Dr Uy Hoang

Introduction: This article is part of the Focus Theme of Methods of Information in Medicine on ?Managing Interoperability and Complexity in Health Systems?. Background: Data heterogeneity is one of the critical problems in analysing, reusing, sharing or linking datasets. Metadata, whilst adding semantic description to data, adds an additional layer of complexity in the heterogeneity of metadata descriptors themselves. This can be managed by using a pre-defined model to extract the metadata, but this can reduce the richness of the data extracted. Objectives: to link the South London Stroke Register (SLSR), the London Air Pollution toolkit (LAP) and the Clinical Practice Research Datalink (CPRD) while transforming data into the Web Ontology Language (OWL) format. Methods: We used a four-step transformation approach to prepare meta-descriptions, convert data, generate and update meta-classes and generate OWL files. We validated the correctness of the transformed OWL files by issuing queries and assessing results against the original source data. Results: We have transformed SLSR LAP and CPRD into OWL format. The linked SLSR and CPRD OWL file contains 3644 male and 3551 female patients. The linked SLSR and LAP OWL file shows that there are 17 out of 35 outward postcode areas, where no overlapping data can support further analysis between SLSR and LAP. Conclusions: Our approach generated a resultant set of transformed OWL formatted files, which are in a query-able format to run individual queries, or can be easily converted into other more suitable formats for further analysis, and the transformation was faithful with no loss or anomalies. Our results have shown that the proposed method provides a promising general approach to address data heterogeneity.

Objectives Our aim was to report on trends in hospitalisation rates for pertussis in England from the 1960s to 2011; and to provide context for the recent unexpected activity of Bordetella pertussis in the UK. Design A retrospective analysis of English national Hospital Episode Statistics (HES, 1968?2011) and the Oxford Record Linkage Study (ORLS, 1963?2011) for people admitted to hospital with whooping cough. Setting England and the Oxford Record Linkage Study area. Main outcome measures Age- and gender-specific hospital admission rates, and summary age- and sex-standardised rates, for people aged under 25 years per 100,000 population in each age group. Results Admission rates declined from the 1960s to the early 1970s. For example, the standardised rates were 12.8 (95% confidence interval 11.2?14.5) per 100,000 in England in 1968 and 4.0 (3.0?4.9) per 100,000 in 1973. They then increased to reach 45.0 (41.4?48.6) per 100,000 in 1978 and 47.4 (43.7?51.1) in 1982. From the late 1980s, admission rates continued to decline, falling to between 1 and 4 per 100,000 in each of the years between 2003 and 2011. While the trend in hospital admissions closely followed that in notifications, the annual ratio between these two measures was not consistent ranging from 1.07 (95% confidence interval 1.00?1.14) to 4.03 (3.79?4.27) notifications per admission over the last 10 years. Conclusions Epidemics of whooping cough in the late 1970s and early 1980s were associated with a significant rise in hospital admission rates. Current admission rates are low, by historical comparison. Vaccine programmes must continue to be fully implemented in order to improve control of pertussis activity.

Film has become an integral part of everyday life in the UK, shaping our beliefs, culture and attitudes. Here, Stella Botchway from the Nuffield Department of Population Health, the University of Oxford and Uy Hoang from Kings College London, Public Health Film society and Nuffield Department of Population Health, University of Oxford discuss how film can be of interest to the public health community as well as the place for public health in film with reflections on the UK?s first public health film festival.

OBJECTIVE: It is well recognised that variation in the geographical distribution of multiple sclerosis (MS) exists. Early studies in England have shown the disease to have been more common in the North than the South. However, this could be an artefact of inaccurate diagnosis and ascertainment, and recent data on MS prevalence are lacking. In the present study, data were analysed to provide a more contemporary map of the distribution of MS in England and, as infectious mononucleosis (IM) has been shown to be associated with the risk of MS, the geographical distribution of IM with that of MS was compared. METHODS: Analysis of linked statistical abstracts of hospital data for England between 1999 and 2005. RESULTS: There were 56,681 MS patients. The admission rate for MS was higher in females (22/10(5); 95% CI 21.8 to 22.3) than males (10.4/10(5); 95% CI 10.2 to 10.5). The highest admission rate for MS was seen for residents of Cumbria and Lancashire (North of England) (20.1/10(5); 95% CI 19.3 to 20.8) and the lowest admission rate was for North West London residents (South of England) (12.4/10(5); 95% CI 11.8 to 13.1). The geographical distributions of IM and MS were significantly correlated (weighted regression coefficient (r (w))=0.70, p<0.0001). Admission rates for MS were lowest in the area quintile with the highest level of deprivation and they were also lowest in the area quintile with the highest percentage of population born outside the UK. A significant association between northernliness and MS remained after adjustment for deprivation and UK birthplace. CONCLUSIONS: The results show the continued existence of a latitude gradient for MS in England and show a correlation with the distribution of IM. The data have implications for healthcare provision, because lifetime costs of MS exceed £1 million per case in the UK, as well as for studies of disease causality and prevention.

Background and Purpose?Outdoor air pollution represents a potentially modifiable risk factor for stroke. We examined the link between ambient pollution and mortality up to 5 years poststroke, especially for pollutants associated with vehicle exhaust. Methods?Data from the South London Stroke Register, a population-based register covering an urban, multiethnic population, were used. Hazard ratios (HR) for a 1 interquartile range increase in particulate matter <2.5 µm diameter (PM2.5) and PM <10 µm (PM10) were estimated poststroke using Cox regression, overall and broken down into exhaust and nonexhaust components. Analysis was stratified for ischemic and hemorrhagic strokes and was further broken down by Oxford Community Stroke Project classification. Results?The hazard of death associated with PM2.5 up to 5 years after stroke was significantly elevated (P=0.006) for all strokes (HR=1.28; 95% confidence interval [CI], 1.08?1.53) and ischemic strokes (HR, 1.32; 95% CI, 1.08?1.62). Within ischemic subtypes, PM2.5 pollution increased mortality risk for total anterior circulation infarcts by 2-fold (HR, 2.01; 95% CI, 1.17?3.48; P=0.012) and by 78% for lacunar infarcts (HR, 1.78; 95% CI, 1.18?2.66; P=0.006). PM10 pollution was associated with 45% increased mortality risk for lacunar infarct strokes (HR, 1.45; 95% CI, 1.06?2.00; P=0.022). Separating PM2.5 and PM10 into exhaust and nonexhaust components did not show increased mortality. Conclusions?Exposure to certain outdoor PM pollution, particularly PM2.5, increased mortality risk poststroke up to 5 years after the initial stroke.

BACKGROUND: The Academic Clinical Fellowship (ACF) programme in England was introduced in 2007 to support the training of clinical academics. AIM: To report on career plans and views of ACF trainees. METHOD: Questionnaire survey of trainees appointed in 2008. RESULTS: Of 102 responders, 63% expected to work eventually wholly in clinical academic posts, 34% in clinical service posts with some teaching and research, and none in clinical service posts with no teaching or research. Of factors that had influenced the choice of an academic career 'a great deal', 83% of responders cited having a 'varied and stimulating career', 79% the 'intellectual environment' of academic departments, 78% the 'challenge of research' and 62% the 'stimulation of teaching'. The most important factors that might dissuade them from eventually pursuing an academic career were 'difficulty obtaining research grants' (specified by 42%), followed by 'competing pressures in the three areas of research, clinical work and teaching', lack of 'pay parity with NHS colleagues', and concerns about adequate availability of academic posts at senior levels. CONCLUSIONS: The responders were highly motivated by the challenges of academic work. However, policymakers need to consider what, if anything, might realistically be done about potentially demotivating factors.

OBJECTIVE: To calculate mortality of people with eating disorders (ED) in England, relative to that of people of the same age and sex, between 2001 and 2009. We were specifically interested in mortality amongst adolescents and young adults (15-24 years), and older adults (25-44 years). METHOD: We analyzed a NHS Hospital Episode Statistics (HES) dataset for all England, linked to death registrations, to calculate age- and sex-specific discharge rates for people with a diagnosis of ED and their subsequent mortality by one year after discharge. RESULTS: The standardized mortality ratio (SMR) for adolescents and young adults with a diagnosis of ED was 7.8 (95% confidence interval: 4.4-11.2). This compares with an SMR for people of the same age with schizophrenia of 10.2 (8.3-12.2), with bipolar disorder of 3.6 (1.1-6.1, and with depression of 4.5 (3.6-5.3). Of the ED, the SMR for anorexia nervosa (AN) in people aged 15-24 was 11.5 (6.0-17.0), for bulimia nervosa (BN) was 4.1 (0-8.7), and eating disorders not otherwise specified (ED NOS) was 1.4 (0-4.0). For older adults aged 25-44 years, the SMR for ED was 10.7 (7.7-13.6). Specifically, for AN was 14.0 (9.2-18.8), for BN was 7.7 (3.5-11.9), and ED NOS was 4.7 (1.4-8.0), for schizophrenia was 7.3 (6.6-7.9), for bipolar disorder was 4.3 (3.5-5.1) and for depression was 4.9 (4.6-5.3). No deaths were recorded below 15 years of age. DISCUSSION: This study confirms the high SMR associated with ED, notably with anorexia and bulimia.

Objective To quantify the extent of ?avoidable mortality? in those with schizophrenia or bipolar disorder and to quantify the effect a reduction in these might have on the mortality gap associated with severe mental illness. Method A cohort was studied of people aged <75 years, discharged from inpatient care with schizophrenia or bipolar disorder in 2006?2007, and followed up for 365 days. Standardised mortality ratios (SMRs) were calculated followed by hypothetical SMRs, estimating the residual mortality gap if ?avoidable? causes and suicide in the cohorts had occurred at the same level as those in the general population. Results Avoidable deaths comprised 60.2% and 59.2% of all deaths in the schizophrenia and bipolar disorder cohorts respectively. All-cause SMRs were 4.23 (95% CI 3.85?4.60) and 2.60 (2.21?3.00) respectively. After discounting the excess attributable to avoidable causes and suicide, the SMRs fell to 2.38 (2.09?2.66) and 1.66 (1.35?1.98) respectively. Conclusion Bringing mortality from avoidable causes and suicide down to general population levels would reduce the overall mortality excess in severe mental illness substantially, by about 50%, but would not eliminate it. Other underlying factors beyond those conventionally considered as ?avoidable? need further research.

A 50-year-old patient who presented with abdominal pain was found to have a suspicious 8×6×9?cm mass in the left upper abdomen on imaging. A complete surgical resection of the mass was performed subsequently and pathology revealed a gastrointestinal stromal tumour. The patient was started on adjuvant Imatinib following the resection. Four years later, reimaging demonstrated no evidence of disease and adjuvant therapy was discontinued. Nine months following discontinuation of Imatinib, routine blood work revealed marked leucocytosis. Further work up including peripheral smear and bone marrow biopsy showed findings consistent with chronic myelogenous leucaemia. Imatinib was restarted and the patient's white cell counts returned to normal range within a month.

Objective Controversy exists over the diagnosis and prevalence of pediatric bipolar disorder (PBD). Although several small surveys suggest that the rate of the PBD diagnosis in clinical settings is higher in the United States than in other countries, no comprehensive cross-national comparisons of clinical practice have been performed. Here, we used longitudinal national datasets from 2000 to 2010 to compare US and English hospital discharge rates for PBD in patients aged 1 to 19 years. Method We used the English National Health Service (NHS) Hospital Episode Statistics (HES) dataset and the United States National Hospital Discharge Survey (NHDS) to compare US and English discharge rates for PBD (bipolar I disorder [BP-I], bipolar II disorder [BP-II], bipolar disorder not otherwise specified [BP-NOS], and cyclothymia). We also conducted cross-national comparisons for all other psychiatric diagnoses in youth and for adults with bipolar disorder (BD). Results There was a 72.1-fold difference in discharge rates for PBD in youth between the United States and England (United States, 100.9 per 100,000 population, 95% confidence interval = 98.1?103.8, versus England, 1.4 per 100,000 population, 95% CI = 1.4?1.5). After controlling for cross-national differences in length of stay, discharge rates for PBD remained 12.5 times higher in the United States than in England. For all other child psychiatric diagnoses, the discharge rate was 3.9-fold higher, and for adults with BD 7.2-fold higher, in the United States than in England. Conclusion The disparity between US and English discharge rates for PBD is markedly greater than the disparity for child psychiatric discharge rates overall and for adult rates of BD. This suggests that the difference in discharge rates for PBD may be due to differing diagnostic practices for PBD in the United States versus in England.

Background Airborne particulate matter (PM) consists of particles from diverse sources, including vehicle exhausts. Associations between short-term PM changes and stroke incidence have been shown. Cumulative exposures over several months, or years, are less well studied; few studies examined ischaemic subtypes or PM source. Aims This study combines a high resolution urban air quality model with a population-based stroke register to explore associations between long-term exposure to PM and stroke incidence. Method Data from the South London Stroke Register from 2005?2012 were included. Poisson regression explored association between stroke incidence and long-term (averaged across the study period) exposure to PM2.5(PM < 2.5 ¼m diameter) and PM10(PM < 10 ¼m), nitric oxide, nitrogen dioxide, nitrogen oxides and ozone, at the output area level (average population = 309). Estimates were standardised for age and sex and adjusted for socio-economic deprivation. Models were stratified for ischaemic and haemorrhagic strokes and further broken down by Oxford Community Stroke Project classification and Trial of ORG 10172 in Acute Stroke Treatment (TOAST) classification. Results 1800 strokes were recorded (incidence = 42.6/100,000 person-years). No associations were observed between PM and overall ischaemic or haemorrhagic incidence. For an interquartile range increase in PM2.5, there was a 23% increase in incidence (Incidence rate ratio = 1.23 (95%CI: 1.03?1.44)) of total anterior circulation infarcts (TACI) and 20% increase for PM2.5 from exhausts (1.20(1.01?1.41)). There were similar associations with PM10, overall (1.21(1.01?1.44)) and from exhausts (1.20(1.01?1.41)). TACI incidence was not associated with non-exhaust sources. There were no associations with other stroke subtypes or pollutants. Conclusion Outdoor air pollution, particularly that arising from vehicle exhausts, may increase risk of TACI but not other stroke subtypes.

Objective To estimate the conversion rate from unipolar depression (ICD10 codes F32?F33) to bipolar disorder (BP) (ICD10 codes F31) in an English national cohort. It was hypothesised that early-onset BP (age <18 years) is a more severe form of the disorder, with a more rapid, and higher rate of conversion from depression to BP. Method This record linkage study used English national Hospital Episode Statistics (HES) covering all NHS inpatient and day case admissions between 1999 and 2011. Results The overall rate of conversion from depression to BP for all ages was 5.65% (95% CI: 5.48?5.83) over a minimum 4-year follow-up period. The conversion rate from depression to BP increased in a linear manner with age from 10?14 years ? 2.21% (95% C: 1.16?4.22) to 30?34 years ? 7.06% (95% CI: 6.44?7.55) (F1,23=77.6, p=0.001, R2=0.77). The time to conversion was constant across the age range. The rate of conversion was higher in females (6.77%; 95% CI: 6.53?7.02) compared to males, (4.17%; 95% CI: 3.95?4.40) (Ç2=194, p<0.0001), and in those with psychotic depression 8.12% (95% CI: 7.65?8.62) compared to non-psychotic depression 5.65% (95% CI: 5.48?5.83) (Ç2=97.0, p<0.0001). Limitations The study was limited to hospital discharges and diagnoses were not standardised. Conclusions Increasing conversion rate from depression to bipolar disorder with age, and constant time for conversion across the age range does not support the notion that early-onset BP is a more severe form of the disorder.

Objective To investigate whether the mortality gap has reduced in recent years between people with schizophrenia or bipolar disorder and the general population. Design Record linkage study. Setting English hospital episode statistics and death registration data for patients discharged 1999-2006. Participants People discharged from inpatient care with a diagnosis of schizophrenia or bipolar disorder, followed for a year after discharge. Main outcome measures Age standardised mortality ratios at each time, comparing the mortality in people with schizophrenia or bipolar disorder with mortality in the general population. Poisson test of trend was used to investigate trend in ratios over time. Results By 2006 standardised mortality ratios in the psychiatric cohorts were about double the population average. The mortality gap widened over time. For people discharged with schizophrenia, the ratio was 1.6 (95% confidence interval 1.5 to 1.8) in 1999 and 2.2 (2.0 to 2.4) in 2006 (P<0.001 for trend). For bipolar disorder, the ratios were 1.3 (1.1 to 1.6) in 1999 and 1.9 (1.6 to 2.2) in 2006 (P=0.06 for trend). Ratios were higher for unnatural than for natural causes. About three quarters of all deaths, however, were certified as natural, and increases in ratios for natural causes, especially circulatory disease and respiratory diseases, were the main components of the increase in all cause mortality. Conclusions The total burden of premature deaths from natural causes in people with schizophrenia or bipolar disorder is substantial. There is a need for better understanding of the reasons for the persistent and increasing gap in mortality between discharged psychiatric patients and the general population, and for continued action to target risk factors for both natural and unnatural causes of death in people with serious mental illness.

Background: Conflicting evidence exists about whether people with a history of nonmelanoma skin cancer (NMSC) are at higher risk of subsequent primary malignant cancers than those without. Methods: An all England record-linked hospital and mortality dataset spanning from 1999 to 2011 was used. We constructed two cohorts: one that comprised people with a history of NMSC (502,490 people), and a control cohort that comprised people without. We ?followed up? these two cohorts electronically to determine observed and expected numbers of people with subsequent primary cancers in each, based on person-years at risk, and calculated standardized risk ratios (RR). Results: Comparing the NMSC cohort with the non-NMSC cohort, the RR for all subsequent malignant cancers combined was 1.36 [95% confidence interval (CI), 1.35?1.37]. Significantly increased RRs (P < 0.05) were found for 26 of the 29 cancer types studied, in particular for salivary gland, melanoma, bone, and upper gastrointestinal tract cancers. The RRs were also particularly high when comparing younger people with and without NMSC. Conclusions: NMSC is strongly associated with a broad spectrum of other primary cancers, particularly in younger age groups. The pattern suggests a genetic or early-acquired etiologic association. Impact: These results represent what can be done using very large, linked, routinely collected administrative datasets; but such datasets lack detail. Further work to establish the mechanisms behind these associations is warranted. Cancer Epidemiol Biomarkers Prev; 23(3); 490?8. ©2014 AACR.

We conducted a nationwide record-linked study using all English NHS hospital admission data and mortality statistics from 1999 to 2011 to evaluate the risk of concurrent or subsequent bullous pemphigoid (BP) in a cohort of 2,873,720 individuals with malignant cancers, when compared with a reference cohort. We calculated standardised rate ratios (RRs) based on person-years at risk, comparing the observed and expected numbers of BP cases in the cancer cohort with those in the reference cohort. Overall, the cohort of people with a record of a malignant cancer was not found to be at greater risk of concurrent or subsequent BP than the cohort of people without a record of a malignant cancer (RR 0.96, 95 % CI 0.88?1.04), although elevated risks of BP were found in sub-cohorts of people with either kidney cancer, laryngeal cancer or lymphoid leukaemia. We also similarly analysed the risk of concurrent and subsequent malignant cancers in a cohort of people with a principal diagnosis of BP, and again found no increased risk as compared with the reference cohort (RR 1.00, 95 % CI 0.92?1.09).

Cities are constantly evolving and so are the living conditions within and between them. Rapid urbanization and the ever-growing need for housing have turned large areas of many cities into concrete landscapes that lack greenery. Green infrastructure can support human health, provide socio-economic and environmental benefits, and bring color to an otherwise grey urban landscape. Sometimes, benefits come with downsides in relation to its impact on air quality and human health, requiring suitable data and guidelines to implement effective greening strategies. Air pollution and human health, as well as green infrastructure and human health, are often studied together. Linking green infrastructure with air quality and human health together is a unique aspect of this article. A holistic understanding of these links is key to enabling policymakers and urban planners to make informed decisions. By critically evaluating the link between green infrastructure and human health via air pollution mitigation, we also discuss if our existing understanding of such interventions is enabling their uptake in practice. Both the natural science and epidemiology approach the topic of green infrastructure and human health very differently. The pathways linking health benefits to pollution reduction by urban vegetation remain unclear and that the mode of green infrastructure deployment is critical to avoid unintended consequences. Strategic deployment of green infrastructure may reduce downwind pollution exposure. However, the development of bespoke design guidelines is vital to promote and optimize greening benefits and measuring green infrastructure?s socio-economic and health benefits are key for their uptake. Greening cities to mitigate pollution effects is on the rise and these needs to be matched by scientific evidence and appropriate guidelines. We conclude that urban vegetation can facilitate broad health benefits, but there is little empirical evidence linking these benefits to air pollution reduction by urban vegetation, and appreciable efforts are needed to establish the underlying policies, design and engineering guidelines governing its deployment.