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Thesis (PhD)--Stellenbosch University, 2012. / ENGLISH ABSTRACT: Left ventricular hypertrophy (LVH) is a strong independent predictor of cardiovascular morbidity and mortality, while its regression is associated with an improved clinical prognosis. It is, therefore, vital to elucidate and fully comprehend the mechanisms that contribute to LVH development and to identify markers that indicate a strong predisposition to the development of severe cardiac hypertrophy, before its occurrence. Hypertrophic cardiomyopathy (HCM) serves as a model to investigate LVH development. This primary cardiac disease is characterised by LVH in the absence of increased external loading conditions and is caused by defective sarcomeric proteins, as a result of mutations within the genes encoding these proteins. However, the hypertrophic phenotype of HCM is largely complex, as we see strong variability in the extent and distribution of LVH in HCM, even in individuals with the same disease-causing mutation from the same family; this points toward the involvement of additional genetic and environmental modifiers. Components of the renin-angiotensin-aldosterone system (RAAS) influence LVH indirectly, through their key role in blood pressure regulation, but also directly, due to the direct cellular hypertrophic effects of some RAAS components. Previous genetic association studies aimed at investigating the contribution of RAAS variants to LVH were largely centred on a subset of polymorphisms within the genes encoding the angiotensin converting enzyme (ACE) and angiotensin II type 1 receptor genes, while the renin section and RAAS components downstream from ACE remained largely neglected. In addition, most previous studies have reported relatively small individual effects for a small subset of RAAS variants on LVH. In the present study we, therefore, employ a family-based genetic association analysis approach to investigate the contribution of the entire RAAS to this complex hypertrophic phenotype by exploring both the individual as well as the compound effects of 84 variants within 22 RAAS genes, in a cohort of 388 individuals from 27 HCM families, in which either of three HCM-founder mutations segregate. During the course of this explorative study, we identified a number of RAAS variants that had significant effects on hypertrophy in HCM, whether alone or within the context of a multi-variant haplotype. Through single variant association analyses, we identified variants within the genes encoding angiotensinogen, renin-binding protein, the mannose-6-phosphate receptor, ACE, ACE2, angiotensin receptors 1 and 2, the mineralocorticoid receptor, as well as the epithelial sodium channel and the Na+/K+-ATPase β-subunits, that contribute to hypertrophy in HCM. Using haplotype-based association analyses, we were able to identify haplotypes within the genes encoding for renin, the mannose-6-phosphate receptor, angiotensin receptor 1, the mineralocorticoid receptor, epithelial sodium channel and Na+/K+-ATPase α- and β subunits, as well as the CYP11B1/B2 locus, that contribute significantly to LVH. In addition, we found that some RAAS variants and haplotypes had statistically significantly different effects in the three HCM founder mutation groups. Finally, we used stepwise selection to identify a set of nine risk-alleles that together predicted a 127.80 g increase in left ventricular mass, as well as a 13.97 mm increase in maximum interventricular septal thickness and a 14.67 mm increase in maximum left ventricular wall thickness in the present cohort. In contrast, we show that a set of previously identified “pro-LVH” polymorphisms rather poorly predicted LVH in the present South African cohort. This is the first RAAS investigation, to our knowledge, to provide clear quantitative effects for a subset of RAAS variants indicative of a risk for LVH development that are representative of the entire pathway. Our findings suggest that the eventual hypertrophic phenotype of HCM is modulated by the compound effect of a number of RAAS modifier loci, where each polymorphism makes a modest contribution towards the eventual phenotype. Research such as that presented here provides a basis on which future studies can build improved risk profiles for LVH development within the context of HCM, and ultimately in all patients with a risk of cardiac hypertrophy. / AFRIKAANSE OPSOMMING: Linker ventrikulêre hipertrofie (LVH) is 'n sterk onafhanklike voorspeller van kardiovaskulêre morbiditeit en mortaliteit, terwyl LVH regressie verband hou met ‘n verbeterde kliniese voorspelling. Dit is dus noodsaaklik om die meganismes wat bydra to LVH ontwikkeling ten volle te verstaan en merkers wat 'n sterk geneigdheid tot die ontwikkeling van ernstige kardiale hipertrofie te identifiseer, voordat dit voorkom. Hipertrofiese kardiomiopatie (HKM) dien as 'n model om LVH ontwikkeling te ondersoek. Hierdie primêre hartsiekte word gekenmerk deur LVH en word meestal veroorsaak deur foutiewe sarkomeer proteïene as gevolg van mutasies binne die gene wat kodeer vir hierdie proteïene. Die hipertrofiese fenotipe van HKM is egter grootliks kompleks; ons sien, by voorbeeld, sterk veranderlikheid in die omvang en die verspreiding van LVH in HKM, selfs in individue met dieselfde siekte-veroorsakende mutasie binne dieselfde gesin, wat dui op die betrokkenheid van addisionele genetiese en omgewing modifiseerders. Komponente van die renien-angiotensien-aldosteroon sisteem (RAAS) beïnvloed LVH indirek, deur middel van hul belangrike rol in bloeddruk regulasie, maar ook direk, as gevolg van die direkte sellulêre hipertrofiese gevolge van sommige RAAS komponente. Vorige genetiese assosiasie studies wat daarop gemik was om die bydrae van RAAS variante LVH te ondersoek, was hoofsaaklik gesentreer op 'n groepie polimorfismes binne die gene wat kodeer vir die “angiotensin converting enzyme” (ACE) en angiotensien II tipe 1-reseptor gene, terwyl die renien gedeelte en RAAS komponente stroomaf van ACE meestal nie ondersoek was nie. Daarbenewens het die meeste vorige studies relatief klein individuele gevolge gerapporteer vir 'n klein groepie RAAS variante op LVH. In die huidige studie het ons dus 'n familie-gebaseerde genetiese assosiasie-analise benadering gebruik om die bydrae van die hele RAAS tot hierdie komplekse hipertrofiese fenotipe te ondersoek deur 'n studie van die individuele-, sowel as die saamgestelde effekte van 84 variante binne 22 RAAS gene, in 'n groep van 388 individue vanaf 27 HKM families, waarin een van drie HCM-stigter mutasies seggregeer. Gedurende die loop van hierdie studie het ons 'n aantal RAAS variante wat ‘n beduidende uitwerking op HKM hipertrofie geïdentifiseer, hetsy alleen of binne die konteks van' n multi-variant haplotipe. Deur middel van enkele variant assosiasie toetsing het ons variante geïdentifiseer binne die gene wat kodeer vir angiotensinogen, renien-bindende proteïen, die mannose-6-fosfaat reseptor, ACE, ACE2, angiotensien reseptore 1 en 2, die mineralokortikoïd reseptor, sowel as die epiteel natrium kanaal en Na+/ K+-ATPase β-subeenhede, wat bydra tot HKM hipertrofie. Deur die gebruik van haplotipe-gebaseerde assosiasie ontleding was ons in staat om haplotipes te identifiseer binne die gene wat kodeer vir renien, die mannose-6-fosfaat reseptor angiotensien reseptor 1, die mineralokortikoïd reseptor, epiteel natrium kanaal en die Na+/ K+-ATPase α-en β subeenhede, sowel as die CYP11B1/B2 lokus, wat aansienlik bydra tot LVH. Verder het ons bevind dat sommige RAAS variante en haplotipes statisties beduidende verskillende effekte gehad het in die drie HKM stigter mutasie groepe. Laastens, het ons stapsgewyse seleksie gebruik om 'n stel van nege risiko-allele wat saam' n toename van 127.80 g in linker ventrikulêre massa, sowel as 'n 13.97 mm toename in maksimum ventrikulêre septale dikte, en' n 14.67 mm verhoging in maksimum linker ventrikulêre wanddikte voorspel, te identifiseer in die huidige kohort. In teenstelling hiermee wys ons dat 'n stel van voorheen geïdentifiseerde "pro-LVH" polimorfismes swakker gevaar het as LVH-voorspellers in die huidige Suid-Afrikaanse kohort. Hierdie is die eerste RAAS ondersoek, tot ons kennis, wat ‘n duidelike kwantitatiewe gevolge vir 'n stel RAAS variante wat ‘n verhoogde risiko tot LVH ontwikkeling aandui, wat verteenwoordigend is van die hele RAAS. Ons bevindinge dui daarop dat die uiteindelike hipertrofiese fenotipe van HKM gemoduleer word deur die saamgestelde effek van 'n aantal RAAS wysiger loki, waar elke polimorfisme ' n beskeie bydrae maak tot die uiteindelike fenotipe. Navorsing soos dié wat hier aangebied word dien as 'n basis waarop toekomstige studies kan bou vir ‘n verbeterde risiko-profiel vir LVH ontwikkeling binne die konteks van die HKM, en uiteindelik in alle pasiënte met' n verhoogde risiko vir kardiale hipertrofie.

Cathepsin S is a protease important in major histocompatibility complex (MHC) class II antigen presentation and also in degrading the extracellular matrix. Studies, most of them experimental, have shown that cathepsin S is involved in different pathological conditions such as obesity, inflammation, atherosclerosis, diabetes, and cancer.    The overall hypothesis of this report is that high levels of circulating cathepsin S, is a biomarker that reflects pathology induced by inflammation and obesity. The overall aim of this report was to investigate possible associations between circulating cathepsin S, inflammation, glucometabolic disturbance, and its associated diseases in the community. As cathepsin S appears to be a novel risk marker for several pathological conditions, we also wanted to examine the effect of dietary intervention on circulating cathepsin S concentrations.    This thesis is based on data from three community-based cohorts, the Uppsala longitudinal study of adult men (ULSAM), the prospective investigation of the vasculature in Uppsala seniors (PIVUS), and a post-hoc study from the randomized controlled NORDIET trial.    In the first study, we identified a cross-sectional positive association between serum cathepsin S and two markers of cytokine-mediated inflammation, CRP and IL-6. These associations were similar in non-obese individuals. In longitudinal analyses, higher cathepsin S at baseline was associated with higher CRP and IL-6 levels after six years of follow-up. In the second study, we identified a cross-sectional association between increased serum levels of cathepsin S and reduced insulin sensitivity. These associations were similar in non-obese individuals. No significant association was observed between cathepsin S and insulin secretion. In longitudinal analysis, higher cathepsin S levels were associated with an increased risk of developing diabetes during the six-year follow-up. In the third study, we found that higher serum levels of cathepsin S were associated with increased mortality risk. Moreover, in the ULSAM cohort, serum cathepsin S was independently associated with cause-specific mortality from cardiovascular disease and cancer. In the fourth study, we identified that adherence to an ad libitum healthy Nordic diet for 6 weeks slightly decreased the levels of plasma cathepsin S in normal or marginally overweight individuals, relative to the control group. Changes in circulating cathepsin S concentrations were correlated with changes in body weight, LDL-C, and total cholesterol.    Conclusion: This thesis shows that circulating cathepsin S is a biomarker that independently reflects inflammation, insulin resistance, the risk of developing diabetes, and mortality risk. Furthermore, a Nordic diet moderately reduced cathepsin S levels in normal-weight and overweight men and women. This effect may be partially mediated by diet-induced weight loss and possibly by reduced LDL-C concentrations.

For over a century, there have been suggestions of a link between what is currently called bipolar disorder and cardiovascular mortality. In the contemporary epidemiological literature, this risk has been confirmed and approximates twice that expected based on age and gender. To date, however, this information has come primarily from clinical samples, which carry considerable risk of selection bias. The studies contained in this dissertation sought to assess this relationship using methods less vulnerable to selection bias and to determine the role that course of illness and treatments for illness may play in the development of vascular disease. In a nationally representative sample, we confirmed a link between mood disorders and vascular disease, which was particularly pronounced in women with bipolar disorder. In subsequent studies, a dose-response relationship between the duration of clinically significant hypomanic or manic symptoms and both cardiovascular mortality and endothelial function was seen. While medication exposure did not appear related to mortality or endothelial function, first generation antipsychotics were associated with arterial stiffness, an effect apparently mediated by elevations in blood pressure. In cross-sectional samples, our data suggests that vasculopathy is not present early in the course of bipolar disorder although is much greater than expected later in the course of illness. This dissertation purports that vasculopathy develops over the long-term course of bipolar disorder, is proportional to symptom burden, and is influenced by health behaviors and treatments. These findings may provide opportunities for clinicians and those afflicted to intervene to address this excess risk of vascular morbidity and mortality.

<p>The aim was to contribute to the optimal use of the resting ECG by exploring, in middle-aged and elderly men, the development and regression of ECG abnormalities; the prognostic value of the ECG for cardiovascular disease compared to conventional risk factors; and the impact of age at baseline and follow-up time for prediction of cardiovascular disease.</p><p>It was based on the Uppsala Study of Adult Men cohort that was started in 1970. Participants were examined at ages 50, 70, 77, and 82, with annual updates on mortality and in-hospital morbidity using national registries. </p><p>The studies indicated that the prevalence of silent MI and frequency of regression of major Q/QS patterns may be higher than previously believed. Considering that persistent T wave abnormalities and ST segment depression carried twice as high a risk for future cardiovascular disease (CVD) mortality as new or reverted abnormalities, the results suggested that serial electrocardiograms (ECG) would contribute to proper risk assessment. Also, the inclusion of ischemic ECG findings significantly increased the predictive power of the Framingham score at age 70 for CVD. </p><p>While hypertension and dyslipidemia were consistent long-term risk factors for myocardial infarction at ages 50 and 70, the length of follow-up period and age at baseline affected the predictive power of ECG abnormalities, fasting insulin, BMI, and smoking. </p><p>For stroke, midlife values for blood pressure and ECG abnormalities retained prognostic value over long follow-up periods, even though they improved when re-measured in elderly participants. ApoB/apoA1 ratio, driven by apoA1, was associated with stroke in elderly but not middle-aged men. Hyperinsulinemia and diabetes mellitus were more specifically associated with ischemic stroke than with any-cause stroke. </p><p>In summary, the resting ECG carried prognostic information beyond conventional risk factors. Even though the low prevalence of ECG abnormalities at the age of 50 calls into question the role of the ECG as a screening tool, the additional risk information it carries with it justifies its regular and repeated registration above the age of 50. </p>

The aim was to contribute to the optimal use of the resting ECG by exploring, in middle-aged and elderly men, the development and regression of ECG abnormalities; the prognostic value of the ECG for cardiovascular disease compared to conventional risk factors; and the impact of age at baseline and follow-up time for prediction of cardiovascular disease. It was based on the Uppsala Study of Adult Men cohort that was started in 1970. Participants were examined at ages 50, 70, 77, and 82, with annual updates on mortality and in-hospital morbidity using national registries. The studies indicated that the prevalence of silent MI and frequency of regression of major Q/QS patterns may be higher than previously believed. Considering that persistent T wave abnormalities and ST segment depression carried twice as high a risk for future cardiovascular disease (CVD) mortality as new or reverted abnormalities, the results suggested that serial electrocardiograms (ECG) would contribute to proper risk assessment. Also, the inclusion of ischemic ECG findings significantly increased the predictive power of the Framingham score at age 70 for CVD. While hypertension and dyslipidemia were consistent long-term risk factors for myocardial infarction at ages 50 and 70, the length of follow-up period and age at baseline affected the predictive power of ECG abnormalities, fasting insulin, BMI, and smoking. For stroke, midlife values for blood pressure and ECG abnormalities retained prognostic value over long follow-up periods, even though they improved when re-measured in elderly participants. ApoB/apoA1 ratio, driven by apoA1, was associated with stroke in elderly but not middle-aged men. Hyperinsulinemia and diabetes mellitus were more specifically associated with ischemic stroke than with any-cause stroke. In summary, the resting ECG carried prognostic information beyond conventional risk factors. Even though the low prevalence of ECG abnormalities at the age of 50 calls into question the role of the ECG as a screening tool, the additional risk information it carries with it justifies its regular and repeated registration above the age of 50.

Cathepsin S is a protease important in major histocompatibility complex (MHC) class II antigen presentation and also in degrading the extracellular matrix. Studies, most of them experimental, have shown that cathepsin S is involved in different pathological conditions such as obesity, inflammation, atherosclerosis, diabetes, and cancer. The overall hypothesis of this report is that high levels of circulating cathepsin S, is a biomarker that reflects pathology induced by inflammation and obesity. The overall aim of this report was to investigate possible associations between circulating cathepsin S, inflammation, glucometabolic disturbance, and its associated diseases in the community. As cathepsin S appears to be a novel risk marker for several pathological conditions, we also wanted to examine the effect of dietary intervention on circulating cathepsin S concentrations. This thesis is based on data from three community-based cohorts, the Uppsala longitudinal study of adult men (ULSAM), the prospective investigation of the vasculature in Uppsala seniors (PIVUS), and a post-hoc study from the randomized controlled NORDIET trial. In the first study, we identified a cross-sectional positive association between serum cathepsin S and two markers of cytokine-mediated inflammation, CRP and IL-6. These associations were similar in non-obese individuals. In longitudinal analyses, higher cathepsin S at baseline was associated with higher CRP and IL-6 levels after six years of follow-up. In the second study, we identified a cross-sectional association between increased serum levels of cathepsin S and reduced insulin sensitivity. These associations were similar in non-obese individuals. No significant association was observed between cathepsin S and insulin secretion. In longitudinal analysis, higher cathepsin S levels were associated with an increased risk of developing diabetes during the six-year follow-up. In the third study, we found that higher serum levels of cathepsin S were associated with increased mortality risk. Moreover, in the ULSAM cohort, serum cathepsin S was independently associated with cause-specific mortality from cardiovascular disease and cancer. In the fourth study, we identified that adherence to an ad libitum healthy Nordic diet for 6 weeks slightly decreased the levels of plasma cathepsin S in normal or marginally overweight individuals, relative to the control group. Changes in circulating cathepsin S concentrations were correlated with changes in body weight, LDL-C, and total cholesterol. Conclusion: This thesis shows that circulating cathepsin S is a biomarker that independently reflects inflammation, insulin resistance, the risk of developing diabetes, and mortality risk. Furthermore, a Nordic diet moderately reduced cathepsin S levels in normal-weight and overweight men and women. This effect may be partially mediated by diet-induced weight loss and possibly by reduced LDL-C concentrations.

L'insuffisance rénale chronique (IRC) est associée à une importante morbidité et mortalité cardio-vasculaire, à laquelle participent la dysfonction endothéliale. Les patients IRC présentent de plus une susceptibilité accrue aux thromboses qu’elles soient veineuses ou artérielles. Les toxines urémiques sont des solutés s'accumulant dans le sérum et les tissus des patients IRC. Parmi elles, les toxines urémiques liées aux protéines ont une toxicité endothéliale démontrée in vitro. Nous avons démontré que l’indoxyl sulfate (IS) et l’indole acetic acide (IAA), deux toxines liées aux protéines provoquent un phénotype pro coagulant de cellules endothéliales en culture via une production accrue de facteur tissulaire (FT). Le facteur tissulaire est un facteur membranaire procoagulant qui initie la cascade de la coagulation en activant le facteur VII via la voie extrinsèque. Nous avons aussi démontré que la production de FT passe par une voie cellulaire préalablement connue pour son implication dans les processus de detoxification : la voie de l’aryl hydrocarbon receptor (AHR). Dans notre travail, nous montrons que l’IS et l’IAA ont un comportement similaire à l’intoxication par la dioxine. Le lien entre FT et AHR n’avait jamais été démontré auparavant. En conclusion, l’IS et l’IAA participent à la dysfonction endothéliale des patients IRC et à la surmortalité cardiovasculaire, en augmentant la production endothéliale de FT et ainsi en provoquant un phénotype pro coagulant des cellules endothéliales. La voie AHR constitue une cible thérapeutique très intéressante dans la problématique de la surmortalité cardiovasculaire des patients IRC. / Chronic kidney disease (CKD) is associated with significant morbidity and cardiovascular mortality, which involves chronic inflammation, oxidative stress and endothelial dysfunction. CKD patients have a higher risk of venous or arterial thrombosis compared to general population. Uremic toxins are molecules that accumulate in the serum and organs of CKD patients. Among them, protein-bound uremic toxins are poorly removed by dialysis, and their endothelial toxicity had been well demonstrated in vitro. In this thesis, we demonstrated that indoxyl sulfate (IS) and indole acetic acid (IAA ), two protein-bound toxins can cause a pro coagulant phenotype of cultured endothelial cells through an increased production of tissue factor (TF ) Tissue factor is a membrane procoagulant factor that initiates the coagulation cascade by activating factor VII via the extrinsic pathway. We also demonstrated that TF increase was produced via a cellular pathway previously known to be involved in the detoxification processes: the aryl hydrocarbon receptor pathway (AHR) . The canonical ligand of AHR is dioxin, well known for its cardiovascular adverse effects. In this work, we showed that IS and IAA had a “dioxin- like effect”. The link between FT and AHR had never been shown earlier. CKD constitutes an endogenous situation similar to dioxin poisoning. In conclusion, the IS and IAA are involved in endothelial dysfunction in CKD patients and cardiovascular mortality by increasing the endothelial production of TF and thus causing a pro- coagulant phenotype of endothelial cells. AHR pathway is a very interesting therapeutic target in the problematic of cardiovascular mortality in CKD patients .

O transtorno de humor bipolar (THB) é uma condição incapacitante e caracterizada pela presença de episódios de humor associados a alterações de cognição e de comportamento. Indivíduos com diagnóstico de THB estão particularmente propensos a múltiplas condições metabólicas. Em uma parcela dos pacientes acometidos pela doença observa-se a neuroprogressão do quadro, com alterações no campo da neuroimagem e de biomarcadores – citocinas inflamatórias, estresse oxidativo e neurotrofinas. Tais fatores parecem também relacionar-se ao aumento do risco cardiovascular (RCV) observado nessa população, visto que a doença cardiovascular (DCV) constitui a principal causa de morte em pacientes com THB. Mesmo conhecendo tal estatística, há escassez de literatura científica abordando avaliação cardiovascular em pacientes bipolares. Dessa forma, a presente tese tem o objetivo de melhorar o entendimento da associação entre neuroprogressão e doença cardiovascular. Para tal, inicialmente conduzimos uma revisão da literatura englobando variáveis associadas ao estadiamento e à neuroprogressão, sobretudo aspectos que se referem a biomarcadores, neuroimagem, cognição, funcionalidade e resposta ao tratamento. Em seguida, foi realizado estudo clínico com o objetivo de avaliar a prevalência de doença aterosclerótica coronariana através do uso do escore de cálcio coronariano (ECC) em pacientes ambulatoriais bipolares tipo 1. Os pacientes incluídos eram bipolares tipo 1, todos eutímicos e tendo assinado o termo de consentimento. Os escores de cálcio foram adquiridos utilizando um scanner Aquilion 64 CXL (Toshiba Medical Systems) e a quantificação realizada através do método de Agatston. Em nosso estudo verificou-se que pacientes com ECC positivo eram mais velhos (média 55.2 anos; p=0.001) e tinham uma média maior de internações psiquiátricas prévias (media 4.7; p=0.04) quando comparados ao grupo com ECC negativo, além de também haver uma associação positiva entre ECC e número de internações psiquiátricas prévias entre toda a amostra do estudo (p<0.001). Nossos resultados sugerem a associação entre idade e maiores escores coronarianos, além da relação entre cálcio coronariano e número de internacões psiquiátricas prévias. É possível que este achado relacione-se ao fato de que pacientes em estágios mais avançados da doença tenham maior carga inflamatória que, juntamente com os fatores de risco para DCV, justificaria o aumento do RCV, sugerindo um possível link entre neuroprogressão no THB e aterosclerose coronariana acelerada. / Bipolar disorder (BD) is a disabling condition characterized by the presence of mood episodes associated with changes in cognition and behavior. Individuals diagnosed with BD are particularly prone to multiple metabolic conditions. In a portion of the patients affected by the disease the neuroprogression is observed, with alterations in the field of neuroimaging and of biomarkers - inflammatory cytokines, oxidative stress and neurotrophins. These factors also seem to be related to the increased cardiovascular risk (CVR) observed in this population, since cardiovascular disease (CVD) is the main cause of death in patients with BD. Even knowing this statistic, there is a paucity of scientific literature addressing cardiovascular evaluation in bipolar patients. Thus, the present thesis aims to improve the understanding of the association between neuroprogression and cardiovascular disease. To this objective, we initially conducted a literature review encompassing variables associated with staging and neuroprogression, especially aspects that refer to biomarkers, neuroimaging, cognition, functionality and response to treatment. Afterwards, a clinical study was performed to evaluate the prevalence of coronary atherosclerotic disease through the use of coronary calcium score (CCS) in outpatient bipolar type 1 patients. The patients included were diagnosed as BD type 1, all of them euthymic and signed the consent form. Calcium scores were acquired using an Aquilion 64 CXL scanner (Toshiba Medical Systems) and quantification performed using the Agatston method. In our study, patients with CCS positive were older (mean 55.2 years; p = 0.001) and had a higher mean of previous psychiatric hospitalizations (mean 4.7, p = 0.04) when compared to the CCS negative group, and there was also a positive association between CCS and number of previous psychiatric hospitalizations among the entire study sample (p<0.001). Our results suggest the association between age and higher coronary scores, as well as the relationship between coronary calcium and the number of previous psychiatric hospitalizations. It is possible that this finding is related to the fact that patients in more advanced stages of the disease have a higher inflammatory load that, together with the risk factors for CVD, would justify the increase of CVR, suggesting a possible link between neuroprogression in BD and accelerated coronary atherosclerosis.

<b>Background:</b> 'Competing risks' are events that either preclude or alter the probability of experiencing the primary study outcome(s). Many standard survival models fail to account for competing risks, introducing an unknown level of bias in their measures of absolute and relative risk. Individuals with type 2 diabetes mellitus (T2DM) and albuminuria are at increased risk of multiple competing causes of mortality, including cardiovascular disease (CVD), cancer and renal disease, yet studies to date have not implemented competing risks methodology. <b>Aim:</b> Using albuminuria in T2DM as a case study, this Thesis set out to quantify differences between standard- and competing-risks-adjusted survival analysis estimates of absolute and relative risk for the outcomes of cardiovascular and cancer mortality. <b>Methods:</b> 86,962 patients aged &ge;35 years with T2DM present on or before 2005 were identified in the Clinical Practice Research Datalink. To quantify differences in measures of absolute risk, cumulative risk estimates for cardiovascular and cancer mortality from standard survival analysis methods (Kaplan-Meier estimator) were compared to those from competing-risks-adjusted methods (cumulative incidence competing risk estimator). Cumulative risk estimates were stratified by patient albuminuria level (normoalbuminuria vs albuminuria). To quantify differences in measures of relative risk, estimates for the effect of albuminuria on the relative hazards of cardiovascular and cancer mortality were compared between standard cause-specific hazard (CSH) models (Cox-proportional-hazards regression), competing risk CSH models (unstratified Lunn-McNeil model), and competing risk subdistribution hazard (SDH) models (Fine-Gray model). <b>Results:</b> Patients with albuminuria, compared to those with normoalbuminuria, were older (p&LT;0.001), had higher systolic blood pressure (p&LT;0.001), had worse glycaemic control (p&LT;0.001), and were more likely to be current or ex-smokers (p&LT;0.001). Over the course of nine years of follow-up 22,512 patients died; 8,800 from CVD, 5,239 from cancer, and 8,473 from other causes. Median follow-up was 7.7 years. In patients with normoalbuminuria, nine-year standard and competing-risks-adjusted cumulative risk estimates for cardiovascular mortality were 11.1% (95% confidence interval (CI): 10.8-11.5%) and 10.2% (95% CI: 9.9-10.5%), respectively. For cancer mortality, these figures were 8.0% (95% CI: 7.7-8.3%) and 7.2% (95% CI: 6.9-7.5%). In patients with albuminuria, standard and competing-risks-adjusted estimates for cardiovascular mortality were 21.8% (95% CI: 20.9-22.7%) and 18.5% (95% CI: 17.8-19.3%), respectively. For cancer mortality, these figures were 10.7% (95% CI: 10.0-11.5%) and 8.6% (8.1-9.2%). For the effect of albuminuria on cardiovascular mortality, hazard ratios from multivariable standard CSH, competing risks CSH, and subdistribution hazard ratios from competing risks SDH models were 1.75 (95% CI: 1.63-1.87), 1.75 (95% CI: 1.64-1.87), and 1.58 (95% CI: 1.48-1.69), respectively. For the effect of albuminuria on cancer mortality, these values were 1.27 (95% CI: 1.16-1.39), 1.28 (95% CI: 1.17-1.40), and 1.11 (95% CI: 1.01-1.21). <b>Conclusions:</b> When evaluating measures of absolute risk, differences between standard and competing-risks-adjusted methods were small in absolute terms, but large in relative terms. For the investigation of epidemiological relationships using relative hazards models, standard survival analysis methods produced near-identical risk estimates to the CSH competing risks methods for the clinical associations evaluated in this Thesis. For the evaluation of risk prediction using relative hazards models, CSH models produced consistently higher risk estimates than SDH models, and their use may lead to over-estimation of the predictive effect of albuminuria on either outcome. Where outcomes are less common (like cancer) CSH models provide poor estimates of risk prediction, and SDH models should be used. This research demonstrates that differences can be present between risk estimates derived using CSH and SDH methods, and that the two are not necessarily interchangeable. Moreover, such differences may be present in other clinical areas.