Imperial College London

Dr Kenan Direk

Faculty of MedicineSchool of Public Health

Principal Data Manager







St Marys Multiple BuildingsSt Mary's Campus





Publication Type

9 results found

Huebner GM, Oreszczyn T, Direk K, Hamilton Iet al., 2022, The relationship between the built environment and subjective wellbeing – Analysis of cross-sectional data from the English Housing Survey, Journal of Environmental Psychology, Vol: 80, ISSN: 0272-4944

This paper assesses how subjective wellbeing is related to housing and neighbourhood characteristics, controlling for personal variables. The secondary data analysis was based on the English Housing Survey, 2017: Housing Stock Data and the English Housing Survey: Fuel Poverty Dataset, 2017, collected in the period April 2016 to March 2018 (N = 9205). Subjective wellbeing was measured with four variables - life satisfaction, the perception of things being worthwhile in life, feeling happy and feeling anxious - that were dichotomized into low and high wellbeing. Logistic regression analysis showed that personal variables are most strongly related to wellbeing but that both housing and neighbourhood variables are also significantly related to it. Finding it difficult to keep the living room warm, being in fuel poverty, and finding it difficult to meet heating costs were associated with lower wellbeing. Low area satisfaction and not feeling safe were also significantly associated with lower wellbeing. The effects of variables are not constant across all four wellbeing measures used which raises the question ‘which wellbeing’ should be addressed. Results also showed that targeting householders with lowest wellbeing and hence in greatest need of wellbeing interventions based on publicly available data would be challenging. Finally, the research community needs to address methodological challenges around identifying the most appropriate covariates, defining wellbeing and considering the measurement of key variables.

Journal article

Huebner GM, Watson NE, Direk K, McKenna E, Webborn E, Hollick F, Elam S, Oreszczyn Tet al., 2021, Survey study on energy use in UK homes during Covid-19, Buildings and Cities, Vol: 2, Pages: 952-969

To contain the spread of Covid-19, governments across the world imposed partial or complete lockdowns. National energy demand decreased in periods of lockdowns; however, as people spent more time at home, residential energy use likely increased. This paper reports the results of a UK survey study (N = 1016 participants) about their energy-use practices during the first lockdown in March 2020. The results indicated that self-reported heating behaviours did not substantially change during lockdown. Regarding appliance use, in particular the duration of usage for televisions and computing equipment has increased and has spread more over the day. Being less able to manage financially was correlated with a greater usage of the smart meter in-home display and a greater attempt to save energy was positively correlated with greater usage of the in-home display, though correlations were small. In summary, the results indicate that home energy-use behaviours, in particular around heating, did not change as much as might have been expected, which might at least partly be explained by the comparatively warm weather during the first lockdown. Corroborating the survey findings with actual energy data is the next essential step to understand findings in more detail. POLICY RELEVANCE Governments are developing policies to support the transition to net zero. Covid-19 has accelerated the transition in behaviours such as home working which may result in a ‘new normal’ energy behaviour and will need to be taken account when planning for net zero. Insights into the changes in behaviour during lockdown indicate it would be oversimplified to assume that electricity and gas use have increased in all homes because of a stay-at-home order. Self-reported heating did not change, whereas electrical appliance usage increased. The sample composition of the household is important for understanding the energy implications. In this study, about half the households did not spend more time

Journal article

Nanjo A, Evans H, Direk K, Hayward AC, Story A, Banerjee Aet al., 2020, Prevalence, incidence, and outcomes across cardiovascular diseases in homeless individuals using national linked electronic health records, EUROPEAN HEART JOURNAL, Vol: 41, Pages: 4011-4020, ISSN: 0195-668X

Journal article

Zewinger S, Kleber ME, Tragante V, McCubrey RO, Schmidt AF, Direk K, Laufs U, Werner C, Koenig W, Rothenbacher D, Mons U, Breitling LP, Brenner H, Jennings RT, Petrakis I, Triem S, Klug M, Filips A, Blankenberg S, Waldeyer C, Sinning C, Schnabel RB, Lackner KJ, Vlachopoulou E, Nygård O, Svingen GFT, Pedersen ER, Tell GS, Sinisalo J, Nieminen MS, Laaksonen R, Trompet S, Smit RAJ, Sattar N, Jukema JW, Groesdonk HV, Delgado G, Stojakovic T, Pilbrow AP, Cameron VA, Richards AM, Doughty RN, Gong Y, Cooper-DeHoff R, Johnson J, Scholz M, Beutner F, Thiery J, Smith JG, Vilmundarson RO, McPherson R, Stewart AFR, Cresci S, Lenzini PA, Spertus JA, Olivieri O, Girelli D, Martinelli NI, Leiherer A, Saely CH, Drexel H, Mündlein A, Braund PS, Nelson CP, Samani NJ, Kofink D, Hoefer IE, Pasterkamp G, Quyyumi AA, Ko Y-A, Hartiala JA, Allayee H, Tang WHW, Hazen SL, Eriksson N, Held C, Hagström E, Wallentin L, Åkerblom A, Siegbahn A, Karp I, Labos C, Pilote L, Engert JC, Brophy JM, Thanassoulis G, Bogaty P, Szczeklik W, Kaczor M, Sanak M, Virani SS, Ballantyne CM, Lee V-V, Boerwinkle E, Holmes MV, Horne BD, Hingorani A, Asselbergs FW, Patel RS, GENIUS-CHD consortium, Krämer BK, Scharnagl H, Fliser D, März W, Speer Tet al., 2017, Relations between lipoprotein(a) concentrations, LPA genetic variants, and the risk of mortality in patients with established coronary heart disease: a molecular and genetic association study., Lancet Diabetes Endocrinol, Vol: 5, Pages: 534-543

BACKGROUND: Lipoprotein(a) concentrations in plasma are associated with cardiovascular risk in the general population. Whether lipoprotein(a) concentrations or LPA genetic variants predict long-term mortality in patients with established coronary heart disease remains less clear. METHODS: We obtained data from 3313 patients with established coronary heart disease in the Ludwigshafen Risk and Cardiovascular Health (LURIC) study. We tested associations of tertiles of lipoprotein(a) concentration in plasma and two LPA single-nucleotide polymorphisms ([SNPs] rs10455872 and rs3798220) with all-cause mortality and cardiovascular mortality by Cox regression analysis and with severity of disease by generalised linear modelling, with and without adjustment for age, sex, diabetes diagnosis, systolic blood pressure, BMI, smoking status, estimated glomerular filtration rate, LDL-cholesterol concentration, and use of lipid-lowering therapy. Results for plasma lipoprotein(a) concentrations were validated in five independent studies involving 10 195 patients with established coronary heart disease. Results for genetic associations were replicated through large-scale collaborative analysis in the GENIUS-CHD consortium, comprising 106 353 patients with established coronary heart disease and 19 332 deaths in 22 studies or cohorts. FINDINGS: The median follow-up was 9·9 years. Increased severity of coronary heart disease was associated with lipoprotein(a) concentrations in plasma in the highest tertile (adjusted hazard radio [HR] 1·44, 95% CI 1·14-1·83) and the presence of either LPA SNP (1·88, 1·40-2·53). No associations were found in LURIC with all-cause mortality (highest tertile of lipoprotein(a) concentration in plasma 0·95, 0·81-1·11 and either LPA SNP 1·10, 0·92-1·31) or cardiovascular mortality (0·99, 0·81-1·2 and 1·13, 0·90-1·40, respectively) o

Journal article

Denaxas S, Direk K, Gonzalez-Izquierdo A, Pikoula M, Cakiroglu A, Moore J, Hemingway H, Smeeth Let al., 2017, Methods for enhancing the reproducibility of biomedical research findings using electronic health records., BioData Min, Vol: 10, ISSN: 1756-0381

BACKGROUND: The ability of external investigators to reproduce published scientific findings is critical for the evaluation and validation of biomedical research by the wider community. However, a substantial proportion of health research using electronic health records (EHR), data collected and generated during clinical care, is potentially not reproducible mainly due to the fact that the implementation details of most data preprocessing, cleaning, phenotyping and analysis approaches are not systematically made available or shared. With the complexity, volume and variety of electronic health record data sources made available for research steadily increasing, it is critical to ensure that scientific findings from EHR data are reproducible and replicable by researchers. Reporting guidelines, such as RECORD and STROBE, have set a solid foundation by recommending a series of items for researchers to include in their research outputs. Researchers however often lack the technical tools and methodological approaches to actuate such recommendations in an efficient and sustainable manner. RESULTS: In this paper, we review and propose a series of methods and tools utilized in adjunct scientific disciplines that can be used to enhance the reproducibility of research using electronic health records and enable researchers to report analytical approaches in a transparent manner. Specifically, we discuss the adoption of scientific software engineering principles and best-practices such as test-driven development, source code revision control systems, literate programming and the standardization and re-use of common data management and analytical approaches. CONCLUSION: The adoption of such approaches will enable scientists to systematically document and share EHR analytical workflows and increase the reproducibility of biomedical research using such complex data sources.

Journal article

Direk K, Lau W, Small KS, Maniatis N, Andrew Tet al., 2014, ABCC5 Transporter is a Novel Type 2 Diabetes Susceptibility Gene in European and African American Populations, Annals of Human Genetics, Vol: 78, Pages: 333-344

Numerous functional studies have implicated PARL in relation to type 2 diabetes (T2D). We hypothesised that conflicting human association studies may be due to neighbouring causal variants being in linkage disequilibrium (LD) with PARL. We conducted a comprehensive candidate gene study of the extended LD genomic region that includes PARL and transporter ABCC5 using three data sets (two European and one African American), in relation to healthy glycaemic variation, visceral fat accumulation and T2D disease.We observed no evidence for previously reported T2D association with Val262Leu or PARL using array and fine-map genomic and expression data. By contrast, we observed strong evidence of T2D association with ABCC5 (intron 26) for European and African American samples (P = 3E−07) and with ABCC5 adipose expression in Europeans [odds ratio (OR) = 3.8, P = 2E−04]. The genomic location estimate for the ABCC5 functional variant, associated with all phenotypes and expression data (P = 1E−11), was identical for all samples (at Chr3q 185,136 kb B36), indicating that the risk variant is an expression quantitative trait locus (eQTL) with increased expression conferring risk of disease. That the association with T2D is observed in populations of disparate ancestry suggests the variant is a ubiquitous risk factor for T2D.

Journal article

Vehof J, Kozareva D, Hysi PG, Harris J, Nessa A, Williams FK, Bennett DLH, McMahon SB, Fahy SJ, Direk K, Spector TD, Hammond CJet al., 2013, Relationship between dry eye symptoms and pain sensitivity., JAMA Ophthalmol, Vol: 131, Pages: 1304-1308

IMPORTANCE: Dry eye disease (DED) is common, but little is known about factors contributing to symptoms of dry eye, given the poor correlation between these symptoms and objective signs at the ocular surface. OBJECTIVE: To explore whether pain sensitivity plays a role in patients' experience of DED symptoms. DESIGN, SETTING, AND PARTICIPANTS: A population-based cross-sectional study of 1635 female twin volunteers, aged 20 to 83 years, from the TwinsUK adult registry. MAIN OUTCOMES AND MEASURES: Dry eye disease was diagnosed if participants had at least 1 of the following: (1) a diagnosis of DED by a clinician, (2) the prescription of artificial tears, and/or (3) symptoms of dry eyes for at least 3 months. A subset of 689 women completed the Ocular Surface Disease Index (OSDI) questionnaire. Quantitative sensory testing using heat stimulus on the forearm was used to assess pain sensitivity (heat pain threshold [HPT]) and pain tolerance (heat pain suprathreshold [HPST]). RESULTS: Of the 1622 participants included, 438 (27.0%) were categorized as having DED. Women with DED showed a significantly lower HPT (P = .03) and HPST (P = .003)--and hence had higher pain sensitivity--than those without DED. A strong significant association between the presence of pain symptoms on the OSDI and the HPT and HPST was found (P = .008 for the HPT and P = .003 for the HPST). In addition, participants with an HPT below the median had DED pain symptoms almost twice as often as those with an HPT above the median (31.2% vs 20.5%; odds ratio, 1.76; 95% CI, 1.15-2.71; P = .01). CONCLUSIONS AND RELEVANCE: High pain sensitivity and low pain tolerance are associated with symptoms of DED, adding to previous associations of the severity of tear insufficiency, cell damage, and psychological factors. Management of DED symptoms is complex, and physicians need to consider the holistic picture, rather than simply treating ocular signs.

Journal article

Direk K, Cecelja M, Astle W, Chowienczyk P, Spector TD, Falchi M, Andrew Tet al., 2013, The relationship between DXA-based and anthropometric measures of visceral fat and morbidity in women, BMC CARDIOVASCULAR DISORDERS, Vol: 13, ISSN: 1471-2261

Journal article

Direk K, Lau W, Small K, Elding H, Maniatis N, Andrew Tet al., 2011, Investigating the PARL / ABCC5 gene region as a susceptibility locus for type 2 diabetes, International Congress of Human Genetics

The PARL gene coding for a mitochondrial protease, has recently been identified as a potential candidate gene for type 2 diabetes (Walder et al., 2005; Civitarese et al., 2010). There is conflicting evidence regarding the association between the non-synonymous Leu262Val (rs3732581) polymorphism in PARL and fasting insulin serum levels - the initial observation (Walder et al., 2005) has failed to replicate in subsequent studies (Fawcett et al., 2006; Powell et al., 2008; Hatunic et al., 2009). However, functional evidence (Walder et al., 2005; Civitarese et al., 2010) exists that empirically demonstrates down-regulation of PARL expression in diabetic subjects. Mitochondrial dysfunction is thought to be a major etiological component of insulin resistance (Turner & Heilbronn, 2008; Patti & Corvera, 2010). Using TwinsUK cohort data, approximately 3000 twins were genotyped for rs3732581. No association was observed between fasting serum insulin and glucose levels and any genotyped PARL SNPs, including Leu262Val. Analyses were conducted using individual SNP association and a multi-locus Malecot model for the PARL/ABCC5 gene region. Using the Wellcome Trust Case Control Consortium (WTCCC) type 2 diabetes data, we also observed no evidence of genotypic association with PARL. However, strong evidence of association for type 2 diabetes was observed in the neighbouring gene ABCC5, immediately upstream of PARL (Malecot model χ2 = 21.7, p = 1.54 x 10-6). In addition, despite no evidence of association with fasting insulin levels in the TwinsUK cohort, ABCC5 and PARL expression levels for subcutaneous adipose tissue samples measured for 776 twins from the same cohort, did show evidence of association (p =< 10-3) between ABCC5 expression and ABCC5 SNPs, but not between PARL expression and PARL SNPs. As PARL and ABCC5 are situated in a region of substantial linkage disequilibrium (LD), we tested the hypothesis that the association between rs3732581 and insulin may be

Conference paper

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