Two view learning: SVM-2K, theory and practice

Kernel methods make it relatively easy to define complex highdimensional feature spaces. This raises the question of how we can identify the relevant subspaces for a particular learning task. When two views of the same phenomenon are available kernel Canonical Correlation Analysis (KCCA) has been shown to be an effective preprocessing step that can improve the performance of classification algorithms such as the Support Vector Machine (SVM). This paper takes this observation to its logical conclusion and proposes a method that combines this two stage learning (KCCA followed by SVM) into a single optimisation termed SVM-2K. We present both experimental and theoretical analysis of the approach showing encouraging results and insights

Prevalence of frailty and prefrailty among community-dwelling older adults in low-income and middle-income countries: a systematic review and meta-analysis

OBJECTIVE: To systematically review the research conducted on prevalence of frailty and prefrailty among community-dwelling older adults in low-income and middle-income countries (LMICs) and to estimate the pooled prevalence of frailty and prefrailty in community-dwelling older adults in LMICs. DESIGN: Systematic review and meta-analysis. PROSPERO registration number is CRD42016036083. DATA SOURCES: MEDLINE, EMBASE, AMED, Web of Science, CINAHL and WHO Global Health Library were searched from their inception to 12 September 2017. SETTING: Low-income and middle-income countries. PARTICIPANTS: Community-dwelling older adults aged ≥60 years. RESULTS: We screened 7057 citations and 56 studies were included. Forty-seven and 42 studies were included in the frailty and prefrailty meta-analysis, respectively. The majority of studies were from upper middle-income countries. One study was available from low-income countries. The prevalence of frailty varied from 3.9% (China) to 51.4% (Cuba) and prevalence of prefrailty ranged from 13.4% (Tanzania) to 71.6% (Brazil). The pooled prevalence of frailty was 17.4% (95% CI 14.4% to 20.7%, I²=99.2%) and prefrailty was 49.3% (95% CI 46.4% to 52.2%, I²=97.5%). The wide variation in prevalence rates across studies was largely explained by differences in frailty assessment method and the geographic region. These findings are for the studies with a minimum recruitment age 60, 65 and 70 years. CONCLUSION: The prevalence of frailty and prefrailty appears higher in community-dwelling older adults in upper middle-income countries compared with high-income countries, which has important implications for healthcare planning. There is limited evidence on frailty prevalence in lower middle-income and low-income countries

Predicting dementia risk in primary care: development and validation of the Dementia Risk Score using routinely collected data

BACKGROUND: Existing dementia risk scores require collection of additional data from patients, limiting their use in practice. Routinely collected healthcare data have the potential to assess dementia risk without the need to collect further information. Our objective was to develop and validate a 5-year dementia risk score derived from primary healthcare data. METHODS: We used data from general practices in The Health Improvement Network (THIN) database from across the UK, randomly selecting 377 practices for a development cohort and identifying 930,395 patients aged 60-95 years without a recording of dementia, cognitive impairment or memory symptoms at baseline. We developed risk algorithm models for two age groups (60-79 and 80-95 years). An external validation was conducted by validating the model on a separate cohort of 264,224 patients from 95 randomly chosen THIN practices that did not contribute to the development cohort. Our main outcome was 5-year risk of first recorded dementia diagnosis. Potential predictors included sociodemographic, cardiovascular, lifestyle and mental health variables. RESULTS: Dementia incidence was 1.88 (95 % CI, 1.83-1.93) and 16.53 (95 % CI, 16.15-16.92) per 1000 PYAR for those aged 60-79 (n = 6017) and 80-95 years (n = 7104), respectively. Predictors for those aged 60-79 included age, sex, social deprivation, smoking, BMI, heavy alcohol use, anti-hypertensive drugs, diabetes, stroke/TIA, atrial fibrillation, aspirin, depression. The discrimination and calibration of the risk algorithm were good for the 60-79 years model; D statistic 2.03 (95 % CI, 1.95-2.11), C index 0.84 (95 % CI, 0.81-0.87), and calibration slope 0.98 (95 % CI, 0.93-1.02). The algorithm had a high negative predictive value, but lower positive predictive value at most risk thresholds. Discrimination and calibration were poor for the 80-95 years model. CONCLUSIONS: Routinely collected data predicts 5-year risk of recorded diagnosis of dementia for those aged 60-79, but not those aged 80+. This algorithm can identify higher risk populations for dementia in primary care. The risk score has a high negative predictive value and may be most helpful in 'ruling out' those at very low risk from further testing or intensive preventative activities

Depression, depressive symptoms and treatments in women who have recently given birth: UK cohort study

OBJECTIVES: To investigate how depression is recognised in the year after child birth and treatment given in clinical practice. DESIGN: Cohort study based on UK primary care electronic health records. SETTING: Primary care. PARTICIPANTS: Women who have given live birth between 2000 and 2013. OUTCOMES: Prevalence of postnatal depression, depression diagnoses, depressive symptoms, antidepressant and non-pharmacological treatment within a year after birth. RESULTS: Of 206 517 women, 23 623 (11%) had a record of depressive diagnosis or symptoms in the year after delivery and more than one in eight women received antidepressant treatment. Recording and treatment peaked 6-8 weeks after delivery. Initiation of selective serotonin reuptake inhibitors (SSRI) treatment has become earlier in the more recent years. Thus, the initiation rate of SSRI treatment per 100 pregnancies (95% CI) at 8 weeks were 2.6 (2.5 to 2.8) in 2000-2004, increasing to 3.0 (2.9 to 3.1) in 2005-2009 and 3.8 (3.6 to 3.9) in 2010-2013. The overall rate of initiation of SSRI within the year after delivery, however, has not changed noticeably. A third of the women had at least one record suggestive of depression at any time prior to delivery and of these one in four received SSRI treatment in the year after delivery.Younger women were most likely to have records of depression and depressive symptoms. (Relative risk for postnatal depression: age 15-19: 1.92 (1.76 to 2.10), age 20-24: 1.49 (1.39 to 1.59) versus age 30-34). The risk of depression, postnatal depression and depressive symptoms increased with increasing social deprivation. CONCLUSIONS: More than 1 in 10 women had electronic health records indicating depression diagnoses or depressive symptoms within a year after delivery and more than one in eight women received antidepressant treatment in this period. Women aged below 30 and from the most deprived areas were at highest risk of depression and most likely to receive antidepressant treatment

Rising adiposity curbing decline in the incidence of myocardial infarction: 20-year follow-up of British men and women in the Whitehall II cohort

Aims To estimate the contribution of risk factor trends to 20-year declines in myocardial infarction (MI) incidence in British men and women. Methods and results From 1985 to 2004, 6379 men and 3074 women in the Whitehall II cohort were followed for incident MI and risk factor trends. Over 20 years, the age-sex-adjusted hazard of MI fell by 74% (95% confidence interval 48-87%), corresponding to an average annual decline of 6.5% (3.2-9.7%). Thirty-four per cent (20-76%) of the decline in MI hazard could be statistically explained by declining non-HDL cholesterol levels, followed by increased HDL cholesterol (17%, 10-32%), reduced systolic blood pressure (13%, 7-24%), and reduced cigarette smoking prevalence (6%, 2-14%). Increased fruit and vegetable consumption made a non-significant contribution of 7% (-1-20%). In combination, these five risk factors explained 56% (34-112%). Rising body mass index (BMI) was counterproductive, reducing the scale of the decline by 11% (5-23%) in isolation. The MI decline and the impact of the risk factors appeared similar for men and women. Conclusion In men and women, over half of the decline in MI risk could be accounted for by favourable risk factor time trends. The adverse role of BMI emphasizes the importance of addressing the rising population BMI

Coding, Recording and Incidence of Different Forms of Coronary Heart Disease in Primary Care

To evaluate the coding, recording and incidence of coronary heart disease (CHD) in primary care electronic medical records.Data were drawn from the UK General Practice Research Database. Analyses evaluated the occurrence of 271 READ medical diagnostic codes, including categories for 'Angina', 'Myocardial Infarction', 'Coronary Artery Bypass Grafting' (CABG), 'percutaneous transluminal coronary angioplasty' (PCTA) and 'Other Coronary Heart Disease'. Time-to-event analyses were implemented to evaluate occurrences of different groups of codes after the index date.Among 300,020 participants aged greater than 30 years there were 75,197 unique occurrences of coronary heart disease codes in 24,244 participants, with 12,495 codes for incident events and 62,702 for prevalent events. Among incident event codes, 3,607 (28.87%) were for angina, 3,262 (26.11%) were for MI, 514 (4.11%) for PCTA, 161 (1.29%) for CABG and 4,951 (39.62%) were for 'Other CHD'. Among prevalent codes, 20,254 (32.30%) were for angina, 3,644 (5.81%) for MI, 34,542 (55.09%) for 'Other CHD' and 4,262 (6.80%) for CABG or PCTA. Among 3,685 participants initially diagnosed exclusively with 'Other CHD' codes, 17.1% were recorded with angina within 5 years, 5.6% with myocardial infarction, 6.3% with CABG and 8.6% with PCTA. From 2000 to 2010, the overall incidence of CHD declined, as did the incidence of angina, but the incidence of MI did not change. The frequency of CABG declined, while PCTA increased.In primary care electronic records, a substantial proportion of coronary heart disease events are recorded with codes that do not distinguish between different clinical presentations of CHD. The results draw attention to the need to improve coding practice in primary care. The results also draw attention to the importance of code selection in research studies and the need for sensitivity analyses using different sets of codes

Is the Recent Rise in Type 2 Diabetes Incidence From 1984 to 2007 Explained by the Trend in Increasing BMI?: Evidence from a prospective study of British men

OBJECTIVE - To estimate the extent to which increasing BMI may explain the rise in type 2 diabetes incidence in British men from 1984 to 2007. RESEARCH DESIGN AND METHODS - A representative cohort ratio of 6,460 British men was followed-up for type 2 diabetes incidence between 1984 (aged 45-65 years) and 2007 (aged 67-89 years). BMI was ascertained at regular intervals before and during the follow-up. RESULTS - Between 1984-1992 and 1999-2007, the age-adjusted hazard of type 2 diabetes more than doubled (hazard ratio 2.33 [95% CI 1.75-3.10]). Mean BMI rose by 1.42 kg/m2 (95% CI 1.10-1.74) between 1984 and 1999; this could explain 26% (95% CI 17-38) of the type 2 diabetes increase. CONCLUSIONS - An appreciable portion of the rise in type 2 diabetes can be attributed to BMI changes. A substantial portion remains unexplained, possibly associated with other determinants such as physical activity. This merits further research. © 2010 by the American Diabetes Association

Social Class Differences in Secular Trends in Established Coronary Risk Factors over 20 Years: A Cohort Study of British Men from 1978–80 to 1998–2000

Background: Coronary heart disease (CHD) mortality in the UK since the late 1970s has declined more markedly among higher socioeconomic groups. However, little is known about changes in coronary risk factors in different socioeconomic groups. This study examined whether changes in established coronary risk factors in Britain over 20 years between 1978-80 and 1998-2000 differed between socioeconomic groups.Methods and Findings: A socioeconomically representative cohort of 7735 British men aged 40-59 years was followed-up from 1978-80 to 1998-2000; data on blood pressure (BP), cholesterol, body mass index (BMI) and cigarette smoking were collected at both points in 4252 survivors. Social class was based on longest-held occupation in middle-age. Compared with men in non-manual occupations, men in manual occupations experienced a greater increase in BMI (mean difference=0.33 kg/m(2); 95%CI 0.14-0.53; p for interaction=0.001), a smaller decline in non-HDL cholesterol (difference in mean change=0.18 mmol/l; 95%CI 0.11-0.25, p for interaction <= 0.0001) and a smaller increase in HDL cholesterol (difference in mean change=0.04 mmol/l; 95%CI 0.02-0.06, p for interaction <= 0.0001). However, mean systolic BP declined more in manual than non-manual groups (difference in mean change=3.6; 95%CI 2.1-5.1, p for interaction <= 0.0001). The odds of being a current smoker in 1978-80 and 1998-2000 did not differ between non-manual and manual social classes (p for interaction = 0.51).Conclusion: Several key risk factors for CHD and type 2 diabetes showed less favourable changes in men in manual occupations. Continuing priority is needed to improve adverse cardiovascular risk profiles in socially disadvantaged groups in the UK

Integrative analysis of gene expression and copy number alterations using canonical correlation analysis

Supplementary Figure 1. Representation of the samples from the tuning set by their coordinates in the first two pairs of features (extracted from the tuning set) using regularized dual CCA, with regularization parameters tx = 0.9, ty = 0.3 (left panel), and PCA+CCA (right panel). We show the representations with respect to both the copy number features and the gene expression features in a superimposed way, where each sample is represented by two markers. The filled markers represent the coordinates in the features extracted from the copy number variables, and the open markers represent coordinates in the features extracted from the gene expression variables. Samples with different leukemia subtypes are shown with different colors. The first feature pair distinguishes the HD50 group from the rest, while the second feature pair represents the characteristics of the samples from the E2A/PBX1 subtype. The high canonical correlation obtained for the tuning samples with regularized dual CCA is apparent in the left panel, where the two points for each sample coincide. Nevertheless, the extracted features have a high generalization ability, as can be seen in the left panel of Figure 5, showing the representation of the validation samples. 1 Supplementary Figure 2. Representation of the samples from the tuning set by their coordinates in the first two pairs of features (extracted from the tuning set) using regularized dual CCA, with regularization parameters tx = 0, ty = 0 (left panel), and tx = 1, ty = 1 (right panel). We show the representations with respect to both the copy number features and the gene expression features in a superimposed way, where each sample is represented by tw