361 research outputs found
The influence of method of contraception and cigarette smoking on menstrual patterns
No full textSummary. Self‐perceived menstrual patterns have been investigated in a sample of 2115 women aged 18–9 years using a postal questionnaire. Seven aspects of ‘abnormal’ menstruation were denned: prolonged periods, heavy periods, frequent periods, irregular periods, intermenstrual bleeding, painful periods and severe premenstrual syndrome. Women who used oral contraceptives were less likely than other women to report any of the seven menstrual abnormalities except for intermenstrual bleeding and severe premenstrual tension. Women who used an intrauterine contraceptive device (IUCD) reported prolonged, heavy, and frequent periods and intermenstrual bleeding more often than other women, but they did not report painful periods with undue frequency. Women who had had a tubal sterilization generally reported menstrual patterns similar to, or slightly less favourable than, women using no contraception or contraceptive methods other than the pill or the IUCD. There was a significant association between smoking habits and each of the abnormal menstrual patterns except for severe premenstrual tension. In every case, the effect of smoking was unfavourable and in almost every case, current smokers reported the worst experience, with ex‐smokers occupying an intermediate position. We believe that these data are of considerable clinical significance and that they offer a basis for a conservative approach to managing menstrual disorders in some women.</p
Promoting Groundwater Reform in the Guadiana Basin
No full textIn many parts of the world, there is a substantial disconnect between existing water institutions and the institutions needed to ensure sustainable water supplies for the future. Implementing large-scale institutional change is politically challenging. In many cases, changes must emerge from political bargaining or negotiation. Accordingly, there is substantial literature looking at applications of negotiation theory to water policy. Carraro, Marchiori, and Sgobbi (2007) review this literature in detail
Comparison of 11 Human Insulin Assays: Implications for Clinical Investigation and Research
Get PDFBACKGROUND: The American Diabetes Association task force on standardization of insulin assays in 1996 showed wide variation in assay bias. Newer assays are specific for insulin, with several now available on automated immunoassay analyzers. METHODS: In 2004, we compared 11 commercially available insulin assays by analyzing 150 serum samples (99 fasting/51 postprandial) from study participants with various degrees of glucose intolerance (exclusions being type 1 diabetes, insulin treatment, or presence of insulin antibodies). All assays were calibrated against International Reference Preparation 66/304. One assay was not specific for insulin and another was an RIA; 10 assays used enzyme/chemiluminescent labels. Bland-Altman difference plots were modified to use the mean insulin from all assays on the x-axis as a common comparator. RESULTS: As in the 1996 study, insulin values from the different assays varied by a factor of 2, with the nonspecific assay ranking in the middle of the distribution. Spearman rank correlation coefficients, for ranking samples vs the mean, were 0.983-0.997. Both offsets and concentration-dependent differences were seen in the modified difference plots. Imprecision (mean CV) for automated assays (3%) was not significantly different from manual assays (5%). Similar values were obtained when one automated assay was run in laboratories in both the UK and the US. Results of 1 assay showed lower insulin concentrations in heparinized plasma than in serum. CONCLUSIONS: Assay performance must be considered before comparing insulin results. The 2-fold variation in insulin results may be related to specificity, manufacturers' calibration procedures or conversion factors
Preanalytical, analytical, and computational factors affect homeostasis model assessment estimates
Get PDFOBJECTIVE: We investigated how beta-cell function and insulin sensitivity or resistance are affected by the type of blood sample collected or choice of insulin assay and homeostatis model assessment (HOMA) calculator (http://www.dtu.ox.ac.uk). RESEARCH DESIGN AND METHODS: Insulin was measured using 11 different assays in serum and 1 assay in heparinized plasma. Fasting subjects with normoglycemia (n = 12), pre-diabetes, i.e., impaired fasting glucose or impaired glucose tolerance (n = 18), or type 2 diabetes (n = 67) were recruited. Patients treated with insulin or those who were insulin antibody-positive were excluded. HOMA estimates were calculated using specific insulin (SI) or radioimmunoassay (RIA) calculators (version 2.2). RESULTS: All glucose values were within model (HOMA) limits but not all insulin results, as 4.3% were 300 pmol/l. beta-Cell function derived from different insulin assays ranged from 67 to 122% (median) for those with normoglycemia (P = 0.026), from 89 to 138% for those with pre-diabetes (P = 0.990), and from 50 to 81% for those with type 2 diabetes (P <0.0001). Furthermore, insulin resistance ranged from 0.8 to 2.0 (P = 0.0007), from 1.9 to 3.2 (P = 0.842), and from 1.5 to 2.9 (P <0.0001), respectively. This twofold variation in HOMA estimates from the various insulin assays studied in serum may be significant metabolically. Insulin was 15% lower in heparinized plasma (used in the original HOMA study) compared with serum, which is now more commonly used. beta-Cell function differed by 11% and insulin resistance by 15% when estimates derived from specific insulin were calculated using the RIA rather than the SI calculator. CONCLUSIONS: To enable comparison of HOMA estimates among individuals and different research studies, preanalytical factors and calculator selection should be standardized with insulin assays traceable to an insulin reference method procedure
The use of HbA1c for new diagnosis of diabetes in those with hyperglycaemia on admission to or attendance at hospital urgently requires research
No full textThe prevalence of diabetes in Birmingham is 11% but it is 22% in hospital inpatients. Queen Elizabeth Hospital in Birmingham (QEHB) serves a multi-ethnic population with 6% Afro-Caribbean, 19% South Asian and 70% White European. A clinical audit of 18,965 emergency admissions to QEHB showed that 5% were undiagnosed but had admission glucose in the ‘diabetes’ range and 16% were in the ‘at risk’ range. The proportion of Afro-Caribbeans (7%) and South Asians (8%) in the ‘diabetes’ range was higher than White Europeans (5%). Given the magnitude of the problem, this paper explores the issues concerning the use of reflex HbA1c testing in the UK for diagnosis of diabetes in hospital admissions. HbA1c testing is suitable for most patients but conditions affecting red blood cell turnover invalidate the results in a small number of people. However, there are pertinent questions relating to the introduction of such testing in the NHS on a routine basis. Literature searches on a topical question ‘Is hyperglycaemia identified during emergency admission/attendance acted upon?’, were performed from 2016 to 2021 and 2016 to 2022. They identified 21 different, relevant, research papers - 5 from Australia, 9 from Europe including 4 from the UK, 5 from America and 1 each from Canada and Africa. These papers revealed an absence of established procedures for the management and follow-up of routinely detected hyperglycaemia using HbA1c when no previous diabetes diagnosis was recorded. Further work is required to determine the role of reflex HbA1c testing for diagnosis of diabetes in admissions with hyperglycaemia, and the cost-effectiveness and role of point-of-care HbA1c testing
UKPDS 60: risk of stroke in type 2 diabetes estimated by the UK Prospective Diabetes Study risk engine.
No full textBACKGROUND AND PURPOSE: People with type 2 diabetes are at elevated risk of stroke compared with those without diabetes. Relative risks have been examined in earlier work, but there is no readily available method for predicting the absolute risk of stroke in a diabetic individual. We developed mathematical models to estimate the risk of a first stroke using data from 4549 newly diagnosed type 2 diabetic patients enrolled in the UK Prospective Diabetes Study. METHODS: During 30 700 person-years of follow-up, 188 first strokes (52 fatal) occurred. Model fitting was carried out by maximum likelihood estimation using the Newton-Raphson method. Diagnostic plots were used to compare survival probabilities calculated by the model with those calculated using nonparametric methods. RESULTS: Variables included in the final model were duration of diabetes, age, sex, smoking, systolic blood pressure, total cholesterol to high-density lipoprotein cholesterol ratio and presence of atrial fibrillation. Not included in the model were body mass index, hemoglobin A1c, ethnicity, and ex-smoking status. The use of the model is illustrated with a hypothetical study power calculation. CONCLUSIONS: This model forecasts the absolute risk of a first stroke in people with type 2 diabetes using variables readily available in routine clinical practice
Diagnosis of diabetes: HbA1c versus WHO criteria
No full textThe authors compared the diagnosis of type 2 diabetes using an HbA 1c cut-off point of ≥6.5% (≥48 mmol/mol) with current World Health Organization (WHO) criteria involving fasting plasma glucose and an oral glucose tolerance test. Diabetes was confirmed in 35% of Australian and 49% of UK participants using WHO criteria and a similar prevalence was obtained using HbA1c - 31% and 46%, respectively. Using HbA1c levels alone for diagnosis does not define the same people with diabetes as the WHO criteria. A considerable number of participants (38% of Australian and 49% of British) diagnosed with diabetes by WHO criteria would not have been diagnosed using a single HbA1c test. More consideration of the use of HbA 1c as a screening test for diabetes is required
United kingdom prospective diabetes study, 30: Diabetic retinopathy at diagnosis of non-insulin-dependent diabetes mellitus and associated risk factors
No full textObjectives: To report on the prevalence of retinopathy in patients with newly diagnosed non-insulin-dependent diabetes mellitus (NIDDM) and to evaluate the relationship of retinopathy to clinical and biochemical variables. Design: A multicenter, randomized, controlled clinical study of therapy in patients with NIDDM. Setting and Patients: Patients were part of the United Kingdom Prospective Diabetes Study, a 23-center study of 2964 white patients who had both eyes photographed and assessed. Outcome Measures: The presence and severity of diabetic retinopathy were evaluated by sex, and the relationship of retinopathy to medical and biochemical parameters was assessed. Results: Retinopathy, defined as microaneurysms or worse lesions in at least 1 eye, was present in 39% of men and 35% of women. Marked retinopathy with cotton wool spots or intraretinal microvascular abnormalities was present in 8% of men and 4% of women. The severity of retinopathy was related in both sexes to higher fasting plasma glucose levels, higher systolic and diastolic blood pressure, lower serum insulin levels, and reduced β-cell function. In addition, in men, increased alcohol consumption was related to increased severity of retinopathy, while leaner women had more severe eye lesions. Visual acuity was normal in most patients, but in men there was a trend for those with more severe retinal lesions to have worse visual acuity. Conclusions: Diabetic retinopathy is common in patients with newly diagnosed NIDDM. Careful ophthalmic assessment at diagnosis is important.</p
Approach to maintaining comparability of biochemical data during long- term clinical trials
No full textOur objective was to design a structured approach to maintaining comparability of biochemical data during a long clinical trial. Maintaining the comparability of clinical and biochemical data obtained in long-term studies is essential, even though analytical methods in the laboratory may be changed, conventions on specimen handling and storage revised, calibration procedures updated, quality-control systems replaced, and secular changes may occur. The United Kingdom Prospective Diabetes Study (UKPDS), a large randomized control trial investigating therapy for type 2 diabetes, was the setting for the study. Data were collected from 5102 subjects randomized since 1977. Our techniques included quality control, external quality assurance, direct comparison of laboratory methods when updating assays and statistical techniques for the detection of unsuspected changes in assay bias, laboratory comparisons of new with old assay methodologies, the realigning of-data to current methods, the use of a suitable reference population for long-term monitoring, and rules to aid decision-making about clinical vs statistical significance. Procedures by which comparability of data is assured should be specified for all long-term trials and, where possible, comparison with reference methods should be detailed to allow results from different laboratories to be compared.</p
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