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To determine the safety of using argon as a deuteron beam stopping material, the 40Ar(d,p)41Ar cross section was measured at average deuteron energies of 3.6 MeV, 5.5 MeV, and 7.0 MeV using an activation method. A 16-MeV deuteron beam produced by Lawrence Berkeley National Laboratory's 88-Inch Cyclotron was degraded to each energy by nickel foils and the front wall of an aluminum gas chamber. The reduced-energy deuterons were used to activate a sample of natAr gas. After each irradiation, the gas chamber's 41Ar activation was measured with a high-purity germanium detector. The cross sections measured were larger than a previous measurement by â¼40%.
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CiclotronsRESUMO
BACKGROUND: Diabetic foot ulcers portend an almost twofold increase in all-cause mortality compared with diabetes on its own. AIM: To investigate the association between diabetic foot ulcers and risk of death. METHODS: We performed a meta-analysis of all observational studies investigating the association between diabetic foot ulcers and all-cause mortality. Risk ratios and risk differences were pooled in a random-effects model. The I2 statistic was used to quantify heterogeneity between studies. RESULTS: Altogether, we identified 11 studies that reported 84 131 deaths from any cause in 446 916 participants with diabetes during a total of 643 499 person-years of follow-up. The crude event rate for all-cause mortality in individuals with diabetes who did not develop foot ulceration was 22% lower at 181.5 deaths (per 1000 person-years) than in those who developed foot ulcers (230.8 per 1000 person-years). Diabetic foot ulceration was associated with an increased risk of all-cause mortality (pooled relative risk 2.45, 95% CI 1.85-2.85). We did not observe any tangible differences in risk of all-cause mortality from diagnosis in studies reporting a mean duration of follow-up of ≤3 years (relative risk 2.43, 95% CI 2.27-2.61) or >3 years (relative risk 2.26, 95% CI 2.13-2.40) years. Funnel plot inspection revealed no significant publication bias among studies included in this meta-analysis. CONCLUSIONS: Our study shows an excess rate of all-cause mortality in people with diabetic foot ulceration when compared to those without foot ulceration. It is imperative that early interventions to prevent foot ulceration and modify cardiovascular disease risk factors are put in place to reduce excess mortality.
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Diabetes Mellitus/epidemiologia , Pé Diabético/epidemiologia , Mortalidade , Causas de Morte , Humanos , PrognósticoRESUMO
AIM: To determine how routinely collected data can inform a risk model to predict de novo foot ulcer presentation in the primary care setting. METHODS: Data were available on 15 727 individuals without foot ulcers and 1125 individuals with new foot ulcers over a 12-year follow-up in UK primary care. We examined known risk factors and added putative risk factors in our logistic model. RESULTS: People with foot ulcers were 4.2 years older (95% CI 3.1-5.2) than those without, and had higher HbA1c % (mean 7.9 ± 1.9 vs 7.5 ± 1.7) / HbA1c mmol/mol (63 ± 21 vs 59 ± 19) (p<0.0001) concentration [+0.45 (95% CI 0.33-0.56), creatinine level [+6.9 µmol/L (95% CI 4.1-9.8)] and Townsend score [+0.055 (95% CI 0.033-0.077)]. Absence of monofilament sensation was more common in people with foot ulcers (28% vs 21%; P<0.0001), as was absence of foot pulses (6.4% vs 4.8%; P=0.017). There was no difference between people with or without foot ulcers in smoking status, gender, history of stroke or foot deformity, although foot deformity was extremely rare (0.4% in people with foot ulcers, 0.6% in people without foot ulcers). Combining risk factors in a single logistic regression model gave modest predictive power, with an area under the receiver-operating characteristic curve of 0.65 (95% CI 0.62-0.67). The prevalence of ulceration in the bottom decile of risk was 1.8% and in the top decile it was 13.4% (compared with an overall prevalence of 6.5%); thus, the presence of all six risk factors gave a relative risk of 7.4 for development of a foot ulcer over 12 years. CONCLUSION: We have made some progress towards defining a variable set that can be used to create a foot ulcer prediction model. More accurate determination of foot deformity/pedal circulation in primary care may improve the predictive value of such a future risk model, as will identification of additional risk variables.
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Diabetes Mellitus Tipo 1/fisiopatologia , Diabetes Mellitus Tipo 2/fisiopatologia , Registros Eletrônicos de Saúde/estatística & dados numéricos , Úlcera do Pé/diagnóstico , Atenção Primária à Saúde , Transtornos de Sensação/fisiopatologia , Adolescente , Adulto , Fatores Etários , Idoso , Idoso de 80 Anos ou mais , Creatinina/sangue , Coleta de Dados , Diabetes Mellitus Tipo 1/epidemiologia , Diabetes Mellitus Tipo 2/epidemiologia , Feminino , Úlcera do Pé/epidemiologia , Úlcera do Pé/fisiopatologia , Hemoglobinas Glicadas/metabolismo , Humanos , Masculino , Pessoa de Meia-Idade , Valor Preditivo dos Testes , Estudos Retrospectivos , Medição de Risco , Autocuidado , Transtornos de Sensação/epidemiologia , Transtornos de Sensação/etiologia , Fumar , Reino Unido/epidemiologia , Adulto JovemRESUMO
Analysis of National Diabetes Audit data from 2011-2012 of newly diagnosed people with type 1 diabetes mellitus (DM) found low initial success rates in much of the UK at 20% on initial training, while an unusually high success rate of 75% achieving target HbA1C<58 mmol/mol (< 7.5%) was found in Cheshire (England average=40.8%). We present a review of the approach taken by the Cheshire Diabetes team in the 12 months following diagnosis. Between 2012 and 2013, 15 consecutive newly diagnosed people with type 1 DM were followed up for 18 months. All received support and advice by community Diabetes Specialist Nurses (DSNs) and Dieticians covering Central and Eastern Cheshire, UK. Mean±SD age at diagnosis was 23±3 years. The period of contact with the DSN service varied from 7-12 weeks. Baseline HbA1C of 99 mmol/mol [11.2%] (95% CI: 86-111 mmol/mol [10.0-12.3%]) declined by ~50% to 49 mmol/mol [6.6%] (41-57 mmol/mol [5.9-7.4%]; F=16.9, p<0.001) at 6 months and did not change between 6-12 months. Of those newly diagnosed with type 1 DM, 84.6% achieved a target HbA1C<58 mmol/mol (<7.5%) and 61.5% met a target<48 mmol/mol (<6.5%). There was no significant weight change during the study. The key elements of this bio-psycho-social approach by the DSN team included providing psychological support, patient engagement, demonstrating positive regard, gaining trust, identifying health-seeking behaviour, providing key decision-making skills and developing a self-management plan. This resulted in improvements in overall glycaemic control well above the national average without untoward weight gain. The UK National Diabetes Audit (2011-2012) in newly diagnosed type 1 diabetics in Cheshire, UK, showed a success rate at 6 months post-diagnosis of 75% achieving a target HbA1C<58 mmol/mol (<7.5%) compared with the national average of 40.8%. Initially thought to be erroneous, these excellent results were confirmed. The approach taken to achieve them is herein described.
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Diabetes Mellitus Tipo 1 , Educação em Enfermagem , Avaliação de Desempenho Profissional , Hemoglobinas Glicadas/metabolismo , Enfermeiras e Enfermeiros , Adulto , Diabetes Mellitus Tipo 1/sangue , Diabetes Mellitus Tipo 1/diagnóstico , Diabetes Mellitus Tipo 1/terapia , Feminino , Seguimentos , Humanos , Masculino , Reino UnidoRESUMO
OBJECTIVE: Painful peripheral neuropathy in people with type 2 diabetes is a disabling complication. We explored associations of this condition with socioeconomic deprivation. RESEARCH DESIGN AND METHODS: The Townsend index of socioeconomic deprivation was examined in the pseudonymised GP records of 15388 (44.1% female) individuals with type 2 diabetes in the Cheshire county of England, and related to prevalence of drug treated painful diabetic neuropathy. We also analysed prescription trends with respect to pharmacotherapy for neuropathy pain relief. RESULTS: Treatment for neuropathic pain was initiated in 3 266 (21.2%) of patients. Those on treatment were older [68.2 (95% CI 67.8-68.7) vs. 66.6 (66.4-66.8) years] than those not on treatment. There was no difference in HbA1c (7%, 55 mmol/mol).There were significant differences between the groups for the Townsend deprivation index, with a greater proportion (30.6% vs. 22.8% of patients with treated neuropathic pain) having a score of ≥1 (Χ(2)=83.9, p<0.0001).Multivariate logistic regression analyses indicated that each unit increment in the Townsend index was associated with an 6% increased odds of requiring neuropathic pain treatment [odds ratio (95%CI) 1.06 (1.05-1.08), p<0.0001] independent of 5 year age band, BMI, gender, systolic BP, eGFR, HbA1C and total cholesterol. CONCLUSIONS: In this study using pseudonymised clinical records, a higher level of socioeconomic deprivation seemingly may predispose to severe neuropathic pain in diabetes requiring pharmacological intervention. Targeted allocation of healthcare resources to this group may offer clinical benefits.
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Diabetes Mellitus Tipo 2/epidemiologia , Neuropatias Diabéticas/epidemiologia , Neuralgia/epidemiologia , Classe Social , Populações Vulneráveis/estatística & dados numéricos , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , Diabetes Mellitus Tipo 2/complicações , Neuropatias Diabéticas/etiologia , Inglaterra/epidemiologia , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Neuralgia/etiologia , Adulto JovemRESUMO
AIMS: With the increasing evidence of adverse consequences because of low vitamin D levels on health demand for vitamin D, screening is increasing. The objective of the study was to assess whether parathyroid hormone (PTH) levels/bone profile is sufficient to identify patients with vitamin D insufficiency or deficiency, or whether vitamin D should be measured directly. METHODOLOGY: A total of 1560 serum specimens, with requests for 25-hydroxyvitamin D (25-OH vitamin D), calcium, phosphate, alkaline phosphatase (ALP), creatinine and PTH on the same sample were analysed at Salford Royal Hospital from November 2010 to November 2012. RESULTS: The prevalence of total vitamin D insufficiency or deficiency (defined as total 25-OH vitamin D < 50 nmol/l) was 62.9% (981/1560) overall, with males having higher proportions (67.2 vs. 59.3 per cent; χ(2) = 8.78, p = 0.003). There was no overall trend in mean serum adjusted calcium across categories of 25-OH vitamin D status but mean serum phosphate was significantly lower (F = 6.53, p < 0.0001) in patients with a 25-OH vitamin D level < 50 nmol/l. However in patients with vitamin D deficiency, a significant proportion had PTH, calcium, phosphate and alkaline phosphatase levels within the laboratory normal range. Even at a 25-OH vitamin D < 10 nmol/l, 71.6% had a normal PTH, 89.8% had normal serum calcium levels, 84.9% had normal phosphate levels and 81.6% had normal serum ALP. CONCLUSIONS: Therefore, despite the costs associated with the measurement of vitamin D, our findings show that no surrogate is adequate for screening for vitamin D deficiency.
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Vitamina D/sangue , Biomarcadores/análise , Biomarcadores/sangue , Cálcio da Dieta/farmacologia , Feminino , Humanos , Masculino , Hormônio Paratireóideo/deficiência , Vitamina D/análise , Deficiência de Vitamina D/sangue , Deficiência de Vitamina D/epidemiologiaRESUMO
OBJECTIVES: To examine the relations between haemostatic factors and lipoproteins with mortality in British Europeans, African-Caribbeans (AfC) and Gujarati Indians. METHODS: A prospective cohort study of 331 subjects (40-79 years), followed-up over 26 years for mortality. Apolipoprotein-A1 (Apo-A1), apolipoprotein-B (Apo-B), factor VII coagulant activity (FVIIc), fibrinogen and von Willebrand Factor (vWF) were measured at baseline in 118 Europeans, 100 AfC and 113 Gujaratis. Aortic pulse wave velocity (aPWV) was measured in 174 participants. RESULTS: 147 (44.4%) subjects died during a median of 24 years follow-up with 69 cardiovascular deaths. Women at baseline had higher, and AfC males the lowest FVIIc and Apo-A1 levels. Baseline age-sex and ethnicity adjusted FVIIc levels were higher in those who died (131.0 vs. 117.4%; P = 0.048). In similarly adjusted partial correlations, Apo-A1 was inversely related to arterial stiffness (ρ = -0.23, P = 0.04). Over the 26 years follow-up, participants below the median (i.e. with lower concentration) of FVIIc, Fibrinogen, Apo-B and vWF had better survival rates than those with higher concentrations; those with higher concentrations of Apo-A1 had better survival. In Cox multivariable regression analyses including sex, ethnicity and aPWV, independently increased risk of all-cause mortality came only from SBP (per 5 mmHg); P = 0.011), age (per year); P < 0.0001 and FVIIc at 7% (per 10-unit; HR 1.07 (1.02, 1.12); P = 0.008. Separately, Apo-A1 (HR 0.12 (0.02, 0.75; P = 0.029) was independently associated with a very significant 88% reduction in all-cause mortality. CONCLUSIONS: Despite a relatively small sample size, long-term follow-up suggests an independent effect of the prothrombotic state (via FVIIc) and apo-A1 (a constituent of HDL) on mortality.
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Antígenos/sangue , Apolipoproteína A-I/sangue , Apolipoproteínas B/sangue , Doenças Cardiovasculares/etnologia , Mortalidade , Fator de von Willebrand/análise , Adulto , Idoso , Antropometria , População Negra/estatística & dados numéricos , Região do Caribe/etnologia , Etnicidade/estatística & dados numéricos , Europa (Continente)/etnologia , Fator VII , Feminino , Fibrinogênio/análise , Seguimentos , Humanos , Índia/etnologia , Estimativa de Kaplan-Meier , Londres/epidemiologia , Masculino , Pessoa de Meia-Idade , Modelos de Riscos Proporcionais , Estudos Prospectivos , Fatores de Risco , Estudos de Amostragem , Trombofilia/sangue , Trombofilia/etnologia , Rigidez Vascular , População Branca/estatística & dados numéricosRESUMO
The hypothesis of the study was that IGF2 gene polymorphisms were associated with longitudinal trends in weight through modification of IGF-II concentration.Observational study that explored associations of the IGF2 gene and baseline circulating IGF-II concentration with 'real-world' longitudinal trends in body-mass index in a type 2 diabetes population.26 haplotype tagging single nucleotide polymorphisms (SNPs) from the IGF2 and H19 genes were studied in 485 Caucasian individuals in the Salford Longitudinal Diabetes Cohort. A generalised-estimating equation (GEE) model was used to separately study the association of SNPs and IGF-II concentration with 8-year longitudinal trends in body-mass index.High serum IGF-II concentration at baseline was associated with weight loss over the study period (ß=-0.006, 95% CI -0.009 to -0.002, p<0.001). 8 SNPs were associated with longitudinal body-mass index trends, of which 4 retained significance after multiple -testing correction. 2 SNPs rs10770063 and rs3842767 were associated with both IGF-II concentration as well as longitudinal weight changes.We report novel associations between polymorphisms in the IGF2 gene, with concentration of circulating IGF-II and also with longitudinal weight change in type 2 diabetes. Our data indicate that the IGF2 gene and its gene product may be important determinants of longitudinal weight trends in type 2 diabetes.
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Índice de Massa Corporal , Diabetes Mellitus Tipo 2 , Fator de Crescimento Insulin-Like II , Polimorfismo de Nucleotídeo Único , Idoso , Idoso de 80 Anos ou mais , Diabetes Mellitus Tipo 2/sangue , Diabetes Mellitus Tipo 2/genética , Diabetes Mellitus Tipo 2/fisiopatologia , Feminino , Seguimentos , Humanos , Fator de Crescimento Insulin-Like II/genética , Fator de Crescimento Insulin-Like II/metabolismo , Masculino , Pessoa de Meia-IdadeRESUMO
INTRODUCTION: Prolactin circulates predominantly as a 23-kDa monomer, and a high-molecular-weight form largely consisting of a complex of prolactin and an anti-prolactin IgG autoantibody, called macroprolactin. This cross-reacts with conventional laboratory assays for prolactin. We here describe how quantitative adjustment for this may assist patient management.In a consecutive series of 218 patients with prolactin elevated to 400 mu/L or more in men (normal range ≤ 180) (n=79, 36.2% of sample) and 1 000 mu/L or more in women (normal range ≤ 500) (n=139, 63.8%) a macroprolactin screen was performed using PEG precipitation. RESULTS: Where present, median macroprolactin as a proportion of total prolactin was in women 13% (percentile 25-percentile 75: 7-25%) and in men 15% (7-30%).The distribution of macroprolactin as a proportion of total prolactin was markedly skewed to the left with 69.7% of women and 62.9% of men having macroprolactin proportion of 20% or less. There was no relation between %macroprolactin and total measured prolactin, age or gender.Of relevance to clinical management, in 24% of men and 20.5% of women, correction for estimated macroprolactin gave an adjusted monomeric prolactin level below the agreed threshold for further investigation, potentially avoiding unnecessarily referral.In our clinical series, quotation of an adjusted monomeric prolactin would have resulted in unnecessary further investigation being avoided in a number of cases. DISCUSSION: Screening for macroprolactin is a key element of laboratory assessment for hyperprolactinaemia.In cases where measured total prolactin is significantly raised, quantitative reporting of estimated monomeric prolactin instead of just 'macroprolactin' positive' can avoid unnecessary investigations.
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Técnicas de Laboratório Clínico/métodos , Hiperprolactinemia/diagnóstico , Prolactina/sangue , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , Calibragem , Técnicas de Laboratório Clínico/normas , Técnicas de Diagnóstico Endócrino/normas , Feminino , Humanos , Hiperprolactinemia/sangue , Masculino , Pessoa de Meia-Idade , Prolactina/análise , Valores de Referência , Estudos Retrospectivos , Caracteres Sexuais , Adulto JovemRESUMO
Exenatide, a glucagon-like peptide-1 (GLP-1) analogue, is an effective glucoregulator for treating overweight individuals, not at target HbA1 c. This prospective study aimed to determine whether estimates of beta cell function (HOMA-B) and insulin sensitivity (HOMA-S) predict response to Exenatide treatment.Prospective data on 43 type 2 diabetes patients were collected for up to 2.8 years in UK primary care. HOMA-B and HOMA-S were estimated prior to initiating Exenatide, with monitoring of cardio-metabolic risk factors.Mean (SD) age and BMI pre-treatment were 54.1±10.5 years and 35.7±7.5 kg/m2 respectively. HbA1c decreased (mean reduction 0.9%, p=0.04; p for trend=0.01) in 61% of patients. In univariate analyses, HOMA-S as a measure of insulin sensitivity was inversely (ß=- 0.41, p 0.009) related to change in HbA1c, with no relation for HOMA-B.In a random effects regression model that included age at baseline, weight, LDL-C, HDL-C and triglycerides, change in HbA1c (ß= - 0.14, p<0.001) and HDL-C (ß= - 0.52, p=0.011) were independently associated with increasing insulin sensitivity (r2=0.52). Thus patients with greater measured insulin sensitivity achieved greater reduction in HbA1c independent of the factors described above.In logistic regression those in the highest tertile of log-HOMA-S were 45% more likely to have a fall in HbA1c with an odds ratio (OR) of 0.55 (95% CI 0.47-0.66) p<0.0001 (log likelihood ratio for the model χ2=71.6, p<0.0001).Patients with greater measured insulin sensitivity achieve greater reduction in HbA1c with Exenatide. Determination of insulin sensitivity may assist in guiding outcome expectation in overweight patients treated with GLP-1 analogues.
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Diabetes Mellitus Tipo 2/tratamento farmacológico , Peptídeo 1 Semelhante ao Glucagon/análogos & derivados , Hemoglobinas Glicadas/análise , Homeostase , Hipoglicemiantes/uso terapêutico , Resistência à Insulina , Índice de Massa Corporal , Diabetes Mellitus Tipo 2/sangue , Diabetes Mellitus Tipo 2/fisiopatologia , Exenatida , Feminino , Humanos , Insulina/sangue , Células Secretoras de Insulina/fisiologia , Lipídeos/sangue , Masculino , Pessoa de Meia-Idade , Modelos Biológicos , Peptídeos/uso terapêutico , Estudos Prospectivos , Resultado do Tratamento , Peçonhas/uso terapêuticoRESUMO
We demonstrate a compact hyperdispersion stretcher and compressor pair that permit chirped-pulse amplification in Nd:YAG. We generate 750 mJ, 0.2 nm FWHM, 10 Hz pulses recompressed to an 8 ps near-transform-limited duration. The dispersion-matched pulse compressor and stretcher impart a chirp of 7300 ps/nm, in a 3 m x 1 m footprint.
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What we believe to be the first demonstration of isotope-specific detection of a low-Z and low density object shielded by a high-Z and high-density material using monoenergetic gamma rays is reported. The isotope-specific detection of LiH shielded by Pb and Al is accomplished using the nuclear resonance fluorescence line of L7i at 478 keV. Resonant photons are produced via laser-based Compton scattering. The detection techniques are general, and the confidence level obtained is shown to be superior to that yielded by conventional x-ray and gamma-ray techniques in these situations.
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A novel time, space, and energy-resolved x-ray spectrometer has been developed which produces, in a single snapshot, a broadband and relatively calibrated spectrum of the x-ray emission from a high-energy density laboratory plasma. The opacity zipper spectrometer (OZSPEC-1) records a nearly continuous spectrum for x-ray energies from 240 to 5800 eV in a single shot. The second-generation OZSPEC-2, detailed in this work, records fully continuous spectra on a single shot from any two of these three bands: 270-650, 660-1580, and 1960-4720 eV. These instruments thus record thermal and line radiation from a wide range of plasmas. These instruments' single-shot bandwidth is unmatched in a time-gated spectrometer; conversely, other broadband instruments are either time-integrated (using crystals or gratings), lack spectral resolution (diode arrays), or cover a lower energy band (gratings). The OZSPECs are based on the zipper detector, a large-format (100x35 mm) gated microchannel plate detector, with spectra dispersed along the 100 mm dimension. OZSPEC-1 and -2 both use elliptically bent crystals of OHM, RAP, and/or PET. Individual spectra are gated in 100 ps. OZSPEC-2 provides one-dimensional spatial imaging with 30-50 microm resolution over a 1500 microm field of view at the source. The elliptical crystal design yields broad spectral coverage with resolution E/DeltaE>500, strong rejection of hard x-ray backgrounds, and negligible source broadening for extended sources. Near-term applications include plasma opacity measurements, detailed spectra of inertial fusion Hohlraums, and laboratory astrophysics experiments.
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OBJECTIVE: Serum testosterone measurement is an integral part of the endocrine assessment of men. Little is known about its variation in relation to migration. We examined within a South Asian group the effect of migration to the UK on androgen levels. DESIGN: Circulating testosterone and SHBG concentrations were measured in 97 Gujarati men resident in India and in 79 men from the same villages of origin living in Birmingham, UK. Free testosterone was calculated by Vermeulen's method. Insulin sensitivity (HOMA-S) was determined from paired fasting plasma intact insulin and glucose values. RESULTS: Circulating testosterone was significantly lower in UK Gujarati men (17.2 nmol/l [15.7-18.7]) vs. Indian Gujarati men (21.7 [20.0-23.5]) (P = 0.0002) (age-adjusted median [95% CI]). There was no difference by migration status in circulating free testosterone. Sex hormone binding globulin (SHBG) levels were lower in UK migrants (16.8 nmol/l [15.5-18.1]) than in nonmigrants (21.9 nmol/l [20.5-23.3]) (P < 0.0001). Testosterone level correlated positively with insulin sensitivity (HOMA-S) (rho 0.16, P = 0.04). In multivariate analysis, total testosterone was independently and positively associated with logSHBG (normalized beta (beta) = 0.29, P = 0.002) and independently and negatively with waist circumference (beta = -0.19, P = 0.04), in a model also including height, age, migration status, leptin and fasting insulin. CONCLUSION: Lower circulating testosterone in UK Gujarati men and its association with markers of insulin sensitivity suggest a profound influence of body composition change with migration on testosterone levels. The lower SHBG in this group restores parity in free testosterone. Account should be taken of SHBG in interpreting testosterone levels in men, as well as in women.
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Povo Asiático , Emigração e Imigração , Testosterona/sangue , Envelhecimento , Biomarcadores/sangue , Glicemia/análise , Composição Corporal , Estatura , Estudos de Casos e Controles , Inglaterra , Humanos , Índia/etnologia , Insulina/sangue , Resistência à Insulina , Proteína 1 de Ligação a Fator de Crescimento Semelhante à Insulina/sangue , Proteína 3 de Ligação a Fator de Crescimento Semelhante à Insulina/sangue , Fator de Crescimento Insulin-Like I/análise , Leptina/sangue , Masculino , Pessoa de Meia-Idade , Análise Multivariada , Globulina de Ligação a Hormônio Sexual/análiseRESUMO
OBJECTIVE: To determine whether pancreatic B-cell function varies in different populations with similar genetic backgrounds but different environments. RESEARCH DESIGN/METHODS: We compared a specific migrant Gujarati community in the UK (n = 205) with people still resident in the same villages of origin in Gujarat, India (n = 246). Pancreatic B-cell function (HOMA-B) was determined and the influence of age, migration and other factors was explored. RESULTS: As anticipated, there was an age-related decline in log(HOMA-B) in both groups. However, the age-related fall in log(HOMA-B) was more pronounced in the UK than in Gujarat (normalized beta-0.29 vs. -0.14, P for difference = 0.03). The decline of HOMA-B with age persisted after adjustment for body mass index (UK beta = -0.31; Gujarat beta = -0.16, P = 0.015, P < 0.001). There was no significant change in insulin sensitivity (HOMA-S) with age at either site, although insulin sensitivity was lower in the UK. Fasting non-estrified fatty acid (NEFA) levels rose with age in the UK but not in Gujarat (P = 0.003 for difference in gradients). In multiple linear regression analysis, lower log(HOMA-B) was independently associated with higher fasting log(NEFA) levels; normalized beta = -0.24, P < 0.001, age; beta = -0.16, P = 0.005, higher log(insulin-like growth factor binding protein-1); beta = -0.19, P = 0.007 and lower body mass index; beta = 0.26, P = 0.001. This model accounted for 25% of the variability in HOMA-B. CONCLUSIONS: HOMA-B as a measure of B-cell function declines more rapidly with age in the migrant UK group than in Gujarat. This may be a direct consequence of chronically higher NEFA exposure in the UK group.
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Ácidos Graxos não Esterificados/metabolismo , Células Secretoras de Insulina/fisiologia , Fatores Etários , Aminoácidos/fisiologia , Índice de Massa Corporal , Cromo/fisiologia , Emigração e Imigração , Inglaterra/etnologia , Feminino , Humanos , Índia/etnologia , Estilo de Vida , Masculino , Pessoa de Meia-Idade , Ácidos Nicotínicos/fisiologiaRESUMO
AIMS/HYPOTHESIS: IGFs and their binding proteins are increasingly recognised as important in understanding the pathogenesis of cardiovascular disease. Low IGFBP-1, particularly coupled with low IGF-I, is associated with increased cardiovascular risk. In relation to structural and regulatory parallels between IGFBP-1 and - 2 we have now examined the hypothesis that IGFBP-2 may be a marker for cardiovascular risk. METHODS: Fasting IGFBP-2, IGFBP-1, IGFBP-3, IGF-I, IGF-II, insulin, C-peptide, glucose, lipids, NEFAs, and HbA1c were measured in a cohort of 163 patients with type 2 diabetes. Individuals were categorised according to the presence or absence of the metabolic syndrome. RESULTS: Patients with the metabolic syndrome had a lower IGFBP-2 concentration. Low circulating IGFBP-2 was associated with elevated fasting glucose (rho = - 0.23, p = 0.003). IGFBP-2 correlated negatively with triglycerides (rho = - 0.19, p = 0.01) and LDL-cholesterol (rho = - 0.20, p = 0.01), and positively with insulin sensitivity (HOMA-S) (rho = 0.26, p = 0.02). Multivariate logistic regression demonstrated that low IGFBP-2 was independently associated with an increased risk of the metabolic syndrome (OR 0.31 [95 % CI 0.11 - 0.90]; p = 0.03). IGFBP-3 did not differ according to the presence or absence of metabolic syndrome. CONCLUSION/INTERPRETATION: Low IGFBP-2 is associated with multiple cardiovascular risk factors similarly to IGFBP-1. Such associations were not apparent for IGFBP-3. Lack of marked prandial regulation of IGFBP-2, in contradistinction to IGFBP-1, may make IGFBP-2 a more robust biomarker for identification of insulin-resistant individuals at high cardiovascular risk in epidemiological studies.
Assuntos
Diabetes Mellitus Tipo 2/sangue , Proteína 2 de Ligação a Fator de Crescimento Semelhante à Insulina/sangue , Síndrome Metabólica/sangue , Biomarcadores/sangue , Glicemia/análise , Pressão Sanguínea , Peptídeo C/sangue , Proteína C-Reativa/análise , Diabetes Mellitus Tipo 2/tratamento farmacológico , Dieta para Diabéticos , Humanos , Hipoglicemiantes/uso terapêutico , Insulina/sangue , Proteína 1 de Ligação a Fator de Crescimento Semelhante à Insulina/sangue , Proteína 3 de Ligação a Fator de Crescimento Semelhante à Insulina/sangue , Lipídeos/sangue , Pessoa de Meia-IdadeRESUMO
BACKGROUND: The insulin-like growth factor (IGF) system is implicated in the pathogenesis of diabetes and cardiovascular disease. OBJECTIVE: We report the effects of total energy intake on the IGF system in two populations with markedly different dietary macronutrient intake and cardiovascular event rate. DESIGN, SUBJECTS AND SETTING: Dietary macronutrient intake was measured in a specific Gujarati migrant community in Sandwell, UK (n=205) compared with people still resident in the same villages of origin in India (n=246). Fasting IGF-I, IGF-binding protein (IGFBP)-1 and IGFBP-3, insulin and glucose (0 and 2-hour) were measured. RESULTS: Total energy and total fat intake were higher in UK migrants, as were IGFBP-3 and IGF-I (mean (95% confidence interval): 145.9 (138.1-153.6) vs. 100.9 (94.6-107.3) ng ml(-1); F=76.6, P<0.001). IGFBP-1 was lower in UK migrants (29.5 (25.9-33.0) vs. 56.5 (50.6-62.5) microg l(-1); F=48.4, P<0.001). At both sites, IGF-I correlated positively with total energy (Spearman's rho=0.45, P<0.001) and total fat (rho=0.44, P<0.001) as did IGFBP-3 with total energy (rho=0.21, P<0.05) and fat (rho=0.26, P<0.001). Conversely, in Indian Gujaratis, IGFBP-1 fell with increasing total energy (rho=-0.27, P<0.001) and fat intake (rho=-0.26, P<0.01) but not in UK Gujaratis. Multiple linear regression modelling showed that increasing quartiles of fat intake were associated with higher IGF-I (beta=0.42, P=0.007) independent of age, body mass index, plasma insulin, fatty acids and 2-hour glucose. CONCLUSION: In these genetically similar groups, migration to the UK and adoption of a different diet is associated with marked changes in the IGF system, suggesting that environmental factors profoundly modulate serum concentrations and actions of IGFs.
Assuntos
Doenças Cardiovasculares/epidemiologia , Dieta , Gorduras na Dieta/administração & dosagem , Ingestão de Energia/fisiologia , Fator de Crescimento Insulin-Like I/metabolismo , Glicemia/metabolismo , Doenças Cardiovasculares/sangue , Doenças Cardiovasculares/etiologia , Carboidratos da Dieta/administração & dosagem , Proteínas Alimentares/administração & dosagem , Emigração e Imigração , Feminino , Humanos , Índia/etnologia , Insulina/sangue , Proteína 1 de Ligação a Fator de Crescimento Semelhante à Insulina/sangue , Proteína 3 de Ligação a Fator de Crescimento Semelhante à Insulina/sangue , Masculino , Pessoa de Meia-Idade , Reino Unido/epidemiologiaRESUMO
Hepatic sex-hormone binding globulin (SHBG) production is down-regulated by insulin and low levels reflect insulin resistance. Because insulin resistance is closely related to the development of cardiovascular disease in different ethnic groups we examined ethnic variation in SHBG across populations with different baseline cardiovascular risk and metabolic syndrome prevalence. Participants were population-based, of European (n = 142), Pakistani (n = 130), and African-Caribbean (AfC) origin (n = 193). SHBG, fasting lipids, and glucose concentrations plus insulin sensitivity (HOMA-S) were determined. Age adjusted SHBG was significantly lower in both Pakistani men and women. Circulating SHBG levels were lower in those with impaired vs. normal glucose homeostasis. SHBG correlated positively with HOMA-S (rho = 0.28, p < 0.001), and negatively with WHR (rho = - 0.38, p < 0.001), BMI (r = - 0.30, p < 0.001), and diastolic blood pressure (rho = - 0.14, p < 0.01) across all ethnic groups. In multivariate logistic regression analysis a low SHBG increased the likelihood of the metabolic syndrome (odds ratio [OR] = 0.42 [0.21 - 0.82], p = 0.01) as did higher fasting NEFA (OR 1.47 [1.04 - 2.08], p = 0.03), low IGFBP-1 concentrations (OR 0.6 [0.44 - 0.81], p = 0.001), age (OR 1.05 [1.02 - 1.09], p = 0.003), and Pakistani ethnicity (p = 0.001) in a model which also contained gender, lnCRP, IGF-I, and IGF-II. As ethnic differences in SHBG level closely parallel differences in insulin resistance. Its measurement may be useful in identifying individuals at particular risk of the metabolic syndrome, for early intervention.
Assuntos
Síndrome Metabólica/sangue , Globulina de Ligação a Hormônio Sexual/análise , Biomarcadores/análise , Biomarcadores/sangue , Doenças Cardiovasculares/sangue , Doenças Cardiovasculares/etnologia , Doenças Cardiovasculares/etiologia , Estudos de Casos e Controles , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Grupos Raciais , Reino UnidoRESUMO
AIMS/HYPOTHESES: We previously reported independent links between the IGF system and the development of impaired glucose tolerance and cardiovascular risk. This study tests the hypothesis that the lifestyle change which accompanies population migration, with attendant increases in cardiovascular risk, is reflected by changes in the IGF system. MATERIALS AND METHODS: We compared a specific Gujarati community in Sandwell, UK (n=205), with people still resident in the same villages of origin near Navsari, India (n=246). We performed anthropometry and measured fasting plasma insulin, IGF-I, insulin-like growth factor binding protein (IGFBP)-1 and IGFBP-3. RESULTS: Daily calorie intake, BMI and WHR were significantly higher in UK Gujaratis than in Indian Gujaratis. IGFBP-1 was significantly lower in UK migrants (mean 29.5 [95% CI 25.9-33.0] vs 56.5 [50.6-62.5] microg/l; F=48.4, p<0.001). Conversely, fasting insulin, IGFBP-3 and IGF-I were all higher in UK Gujaratis (mean IGF-I 145.9 [138.1-153.6]ng/ml in UK Gujaratis and 100.9 [94.6-107.3] ng/ml in Navsari Gujaratis; F=76.6, p<0.001). These differences were still apparent when adjustment was made for BMI by location for IGF-I (F=57.4, p<0.001) and IGFBP-3 (F=5.7, p=0.02), but were no longer apparent for IGFBP-1 and insulin. At the population level, the decrease in IGFBP-1 for a given increase in insulin was significantly smaller in UK Gujaratis, suggesting greater hepatic insulin resistance in this group. CONCLUSIONS/INTERPRETATION: Environmental factors have profound effects on circulating IGF system components and on the relationship between IGFBP-1, IGF-I and related metabolic variables. This may have long-term implications for the development of worsening glucose tolerance and cardiovascular disease.