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1.
Can Pharm J (Ott) ; 154(3): 205-212, 2021.
Article in English | MEDLINE | ID: mdl-34104274

ABSTRACT

OBJECTIVE: The use of antipsychotics to treat seniors in long-term care facilities (LTCFs) has raised concern because of health consequences (i.e., increased risk of falls, stroke, death) in this vulnerable population. This study measured geographic patterns of antipsychotic utilization among seniors living in LTCFs in Newfoundland and Labrador (NL) and assessed potential inappropriateness. METHOD: We analyzed prescription records among adults 66 years and older with provincial prescription drug coverage admitted to LTCFs in NL between April 1, 2011, and March 31, 2014. Patterns of use were analyzed across the 4 regional health authorities (RHAs) in NL and LTCFs. Logistic, Poisson and linear regression models were used to test variations in prevalence, rate and volume of antipsychotic utilization. To assess potential inappropriateness of antipsychotic use, we analyzed data from Resident Assessment Instrument-Minimum Data Set (RAI-MDS) 2.0 forms from NL LTCFs between January 1, 2016, and December 31, 2018. Pearson chi-squared analysis was performed at the RHA and LTCF levels to determine changes in percentage of total prescriptions or antipsychotic prescriptions without psychosis. RESULTS: Between 2011 and 2014, 2843 seniors were admitted to LTCFs across NL; of these, 1323 residents were prescribed 1 or more antipsychotics. Within the 3-year period, the percentage of antipsychotic use across facilities ranged from 35% to 78%. Using data from 27,260 RAI-MDS 2.0 assessments between 2016 and 2018, 71% (6995/9851) of antipsychotic prescriptions were potentially inappropriate. DISCUSSION: There is substantial variation across NL regions concerning the utilization of antipsychotics for senior in LTCFs. Facility size and management styles may be reasons for this. CONCLUSION: With nearly three-quarters of antipsychotic prescriptions shown to be potentially inappropriate, systematic interventions to assess indications for antipsychotic use are warranted. Can Pharm J (Ott) 2021;154:xx-xx.

2.
JAMA ; 314(9): 895-903, 2015 Sep 01.
Article in English | MEDLINE | ID: mdl-26325558

ABSTRACT

IMPORTANCE: The use of genome-wide tests to provide molecular diagnosis for individuals with autism spectrum disorder (ASD) requires more study. OBJECTIVE: To perform chromosomal microarray analysis (CMA) and whole-exome sequencing (WES) in a heterogeneous group of children with ASD to determine the molecular diagnostic yield of these tests in a sample typical of a developmental pediatric clinic. DESIGN, SETTING, AND PARTICIPANTS: The sample consisted of 258 consecutively ascertained unrelated children with ASD who underwent detailed assessments to define morphology scores based on the presence of major congenital abnormalities and minor physical anomalies. The children were recruited between 2008 and 2013 in Newfoundland and Labrador, Canada. The probands were stratified into 3 groups of increasing morphological severity: essential, equivocal, and complex (scores of 0-3, 4-5, and ≥6). EXPOSURES: All probands underwent CMA, with WES performed for 95 proband-parent trios. MAIN OUTCOMES AND MEASURES: The overall molecular diagnostic yield for CMA and WES in a population-based ASD sample stratified in 3 phenotypic groups. RESULTS: Of 258 probands, 24 (9.3%, 95%CI, 6.1%-13.5%) received a molecular diagnosis from CMA and 8 of 95 (8.4%, 95%CI, 3.7%-15.9%) from WES. The yields were statistically different between the morphological groups. Among the children who underwent both CMA and WES testing, the estimated proportion with an identifiable genetic etiology was 15.8% (95%CI, 9.1%-24.7%; 15/95 children). This included 2 children who received molecular diagnoses from both tests. The combined yield was significantly higher in the complex group when compared with the essential group (pairwise comparison, P = .002). [table: see text]. CONCLUSIONS AND RELEVANCE: Among a heterogeneous sample of children with ASD, the molecular diagnostic yields of CMA and WES were comparable, and the combined molecular diagnostic yield was higher in children with more complex morphological phenotypes in comparison with the children in the essential category. If replicated in additional populations, these findings may inform appropriate selection of molecular diagnostic testing for children affected by ASD.


Subject(s)
Child Development Disorders, Pervasive/genetics , Exome , Microarray Analysis/methods , Molecular Diagnostic Techniques/methods , Asperger Syndrome/diagnosis , Asperger Syndrome/genetics , Autistic Disorder/diagnosis , Autistic Disorder/genetics , Child , Child Development Disorders, Pervasive/diagnosis , Child Development Disorders, Pervasive/pathology , Child, Preschool , Female , Humans , Male , Microarray Analysis/statistics & numerical data , Molecular Diagnostic Techniques/statistics & numerical data , Mutation , Oligonucleotide Array Sequence Analysis/statistics & numerical data , Phenotype , Sequence Analysis, DNA/methods , Sequence Analysis, Protein/methods
3.
Respir Res ; 13: 64, 2012 Aug 01.
Article in English | MEDLINE | ID: mdl-22853774

ABSTRACT

BACKGROUND: Idiopathic pulmonary fibrosis (IPF) is an adult-onset Idiopathic Interstitial Pneumonia (IIP) usually diagnosed between age 50 to 70 years. Individuals with Familial Pulmonary Fibrosis (FPF) have at least one affected first or second-degree relative and account for 0.5-20% of cases. METHODS: We ascertained and collected DNA samples from a large population-based cohort of IPF patients from Newfoundland, Canada. For each proband, a family history was documented and medical records were reviewed. Each proband was classified as familial (28 patients) or sporadic (50 patients) and all 78 probands were screened for variants in four highly penetrant, adult-onset PF genes (SFTPC, SFTPA2, TERT,TERC). RESULTS: Seventy-eight IPF probands were enrolled of whom 28 (35.9%) had a positive family history. These 28 familial patients led to the recruitment of an additional 49 affected relatives (total of 77 FPF patients). By age 60 years, 42% of the familial cohort had been diagnosed with PF compared with only 16% of the sporadic patient collection (χ2 = 8.77, p = 0.003). Mean age of diagnosis in the familial group was significantly younger than the sporadic group (61.4 years vs. 66.6 yrs, p = 0.012) with a wider age range of diagnosis (19-92 years compared with 47-82 years). Thirty-three of 77 (42.8%) FPF patients had a tissue diagnosis and all but five had usual interstitial pneumonia histology. Compared with other published case series, the familial IIP histologies were more homogeneous. Three of 28 familial probands (10.7%) and none of the 50 sporadic probands had pathogenic variants in the four genes tested. All three familial probands had mutations in TERT. Other phenotypes associated with telomerase deficiency were present in these families including cirrhosis, bone marrow hypoplasia and premature graying. Telomere length assays were performed on mutation carriers from two families and confirmed telomere-related deficiency. CONCLUSION: The proportion of familial cases in our cohort is higher than any previously reported estimate and we suggest that this is due to the fact that Newfoundland cohort is ethnically homogeneous and drawn from a founder population. In our patient collection, diagnosis with IPF prior to age 45 years predicted familial disease. In two of the three TERT mutation families, the pedigree appearance is consistent with genetic anticipation. In the other 25 FPF families negative for mutations in known PF genes, we did not identify other telomerase associated medical problems (bone marrow dysfunction, cirrhosis) and we hypothesize that there are novel PF genes segregating in our population.


Subject(s)
Idiopathic Pulmonary Fibrosis/diagnosis , Idiopathic Pulmonary Fibrosis/genetics , Adult , Age of Onset , Aged , Aged, 80 and over , Bone Marrow Diseases/genetics , Cohort Studies , Female , Founder Effect , Genetic Association Studies , Humans , Idiopathic Pulmonary Fibrosis/epidemiology , Male , Middle Aged , Mutation , Newfoundland and Labrador/epidemiology , Pulmonary Surfactant-Associated Protein A/genetics , Pulmonary Surfactant-Associated Protein C/genetics , Telomerase/genetics , Young Adult
4.
Methods Mol Biol ; 2249: 17-34, 2021.
Article in English | MEDLINE | ID: mdl-33871836

ABSTRACT

Clinical epidemiological research entails assessing the burden and etiology of disease, the diagnosis and prognosis of disease, the efficacy of preventive measures or treatments, the analysis of the risks and benefits of diagnostic and therapeutic maneuvers, and the evaluation of health care services. In all areas, the main focus is to describe the relationship between exposure and outcome and to determine one of the following: prevalence, incidence, cause, prognosis, or effect of treatment. The accuracy of these conclusions is determined by the validity of the study. Validity is determined by addressing potential biases and possible confounders that may be responsible for the observed association. Therefore, it is important to understand the types of bias that exist and also to be able to assess their impact on the magnitude and direction of the observed effect. The following chapter reviews the epidemiological concepts of selection bias, information bias, intervention bias, and confounding and discusses ways in which these sources of bias can be minimized.


Subject(s)
Bias , Confounding Factors, Epidemiologic , Humans , Incidence , Prevalence , Research Design , Selection Bias
5.
Heart Rhythm ; 17(7): 1159-1166, 2020 07.
Article in English | MEDLINE | ID: mdl-32120009

ABSTRACT

BACKGROUND: High-level exercise has been associated with a malignant phenotype in desmosomal and genotype-negative forms of arrhythmogenic right ventricular cardiomyopathy (ARVC). This is the first study to examine this issue with ARVC secondary to the TMEM43 p.S358L mutation. OBJECTIVE: The purpose of this study was to evaluate the impact of exercise on arrhythmic risk and cardiac death in TMEM43 p.S358L ARVC. METHODS: Individuals with the TMEM43 p.S358L mutation enrolled in a prospective registry who had received a primary prevention implantable cardioverter-defibrillator (ICD) were invited to complete the modified Paffenbarger Physical Activity Questionnaire to assess their physical activity in the year before their ICD implantation. Time-to-event analyses using unadjusted and adjusted Cox proportional hazards models evaluated associations between physical activity and first appropriate ICD discharge secondary to malignant ventricular arrhythmia or cardiac death. RESULTS: In 80 subjects with the TMEM43 p.S358L mutation, exercise ≥9.0 metabolic equivalent of task (MET)-hours/day (high level) in the year before ICD implantation was associated with an adjusted 9.1-fold increased hazard of first appropriate ICD discharge (there were no deaths) relative to physical activity <9.0 MET-hours/day (moderate level) (95% confidence interval [CI] 3.3-24.6 MET-hours/day; P < .001). The median age from birth to first appropriate ICD discharge was 58.5 years (95% CI 56.5-60.5 years) vs 35.8 years (95% CI 28.2-43.4 years) (P < .001) in subjects in moderate- and high-level exercise groups, respectively. CONCLUSION: Exercise ≥9.0 MET-hours/day is associated with an increased risk of malignant ventricular arrhythmias in the TMEM43 p.S358L subtype of ARVC. Extrapolating these data, we suggest molecular testing be offered in early childhood to inform exercise choices reflective of the genotype.


Subject(s)
Arrhythmogenic Right Ventricular Dysplasia/prevention & control , DNA/genetics , Exercise/physiology , Membrane Proteins/genetics , Mutation , Primary Prevention/methods , Adult , Arrhythmogenic Right Ventricular Dysplasia/genetics , Arrhythmogenic Right Ventricular Dysplasia/physiopathology , DNA Mutational Analysis , Female , Humans , Male , Membrane Proteins/metabolism , Phenotype , Prospective Studies , Risk Factors
6.
Methods Mol Biol ; 473: 171-86, 2009.
Article in English | MEDLINE | ID: mdl-19160738

ABSTRACT

Clinical epidemiological research in genetic diseases entails the assessment of phenotypes, the burden and etiology of disease, and the efficacy of preventive measures or treatments in populations. In all areas, the main focus is to describe the relationship between exposure and outcome and determine one of the following: prevalence, incidence, cause, prognosis, or effect of treatment. The accuracy of these conclusions is determined by the validity of the study. Validity is determined by addressing potential biases and possible confounders that may be responsible for the observed association. Therefore, it is important to understand the types of bias that exist and be able to assess their impact on the magnitude and direction of the observed effect. This chapter reviews the epidemiological concepts of selection bias, information bias, and confounding and discusses ways in which these sources of bias can be minimized.


Subject(s)
Bias , Genetic Diseases, Inborn/epidemiology , Selection Bias , Clinical Trials as Topic , Humans , Research Design
7.
Fam Cancer ; 6(1): 1-12, 2007.
Article in English | MEDLINE | ID: mdl-17039271

ABSTRACT

To compare the phenotypic expression of three different MSH2 mutations causing Lynch syndrome, 290 family members at 50% risk of inheriting a mutation were studied. Two truncating mutations of the MSH2 gene have been identified in Newfoundland: an exon 8 deletion in five families (N=74 carriers) and an exon 4-16 deletion in one family (N=65 carriers). The third mutation was an intron 5 splice site mutation resulting in deletion of exon 5 in RNA and occurred in 12 families (N=151 carriers). Age to onset of first cancer, first colorectal cancer (CRC), first extracolonic cancers and death were compared. By age 60, 89% of family members with the intron 5 mutation, 81% with the exon 8 deletion, and 85% with the exon 4-16 deletion had developed cancer. For all three mutations males had a higher age-related risk of CRC and death compared to females. In the intron 5 splice site mutation carriers, the number of transitional cell cancers of the urinary tract was significantly lower and time to first ovarian cancer was significantly higher than in the carriers of the genomic deletions. The incidence of CRC in MSH2 mutation carriers, exposed to the same environment, is not modified by the specific mutation, although there is a suggestion that type of mutation may influence development of some extracolonic cancers.


Subject(s)
Biomarkers, Tumor , Colorectal Neoplasms, Hereditary Nonpolyposis/genetics , Gene Deletion , MutS Homolog 2 Protein/genetics , Point Mutation/genetics , Adult , Age of Onset , Aged , Aged, 80 and over , Causality , Colorectal Neoplasms, Hereditary Nonpolyposis/epidemiology , Comorbidity , DNA Mutational Analysis , Endometrial Neoplasms/epidemiology , Endometrial Neoplasms/genetics , Female , Founder Effect , Gene Expression , Genetic Predisposition to Disease , Germ-Line Mutation/genetics , Humans , Male , Middle Aged , Newfoundland and Labrador/epidemiology , Ovarian Neoplasms/epidemiology , Ovarian Neoplasms/genetics , Pedigree , Phenotype , Prevalence , Rectal Neoplasms/epidemiology , Rectal Neoplasms/genetics , Risk Factors , Sequence Analysis, DNA , Sex Distribution
8.
J Am Coll Cardiol ; 45(3): 400-8, 2005 Feb 01.
Article in English | MEDLINE | ID: mdl-15680719

ABSTRACT

OBJECTIVES: We sought to determine the impact of implantable cardioverter-defibrillator (ICD) therapy in patients with familial arrhythmogenic right ventricular cardiomyopathy (ARVC). BACKGROUND: Arrhythmogenic right ventricular cardiomyopathy is a cause of sudden cardiac death, which may be prevented by ICD. METHODS: We studied 11 families in which a 3p25 deoxyribonucleic acid (DNA) haplotype at locus ARVD5 segregated with disease and compared mortality in subjects who received an ICD with that in control subjects who were matched for age, gender, ARVC status, and family. Subjects (n = 367) at 50% a priori risk of inheriting ARVC were classified as high risk (HR) (n = 197), low risk (n = 92), or unknown (n = 78) on the basis of clinical events, DNA haplotyping, and/or pedigree position. Forty-eight HR subjects (30 males, [median age 32 years] and 18 females [median age 41 years]) were followed after ICD (secondary to ventricular tachycardia [VT] in 27%). Survival was compared with 58 HR control subjects who were alive at the same age to-the-day at which the ICD subject received the device. RESULTS: In the HR group, 50% of males were dead by 39 years and females by 71 years: relative risk of death was 5.1 (95% confidence interval 3 to 8.5) for males. The five-year mortality rate after ICD in males was zero compared with 28% in control subjects (p = 0.009). Within five years, the ICD fired for VT in 70% and for VT >240 beats/min in 30%, with no difference in discharge rate when analyzed by ICD indication. CONCLUSIONS: The unknown mutation at the ARVD5 locus causing ARVC results in high mortality. Risk stratification using genetic haplotyping and ICD therapy produced improved survival for males.


Subject(s)
Arrhythmogenic Right Ventricular Dysplasia/mortality , Arrhythmogenic Right Ventricular Dysplasia/therapy , Death, Sudden, Cardiac/prevention & control , Defibrillators, Implantable , Adolescent , Adult , Arrhythmogenic Right Ventricular Dysplasia/genetics , Case-Control Studies , Chromosomes, Human, Pair 3/genetics , Death, Sudden, Cardiac/etiology , Female , Follow-Up Studies , Genotype , Humans , Male , Middle Aged , Pedigree , Risk Assessment , Survival Rate , Treatment Outcome
9.
Clin Cancer Res ; 11(19 Pt 1): 6853-61, 2005 Oct 01.
Article in English | MEDLINE | ID: mdl-16203774

ABSTRACT

PURPOSE: Newfoundland has one of the highest rates of colorectal cancer in North America. The most common hereditary form of colorectal cancer is hereditary nonpolyposis colorectal cancer caused by mutations in genes involved in mismatch repair. Our purpose was to determine the proportion of hereditary colorectal cancer and to determine the genetic basis of disease in both population and clinically referred cohorts from Newfoundland. EXPERIMENTAL DESIGN: Seventy-eight colorectal cancer patients were accrued over a 2-year period from the Avalon Peninsula of Newfoundland. We also examined 31 hereditary nonpolyposis colorectal cancer-like families, which had been referred to the Provincial Medical Genetics Program. Tumors from probands were tested by immunohistochemistry for deficiencies in MLH1, MSH2, and MSH6 proteins and tested for DNA microsatellite instability. Mutation analyses of MLH1, MSH2, and MSH6 were undertaken by direct sequencing and an assay to detect deletions, amplifications, and rearrangements in MSH2 and MLH1. RESULTS: We identified eight population-based families that fulfill the Amsterdam I or II criteria, 4 (50%) of which seem to have hereditary cancer not attributable to the most commonly mutated mismatch repair genes. In addition, in 16 of 21 (76%) referred families fulfilling Amsterdam I or II criteria, no mutations were found in the three most commonly altered mismatch repair genes, and tumor analyses corroborated these findings. CONCLUSIONS: It seems that strong and novel genetic causes of hereditary colorectal cancer are responsible for a high proportion of colorectal cancer in this population. Conditions are suitable for the identification of these genes by linkage studies of large Newfoundland cancer families.


Subject(s)
Colorectal Neoplasms/epidemiology , Colorectal Neoplasms/genetics , Genetic Linkage , Genetic Predisposition to Disease , Adaptor Proteins, Signal Transducing , Adult , Age Factors , Aged , Base Pair Mismatch , Carrier Proteins/genetics , Cohort Studies , Colorectal Neoplasms, Hereditary Nonpolyposis/genetics , DNA Methylation , DNA Repair , DNA-Binding Proteins/genetics , Female , Genetic Variation , Humans , Immunohistochemistry , Male , Microsatellite Repeats , Middle Aged , Models, Genetic , MutL Protein Homolog 1 , MutS Homolog 2 Protein/genetics , Mutation , Newfoundland and Labrador , Nuclear Proteins/genetics , Promoter Regions, Genetic , Sequence Analysis, DNA , Time Factors
10.
Article in English | MEDLINE | ID: mdl-26966288

ABSTRACT

BACKGROUND: We previously showed a survival benefit of the implantable cardioverter defibrillator (ICD) in males with arrhythmogenic right ventricular cardiomyopathy caused by a p.S358L mutation in TMEM43. We present long-term data (median follow-up 8.5 years) after ICD for primary (PP) and secondary prophylaxis in males and females, determine whether ICD discharges for ventricular tachycardia/ventricular fibrillation were equivalent to an aborted death, and assess relevant clinical predictors. METHODS AND RESULTS: We studied 24 multiplex families segregating an autosomal dominant p.S358L mutation in TMEM43. We compared survival in 148 mutation carriers with an ICD to 148 controls matched for age, sex, disease status, and family. Of 80 male mutation carriers with ICDs (median age at implantation 31 years), 61 (76%) were for PP; of 68 females (median age at implantation 43 years), 66 (97%) were for PP. In males, irrespective of indication, survival was better in the ICD groups compared with control groups (relative risk 9.3 [95% confidence interval 3.3-26] for PP and 9.7 [95% confidence interval 3.2-29.6] for secondary prophylaxis). For PP females, the relative risk was 3.6 (95% confidence interval 1.3-9.5). ICD discharge-free survival for ventricular tachycardia/ventricular fibrillation ≥ 240 beats per minute was equivalent to the control survival rate. Ectopy (≥ 1000 premature ventricular complexes/24 hours) was the only independent clinical predictor of ICD discharge in males, and no predictor was identified in females. CONCLUSIONS: ICD therapy is indicated for PP in postpubertal males and in females ≥ 30 years with the p.S358L TMEM43 mutation. ICD termination of rapid ventricular tachycardia/ventricular fibrillation can reasonably be considered an aborted death.


Subject(s)
Arrhythmogenic Right Ventricular Dysplasia/therapy , Death, Sudden, Cardiac/prevention & control , Defibrillators, Implantable , Electric Countershock/instrumentation , Membrane Proteins/genetics , Mutation , Primary Prevention/instrumentation , Secondary Prevention/instrumentation , Tachycardia, Ventricular/therapy , Ventricular Fibrillation/therapy , Adult , Age Factors , Arrhythmogenic Right Ventricular Dysplasia/diagnosis , Arrhythmogenic Right Ventricular Dysplasia/genetics , Arrhythmogenic Right Ventricular Dysplasia/mortality , Arrhythmogenic Right Ventricular Dysplasia/physiopathology , DNA Mutational Analysis , Death, Sudden, Cardiac/etiology , Electrocardiography , Female , Genetic Predisposition to Disease , Heredity , Humans , Kaplan-Meier Estimate , Male , Middle Aged , Patient Selection , Pedigree , Phenotype , Proportional Hazards Models , Retrospective Studies , Risk Factors , Sex Factors , Tachycardia, Ventricular/diagnosis , Tachycardia, Ventricular/genetics , Tachycardia, Ventricular/mortality , Tachycardia, Ventricular/physiopathology , Time Factors , Treatment Outcome , Ventricular Fibrillation/diagnosis , Ventricular Fibrillation/genetics , Ventricular Fibrillation/mortality , Ventricular Fibrillation/physiopathology
11.
Healthc Manage Forum ; 18(3): 6-12, 50-7, 2005.
Article in English, French | MEDLINE | ID: mdl-16323463

ABSTRACT

In 1996, the St. John's region had a population of 8,435 > or = 75 years, with 996 nursing home (NH) beds and 550 supervised care (SC) beds. A single entry system to these institutions was implemented in 1995. To determine the impact of the single entry system, the demographic and clinical characteristics of NH residents were assessed in 1997 (N = 1,044) and in 2003 (N = 963). To determine the efficiency of placement and the need for long-term care beds, two incident cohorts requesting placement were studied in 1995/96 (N = 467) and in 1999/2000 (N = 464). Degree of disability was determined using the Residents Utilization Groups III classification (RUG-III) and the Alberta Resident Classification Score (ARCS), and time to placement and to death was measured. In prevalent NH residents, the percentage without RUGS-III disability decreased from 18.5% in 1997 and to 9.9% in 2003. The proportion recommended for NH was 75% in 1995/96 and 72% in 1999/2000, despite the fact that the proportion with RUGS-III disability was 64% in both periods. Using a decision tree, optimal placement for the 1999/2000 cohort was 36% to SC, 20% to SC for the cognitively impaired, and 44% to NH. Predicted need for long-term care beds in 2004 matched poorly with current provision of NH and SC beds, and the mismatch will be worse in 2014. It was concluded that the single entry system was associated with improved appropriateness of NH bed utilization. However, there was a mismatch in need for and provision of institutional long-term care. Investment in the reconfiguration of long-term care beds by case mix and by geography is necessary.


Subject(s)
Beds/statistics & numerical data , Needs Assessment/classification , Nursing Homes , Aged , Aged, 80 and over , Cohort Studies , Female , Humans , Male , National Health Programs , Newfoundland and Labrador
12.
Methods Mol Biol ; 1281: 333-48, 2015.
Article in English | MEDLINE | ID: mdl-25694320

ABSTRACT

Clinical epidemiological research in genetic diseases entails assessment of phenotypes, the burden and etiology of disease, and the efficacy of preventive measures or treatments in populations. In all areas, the main focus is to describe the relationship between exposure and outcome and to determine one of the following: prevalence, incidence, cause, prognosis, or effect of treatment. The accuracy of these conclusions is determined by the validity of the study. Validity is determined by addressing potential biases and possible confounders that may be responsible for the observed association. Therefore, it is important to understand the types of bias that exist and also to be able to assess their impact on the magnitude and direction of the observed effect. The following chapter reviews the epidemiological concepts of selection bias, information bias, and confounding and discusses ways in which these sources of bias can be minimized.


Subject(s)
Bias , Biomedical Research/methods , Genetic Research , Epidemiologic Studies , Humans
13.
PLoS One ; 7(7): e38953, 2012.
Article in English | MEDLINE | ID: mdl-22911682

ABSTRACT

Prognosis in colorectal cancer patients is quite variable, even after adjustment for clinical parameters such as disease stage and microsatellite instability status. It is possible that the psychological distress experienced by patients, including anxiety and depression, may be correlated with poor prognosis. In the present study, we hypothesize that genetic variations within three genes biologically linked to the stress response, namely serotonin transporter (SLC6A4), brain-derived neurotrophic factor (BDNF), and arginine vasopressin receptor (AVPR1B) genes are associated with prognosis in colorectal cancer patients. We used a population-based cohort of 280 patients who were followed for up to 12.5 years after diagnosis. Our multivariate analysis showed that a tagSNP in the SLC6A4 gene (rs12150214) was a predictor of shorter overall survival (HR: 1.572, 95%CI: 1.142-2.164, p = 0.005) independent of stage, age, grade and MSI status. Additionally, a multivariate analysis using the combined genotypes of three polymorphisms in this gene demonstrated that the presence of any of the minor alleles at these polymorphic loci was an independent predictor of both shorter overall survival (HR: 1.631, 95%CI: 1.190-2.236, p = 0.002) and shorter disease specific survival (HR: 1.691, 95%CI: 1.138-2.512, p = 0.009). The 5-HTT protein coded by the SLC6A4 gene has also been implicated in inflammation. While our results remain to be replicated in other patient cohorts, we suggest that the genetic variations in the SLC6A4 gene contribute to poor survival in colorectal cancer patients.


Subject(s)
Colorectal Neoplasms/genetics , Colorectal Neoplasms/mortality , Genetic Variation , Serotonin Plasma Membrane Transport Proteins/genetics , Adult , Aged , Aged, 80 and over , Alleles , Female , Genotype , Humans , Linkage Disequilibrium , Male , Middle Aged , Neoplasm Grading , Neoplasm Staging , Polymorphism, Single Nucleotide , Prognosis , Retrospective Studies , Serotonin Plasma Membrane Transport Proteins/metabolism
14.
Am J Surg Pathol ; 34(12): 1820-9, 2010 Dec.
Article in English | MEDLINE | ID: mdl-21107088

ABSTRACT

Identifying colorectal cancers (CRCs) with high levels of microsatellite instability (MSI-H) is clinically important. MSI-H is a positive prognostic marker for CRC, a predictive marker for resistance to standard 5-fluorouracil-based adjuvant chemotherapy, and an important feature for identifying individuals and families with Lynch syndrome. Our aim was to compare and improve upon the existing predictive pathology models for MSI-H CRCs. We tested 2 existing models used to predict MSI-H tumors, (1) Revised Bethesda Guidelines and (2) MsPath, in our population-based cohort of CRCs diagnosed less than 75 years from Newfoundland (N=710). We also scored additional histologic features not described in the other models. From this analysis, we developed a model for the prediction of MSI-H CRCs; Pathologic Role in Determination of Instability in Colorectal Tumors (PREDICT). An independent pathologist validated this model in a second cohort of all CRCs (N=276). Tumor histology was a better predictor of MSI status than was personal and family history of cancer. MsPath identified MSI-H CRCs with a sensitivity of 92.1% and a specificity of 37.8%, whereas the Revised Bethesda Guidelines had a sensitivity of 81.3% and a specificity of 39.5%. PREDICT included some new histology features, including peritumoral lymphocytic reaction and increased proportion of plasma cells in the tumor stroma. PREDICT was superior to both existing models in the development cohort with a sensitivity of 97.4% and a specificity of 53.9%. In the validation cohort, sensitivity was 96.9% and specificity 76.6%. We conclude that PREDICT is a good predictor of MSI-H CRC.


Subject(s)
Adenocarcinoma/genetics , Adenocarcinoma/pathology , Colorectal Neoplasms/genetics , Colorectal Neoplasms/pathology , Microsatellite Instability , Adult , Aged , Aged, 80 and over , Family Health , Female , Humans , Male , Middle Aged , Models, Genetic , Predictive Value of Tests , Young Adult
15.
Cancer Epidemiol Biomarkers Prev ; 19(7): 1831-9, 2010 Jul.
Article in English | MEDLINE | ID: mdl-20570909

ABSTRACT

BACKGROUND: The serrated pathway represents a distinct molecular pathway of colorectal carcinogenesis and is associated with the p.V600E BRAF mutation. The objective of this study is to characterize the cancer family history and clinicopathologic features of colorectal cancer (CRC) patients according to the microsatellite instability (MSI) and BRAF mutation status of their tumors. METHODS: The tumors from 558 population-based CRC patients underwent pathologic examination and molecular analysis for MSI, BRAF, and germline mutations in mismatch repair genes MUTYH and APC. The cancer history in first-degree relatives (FDR) of index patients was ascertained. RESULTS: The risk of CRC in FDRs of index patients with MSI-H BRAF mutation [hazard ratio (HR) = 2.49; 95% confidence interval (95% CI), 1.57- 3.93] and microsatellite-stable BRAF mutation tumors (HR = 1.64; 95% CI, 1.01-2.66) was significantly elevated compared with FDRs of index patients with microsatellite-stable BRAF wild-type tumors. The incidence of nonmelanoma skin cancer was also significantly elevated in FDRs of patients with BRAF mutation CRC (HR = 2.52; 95% CI, 1.31-4.86). Furthermore, BRAF mutation CRC was associated with a distinct clinical, molecular, and pathologic phenotype. CONCLUSIONS: The increased incidence of cancer in FDRs of index CRC patients with the p.V600E BRAF mutation may be explained by a genetic predisposition to develop cancer through the serrated pathway of colorectal carcinogenesis. IMPACT: Family members of BRAF CRC patients have an increased predisposition to develop cancer. Future work should aim to identify the causative genetic factors.


Subject(s)
Colorectal Neoplasms/genetics , Germ-Line Mutation , Proto-Oncogene Proteins B-raf/genetics , Adult , Colorectal Neoplasms/enzymology , Colorectal Neoplasms/pathology , DNA Glycosylases/genetics , DNA Mutational Analysis , Family Health , Female , Genes, APC , Genetic Predisposition to Disease , Humans , Male , Microsatellite Instability , Middle Aged
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