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    ABSTRACT: David S Wald speaks to Caroline Telfer, Assistant Commissioning Editor. David S Wald is a Consultant Cardiologist and Reader in Preventive Cardiology. He trained at Oxford University (UK) and Imperial College of Science and Technology, London (UK). His work combines interventional and preventive approaches to cardiovascular disease. He is currently leading a multicenter randomized trial assessing the value of preventive angioplasty in patients with acute myocardial infarction and a UK trial of a polypill for people over the age of 50 years for the prevention of ischemic heart disease and stroke.
    Future Cardiology 07/2013; 9(4):465-6. DOI:10.2217/fca.13.29
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    ABSTRACT: The aim of this study was to quantify the maternal age-specific risk for trisomy 21 mosaicism. Data were obtained on 322 trisomy 21 diagnoses with mosaicism and 27,943 simple trisomy 21 diagnoses recorded in the National Down Syndrome Cytogenetic Register from 1989 to 2009 in England and Wales. Trisomy 21 cases with mosaicism have a mean maternal age of 33.1 years compared to 35.0 years for free trisomy 21 cases. Sixty-seven percent of trisomy 21 diagnoses with mosaicism are maternal age dependent, with a risk 0.8% that of the corresponding maternal age specific risk for simple trisomy 21. However 33% (0.8 per 100,000 births) are not maternal age dependent, indicating that maternal age is not the only risk factor for mosaicism. Trisomy 21 diagnoses with mosaicism are more likely to be female than free trisomy 21 diagnoses, however there was no association of fetal sex with maternal age which indicates that there is another factor involved in the presence of mosaicism not associated with maternal age, but associated with fetal sex. © 2012 Wiley Periodicals, Inc.
    American Journal of Medical Genetics Part A 10/2012; 158A(10):2482-4. DOI:10.1002/ajmg.a.35571
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    ABSTRACT: Dividing people into 'hypertensives' and 'normotensives' is commonplace but problematic. The relationship between blood pressure and cardiovascular disease is continuous. The Prospective Studies Collaboration analysis shows a continuous straight line dose-response relationship across the entire population down to blood pressure levels of 115 mmHg systolic and 75 mmHg diastolic, the confidence limits on the individual data points being sufficiently narrow to exclude even a minor deviation from a linear relationship. Meta-analysis of randomized controlled trials shows that blood pressure-lowering drugs produce similar proportional reductions in risk of coronary heart disease (CHD) and stroke irrespective of pre-treatment blood pressure, down to levels of 110 mmHg systolic and 70 mmHg diastolic. There are also now sufficient trial data to show a statistically significant risk reduction in 'normotensive' people without known vascular disease on entry. The straight line (log-linear) relationship means that the benefit derived from lowering blood pressure is proportional to existing risk, so the decision on whom to treat with blood pressure-lowering drugs should depend on a person's overall absolute risk irrespective of blood pressure. In primary prevention, basing treatment on age alone rather than overall absolute risk entails little loss of efficacy and may be preferred on the basis of simplicity and avoidance of anxiety in telling people they are at elevated risk.
    Annals of Medicine 06/2012; 44 Suppl 1(S1):S30-5. DOI:10.3109/07853890.2012.687832
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    ABSTRACT: This study describes the characteristics of karyotypes leading to phenotypic Down syndrome (trisomy 21) in 29,256 cases diagnosed between 1989 and 2009 in England and Wales included in the National Down Syndrome Cytogenetic Register (NDSCR). The frequency of occurrence of the different karyotypes, proportions diagnosed prenatally, sex ratios, mean maternal age, and proportions of mothers with recurrences were analyzed. Nearly 97% of all cases were free trisomy 21; 2.9% contributory trisomy 21, 0.3% double or triple aneuploidies; 1% of all were mosaics. Mean maternal age of free trisomy 21 cases was 35 years, 54% were male, and 1% of mothers had recurrences. Free trisomy 21 mosaics had a lower mean maternal age (33 years), a lower proportion of males (39.5%), and 2.5% of mothers had recurrences. The majority of contributory translocations were Robertsonian or rea (21;21). Their mothers were younger, particularly those of Robertsonian translocations (28 years). Of the Robertsonian der (14;21) translocations of known parental origin, 54% were de novo, 41% maternal and 5% paternal and 15.8% of mothers of those of maternal origin had recurrences. Multiple aneuploidies have the highest proportion of males (67%), highest proportion of mosaics (40%), a mean maternal age of 37 years, and no mothers had a recurrence. The size of this national register allowed the frequency of occurrence of the rarer karyotypes of Down syndrome to be estimated and their epidemiology described.
    American Journal of Medical Genetics Part A 05/2012; 158A(5):1151-7. DOI:10.1002/ajmg.a.35248
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    ABSTRACT: To assess the value of population screening for adult hypothyroidism. Healthy people attending for a general health assessment. A thyroid-stimulating hormone (TSH) measurement was performed on people attending for a general health assessment (women aged 50-79 [35-49 with a family history of thyroid disease] and men aged 65-79). Those with TSH levels above 4.0 mU/L were invited to join a randomized double-blind crossover trial of thyroxine and placebo, each given in random order for four months. On entry a second blood sample was collected for a TSH measurement after the end of the trial to determine whether this would help select individuals for thyroxine treatment. The daily thyroxine dose started at 50 µg and if necessary was increased to achieve a TSH level of 0.6-2.0 mU/L. There were 341 (8%) people with a TSH level above 4.0 mU/L, 110 met eligibility criteria (64 agreed to participate), and 56 (49 women, 7 men) completed the trial. Among the 15 individuals with a repeat TSH measurement above 4.5 mU/L, 11 reported feeling better on thyroxine than placebo and none reported feeling better on placebo (P = 0.001; four felt no different), indicating that in this group 73% benefitted (i.e. 11/15; 95% CI 45-92%). The main symptoms relieved were tiredness and loss of memory. There was no indication of harm. In the 41 individuals with a repeat serum TSH of 4.5 mU/L or less: 10 reported feeling better on thyroxine than placebo and 16 better on placebo (P = 0.42, 15 felt no different). Thus about 8% of men and women in the specified age groups had a TSH above 4.0 mU/L, and of these about a quarter had a repeat TSH above 4.5 mU/L, of whom about half would benefit from thyroxine treatment. The results indicate that screening for hypothyroidism would be worthwhile. Approximately 1% of people screened would have a better quality of life. Pilot screening programmes for adult hypothyroidism are justified.
    Journal of Medical Screening 01/2010; 17(4):164-9. DOI:10.1258/jms.2010.010057
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    ABSTRACT: To describe trends in the numbers of Down's syndrome live births and antenatal diagnoses in England and Wales from 1989 to 2008. Design and setting The National Down Syndrome Cytogenetic Register holds details of 26488 antenatal and postnatal diagnoses of Down's syndrome made by all cytogenetic laboratories in England and Wales since 1989. Antenatal screening, diagnosis, and subsequent termination of Down's syndrome pregnancies. The number of live births with Down's syndrome. Despite the number of births in 1989/90 being similar to that in 2007/8, antenatal and postnatal diagnoses of Down's syndrome increased by 71% (from 1075 in 1989/90 to 1843 in 2007/8). However, numbers of live births with Down's syndrome fell by 1% (752 to 743; 1.10 to 1.08 per 1000 births) because of antenatal screening and subsequent terminations. In the absence of such screening, numbers of live births with Down's syndrome would have increased by 48% (from 959 to 1422), since couples are starting families at an older age. Among mothers aged 37 years and older, a consistent 70% of affected pregnancies were diagnosed antenatally. In younger mothers, the proportions of pregnancies diagnosed antenatally increased from 3% to 43% owing to improvements in the availability and sensitivity of screening tests. Since 1989, expansion of and improvements in antenatal screening have offset an increase in Down's syndrome resulting from rising maternal age. The proportion of antenatal diagnoses has increased most strikingly in younger women, whereas that in older women has stayed relatively constant. This trend suggests that, even with future improvements in screening, a large number of births with Down's syndrome are still likely, and that monitoring of the numbers of babies born with Down's syndrome is essential to ensure adequate provision for their needs.
    BMJ (online) 10/2009; 339:b3794. DOI:10.1136/bmj.b3794
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    ABSTRACT: To determine the quantitative efficacy of different classes of blood pressure lowering drugs in preventing coronary heart disease (CHD) and stroke, and who should receive treatment. Meta-analysis. Data source Medline (1966-2007). Randomised trials of blood pressure lowering drugs recording CHD events and strokes. 108 trials studied differences in blood pressure between study drug and placebo (or control group not receiving the study drug) ("blood pressure difference trials"), and 46 trials compared drugs ("drug comparison trials"). Seven trials with three randomised groups fell into both categories. The results were interpreted in the context of those expected from the largest published meta-analysis of cohort studies, totalling 958 000 people. 464 000 people defined into three mutually exclusive categories: participants with no history of vascular disease, a history of CHD, or a history of stroke. In the blood pressure difference trials beta blockers had a special effect over and above that due to blood pressure reduction in preventing recurrent CHD events in people with a history of CHD: risk reduction 29% (95% confidence interval 22% to 34%) compared with 15% (11% to 19%) in trials of other drugs. The extra effect was limited to a few years after myocardial infarction, with a risk reduction of 31% compared with 13% in people with CHD with no recent infarct (P=0.04). In the other blood pressure difference trials (excluding CHD events in trials of beta blockers in people with CHD), there was a 22% reduction in CHD events (17% to 27%) and a 41% (33% to 48%) reduction in stroke for a blood pressure reduction of 10 mm Hg systolic or 5 mm Hg diastolic, similar to the reductions of 25% (CHD) and 36% (stroke) expected for the same difference in blood pressure from the cohort study meta-analysis, indicating that the benefit is explained by blood pressure reduction itself. The five main classes of blood pressure lowering drugs (thiazides, beta blockers, angiotensin converting enzyme inhibitors, angiotensin receptor blockers, and calcium channel blockers) were similarly effective (within a few percentage points) in preventing CHD events and strokes, with the exception that calcium channel blockers had a greater preventive effect on stroke (relative risk 0.92, 95% confidence interval 0.85 to 0.98). The percentage reductions in CHD events and stroke were similar in people with and without cardiovascular disease and regardless of blood pressure before treatment (down to 110 mm Hg systolic and 70 mm Hg diastolic). Combining our results with those from two other studies (the meta-analyses of blood pressure cohort studies and of trials determining the blood pressure lowering effects of drugs according to dose) showed that in people aged 60-69 with a diastolic blood pressure before treatment of 90 mm Hg, three drugs at half standard dose in combination reduced the risk of CHD by an estimated 46% and of stroke by 62%; one drug at standard dose had about half this effect. The present meta-analysis also showed that drugs other than calcium channel blockers (with the exception of non-cardioselective beta blockers) reduced the incidence of heart failure by 24% (19% to 28%) and calcium channel blockers by 19% (6% to 31%). With the exception of the extra protective effect of beta blockers given shortly after a myocardial infarction and the minor additional effect of calcium channel blockers in preventing stroke, all the classes of blood pressure lowering drugs have a similar effect in reducing CHD events and stroke for a given reduction in blood pressure so excluding material pleiotropic effects. The proportional reduction in cardiovascular disease events was the same or similar regardless of pretreatment blood pressure and the presence or absence of existing cardiovascular disease. Guidelines on the use of blood pressure lowering drugs can be simplified so that drugs are offered to people with all levels of blood pressure. Our results indicate the importance of lowering blood pressure in everyone over a certain age, rather than measuring it in everyone and treating it in some.
    BMJ (online) 02/2009; 338(7705):b1665. DOI:10.1136/bmj.b1665
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    ABSTRACT: The objective of this study is to determine the risk of fetal loss (spontaneous abortion or stillbirth) following a prenatal diagnosis of trisomy 13 (T13; Patau syndrome) or trisomy 18 (T18; Edwards syndrome). Five regional congenital anomaly registers in England and Wales provided details on the outcomes of 198 pregnancies prenatally diagnosed with T13 and 538 prenatally diagnosed with T18. For each pregnancy the time from prenatal diagnosis until birth, miscarriage or termination occurred was calculated and these times were analyzed using Kaplan-Meier survival functions. Our results showed that between 12 weeks gestation and term an estimated 49% (95% CI: 29-73%) of pregnancies diagnosed with T13 and 72% (61-81%) of pregnancies diagnosed with T18 ended in a miscarriage or stillbirth. Between 18 weeks and term the proportions were 42% (18-72%) for T13 and 65% (57-79%) for T18 and between 24 weeks and term the proportions were 35% (5-70%) for T13 and 59% (49-77%) for T18. Male fetuses with T18 appeared to be more likely to be lost than female fetuses. These are the most precise estimates currently available for the risk of loss in a general population. These estimates should be useful in counseling women who are carrying an affected fetus and knowing the risk of fetal loss is essential to compare the performance of prenatal screening programs occurring in the first and second trimester.
    American Journal of Medical Genetics Part A 04/2008; 146(7):827-32. DOI:10.1002/ajmg.a.32220
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    ABSTRACT: The birth prevalence of sex chromosome trisomies (SCT), that is individuals with an XYY, XXY or XXX sex chromosome constitution, is traditionally based on six surveys of unselected newborns carried out in the 1960s and early 1970s. All three SCTs had a prevalence of 1 in 1000 same sex births. We re-examined these prevalences based on additional cytogenetic studies of newborn surveys, spontaneous abortions, perinatal deaths and prenatal diagnoses. The more recent newborn surveys suggest there has been an increase in the prevalence of XXYs, but not of the other two SCTs since the original newborn series. The prevalence of XXYs has risen from 1.09 to 1.72 per 1000 male births (P=0.023). We suggest that such an increase, in the absence of an increase in the prevalence of XXX, is unlikely to be due to increased maternal age. As XXY is the only chromosome abnormality known where a substantial proportion ( approximately 50%) arise as the result of non-disjunction at the first paternal meiotic division, we speculate that some factor may be interfering with pairing and/or recombination of the sex bivalent at the paternal MI division.
    European Journal of HumanGenetics 03/2008; 16(2):163-70. DOI:10.1038/sj.ejhg.5201956
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    ABSTRACT: Increasing intake of folic acid would be a relatively cheap and simple way of reducing heart disease, if it works. Can we draw a definitive conclusion from the current evidence?
    BMJ (online) 12/2006; 333(7578):1114-7. DOI:10.1136/bmj.39000.486701.68
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