Incidence of Subsequent Mental Health Disorders and Social Adversity Following Pediatric Concussion: A Longitudinal, Population-Based Study.

OBJECTIVE: To determine the long-term risk of new adverse psychosocial outcomes among adolescents diagnosed with a concussion compared with those not diagnosed. STUDY DESIGN: A retrospective, population-based cohort study was conducted. Adolescents (10-18 years) with a physician-diagnosed concussion between 2000 and 2005 were matched on neighborhood and age with 5 controls without concussion from the general population. New-onset mental health disorders, medication use, social, and justice outcomes were extracted using datasets linked to the population data repository. Adolescents were followed for 11-16 years. Adjusted hazard ratios (95% CIs) were estimated. RESULTS: In total, 2082 adolescents with a concussion were matched to 10 510 without. Adolescents with a concussion had an increased risk of any mental health disorder (HR 1.34; 95% CI 1.25-1.45), mood disorder (HR 1.30; 95% 1.18-1.43), psychosis (HR 1.43; 95% CI 1.18-1.74), substance abuse disorder (HR 1.67; 95% 1.31-2.14), and receiving a psychotropic prescription (HR 1.31; 95% CI 1.20-1.42). Female adolescents had an increased risk of ADHD following concussion (HR 1.89; 95% CI 1.17-3.05). Adolescents with a concussion had an increased risk of being accused (HR 1.22; 95% CI 1.11-1.34), victim (HR 1.29; 95% CI 1.11-1.48), or witness (HR 1.16; 95% CI 1.01-1.32) of a crime, or contact with Child and Family Services (HR 1.33; 95% CI 1.10-1.62). There was no association between concussion and attempting or completing suicide, receiving housing support, or collecting income support. CONCLUSIONS: Concussion was associated with an increased risk for multiple adverse psychosocial outcomes. Future work should focus on early identification of those at risk of these outcomes to help optimize longitudinal medical care and support.

Administrative Data Is Insufficient to Identify Near-Future Critical Illness: A Population-Based Retrospective Cohort Study.

Background: Prediction of future critical illness could render it practical to test interventions seeking to avoid or delay the coming event. Objective: Identify adults having >33% probability of near-future critical illness. Research Design: Retrospective cohort study, 2013-2015. Subjects: Community-dwelling residents of Manitoba, Canada, aged 40-89 years. Measures: The outcome was a near-future critical illness, defined as intensive care unit admission with invasive mechanical ventilation, or non-palliative death occurring 30-180 days after 1 April each year. By dividing the data into training and test cohorts, a Classification and Regression Tree analysis was used to identify subgroups with ≥33% probability of the outcome. We considered 72 predictors including sociodemographics, chronic conditions, frailty, and health care utilization. Sensitivity analysis used logistic regression methods. Results: Approximately 0.38% of each yearly cohort experienced near-future critical illness. The optimal Tree identified 2,644 mutually exclusive subgroups. Socioeconomic status was the most influential variable, followed by nursing home residency and frailty; age was sixth. In the training data, the model performed well; 41 subgroups containing 493 subjects had ≥33% members who developed the outcome. However, in the test data, those subgroups contained 429 individuals, with 20 (4.7%) experiencing the outcome, which comprised 0.98% of all subjects with the outcome. While logistic regression showed less model overfitting, it likewise failed to achieve the stated objective. Conclusions: High-fidelity prediction of near-future critical illness among community-dwelling adults was not successful using population-based administrative data. Additional research is needed to ascertain whether the inclusion of additional types of data can achieve this goal.

Accuracy of Administrative Hospital Data to Identify Use of Life Support Modalities. A Canadian Study.

Rationale: Accurately identifying use of life support in hospital administrative data enhances the data's value for quality improvement and research in critical illness.Objectives: To assess the accuracy of administrative hospital data for identifying invasive mechanical ventilation (IMV), acute renal replacement therapy (RRT), and intravenous vasoactive drugs in unselected adult intensive care unit (ICU) patients.Methods: We employed the administrative dataset of the Discharge Abstract Database from the Province of Manitoba during 2007-2012, using nationally standardized diagnosis and procedure codes to identify the three types of life support. The criterion standard was the Winnipeg ICU Database, which contains daily clinical information about all admissions to all 11 adult ICUs within the Winnipeg Regional Health Authority. For all individuals aged 40 years or older at ICU admission, we calculated sensitivity, specificity, positive predictive value (PPV), and negative predictive value of the administrative data for identifying life support. We also assessed the ability of the administrative data to identify overlapping use of the forms of life support.Results: Over the study period, there were 20,764 eligible ICU admissions; 52.6% (10,914) involved IMV, 46.8% (9,724) involved vasoactive agents, and 4.4% (907) involved acute RRT. Identification of IMV from administrative data procedure codes was good, with all four parameters exceeding 90%. The procedure code for use of selected vasoactive drugs had a sensitivity of zero; addition of diagnosis codes for shock raised the sensitivity to only 23% (95% confidence interval [CI], 22-24%). Both the sensitivity and specificity for acute RRT procedure codes exceeded 92%, but owing to low prevalence of RRT, the PPV was only 55% (95% CI, 53-58%). Addition of diagnosis codes for acute renal failure did not appreciably improve performance. Overlapping use of the three types of life support was substantial. Among those receiving any one of the types of life support, 68-76% received at least one of the two other types assessed. Considering use of any one or more of the three forms of life support, the administrative data had a PPV of 97% (95% CI, 96-97%) and a negative predictive value of 69% (95% CI, 68-70%).Conclusions: Administrative data accurately identify IMV but not use of vasoactive drugs or acute RRT.

Academic Outcomes in High-School Students after a Concussion: A Retrospective Population-Based Analysis.

BACKGROUND: Many concussion symptoms, such as headaches, vision problems, or difficulty remembering or concentrating may deleteriously affect school functioning. Our objective was to determine if academic performance was lower in the academic calendar year that students sustain a concussion compared to the previous year when they did not sustain a concussion. METHODS: Using Manitoba Health and Manitoba Education data, we conducted a population-based, controlled before-after study from 2005-2006 to 2010-2011 academic years. Grade 9-12 students with an ICD9/10 code for concussion were matched to non-concussed controls. Overall changes in grade point average (GPA) were compared for the academic year prior to the concussion to the academic year the concussion occurred (or could have occurred among non-concussed matched students). RESULTS: Overall, 8240 students (1709 concussed, 6531 non-concussed students) were included. Both concussed and non-concussed students exhibited a lower overall GPA from one year to the next. Having sustained a concussion resulted in a -0.90% (95% CI: -1.88, 0.08) reduction in GPA. Over the same period, non-concussed matched students' GPA reduced by -0.57% (95% CI: -1.32, 0.19). Students who sustained a concussion during high school were just as likely to graduate within four years as their non-concussed peers (ORadj: 0.84; 95% CI: 0.73, 1.02). CONCLUSIONS: We found that, at a population level, a concussion had minimal long-term effects on academic performance during high school. While academic accommodations and Return-to-Learn programs are an important component of pediatric concussion management, research is needed to identify risk factors for poor academic performance after a concussion and who should receive these programs.

Neurodevelopmental Assessment in Kindergarten in Children Exposed to General Anesthesia before the Age of 4 Years: A Retrospective Matched Cohort Study.

BACKGROUND: Animal studies demonstrate general anesthetic (GA) toxicity in the developing brain. Clinical reports raise concern, but the risk of GA exposure to neurodevelopment in children remains uncertain. METHODS: The authors undertook a retrospective matched cohort study comparing children less than 4 yr of age exposed to GA to those with no GA exposure. The authors used the Early Development Instrument (EDI), a 104-component questionnaire, encompassing five developmental domains, completed in kindergarten as the outcome measure. Mixed-effect logistic regression models generated EDI estimates for single versus multiple GA exposure and compared both single and multiple exposures by the age of 0 to 2 or 2 to 4 yr. Known sociodemographic and physical confounders were incorporated as covariates in the models. RESULTS: A total of 18,056 children were studied: 3,850 exposed to a single GA and 620 exposed to two or more GA, who were matched to 13,586 nonexposed children. In children less than 2 yr of age, there was no independent association between single or multiple GA exposure and EDI results. Paradoxically, single exposure between 2 and 4 yr of age was associated with deficits, most significant for communication/general knowledge (estimate, -0.7; 95% CI, -0.93 to -0.47; P < 0.0001) and language/cognition (estimate, -0.34; 95% CI, -0.52 to -0.16; P < 0.0001) domains. Multiple GA exposure at the age of 2 to 4 yr did not confer greater risk than single GA exposure. CONCLUSIONS: These findings refute the assumption that the earlier the GA exposure in children, the greater the likelihood of long-term neurocognitive risk. The authors cannot confirm an association between multiple GA exposure and increased risk of neurocognitive impairment, increasing the probability of confounding to explain the results.

Sustained Use of Benzodiazepines and Escalation to High Doses in a Canadian Population.

OBJECTIVE: "Antibenzodiazepine" campaigns have been conducted worldwide to limit the prescribing of these drugs because of concerns about inappropriate use and addiction. The causal relationship between long-term use and escalation to high doses has not been proven. This study assessed the extent of dose escalation among individuals who were long-term users of benzodiazepines or Z-hypnotics. METHODS: A population-based study was conducted in the Canadian province of Manitoba using administrative health databases. Sustained use was defined as continuous use for at least two years (N=12,598). Dose escalation, measured in diazepam milligram equivalents (DMEs) per day and observed at six-month intervals, was assessed by using latent-class trajectory analysis. Characteristics of individuals with sustained use were described. RESULTS: The analysis revealed four distinct groups. Two groups (<8% of the cohort) showed escalation to high doses (over 40 DMEs). More than 55% of high-dose escalators were in the 0- to 44-year age group, 75% lived in urban areas, and approximately 75% had a diagnosis of depression. Clonazepam was the drug most commonly involved with dose escalation; among individuals escalating to doses higher than 60 DMEs, 91% were using clonazepam. Rates of "doctor shopping" and "pharmacy hopping" were higher among younger adults, compared with older adults. Younger adults also had higher rates of concomitant antidepressant therapy. CONCLUSIONS: A limited segment of a population that received benzodiazepine prescriptions was classified as sustained users, and a small proportion of that group escalated to doses higher than those recommended by product monographs and clinical guidelines.

The effect of neighborhood socioeconomic status on education and health outcomes for children living in social housing.

OBJECTIVES: We explored differences in health and education outcomes between children living in social housing and not, and effects of social housing's neighborhood socioeconomic status. METHODS: In this cohort study, we used the population-based repository of administrative data at the Manitoba Centre for Health Policy. We included children aged 0 to 19 years in Winnipeg, Manitoba, in fiscal years 2006-2007 to 2008-2009 (n = 13,238 social housing; n = 174,017 others). We examined 5 outcomes: age-2 complete immunization, a school-readiness measure, adolescent pregnancy (ages 15-19 years), grade-9 completion, and high-school completion. Logistic regression and generalized estimating equation modeling generated rates. We derived neighborhood income quintiles (Q1 lowest, Q5 highest) from average household income census data. RESULTS: Children in social housing fared worse than comparative children within each neighborhood income quintile. When we compared children in social housing by quintile, preschool indicators (immunization and school readiness) were similar, but adolescent outcomes (grade-9 and high-school completion, adolescent pregnancy) were better in Q3 to Q5. CONCLUSIONS: Children in social housing had poorer health and education outcomes than all others, but living in social housing in wealthier areas was associated with better adolescent outcomes.

Evaluating the effectiveness of cervical cancer screening invitation letters.

OBJECTIVE: The objective of this study was to evaluate the effectiveness of an invitation letter on cervical screening participation among unscreened women 30 to 69 years of age. METHODS: A cluster randomized trial design was used in which unscreened women (n=31,452) were randomized by the forward sortation area (FSA) of their postal code to an intervention group that was sent an invitation letter (n=17,068) or a group that was not sent an invitation letter (n=14,384). RESULTS: Six months after the letters were mailed, 1,010 women in the intervention group (5.92%) and 441 women in the control group (3.06%) had a Pap test. After adjusting for variables that have previously shown to influence screening participation, women who were sent an invitation letter were significantly more likely to have had a Pap test in the next 6 months compared with women who were not sent an invitation letter (odds ratio [OR]=2.60, 95% confidence interval [CI] 2.09-3.35, p<0.001). Overall, the effectiveness of the invitation letter improved with increasing age (p=0.02). CONCLUSIONS: Sending invitation letters increased cervical screening participation but because the overall effect was small, additional strategies that remove barriers to screening for unscreened women are also necessary.

Rates of readmission and death associated with leaving hospital against medical advice: a population-based study.

BACKGROUND: Leaving hospital against medical advice may have adverse consequences. Previous studies have been limited by evaluating specific types of patients, small sample sizes and incomplete determination of outcomes. We hypothesized that leaving hospital against medical advice would be associated with increases in subsequent readmission and death. METHODS: In a population-based analysis involving all adults admitted to hospital and discharged alive in Manitoba from Apr. 1, 1990, to Feb. 28, 2009, we evaluated all-cause 90-day mortality and 30-day hospital readmission. We used multivariable regression, adjusted for age, sex, socioeconomic status, year of hospital admission, patient comorbidities, hospital diagnosis, past frequency of admission to hospital, having previously left hospital against medical advice and data clustering (patients with multiple admissions). For readmission, we assessed both between-person and within-person effects of leaving hospital against medical advice. RESULTS: Leaving against medical advice occurred in 21 417 of 1 916 104 index hospital admissions (1.1%), and was associated with higher adjusted rates of 90-day mortality (odds ratio [OR] 2.51, 95% confidence interval [CI] 2.18-2.89), and 30-day hospital readmission (within-person OR 2.10, CI 1.99-2.21; between-person OR 3.04, CI 2.79-3.30). In our additional analyses, elevated rates of readmission and death associated with leaving against medical advice were manifest within 1 week and persisted for at least 180 days after discharge. INTERPRETATION: Adults who left the hospital against medical advice had higher rates of hospital readmission and death. The persistence of these effects suggests that they are not solely a result of incomplete treatment of acute illness. Interventions aimed at reducing these effects may need to include longitudinal interventions extending beyond admission to hospital.

Social gradients in surgical sterilization rates: opposing patterns for males and females.

OBJECTIVE: The purpose of this study was to analyze population-based rates of surgical sterilization by sex, income, age group, and location of residence (urban, rural, or remote) among a universally insured population. METHODS: The study included all 1.2 million residents of Manitoba. Data from comprehensive hospital and medical visit records were used to calculate rates of vasectomy and tubal ligation among the population aged 20 to 55 years. Analyses were carried out with generalized linear modelling, using administrative data housed at the Manitoba Centre for Health Policy. RESULTS: There were significant income-related gradients in sterilization rates for both sexes (P < 0.001), but the trends were in opposite directions for males and females. Tubal ligation rates were highest in low-income areas, and decreased with income, whereas vasectomy rates were lowest in low-income areas and increased with income. Rates also varied considerably by age and area of residence (urban, rural, or remote). CONCLUSION: These results are potentially worrying because tubal ligation is more invasive, associated with higher risks, and more costly than vasectomy. It would therefore be expected to be less common than vasectomy among all groups, not just those in higher income areas. The results contribute unique population-based procedure rates, which are not subject to biases that can affect survey-based studies. The findings may reflect underlying differences across income groups in decision-making regarding reproductive health issues.

Objectif : Cette étude avait pour but d'analyser les taux en population générale de stérilisation chirurgicale en fonction du sexe, du revenu, du groupe d'âge et du lieu de résidence (urbain, rural ou éloigné) au sein d'une population bénéficiant d'une assurance maladie universelle. Méthodes : L'étude s'est penchée sur les 1,2 million de résidents du Manitoba. Des données issues de dossiers exhaustifs de consultation hospitalière et médicale ont été utilisées pour calculer les taux de vasectomie et de ligature des trompes chez les membres de la population dont l'âge se situait entre 20 et 55 ans. Des analyses ont été menées au moyen d'une modélisation linéaire généralisée, en utilisant les données administratives du Manitoba Centre for Health Policy. Résultats : Les taux de stérilisation chez les deux sexes (P < 0,001) présentaient des gradients significatifs liés au revenu; toutefois, les tendances étaient opposées chez les hommes et les femmes. Les taux de ligature des trompes atteignaient leur apogée dans les régions à faible revenu et étaient inversement proportionnels au revenu, tandis que les taux de vasectomie atteignaient leur plus bas niveau dans les régions à faible revenu et étaient proportionnels au revenu. Ces taux variaient également de façon considérable en fonction de l'âge et du lieu de résidence (urbain, rural ou éloigné). Conclusion : Ces résultats sont potentiellement troublants, en raison du fait que la ligature des trompes est une intervention plus effractive, associée à plus de risques et plus coûteuse que la vasectomie. On serait donc en droit de s'attendre à ce qu'elle soit moins courante que la vasectomie dans tous les groupes, et non seulement dans les groupes des régions à revenu élevé. Ces résultats donnent des taux d'intervention en population générale uniques, lesquels ne sont pas assujettis aux biais qui peuvent affecter les études fondées sur des sondages. Nos constatations pourraient refléter des différences sous-jacentes, d'un groupe de revenu à l'autre, en ce qui concerne la prise de décision en matière de questions de santé génésique.

Concordance with ASCO guidelines for surveillance after colorectal cancer treatment: a population-based analysis.

PURPOSE: Intensive surveillance after curative treatment of colorectal cancer (CRC) is associated with improved overall survival. This study examined concordance with the 2005 ASCO surveillance guidelines at the population level. METHODS: A cohort of 250 patients diagnosed with stage II or III CRC in 2004 and alive 42 months after diagnosis was identified from health administrative data in Manitoba, Canada. Colonoscopy, liver imaging, and carcinoembryonic antigen (CEA) testing were assessed over 3 years. Guidelines were met if patients had at least one colonoscopy in 3 years and at least one liver imaging test and three CEA tests annually. Multivariate logistic regression assessed the effect of patient and physician characteristics and disease and treatment factors on guideline concordance. RESULTS: Guidelines for colonoscopy, liver imaging, and CEA were met by 80.4%, 47.2%, and 22% of patients, respectively. Guideline concordance for colonoscopy was predicted by annual contact with a surgeon, higher income, and the diagnosis of colon (rather than rectal) cancer. Adherence was lower in those older than 70 years and with higher comorbidity. For liver imaging, significant predictors were annual contact with an oncologist, receipt of chemotherapy, and diagnosis of colon cancer. Concordance with CEA guidelines was higher with annual contact with an oncologist and high levels of family physician contact, and lower in urban residents, in those older than 70, and in those with stage II disease. CONCLUSION: Completion of recommended liver imaging and CEA testing fall well below guidelines in Manitoba, whereas colonoscopy is better provided. Addressing this gap should improve outcomes for CRC survivors.

Papanicolaou test utilization and frequency of screening opportunities among women diagnosed with cervical cancer.

BACKGROUND: Although the importance of Papanicolaou (Pap) smear test screening in reducing the incidence of cervical cancer is well established, in 1994-95 one in 4 women in Manitoba aged 18 to 69 years reported never having had a Pap test or not having had a Pap test in the last 3 years. The objectives of this study were to examine the screening history of women in Manitoba diagnosed with invasive cervical cancer and to explore whether opportunities for screening were missed. METHODS: In this case-control study women aged 18 years and older who resided in Manitoba and were diagnosed with invasive cervical cancer between 1989 and 2001 were each matched by age and area of residence to 5 controls, (N = 4009). Conditional logistic regression analyses were used to examine the association between Pap test utilization and the likelihood of diagnosis with invasive cervical cancer. Generalized linear models using the negative binomial distribution were used to assess the association between cancer status and rates of prior Pap testing and of opportunities to be screened. Logistic generalized estimating equation models were used for the analysis of physician characteristics. RESULTS: Forty-six percent of women in Manitoba diagnosed with invasive cervical cancer and 67% of the control group had received a Pap test in the 5 years before the case's diagnosis. After adjustment for age, income and residence, the rate of Pap testing was significantly higher in the control group (rate ratio [RR] = 1.57, 95% confidence interval [CI] 1.44-1.73). Conversely, when cervical cancer was the outcome, women who had not had Pap tests were more likely to be diagnosed with invasive cervical cancer (odds ratio [OR] = 2.77, 95% CI 2.30-3.30) than women who did have a Pap test. Although women diagnosed with invasive cervical cancer had fewer Pap tests, they had had as many opportunities to be screened as controls (RR = 1.04, 95% CI 0.96-1.12). Compared with urban family physicians, rural family physicians were less likely to provide Pap tests (OR = 0.68, 95% CI 0.58-0.80) and specialists were more likely to provide Pap tests (OR = 1.70, 95% CI 1.30-2.22). CONCLUSIONS: Women who were diagnosed with invasive cervical cancer in the province of Manitoba, Canada, had fewer Pap tests but the same frequency of opportunities to be screened as matched controls. These results reinforce the need to educate women about cervical cancer screening and the importance of receiving Pap tests.

The relative efficacies of gastroprotective strategies in chronic users of nonsteroidal anti-inflammatory drugs.

BACKGROUND & AIMS: There are numerous gastroprotective strategies recommended for reducing the risk of upper gastrointestinal (GI) complications in long-term users of nonsteroidal anti-inflammatory drugs (NSAIDs). The relative efficacy of the different strategies alone or in combination is uncertain. METHODS: We used the Manitoba Population Health Research Data Repository to perform a population-based matched case-control analysis. All NSAID users (nonselective and cyclooxygenase [COX]-2-specific) users admitted to the hospital with a primary diagnosis for an upper gastrointestinal complication were matched to NSAID-using controls in the community. We used conditional logistic regression analysis to determine the relative efficacy of different gastroprotective strategies (proton pump inhibitors [PPIs], COX-2 inhibitors, and low-dose/high-dose misoprostol) either alone or in combination and to adjust for multiple pertinent covariates. RESULTS: A total of 1382 NSAID/COX-2 users with upper GI complications were matched to 33,957 age- and sex-matched controls. Cotherapy with PPIs or misoprostol or use of a COX-2 inhibitor all significantly reduced the risk of upper GI complications. COX-2 inhibitors were not statistically more likely to prevent upper GI complications than PPIs, although they were superior to low-dose misoprostol. The combination of COX-2 inhibitors with a PPI was associated with the greatest degree of upper GI complication risk reduction. CONCLUSIONS: All of the commonly accepted gastroprotective strategies reduce the risk of upper GI complications in NSAID users, although the combination of COX-2 inhibitors with PPIs promotes the greatest risk reduction for NSAID-related upper GI complications. Celecoxib use specifically may be superior to the combination of nonselective NSAIDs with a PPI.

The incidence of methylphenidate use by Canadian children: what is the impact of socioeconomic status and urban or rural residence?

OBJECTIVE: To examine socioeconomic, demographic, and behavioural factors that influence the incidence of methylphenidate use among children aged 4 to 13 years. METHOD: A total of 11,316 children, aged 2 through 11 years, from Cycle 1 (1994-95) of the National Longitudinal Survey of Children and Youth were followed up 2 years later in Cycle 2 (1996-97). The outcome measure was methylphenidate use in Cycle 2. Individual-level explanatory variables included sex, age, socioeconomic status (SES), mother's age at birth of child, lone-parent family status, parental working status, and hyperactivity-impulsivity and inattention probabilities. Area-level explanatory variables included income and rural or urban residence. We used hierarchical linear modelling to examine individual- and area-level factors that predicted methylphenidate use. RESULTS: The strongest predictors of methylphenidate use were behavioural: children with high hyperactive-impulsive and (or) inattention behaviours in 1994, compared with children low on these behaviours, were 4.5 to 6 times more likely to use methylphenidate 2 years later. SES remained a significant predictor of the incidence of methylphenidate use, even when other significant predictors were held constant, with lower SES being associated with higher use. Area-level income also predicted methylphenidate use. CONCLUSION: Even when children with similar behavioural symptoms and demographic characteristics were compared, socioeconomic factors had a significant impact on incidence of methylphenidate use.

Influence of direct referrals on time to diagnosis after an abnormal breast screening result.

This study examined the influence of a direct referral process implemented by a population-based provincial breast screening program on the time from screening to first procedure, first procedure to diagnosis, and screening to diagnosis following an abnormal breast screening result. The direct referral process shifted the responsibility for the coordination of diagnostic follow-up procedures from the family physician to the screening program. Three cohorts of women were included: a control cohort (screened prior to the initiation of a direct referral process, n = 1347), a usual care cohort (screened after the initiation of a direct referral process but for whom permission to refer was denied by the family physician, n = 1225), and a direct referral cohort (screened after the initiation of the direct referral process and for whom permission to refer was given by the family physician, n = 1232). The direct referral cohort was subdivided into women referred to a breast health centre (BHC group) (n = 606) and women referred to a diagnostic facility (diagnostic group) (n = 626). The direct referral cohort completed all three time intervals significantly faster than the other two cohorts (P < 0.0001). The diagnostic group experienced a significantly lower time from screening to the first procedure than the other cohorts or the BHC group (P < 0.0001). However, the BHC group had a significantly lower time from first procedure to diagnosis than the other cohorts or the diagnostic group (P < 0.0001). The control and the usual care cohorts were not significantly different from each other (P = 0.6250). The direct referral process significantly reduced the time to diagnosis after an abnormal screening result.

Factor analysis of ethnic variation in the multiple metabolic (insulin resistance) syndrome in three Canadian populations.

This study describes and compares the pattern of risk factor clustering in multiple metabolic (insulin resistance) syndrome (MMS) in three Canadian ethnic groups (Indians, Inuit, non-Aboriginal Canadians). Three cross-sectional, population-based sample surveys in three contiguous regions of Canada were conducted during the late 1980s and early 1990s (Ontario, Manitoba, Northwest Territories). The combined dataset consists of 873 Cree-Ojibwa Indians from northern Ontario and Manitoba, 387 Inuit from the Northwest Territories, and 2,670 non-Aboriginal Canadians (predominantly of European origin) in the province of Manitoba. The samples are representative of the noninstitutionalized, adult population of their respective catchment areas. Factor analysis transformed 10 anthropometric and metabolic variables into three uncorrelated factors. Three factors, which together account for 64.3% of the variance, can be identified: an "obesity factor" (factor loadings for weight, height, waist and hip girth, and HDL-cholesterol); a "blood pressure factor" (factor loadings for mean systolic and diastolic BP and total cholesterol); and a "lipid/glucose factor" (factor loadings for triglycerides, total cholesterol, HDL, and fasting plasma glucose). Fasting insulin is available for only a subset of the data and separate analysis shows that it groups with glucose. Factor scores generated by the factor analysis differ according to ethnic group, diabetes status, and sex on multivariate analysis of variance. Indians have the highest scores for all three factors. Inuit have the lowest obesity scores and are not significantly different from non-Aboriginal people with regard to the other two factors. MMS is prevalent in diverse ethnic groups but varies in the pattern of phenotypic expression, with some components more prominent in some groups.