Biomedical subjects

Stephen C Newman

Publications and source records attributed to Stephen C Newman.

12 recordsLinked to original sources

PubMed2006

Type 2 diabetes does not increase risk of depression.

BACKGROUND: Although diabetes mellitus has a strong association with the presence of depression, it is unclear whether diabetes itself increases the risk of developing depression. The objective of our study was to evaluate whether people with diabetes have a greater incidence of depression than those without diabetes. METHODS: We conducted a population-based retrospective cohort study using the administrative databases of Saskatchewan Health from 1989 to 2001. People older than 20 years with newly identified type 2 diabetes were identified by means of diagnostic codes and prescription records and compared with a nondiabetic cohort. Depression was ascertained via diagnostic codes and prescriptions for antidepressants. Cox regression analysis was used to estimate hazard ratios (HRs) and 95% confidence intervals (CIs) after adjusting for age, sex, frequency of visits to physicians and presence of comorbidities. RESULTS: We identified 31 635 people with diabetes and 57 141 without. Those with diabetes were older (61.4 v. 46.8 yr; p < 0.001), were more likely to be male (55.4% v. 49.8%; p < 0.001) and had more physician visits during the year after their index date (mean 14.5 v. 5.9; p < 0.001). The incidence of new-onset depression was similar in both groups (6.5 v. 6.6 per 1000 person-years among people with and without diabetes, respectively). Similarity of risk persisted after controlling for age, sex, number of physician visits and presence of prespecified comorbidities (adjusted HR 1.04, 95% CI 0.94- 1.15). Other chronic conditions such as arthritis (HR 1.18) and stroke (HR 1.73) were associated with the onset of depression. INTERPRETATION: Using a large, population-based administrative cohort, we found little evidence that type 2 diabetes increases the risk of depression once comorbid diseases and the burden of diabetes complications were accounted for.

Adult↗

PubMed2006

A population-based family study of DSM-III generalized anxiety disorder.

BACKGROUND: A recent meta-analysis provides evidence that generalized anxiety disorder (GAD) is familial. However, two of the key studies relied on subjects who were self-selected or recruited from the clinic setting, thereby limiting generalizability. METHOD: We conducted a family study of GAD in which probands and controls came from a community sample originally enrolled in a prevalence study in Edmonton, Canada. One hundred and sixty probands, 764 controls and 2386 first-degree relatives (FDRs) were interviewed using the Diagnostic Interview Schedule (DIS); lifetime diagnoses were made according to DSM-III criteria without exclusions. Logistic regression analysis was performed with GAD (in a proband) as the 'exposure', and GAD in an FDR as the 'outcome'. Several analytic strategies were used to control for potential confounding by major depressive disorder (MDD) and several anxiety disorders (panic disorder, phobic disorders, obsessive-compulsive disorder, and post-traumatic stress disorder). RESULTS: The odds ratios for the association between GAD in a proband and GAD in an FDR were in the range 1.4-1.8 when the entire FDR sample was analysed, and in the range 2.1-2.8 when we restricted to FDRs who were children of probands and controls. CONCLUSION: In the community setting, GAD exhibits mild to moderate familial aggregation.

Anxiety Disorders↗

PubMed2006

Causal analysis of case-control data.

In a series of papers, Robins and colleagues describe inverse probability of treatment weighted (IPTW) estimation in marginal structural models (MSMs), a method of causal analysis of longitudinal data based on counterfactual principles. This family of statistical techniques is similar in concept to weighting of survey data, except that the weights are estimated using study data rather than defined so as to reflect sampling design and post-stratification to an external population. Several decades ago Miettinen described an elementary method of causal analysis of case-control data based on indirect standardization. In this paper we extend the Miettinen approach using ideas closely related to IPTW estimation in MSMs. The technique is illustrated using data from a case-control study of oral contraceptives and myocardial infarction.

Journal Article↗

PubMed2006

Alteration of decreased plasma NO metabolites and platelet NO synthase activity by paroxetine in depressed patients.

Although major depression (MD) and cardiovascular disease (CVD) have been conclusively linked in the literature, the mechanism associating MD and CVD is yet undetermined. The purpose of this paper is to further investigate a potential mechanism involving nitric oxide (NO) and to examine the effect of the selective serotonin reuptake inhibitor paroxetine on NO production by both platelets and the endothelium. In total, 17 subjects with MD and 12 healthy controls (HCs) with no known history of cardiovascular illness completed the study. Paroxetine was administered to both the MD patients and HCs over an 8-week period, and then medication was discontinued. Blood samples were taken at various times throughout paroxetine treatment and after discontinuation. Plasma NO metabolite (NOx) levels were measured by a chemiluminescence method. Platelet endothelial NO synthase (eNOS) activity was examined through the conversion of L-[14C]arginine to L-[(14)C]citrulline. Data were analyzed using t-tests and a linear mixed effects model. Baseline levels of both plasma NOx and platelet NOS activity were significantly lower in subjects with MD compared to HCs. Throughout paroxetine treatment, plasma NOx levels increased in both HCs and MD patients. However, platelet eNOS activity decreased in HCs, while no statistically significant change was evidenced in MD patients. These data suggest that, in MD patients, decreased peripheral production of NO, a potential contributor to increased cardiovascular risk, is modified by administration of the antidepressant paroxetine.

Adult↗

PubMed2005

An ecologic study of parasuicide in Edmonton and Calgary.

OBJECTIVE: From 1986 to 1999, the suicide rate in the Edmonton Regional Health Authority (RHA) was greater than that in the Calgary RHA (mean rate ratio 1.4). We conducted a study to determine whether a similar relation holds for parasuicide, and if so, whether the pattern can be explained at the ecologic level by sociodemographic factors. METHODS: The Edmonton and Calgary RHAs provided data on emergency department visits for nonfatal intentional self-injury for 1997. We obtained sociodemographic data from the 1996 national census for the Edmonton and Calgary census metropolitan areas (CMAs) from Statistics Canada's public-use files. In each CMA, which is nearly coterminous with the corresponding RHA, we created 10 geographic areas based on average income. We analyzed the data at the ecologic level, using linear regression and multilevel Poisson regression. RESULTS: The parasuicide rate in the Edmonton CMA was greater than that in the Calgary CMA (rate ratio 1.3). In both CMAs, the parasuicide rate decreased as average income increased. In the final regression models, the only independent variables were average income, CMA, and their interaction term (linear regression model R2 = 0.82). CONCLUSIONS: The parasuicide rate in the Edmonton CMA is elevated, compared with that in the Calgary CMA. At the ecologic level, much of the variation in rates can be explained by average income and CMA. The high degree of correlation among the sociodemographic variables suggests that it may not be low income per se that is affecting the parasuicide rate but, rather, the consequences of belonging to a socially disadvantaged stratum of society.

Adolescent↗

PubMed2005

History of depression increases risk of type 2 diabetes in younger adults.

OBJECTIVE: The purpose of this study was to assess the history of previous depression in people with incident diabetes compared with people without diabetes. RESEARCH DESIGN AND METHODS: We conducted a population-based nested case-control study using the administrative databases of Saskatchewan Health to assess the study objective. We identified cases of type 2 diabetes based on diagnostics codes and prescription records for individuals over the age of 20 years. For each case subject, two control subjects were randomly selected from the nondiabetic population during the same index year. History of depression, based on diagnostic codes and antidepressant prescription, was ascertained up to 3 years before index date. Simple and multivariate logistic regression analysis was used to estimate the odds ratio (OR) and 95% CIs, after adjusting for age, sex, and frequency of physician visits. RESULTS: Individuals with newly diagnosed diabetes (1,622 of 33,257; 4.9%) were 30% more likely to have had a previous history of depression compared with people without diabetes (2,279 of 59,420; 3.8%). This increased risk remained after controlling for sex and number of physician visits but was limited to subjects 20-50 years of age (adjusted OR 1.23 [95% CI 1.10-1.37]) and not in those aged > or =51 years (0.92 [0.84-1.00]). CONCLUSIONS: Depression appears to increase the risk of developing diabetes by approximately 23% in younger adults. This provides information regarding the temporality of the relationship between diabetes and depression.

Adult↗

PubMed2005

Prevalence and predictors of depression in elderly Canadians: The Canadian Study of Health and Aging.

Depression in elderly Canadians is an important but often unrecognized public health problem. Numerous studies have examined depression in the general community, but studies of depression in the elderly have generally been small and limited. The Canadian Study of Health and Aging (CSHA) includes a large and national representation of both the cognitively intact and the cognitively impaired elderly. The current analyses of 2,341 participants from the CSHA who completed a clinical rating scale for depression have two objectives: 1) to determine the prevalence of minor and major depression and 2) to examine the importance of several risk factors. The prevalences of major and minor depression were 2.6 percent and 4.0 percent, respectively, and were higher for females, specifically those in institutions, those who reported that their health problems limited activities, and those with chronic health conditions. Women were more likely to exhibit depression (OR = 3.5; 95% CI: 1.4-8.8) than men, and those with dementia more likely to exhibit depression than those without (OR = 2.4; 95% CI: 0.9-3.1). Depression is a significant mental health problem among elderly Canadians, particularly among women and those with physical limitations. More attention should be paid to the detection and treatment of depression in the elderly, particularly among those most at risk.

Age Distribution↗

PubMed2004

Commonalities in the classical, collapsibility and counterfactual concepts of confounding.

OBJECTIVES: Three definitions of confounding are available in the epidemiologic literature, namely, the classical, collapsibility, and counterfactual. The classical and collapsibility definitions are intuitively appealing but, especially in the case of the latter, there are shortcomings. The more recent counterfactual definition overcomes these limitations but at the cost of increased abstraction. One of the aims of this article is to demonstrate that under certain conditions the three definitions of confounding have key features in common. CONCLUSIONS: The counterfactual definition of confounding addresses the inherent shortcomings of the classical and collapsibility definitions, and forms the basis of innovative methods of data analysis.

Cohort Studies↗

PubMed2003

A population-based study of the association between pathological gambling and attempted suicide.

The association between pathological gambling and attempted suicide was examined using data from a prevalence study conducted in Edmonton, Alberta, Canada. The sample size was 7,214, the questionnaire was the Diagnostic Interview Schedule, and diagnoses were made on a lifetime basis according to DSM-III criteria. Logistic regression analysis was performed, with attempted suicide as the dependent variable. The odds ratio for pathological gambling was statistically significant (odds ratio = 4.91; 95% confidence interval = [1.41,17.1]) when major depression was the only comorbid mental disorder in the model. As terms for additional mental disorders were included, pathological gambling ceased to be statistically significant. It was concluded that a history of pathological gambling is associated with previous attempted suicide, and that the association may be due to a common factor--"mental illness."

Adolescent↗

PubMedDate not supplied

Test-retest and case-control study of psychological symptoms and social adjustment following parasuicide.

Numerous studies have been conducted in which cases of parasuicide have been followed for repeat parasuicide. By comparison, there have been relatively few studies of other morbidity endpoints. Over a 1-year period, 507 cases of parasuicide and 200 controls were recruited from emergency departments in Edmonton, Canada and interviewed using the Beck Hopelessness Scale, Beck Depression Inventory, State Anger Scale, Trait Anger Scale, Self-Esteem Scale, and Social Adjustment Scale. Over the ensuing 1 to 2 years, 414 cases were reinterviewed using the same questionnaires. Mean symptom scores on all questionnaires improved over the course of follow-up, but did not reach control levels. The pattern of improvement varied according to questionnaire. Only half of cases received treatment for the parasuicide from a psychiatrist, psychologist, or other health care provider during the 3 months following the emergency department visit.

Adjustment Disorders↗

PubMedDate not supplied

Treatment seeking for obsessive-compulsive disorder: role of obsessive-compulsive disorder symptoms and comorbid psychiatric diagnoses.

Previous research has indicated that individuals afflicted with obsessive-compulsive disorder (OCD) have a very low rate of seeking help from mental health professionals. From standardized psychiatric interviews of 7,214 residents of Edmonton, Canada, we identified 172 subjects with a lifetime diagnosis of OCD; 63 (36.6%) had consulted a doctor about their symptoms. Total number of OCD symptoms (odds ratio [OR] = 2.23) and severe obsessions of violence and other unpleasant thoughts (OR = 2.52) were significantly associated with treatment seeking in multivariate analysis. The absence of association between compulsions and treatment seeking was corroborated by a very low prevalence of treatment seeking (17.3%) in individuals suffering from compulsions only. Our findings suggest that there is a need to teach the public about compulsions, and such a strategy may enhance future public health education programs.

Adult↗

PubMedDate not supplied

Human immunodeficiency virus (HIV) and hepatitis C virus (HCV) in a Northern Alberta population.

OBJECTIVE: To describe the demographics and estimate the prevalence of hepatitis C virus (HCV) in a cohort of Human Immunodeficiency Virus (HIV) positive patients in Northern Alberta. METHODS: A cross-sectional (prevalence) study was performed on a cohort of HIV-positive patients. HCV testing was not widely available until December 1989, and the more sensitive, second generation immunoassay was not available until 1992. To reduce the effect of testing bias, we restricted consideration of HCV status to patients first seen January 1, 1992 onward. RESULTS: Forty-four percent of patients in the whole cohort were tested for HCV (564/1,276) and 62% (505/809) of patients entered since January 1, 1992 were tested for HCV. During the period January 1, 1992-December 31, 1999, the prevalence of HCV in our cohort of northern Alberta HIV-positive patients was at least 37.9% (307/809) and was 60.8% (307/505) among those who were tested for HCV in 1992 or later. The mean age of the co-infected group was 33.6 years, 66.1% were male, 91.2% were injection drug users (IDUs), 56.8% were Caucasian, and 40.0% were Aboriginal. A statistically significant difference was found between the HCV-negative cohort, the HCV co-infected cohort, and the HCV-untested cohort for the following variables: risk behaviour, gender, ethnic status, death, occurrence of an AIDS-defining illness (p < 00.0001), and mean baseline CD4 cell count (p = 0.002). CONCLUSION: A high proportion of the HIV-infected IDUs was co-infected with HCV. Compared to the HCV-negative group, the co-infected group appears to have had less advanced HIV disease. This is likely a reflection of more recent HIV infection in the HCV co-infected group.

Adult↗