory markers, adipokines, blood pressure, and fasting plasma glucose and insulin. RESULTS: The mean BMI in the subjects and controls was 28.7 and 28.2 kg/m(2), respectively. Subjects had higher levels of plasma high-sensitivity C-reactive protein (3.0 vs. 2.0 mg/liter; P < 0.001), lower levels of adiponectin (4.7 vs. 6.6 mg/liter; P < 0.001), and, after adjustment for age, BMI, gender, smoking, statin, and beta-blocker use, higher systolic (P = 0.001) and diastolic (P = 0.05) blood pressures. Fasting plasma glucose, insulin, and homeostasis model of assessment-insulin resistance were all significantly higher in subjects than controls (P < 0.0001). CONCLUSIONS: Identification of people solely on the basis of an elevated plasma triglyceride and a low HDL-C uncovers an overweight group of people who have a generalized metabolic disorder. In contrast, overweight people with normal plasma lipids have normal glucose and insulin metabolism, low levels of inflammatory markers, and normal blood pressure. Such people may thus be at relatively low risk of developing diabetes and cardiovascular disease despite being overweight.
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BACKGROUND/OBJECTIVES: To assess the distribution of interleukin (IL)-1β, IL-6, tumour necrosis factor (TNF)-α and C-reactive protein (CRP) according to the different definitions of metabolically healthy obesity (MHO). SUBJECTS/METHODS: A total of 881 obese (body mass index (BMI) > or =30 kg/m2) subjects derived from the population-based CoLaus Study participated in this study. MHO was defined using six sets of criteria including different combinations of waist, blood pressure, total high-density lipoprotein cholesterol or low-density lipoprotein -cholesterol, triglycerides, fasting glucose, homeostasis model, high-sensitivity CRP, and personal history of cardiovascular, respiratory or metabolic diseases. IL-1β, IL-6 and TNF-α were assessed by multiplexed flow cytometric assay. CRP was assessed by immunoassay. RESULTS: On bivariate analysis some, but not all, definitions of MHO led to significantly lower levels of IL-6, TNF-α and CRP compared with non-MH obese subjects. Most of these differences became nonsignificant after multivariate analysis. An posteriori analysis showed a statistical power between 9 and 79%, depending on the inflammatory biomarker and MHO definition considered. Further increasing sample size to overweight+obese individuals (BMI > or =25 kg/m2, n=2917) showed metabolically healthy status to be significantly associated with lower levels of CRP, while no association was found for IL-1β. Significantly lower IL-6 and TNF-α levels were also found with some but not all MHO definitions, the differences in IL-6 becoming nonsignificant after adjusting for abdominal obesity or percent body fat. CONCLUSIONS: MHO individuals present with decreased levels of CRP and, depending on MHO definition, also with decreased levels in IL-6 and TNF-α. Conversely, no association with IL-1β levels was found.
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Drosophila melanogaster is a model organism instrumental for numerous biological studies. The compound eye of this insect consists of some eight hundred individual ommatidia or facets, ca. 15 µm in cross-section. Each ommatidium contains eighteen cells including four cone cells secreting the lens material (cornea). High-resolution imaging of the cornea of different insects has demonstrated that each lens is covered by the nipple arrays--small outgrowths of ca. 200 nm in diameter. Here we for the first time utilize atomic force microscopy (AFM) to investigate nipple arrays of the Drosophila lens, achieving an unprecedented visualization of the architecture of these nanostructures. We find by Fourier analysis that the nipple arrays of Drosophila are disordered, and that the seemingly ordered appearance is a consequence of dense packing of the nipples. In contrast, Fourier analysis confirms the visibly ordered nature of the eye microstructures--the individual lenses. This is different in the frizzled mutants of Drosophila, where both Fourier analysis and optical imaging detect disorder in lens packing. AFM reveals intercalations of the lens material between individual lenses in frizzled mutants, providing explanation for this disorder. In contrast, nanostructures of the mutant lens show the same organization as in wild-type flies. Thus, frizzled mutants display abnormal organization of the corneal micro-, but not nano-structures. At the same time, nipples of the mutant flies are shorter than those of the wild-type. We also analyze corneal surface of glossy-appearing eyes overexpressing Wingless--the lipoprotein ligand of Frizzled receptors, and find the catastrophic aberration in nipple arrays, providing experimental evidence in favor of the major anti-reflective function of these insect eye nanostructures. The combination of the easily tractable genetic model organism and robust AFM analysis represents a novel methodology to analyze development and architecture of these surface formations.
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Plasma concentrations of total cholesterol, low-density lipoprotein cholesterol, high-density lipoprotein cholesterol and triglycerides are among the most important risk factors for coronary artery disease (CAD) and are targets for therapeutic intervention. We screened the genome for common variants associated with plasma lipids in >100,000 individuals of European ancestry. Here we report 95 significantly associated loci (P < 5 x 10(-8)), with 59 showing genome-wide significant association with lipid traits for the first time. The newly reported associations include single nucleotide polymorphisms (SNPs) near known lipid regulators (for example, CYP7A1, NPC1L1 and SCARB1) as well as in scores of loci not previously implicated in lipoprotein metabolism. The 95 loci contribute not only to normal variation in lipid traits but also to extreme lipid phenotypes and have an impact on lipid traits in three non-European populations (East Asians, South Asians and African Americans). Our results identify several novel loci associated with plasma lipids that are also associated with CAD. Finally, we validated three of the novel genes-GALNT2, PPP1R3B and TTC39B-with experiments in mouse models. Taken together, our findings provide the foundation to develop a broader biological understanding of lipoprotein metabolism and to identify new therapeutic opportunities for the prevention of CAD.
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BACKGROUND AND OBJECTIVES: The SBP values to be achieved by antihypertensive therapy in order to maximize reduction of cardiovascular outcomes are unknown; neither is it clear whether in patients with a previous cardiovascular event, the optimal values are lower than in the low-to-moderate risk hypertensive patients, or a more cautious blood pressure (BP) reduction should be obtained. Because of the uncertainty whether 'the lower the better' or the 'J-curve' hypothesis is correct, the European Society of Hypertension and the Chinese Hypertension League have promoted a randomized trial comparing antihypertensive treatment strategies aiming at three different SBP targets in hypertensive patients with a recent stroke or transient ischaemic attack. As the optimal level of low-density lipoprotein cholesterol (LDL-C) level is also unknown in these patients, LDL-C-lowering has been included in the design. PROTOCOL DESIGN: The European Society of Hypertension-Chinese Hypertension League Stroke in Hypertension Optimal Treatment trial is a prospective multinational, randomized trial with a 3 × 2 factorial design comparing: three different SBP targets (1, <145-135; 2, <135-125; 3, <125 mmHg); two different LDL-C targets (target A, 2.8-1.8; target B, <1.8 mmol/l). The trial is to be conducted on 7500 patients aged at least 65 years (2500 in Europe, 5000 in China) with hypertension and a stroke or transient ischaemic attack 1-6 months before randomization. Antihypertensive and statin treatments will be initiated or modified using suitable registered agents chosen by the investigators, in order to maintain patients within the randomized SBP and LDL-C windows. All patients will be followed up every 3 months for BP and every 6 months for LDL-C. Ambulatory BP will be measured yearly. OUTCOMES: Primary outcome is time to stroke (fatal and non-fatal). Important secondary outcomes are: time to first major cardiovascular event; cognitive decline (Montreal Cognitive Assessment) and dementia. All major outcomes will be adjudicated by committees blind to randomized allocation. A Data and Safety Monitoring Board has open access to data and can recommend trial interruption for safety. SAMPLE SIZE CALCULATION: It has been calculated that 925 patients would reach the primary outcome after a mean 4-year follow-up, and this should provide at least 80% power to detect a 25% stroke difference between SBP targets and a 20% difference between LDL-C targets.
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HIV-infected individuals may have accelerated atherogenesis and an increased risk for premature coronary artery disease. Dyslipidemia represents a key pro-atherogenic mechanism. In HIV-infected patients, dyslipidemia is typically attributed to the adverse effects of antiretroviral therapy. Nine recent genome-wide association studies have afforded a comprehensive, unbiased inventory of common SNPs at 36 genetic loci that are reproducibly associated with dyslipidemia in the general population. Genome-wide association study-validated SNPs have now been demonstrated to contribute to dyslipidemia in the setting of HIV infection and antiretroviral therapy. In a Swiss HIV-infected study population, a similar proportion of serum lipid variability was explained by antiretroviral therapy and by genetic background. In the individual patient, both antiretroviral therapy and the cumulative effect of SNPs contribute to the risk of high low-density lipoprotein cholesterol, low high-density lipoprotein cholesterol and hypertriglyceridemia. Genetic variants presumably contribute to additional major metabolic complications in HIV-infected individuals, including diabetes mellitus and coronary artery disease. In an effort to explain an increasing proportion of the heritability of complex metabolic traits, ongoing large-scale gene resequencing studies are focusing on the effects of rare SNPs and structural genetic variants.
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BACKGROUND: Administration of protease inhibitors (PIs) to HIV-infected individuals has been associated with hyperlipidemia. In this study, we characterized the lipoprotein profile in subjects receiving ritonavir, indinavir, or nelfinavir, alone or in combination with saquinavir. METHODS AND RESULTS: Plasma lipoprotein levels were quantified in 93 HIV-infected adults receiving PIs. Comparison was done with pretreatment values and with 28 nonPI-treated HIV-infected subjects. An elevation in plasma cholesterol levels was observed in all PI-treated groups but was more pronounced for ritonavir (2.0+/-0.3 mmol/L [mean+/-SEM], n=46, versus 0.1+/-0.2 mmol/L in nonPI treated group, P<0.001) than for indinavir (0.8+/-0.2 mmol/L, n=26, P=0.03) or nelfinavir (1.2+/-0.2 mmol/L, n=21, P=0.01). Administration of ritonavir, but not indinavir or nelfinavir, was associated with a marked elevation in plasma triglyceride levels (1.83+/-0.46 mmol/L, P=0.002). Plasma HDL-cholesterol levels remained unchanged. Combination of ritonavir or nelfinavir with saquinavir did not further elevate plasma lipid levels. A 48% increase in plasma levels of lipoprotein(a) was detected in PI-treated subjects with pretreatment Lp(a) values >20 mg/dL. Similar changes in plasma lipid levels were observed in 6 children receiving ritonavir. CONCLUSIONS: Administration of PIs to HIV-infected individuals is associated with a marked, compound-specific dyslipidemia. The risk of pancreatitis and premature atherosclerosis due to PI-associated dyslipidemia remains to be established.
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Elevated low-density lipoprotein (LDL) levels induce activation of the p38 mitogen-activated protein kinase (MAPK), a stress-activated protein kinase potentially participating in the development of atherosclerosis. The nature of the lipoprotein components inducing p38 MAPK activation has remained unclear however. We show here that both LDLs and high-density lipoproteins (HDLs) have the ability to stimulate the p38 MAPKs with potencies that correlate with their cholesterol content. Cholesterol solubilized in methyl-beta-cyclodextrin was sufficient to activate the p38 MAPK pathway. Liposomes made of phosphatidylcholine (PC) or sphingomyelin, the two main phospholipids found in lipoproteins, were unable to stimulate the p38 MAPKs. In contrast, PC liposomes loaded with cholesterol potently activated this pathway. Reducing the cholesterol content of LDL particles lowered their ability to activate the p38 MAPKs. Cell lines representative of the three main cell types found in blood vessels (endothelial cells, smooth muscle cells and fibroblasts) all activated their p38 MAPK pathway in response to LDLs or cholesterol-loaded PC liposomes. These results indicate that elevated cholesterol content in lipoproteins, as seen in hypercholesterolemia, favors the activation of the stress-activated p38 MAPK pathway in cells from the vessel wall, an event that might contribute to the development of atherosclerosis.
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Adiponutrin (PNPLA3) is a predominantly liver-expressed transmembrane protein with phospholipase activity that is regulated by fasting and feeding. Recent genome-wide association studies identified PNPLA3 to be associated with hepatic fat content and liver function, thus pointing to a possible involvement in the hepatic lipoprotein metabolism. The aim of this study was to examine the association between two common variants in the adiponutrin gene and parameters of lipoprotein metabolism in 23,274 participants from eight independent West-Eurasian study populations including six population-based studies [Bruneck (n = 800), KORA S3/F3 (n = 1644), KORA S4/F4 (n = 1814), CoLaus (n = 5435), SHIP (n = 4012), Rotterdam (n = 5967)], the SAPHIR Study as a healthy working population (n = 1738) and the Utah Obesity Case-Control Study including a group of 1037 severely obese individuals (average BMI 46 kg/m2) and 827 controls from the same geographical region of Utah. We observed a strong additive association of a common non-synonymous variant within adiponutrin (rs738409) with age-, gender-, and alanine-aminotransferase-adjusted lipoprotein concentrations: each copy of the minor allele decreased levels of total cholesterol on average by 2.43 mg/dl (P = 8.87 x 10(-7)), non-HDL cholesterol levels by 2.35 mg/dl (P = 2.27 x 10(-6)) and LDL cholesterol levels by 1.48 mg/dl (P = 7.99 x 10(-4)). These associations remained significant after correction for multiple testing. We did not observe clear evidence for associations with HDL cholesterol or triglyceride concentrations. In conclusion, our study suggests that adiponutrin is involved in the metabolism of apoB-containing lipoproteins.
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Background: Short-term OE (oleoyl-estrone) treatment causes significant decreases in rat weight mainly due to adipose tissue loss. The aim of this work was to determine if OE treatment affects the expression of genes that regulate lipid metabolism in white adipose tissue. Results: Gene expression in adipose tissue from female treated rats (48 hours) was analysed by hybridization to cDNA arrays and levels of specific mRNAs were determined by real-time PCR. Treatment with OE decreased the expression of 232 genes and up-regulated 75 other genes in mesenteric white adipose tissue. The use of real-time PCR validate that, in mesenteric white adipose tissue, mRNA levels for Lipoprotein Lipase (LPL) were decreased by 52%, those of Fatty Acid Synthase (FAS) by 95%, those of Hormone Sensible Lipase (HSL) by 32%, those of Acetyl CoA Carboxylase (ACC) by 92%, those of Carnitine Palmitoyltransferase 1b (CPT1b) by 45%, and those of Fatty Acid Transport Protein 1 (FATP1) and Adipocyte Fatty Acid Binding Protein (FABP4) by 52% and 49%, respectively. Conversely, Tumour Necrosis Factor (TNF¿) values showed overexpression (198%). Conclusion: Short-term treatment with OE affects adipose tissue capacity to extract fatty acids from lipoproteins and to deal with fatty acid transport and metabolism.
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Résumé La voie de signalisation de Wnt est extrêmement conservée au cours de l'évolution. Les protéines Wnt sont des molécules sécrétées qui se lient à la famille de récepteurs Frizzled. Cette interaction mène à la stabilisation de la protéine β-caténine, qui va s'accumuler dans le cytoplasme puis migrer dans le noyau où elle peut s'hétérodimériser avec les facteurs de transcription de la famille TCF/LEF. Il a été démontré que cette voie de signalisation joue un rôle important durant la lymphopoïèse et de récents résultats suggèrent un rôle clé de cette voie dans le renouvellement des Cellules Souches Hématopoïétique (CSH). Des études se basant sur un système de surexpression de protéines montrent clairement que la voie Wnt peut influencer l'hématopoïèse. Cependant, le rôle de la protéine β-caténine dans le système hématopoïétique n'a jamais été testé directement. Ce projet de thèse se propose d'étudier la fonction de la protéine β-caténine par sa délétion inductible via le système Cre-loxP. De façon surprenante, nous avons pu démontrer que les progéniteurs de la moelle osseuse, déficients en β-caténine, ne montrent aucune altération dans leur capacité à s'auto-renouveler et/ou à reconstituer toutes les lignées hématopoïétiques (myéloïde, érythroïde et lymphoïde) dans les souris-chimères. De plus, le développement, la survie des thymocytes ainsi que la prolifération des cellules T périphériques induite par un antigène, sont indépendants de β-caténine. Ces résultats suggèrent soit que la protéine β-caténine ne joue pas un rôle primordial dans le système hématopoiétique, soit que son absence pourrait être compensée par une autre protéine. Un candidat privilégié susceptible de se substituer à β-caténine, serait plakoglobine, aussi connu sous le nom de γ-caténine. En effet, ces deux protéines partagent de multiples caractéristiques structurelles. Afin de démontrer que la protéine γ-caténine peut compenser l'absence de β-caténine, nous avons généré des souris dans lesquelles, le système hématopoïétique est déficient pour ces deux protéines. Cette déficience combinée de β- caténine et γ-caténine ne perturbe pas la capacité des Cellules Souche Hématopoïétique-Long Terme (CSH-LT) de se renouveler, par contre elle agit sur un progéniteur précoce déjà différencié de la moelle osseuse. Ces résultats mettent en évidence que la protéine γ-caténine est capable de compenser l'absence de protéine β-caténine dans le système hématopoïétique. Par conséquent, ce travail contribue à une meilleure connaissance de la cascade Wnt dans l'hématopoïèse. Summary The canonical Wnt signal transduction pathway is a developmentally highly conserved. Wnts are secreted molecules which bind to the family of Frizzled receptors in a complex with the low density lipoprotein receptor related protein (LRP-5/6). This initial activation step leads to the stabilization and accumulation of β-catenin, first in the cytoplasm and subsequently in the nucleus where it forms heterodimers with TCF/LEF transcription factor family members. Wnt signalling has been shown to be important during early lymphopoiesis and has more recently, been suggested to be a key player in self-renewal of haematopoietic stem cells (HSCs). Although mostly gain of function studies indicate that components of the Wnt signalling pathway can influence the haematopoietic system, the role of β-catenin has never been directly investigated. The aim of this thesis project is to investigate the putatively critical role of β-catenin in vivo using the Cre-loxP mediated conditional loss of function approach. Surprisingly, β-catenin deficient bone marrow (BM) progenitors arc not impaired in their ability to self-renew and/or to reconstitute all haematopoietic lineages (myeloid, erythroid and lymphoid) in both mixed and straight bone marrow chimeras. In addition, both thymocyte development and survival, and antigen-induced proliferation of peripheral T cells are β- catenin independent. Our results do not necessarily exclude the possibility of an important function for β-catenin mediated Wnt signalling in the haematopoietic system, it rather raises the question that β-catenin is compensated for by another protein. A prime candidate that may take over the function of β-catenin in its absence, is the close relative plakoglobin, also know as γ-catenin. This protein shares multiple structural features with β-catenin. In order to investigate whether γ-catenin can compensate for the loss of β-catenin we have generated mice in which the haematopoietic compartment is deficient for both proteins. Combined deficiency of β-catenin and γ-catenin does not perturb Long Term-Haematopoietic Stem Cells (LT-HSC) self renewal, but affects an already lineage committed progenitor population within the BM. Our results demonstrate that y-catenin can indeed compensate for the loss of β-catenin within the haematopoietie system.
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Self-reported drinking habits were examined in a random sample of 1067 persons aged 25-64 years in the Seychelles, a country in epidemiological transition where consumption of home-brewed, mostly unregistered beverages has been traditionally high. Alcohol consumption was calculated from respondents reporting at least one drink per week ('regular drinkers'). Among men, 51.1% were regular drinkers and had average intake of 112.1 ml alcohol a day. Among women, 5.9% were regular drinkers and had 49.7 ml alcohol a day. Frequency of drinking, but not amount per drinker, was slightly less in the 25-34-year than older-age categories. Home-brews (mostly palm toddy and fermented sugar cane juice) were consumed by 52% of regular drinkers and accounted for 54% of the total alcohol intake reported by all regular drinkers. Based on the reported consumption by regular drinkers only, the average annual alcohol consumption amounted respectively to 20.7 litres and 1.2 litres per man and woman aged 25-64 years, or, using extrapolation, 13.2 litres and 0.8 litres per man and woman respectively of the total population. These values may underestimate the true figures by half, since reported beer consumption accounted for 53% of beer sales. Socio-economic status was associated strongly and inversely with home-brew consumption, but slightly and positively with consumption of commercially marketed beverages. Alcohol intake was associated with smoking, high-density lipoprotein cholesterol, carbohydrate-deficient transferrin and blood pressure, but not with age and body mass index. In conclusion, these data show high alcohol consumption in the Seychelles with an important gender difference, a large proportion of alcohol derived from home-brews, and opposite tendencies for the relationships between socio-economic status and home-made or commercially marketed beverages.