52 resultados para Proportional Hazards Models

em QUB Research Portal - Research Directory and Institutional Repository for Queen's University Belfast


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Background & Aims: Esophageal adenocarcinoma arises from Barrett's esophagus (BE); patients with this cancer have a poor prognosis. Identification of modifiable lifestyle factors that affect the risk of progression from BE to esophageal adenocarcinoma might prevent its development. We investigated associations among body size, smoking, and alcohol use with progression of BE to neoplasia. Methods: We analyzed data from patients with BE identified from the population-based Northern Ireland BE register, diagnosed between 1993 and 2005 with specialized intestinal metaplasia (n = 3167). Data on clinical, demographic, and lifestyle factors related to diagnosis of BE were collected from hospital case notes. We used the Northern Ireland Cancer Registry to identify which of these patients later developed esophageal adenocarcinoma, adenocarcinomas of the gastric cardia, or esophageal high-grade dysplasia. Cox proportional hazards models were used to associate lifestyle factors with risk of progression.
Results: By December 31, 2008, 117 of the patients with BE developed esophageal high-grade dysplasia or adenocarcinomas of the esophagus or gastric cardia. Current tobacco smoking was significantly associated with an increased risk of progression (hazard ratio = 2.03; 95% confidence interval, 1.29-3.17) compared with never smoking, and across all strata of smoking intensity. Alcohol consumption was not related to risk of progression. Measures of body size were infrequently reported in endoscopy reports, and body size was not associated with risk of progression.
Conclusions: Smoking tobacco increases the risk of progression to cancer or high-grade dysplasia 2-fold among patients with BE, compared with patients with BE that have never smoked. Smoking cessation strategies should be considered for patients with BE.

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To determine whether immunocomplexes (ICs) containing advanced glycation end product (AGE)-LDL (AGE-LDL) and oxidized LDL (oxLDL) contribute to the development of retinopathy over a 16-year period in subjects with type 1 diabetes.

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Objective: The incidence of oesophageal adenocarcinoma (EAC) has increased rapidly over the past 40 years and accumulating evidence suggests that obesity, as measured by body mass index (BMI), is a major risk factor. It remains unclear whether abdominal obesity is associated with EAC and gastric adenocarcinoma.

Design: Cox proportional hazards regression was used to examine associations between overall and abdominal obesity with EAC and gastric adenocarcinoma among 218 854 participants in the prospective NIHeAARP cohort.

Results: 253 incident EAC, 191 gastric cardia adenocarcinomas and 125 gastric non-cardia adenocarcinomas accrued to the cohort. Overall obesity (BMI) was positively associated with EAC and gastric
cardia adenocarcinoma risk (highest ($35 kg/m2) vs referent (18.5e<25 kg/m2); HR 2.11, 95% CI 1.09 to 4.09 and HR 3.67, 95% CI 2.00 to 6.71, respectively). Waist circumference was also positively associated with EAC and gastric cardia adenocarcinoma risk (highest vs referent; HR 2.01, 95% CI 1.35 to 3.00 and HR 2.22, 95% CI 1.43 to 3.47, respectively), whereas waist-to-hip ratio (WHR) was positively associated with EAC risk only (highest vs referent; HR 1.81, 95% CI 1.24 to 2.64) and persisted in patients with normal BMI (18.5e<25 kg/m2). Mutual adjustment of WHR and BMI attenuated
both, but did not eliminate the positive associations for either with risk of EAC. In contrast, the majority of the anthropometric variables were not associated with adenocarcinomas of the gastric non-cardia.

Conclusion Overall obesity was associated with a higher risk of EAC and gastric cardia adenocarcinoma, whereas abdominal obesity was found to be associated with increased EAC risk; even in people with normal BMI

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Endometrial cancer risk has been directly associated with glycemic load. However, few studies have investigated this link, and the etiological role of specific dietary carbohydrate components remains unclear. Our aim was to investigate associations of carbohydrate intake, glycemic index, and glycemic load with endometrial cancer risk in the US Prostate, Lung, Colorectal and Ovarian Cancer Screening Trial. Recruitment took place in 1993-2001. Over a median of 9.0 years of follow-up through 2009, 386 women developed endometrial cancer among 36,115 considered in the analysis. Dietary intakes were assessed using a 124-item diet history questionnaire. Cox proportional hazards models were applied to calculate hazard ratios and 95% confidence intervals. Significant inverse associations were detected between endometrial cancer risk and total available carbohydrate intake (hazard ratio (HR) = 0.66, 95% confidence interval (CI): 0.49, 0.90), total sugars intake (HR = 0.71, 95% CI: 0.52, 0.96), and glycemic load (HR = 0.63, 95% CI: 0.46, 0.84) when women in the highest quartile of intake were compared with those in the lowest. These inverse associations were strongest among overweight and obese women. No associations with endometrial cancer risk were observed for glycemic index or dietary fiber. Our findings contrast with previous evidence and suggest that high carbohydrate intakes and glycemic loads are protective against endometrial cancer development. Further clarification of these associations is warranted.

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BACKGROUND:

Many studies have suggested that caregiving has a detrimental impact on health. However, these conclusions are challenged by research which finds evidence of a comparative survivorship advantage, as well as work which controls for group differences in the demand for care.

METHODS:

We use a large record linkage study of England and Wales to investigate the mortality risks of carers identified in the 2001 Census. The analysis focuses on individuals aged 35-74 living with others in private households and a distinction is made between those providing 1-19 and 20 or more hours of care per week. Logit models identify differences in carers' health at baseline and postcensal survival is analysed using Cox proportional hazards models.

RESULTS:

12.2% of study members reported providing 1-19 h of care and 5.4% reported providing 20 or more hours. While carers were significantly more likely to report poorer health at baseline, survival analyses suggested that they were at a significantly lower risk of dying. This comparative advantage also held when the analyses were restricted to individuals living with at least one person with poor health.

CONCLUSIONS:

The comparative mortality advantage revealed in this analysis challenges common characterisations of carers' health and draws attention to important differences in the way carers are defined in existing analyses. The survival results are consistent with work using similar data for Northern Ireland. However, the study also affords more uniform conclusions about carers' baseline health and this provides grounds for questioning existing hypotheses about the reasons for this advantage.

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Background: Durkheim’s seminal historical study demonstrated that religious affiliation reduces suicide risk, but it is unclear whether this protective effect persists in modern, more secular societies.

Aims: To examine suicide risk according to Christian religious affiliation and by inference to examine underlying mechanisms for suicide risk. If church attendance is important, risk should be lowest for Roman Catholics and highest for those with no religion; if religiosity is important, then ‘conservative’ Christians should fare best.

Method: A 9-year study followed 1 106 104 people aged 16–74 years at the 2001 UK census, using Cox proportional hazards models adjusted for census-based cohort attributes.

Results: In fully adjusted models analysing 1119 cases of suicide, Roman Catholics, Protestants and those professing no religion recorded similar risks. The risk associated with conservative Christians was lower than that for Catholics (HR = 0.71, 95% CI 0.52–0.97).

Conclusions: The relationship between religious affiliation and suicide established by Durkheim may not pertain in societies where suicide rates are highest at younger ages. Risks are similar for those with and without a religious affiliation, and Catholics (who traditionally are characterised by higher levels of church attendance) do not demonstrate lower risk of suicide. However, religious affiliation is a poor measure of religiosity, except for a small group of conservative Christians, although their lower risk of suicide may be attributable to factors such as lower risk behaviour and alcohol consumption.

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Background There has been an increasing interest in the health effects of long
working hours, but little empirical evidence to substantiate early
10 case series suggesting an increased mortality risk. The aim of the
current study is to quantify the mortality risk associated with long
working hours and to see if this varies by employment relations and
conditions of occupation.
Methods A census-based longitudinal study of 414 949 people aged 20-59/64
15 years, working at least 35 h/week, subdivided into four occupational
classes (managerial/professional, intermediate, own account workers,
workers in routine occupations) with linkage to deaths records
over the following 8.7 years. Cox proportional hazards models were
used to examine all-cause and cause-specific mortality risk.
20 Results Overall 9.4% of the cohort worked 55 or more h/week, but this
proportion was greater in the senior management and professional
occupations and in those who were self-employed. Analysis of 4447
male and 1143 female deaths showed that hours worked were
associated with an increased risk of all-cause mortality only for
25 men working for more than 55 or more h/week in routine/semiroutine
occupations [adjusted hazard ratios (adjHR) 1.31: 95%
confidence intervals (CIs) 1.11, 1.55)] compared with their peers
working 35–40 h/week. Their equivalent risk of death from cardiovascular
disease was (adjHR 1.49: 95% CIs 1.10, 2.00).
30 Conclusions These findings substantiate and add to the earlier studies indicating
the deleterious impact of long working hours but also suggest that
the effects are moderated by employment relations or conditions of
occupation. The policy implications of these findings are discussed.

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Background: More accurate coronary heart disease (CHD) prediction, specifically in middle-aged men, is needed to reduce the burden of disease more effectively. We hypothesised that a multilocus genetic risk score could refine CHD prediction beyond classic risk scores and obtain more precise risk estimates using a prospective cohort design.

Methods: Using data from nine prospective European cohorts, including 26,221 men, we selected in a case-cohort setting 4,818 healthy men at baseline, and used Cox proportional hazards models to examine associations between CHD and risk scores based on genetic variants representing 13 genomic regions. Over follow-up (range: 5-18 years), 1,736 incident CHD events occurred. Genetic risk scores were validated in men with at least 10 years of follow-up (632 cases, 1361 non-cases). Genetic risk score 1 (GRS1) combined 11 SNPs and two haplotypes, with effect estimates from previous genome-wide association studies. GRS2 combined 11 SNPs plus 4 SNPs from the haplotypes with coefficients estimated from these prospective cohorts using 10-fold cross-validation. Scores were added to a model adjusted for classic risk factors comprising the Framingham risk score and 10-year risks were derived.

Results: Both scores improved net reclassification (NRI) over the Framingham score (7.5%, p = 0.017 for GRS1, 6.5%, p = 0.044 for GRS2) but GRS2 also improved discrimination (c-index improvement 1.11%, p = 0.048). Subgroup analysis on men aged 50-59 (436 cases, 603 non-cases) improved net reclassification for GRS1 (13.8%) and GRS2 (12.5%). Net reclassification improvement remained significant for both scores when family history of CHD was added to the baseline model for this male subgroup improving prediction of early onset CHD events.

Conclusions: Genetic risk scores add precision to risk estimates for CHD and improve prediction beyond classic risk factors, particularly for middle aged men.

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OBJECTIVES: Risk stratification of Barrett's esophagus (BE) patients based on clinical and endoscopic features may help to optimize surveillance practice for esophageal adenocarcinoma (EAC) development. The aim of this study was to investigate patient symptoms and endoscopic features at index endoscopy and risk of neoplastic progression in a large population-based cohort of BE patients.

METHODS: A retrospective review of hospital records relating to incident BE diagnosis was conducted in a subset of patients with specialized intestinal metaplasia from the Northern Ireland BE register. Patients were matched to the Northern Ireland Cancer Registry to identify progressors to EAC or esophageal high-grade dysplasia (HGD). Cox proportional hazards models were applied to evaluate the association between endoscopic features, symptoms, and neoplastic progression risk.

RESULTS: During 27,997 person-years of follow-up, 128 of 3,148 BE patients progressed to develop HGD/EAC. Ulceration within the Barrett's segment, but not elsewhere in the esophagus, was associated with an increased risk of progression (hazard ratio (HR) 1.72; 95% confidence interval (CI): 1.08–2.76). Long-segment BE carried a significant sevenfold increased risk of progression compared with short-segment BE; none of the latter group developed EAC during the study period. Conversely, the absence of reflux symptoms was associated with an increased risk of cancer progression (HR 1.61; 95% CI: 1.05–2.46).

CONCLUSIONS: BE patients presenting with a long-segment BE or Barrett's ulcer have an increased risk of progressing to HGD/EAC and should be considered for more intense surveillance. The absence of reflux symptoms at BE diagnosis is not associated with a reduced risk of malignant progression, and may carry an increased risk of progression.

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Aromatase inhibitors effectively prevent breast cancer recurrence and development of new contralateral tumours in postmenopausal women. We assessed the efficacy and safety of the aromatase inhibitor anastrozole for prevention of breast cancer in postmenopausal women who are at high risk of the disease.

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Background: Previous research demonstrates various associations between depression, cardiovascular disease (CVD) incidence and mortality, possibly as a result of the different methodologies used to measure depression and analyse relationships. This analysis investigated the association between depression, CVD incidence (CVDI) and mortality from CVD (MCVD), smoking related conditions (MSRC), and all causes (MALL), in a sample data set, where depression was measured using items from a validated questionnaire and using items derived from the factor analysis of a larger questionnaire, and analyses were conducted based on continuous data and grouped data.

Methods: Data from the PRIME Study (N=9798 men) on depression and 10-year CVD incidence and mortality were analysed using Cox proportional hazards models.

Results: Using continuous data, both measures of depression resulted in the emergence of positive associations between depression and mortality (MCVD, MSRC, MALL). Using grouped data, however, associations between a validated measure of depression and MCVD, and between a measure of depression derived from factor analysis and all measures of mortality were lost.

Limitations: Low levels of depression, low numbers of individuals with high depression and low numbers of outcome events may limit these analyses, but levels are usual for the population studied.

Conclusions: These data demonstrate a possible association between depression and mortality but detecting this association is dependent on the measurement used and method of analysis. Different findings based on methodology present clear problems for the elucidation and determination of relationships. The differences here argue for the use of validated scales where possible and suggest against over-reduction via factor analysis and grouping.

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BACKGROUND: Epidemiological and laboratory studies suggest that β-blockers may reduce cancer progression in various cancer sites. The aim of this study was to conduct the first epidemiological investigation of the effect of post-diagnostic β-blocker usage on colorectal cancer-specific mortality in a large population-based colorectal cancer patient cohort.

PATIENTS AND METHODS: A nested case-control analysis was conducted within a cohort of 4794 colorectal cancer patients diagnosed between 1998 and 2007. Patients were identified from the UK Clinical Practice Research Datalink and confirmed using cancer registry data. Patients with a colorectal cancer- specific death (data from the Office of National Statistics death registration system) were matched to five controls. Conditional logistic regression was applied to calculate odds ratios (OR) and 95% confidence intervals (95% CIs) according to β-blocker usage (data from GP-prescribing records).

RESULTS: Post-diagnostic β-blocker use was identified in 21.4% of 1559 colorectal cancer-specific deaths and 23.7% of their 7531 matched controls, with little evidence of an association (OR = 0.89 95% CI 0.78-1.02). Similar associations were found when analysing drug frequency, β-blocker type or specific drugs such as propranolol. There was some evidence of a weak reduction in all-cause mortality in β-blocker users (adjusted OR = 0.88; 95% CI 0.77-1.00; P = 0.04) which was in part due to the marked effect of atenolol on cardiovascular mortality (adjusted OR = 0.62; 95% CI 0.40-0.97; P = 0.04).

CONCLUSIONS: In this novel, large UK population-based cohort of colorectal cancer patients, there was no evidence of an association between post-diagnostic β-blocker use and colorectal cancer-specific mortality.

CLINICAL TRIALS NUMBER: NCT00888797.

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PURPOSE: To investigate whether statins used after colorectal cancer diagnosis reduce the risk of colorectal cancer-specific mortality in a cohort of patients with colorectal cancer.

PATIENTS AND METHODS: A cohort of 7,657 patients with newly diagnosed stage I to III colorectal cancer were identified from 1998 to 2009 from the National Cancer Data Repository (comprising English cancer registry data). This cohort was linked to the United Kingdom Clinical Practice Research Datalink, which provided prescription records, and to mortality data from the Office of National Statistics (up to 2012) to identify 1,647 colorectal cancer-specific deaths. Time-dependent Cox regression models were used to calculate hazard ratios (HR) for cancer-specific mortality and 95% CIs by postdiagnostic statin use and to adjust these HRs for potential confounders.

RESULTS: Overall, statin use after a diagnosis of colorectal cancer was associated with reduced colorectal cancer-specific mortality (fully adjusted HR, 0.71; 95% CI, 0.61 to 0.84). A dose-response association was apparent; for example, a more marked reduction was apparent in colorectal cancer patients using statins for more than 1 year (adjusted HR, 0.64; 95% CI, 0.53 to 0.79). A reduction in all-cause mortality was also apparent in statin users after colorectal cancer diagnosis (fully adjusted HR, 0.75; 95% CI, 0.66 to 0.84).

CONCLUSION: In this large population-based cohort, statin use after diagnosis of colorectal cancer was associated with longer rates of survival.

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INTRODUCTION: Smoking is known to be a major cause of death among middle-aged adults, but evidence on its impact and the benefits of smoking cessation among older adults has remained limited. Therefore, we aimed to estimate the influence of smoking and smoking cessation on all-cause mortality in people aged ≥60 years.

METHODS: Relative mortality and mortality rate advancement periods (RAPs) were estimated by Cox proportional hazards models for the population-based prospective cohort studies from Europe and the U.S. (CHANCES [Consortium on Health and Ageing: Network of Cohorts in Europe and the U.S.]), and subsequently pooled by individual participant meta-analysis. Statistical analyses were performed from June 2013 to March 2014.

RESULTS: A total of 489,056 participants aged ≥60 years at baseline from 22 population-based cohort studies were included. Overall, 99,298 deaths were recorded. Current smokers had 2-fold and former smokers had 1.3-fold increased mortality compared with never smokers. These increases in mortality translated to RAPs of 6.4 (95% CI=4.8, 7.9) and 2.4 (95% CI=1.5, 3.4) years, respectively. A clear positive dose-response relationship was observed between number of currently smoked cigarettes and mortality. For former smokers, excess mortality and RAPs decreased with time since cessation, with RAPs of 3.9 (95% CI=3.0, 4.7), 2.7 (95% CI=1.8, 3.6), and 0.7 (95% CI=0.2, 1.1) for those who had quit <10, 10 to 19, and ≥20 years ago, respectively.

CONCLUSIONS: Smoking remains as a strong risk factor for premature mortality in older individuals and cessation remains beneficial even at advanced ages. Efforts to support smoking abstinence at all ages should be a public health priority.

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Detection of pretreatment disseminated cells (pre-DTC) reflecting its homing to bone marrow (BM) in prostate cancer (PCa) might improve the current model to predict recurrence or survival in men with nonmetastatic disease despite of primary treatment. Thereby, pre-DTC may serve as an early prognostic biomarker. Post-treatment DTCs (post-DTC) finding may supply the clinician with additional predictive information about the possible course of PCa. To assess the prognostic impact of DTCs in BM aspirates sampled before initiation of primary therapy (pre-DTC) and at least 2 years after (post-DTC) to established prognostic factors and survival in patients with PCa. Available BM of 129 long-term follow-up patients with T1-3N0M0 PCa was assessed in addition to 100 BM of those in whom a pretreatment BM was sampled. Patients received either combined therapy [n = 81 (63%)], radiotherapy (RT) with different duration of hormone treatment (HT) or monotherapy with RT or HT alone [n = 48 (37%)] adapted to the criteria of the SPCG-7 trial. Mononuclear cells were deposited on slides according to the cytospin methodology and DTCs were identified by immunocytochemistry using the pancytokeratin antibodies AE1/AE3. The median age of men at diagnosis was 64.5 years (range 49.5-73.4 years). The median long-term follow-up from first BM sampling to last observation was 11 years. Categorized clinically relevant factors in PCa showed only pre-DTC status as the statistically independent parameter for survival in the multivariate analysis. Pre-DTCs homing to BM are significantly associated with clinically relevant outcome independent to the patient's treatment at diagnosis with nonmetastatic PCa.