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Stewart B Harris

Publications and source records attributed to Stewart B Harris.

34 records · Page 2Linked to original sources
PubMed2004

Lifestyle management for type 2 diabetes. Are family physicians ready and willing?

OBJECTIVE: To determine practices and perceptions of family physicians regarding lifestyle interventions to prevent and manage type 2 diabetes (T2D). DESIGN: Confidential mailed survey. SETTING: Canadian family practices. PARTICIPANTS: Random, stratified sample of 1499 respondents to the 2001 National Family Physician Workforce Survey. MAIN OUTCOME MEASURES: Physicians' self-reported practice patterns and perceptions of lifestyle counseling for patients at risk for, and diagnosed with, T2D. RESULTS: Response rate was 53% (749/1410). Respondents frequently asked patients at risk for, or diagnosed with, T2D about physical activity and weight loss, but far fewer provided written advice, particularly about physical activity. Respondents thought counseling with such interventions as generic patient handouts was preferable to more intensive lifestyle management strategies, such as appointments to provide stage-matched counseling on physical activity. Most respondents thought family physicians should perform lifestyle interventions but realized they are confounded by such barriers as patients' lack of interest and limited referral resources. CONCLUSION: Family physicians keen to implement lifestyle interventions for T2D are hampered by barriers and use of ineffective strategies.

Adult↗
PubMed2003

Patient satisfaction and quality of care in walk-in clinics, family practices and emergency departments: the Ontario Walk-In Clinic Study.

BACKGROUND: Although walk-in clinics are an increasingly common feature of Ontario's health care system, the quality of care they provide is the subject of continuing debate. In this study we examined differences in patient satisfaction and quality of care for common acute conditions in walk-in clinics, family practices and emergency departments. METHODS: For this prospective cohort study, we recruited 12 walk-in clinics, 16 family practices and 13 emergency departments from 11 geographic areas in greater Toronto, Hamilton-Burlington and London, Ont. An expert review panel selected and established quality-of-care criteria for 8 common acute conditions. Patients who sought initial care for 1 of the 8 conditions were recruited by an on-site data collector. We used a questionnaire to assess the satisfaction of 433 patients with patient-centred communication, the physician's attitude and any delay in the waiting room during the study visit. Abstractors reviewed 600 charts for the study patients to assess whether the quality-of-care criteria had been met. A quality score for each case was computed as the percentage of applicable criteria that were met. Mean quality scores for the 3 settings were computed, with adjustment for potentially confounding variables (sex, age, city and diagnosis). RESULTS: After adjustment for 12 patient characteristics, walk-in clinic patients were significantly more satisfied than emergency department patients on all 3 satisfaction scales. Family practice patients were more satisfied than walk-in clinic patients on all 3 satisfaction scales, but the difference was statistically significant only for satisfaction with waiting time. Adjusted mean quality-of-care scores were 73.1% for emergency departments, 69.9% for walk-in clinics and 64.1% for family practices. The scores for walk-in clinics and emergency departments were significantly higher than that for family practices. INTERPRETATION: Satisfaction with waiting time was highest among family practice patients. Both family practices and walk-in clinics were perceived more positively than emergency departments on all 3 dimensions of satisfaction. Overall quality-of-care scores were higher in walk-in clinics and emergency departments than in family practices.

Adolescent↗
PubMed2003

Genes, environment and Oji-Cree type 2 diabetes.

The prevalence of type 2 diabetes in Canadian Oji-Cree is among the highest in the world. Our research has uncovered genetic determinants of Oji-Cree type 2 diabetes and related metabolic traits. The most important genetic discovery by far was the private G319S mutation in transcription factor HNF-1alpha, encoded by the HNF1A gene. HNF1A G319S was discovered by candidate gene sequencing and would have been missed using the currently favored strategy of genome-wide scanning. G319S was associated with increased odds of having type 2 diabetes across the whole study sample and in all subgroups, including adolescent Oji-Cree. Furthermore, G319S had specificity and positive predictive value of 97% and 95%, respectively, for developing type 2 diabetes by age 50. The protein bearing the G319S mutation had impaired function in vitro. Sigmoidal modeling showed that each dose of the G319S allele accelerated the median age of diabetes onset by about 7 yr. This approach also showed that environment more strongly accelerated the median age-of-onset of Oji-Cree diabetes onset than did G319S, which could have implications for intervention strategies to reduce the burden of this epidemic. There is also evidence for genetic determination of related metabolic traits in the Oji-Cree.

Adolescent↗
PubMed2003

Free fatty acid-mediated impairment of glucose-stimulated insulin secretion in nondiabetic Oji-Cree individuals from the Sandy Lake community of Ontario, Canada: a population at very high risk for developing type 2 diabetes.

The Oji-Cree population of the Sandy Lake region of Ontario, Canada, has the third highest prevalence of type 2 diabetes in the world. Changes in their diet and physical activity over the past half-century, particularly the marked increase in consumption of dietary fats, are felt to be important factors accounting for this epidemic. The aim of the present study was to examine the beta-cell response to a 48-h approximately twofold elevation of plasma free fatty acids (FFAs) (induced by Intralipid and heparin infusion) in members of the Sandy Lake Oji-Cree population (n = 12) and to compare the response to that in healthy age-matched nondiabetic Caucasian subjects (n = 16). The insulin secretion rate, insulin sensitivity index (S(I)), and disposition index (D(I)) (an index of insulin secretion that takes into account the ambient S(I)) were assessed in response to a 4-h graded intravenous glucose infusion followed by a 20 mmol/l 2-h hyperglycemic clamp. Total insulin secretory response to the graded glucose infusion did not change after a 48-h FFA elevation versus saline control in Caucasians and increased by approximately 30% in Oji-Cree individuals (P = 0.04 for difference between the two groups). Infusion of heparin-Intralipid reduced S(I) by approximately 40% in both groups (P = 0.002). Although D(I) was markedly reduced by heparin-Intralipid infusion in Caucasians (by approximately 40%), it was reduced by only 15% in Oji-Cree individuals (P = 0.03 for difference of response between the two groups). However, S(I) and D(I) in the Oji-Cree individuals were already much lower than in Caucasians at baseline, in keeping with the very high risk of type 2 diabetes in this population. It is concluded that Oji-Cree individuals from a community at very high risk for developing type 2 diabetes are not more susceptible to the FFA-induced desensitization of glucose-stimulated insulin secretion than healthy non-Natives and, in fact, appear to be less susceptible. Whether this reflects an inherent resistance to lipotoxicity or an already-present lipotoxic effect in this population will require further study.

Blood Glucose↗
PubMed2003

Adiponectin in a native Canadian population experiencing rapid epidemiological transition.

OBJECTIVE: Adiponectin is emerging as an important protein in the etiology of obesity and related metabolic disorders. The objectives of this study were to determine cross-sectional and prospective associations of adiponectin concentration with adiposity, type 2 diabetes, and cardiovascular disease (CVD) risk factors in a population-based study of Native Canadians, a group experiencing dramatic increases in diabetes and CVD. RESEARCH DESIGN AND METHODS: During the 1993-1995 baseline survey, samples for glucose, insulin, adiponectin, and lipids were collected after an overnight fast. Waist circumference and percent body fat were measured, and a 75-g oral glucose tolerance test was administered: n = 505 with normal glucose tolerance (NGT), 74 with impaired glucose tolerance (IGT), and 149 with diabetes. In 1998, 95 high-risk subjects, defined as those who, at baseline, had either IGT or NGT with an elevated 2-h glucose concentration (>/==" BORDER="0">7.0 mmol/l), participated in a follow-up examination using the protocol used at baseline. RESULTS: After adjustment for covariates including percent body fat and homeostasis model assessment of insulin resistance (HOMA-IR), adiponectin concentrations were significantly lower among men versus women (10.8 vs. 15.0 micro g/ml, P < 0.0001) and among diabetic versus NGT subjects (11.1 vs. 13.1 micro g/ml, P < 0.05). Adiponectin was inversely correlated with percent body fat, waist circumference, HOMA-IR, and triglyceride and positively correlated with HDL (r = |0.30|-|0.44|, all P < 0.0001). In multivariate linear regression analysis in nondiabetic subjects, HDL and percent body fat were significantly related to adiponectin variation among both men and women (R(2) = 28-29%). Factor analysis returned three underlying factors among these variables, with adiponectin loading on the second factor along with insulin, waist circumference, triglyceride, and HDL. In the follow-up study, higher adiponectin at baseline was significantly associated with increases in HDL (r = 0.24, P = 0.03) and decreases in HOMA-IR (r = -0.29, P = 0.009) after adjustment for covariates, including age, adiposity, and diabetes status at baseline and follow-up. CONCLUSIONS: These population-based findings support the hypothesis that low circulating levels of adiponectin are an important determinant of risk of CVD.

Adiponectin↗
PubMed2003

Type 2 diabetes in family practice. Room for improvement.

OBJECTIVE: To further knowledge of diabetes management in family practice. DESIGN Retrospective, observational chart audit study. SETTING: Southwestern Ontario. PARTICIPANT: A random sample of non-academic family physicians and a random selection of their patients with type 2 diabetes mellitus. MAIN OUTCOME MEASURES: Glycemic control as measured by HbA1c and adherence to recommendations in clinical practice guidelines (CPGs). RESULTS: Eighty-four percent of patients had at least one HbA1c test ordered in the previous year. Overall mean HbA1c was 0.079 and half-the patients had levels deemed acceptable by 1992 CPGs. Screening for microvascular complications was disappointing; only 28% were tested for microalbuminuria, and 15% were examined for diabetes-related foot conditions. Screening for macrovascular complications was more comprehensive; blood pressure was measured in 88%, and lipid profiles documented in 48%, of patient charts. CONCLUSION: Management of glycemic control and screening for microvascular and macrovascular disease in family practice can be improved.

Adult↗
PubMed2003

Lifestyle interventions for type 2 diabetes. Relevance for clinical practice.

OBJECTIVE: To review evidence from literature on type 2 diabetes pertinent to physical activity and diet and lifestyle modification, and to determine the relevance of this evidence to clinical practice. QUALITY OF EVIDENCE: Direct (level I) evidence supports interventions for physical activity and diet modification for primary prevention and management of type 2 diabetes. Few studies examine the effectiveness of primary health care providers' making such interventions. MAIN MESSAGE: Family physicians have an important role in identifying people at risk of developing type 2 diabetes and managing those diagnosed with the disease, yet they struggle to deliver practice-based interventions that promote sustainable behaviour change among their patients. CONCLUSION: It is evident that supporting patients to make changes in their physical activity and dietary habits can prevent onset of type 2 diabetes. Translating this finding into effective recommendations for clinical practice requires further effort and evaluation.

Diabetes Mellitus, Type 2↗
PubMed2002

HNF-1alpha G319S, a transactivation-deficient mutant, is associated with altered dynamics of diabetes onset in an Oji-Cree community.

The prevalence of type 2 diabetes mellitus in the Oji-Cree of northwestern Ontario is the third highest in the world. A private mutation, G319S, in HNF1A, which encodes hepatic nuclear factor-1alpha (HNF-1alpha), was associated with Oji-Cree type 2 diabetes and was found in approximately 40% of affected subjects. The G319S mutation reduced the in vitro ability of HNF-1alpha to activate transcription by approximately 50%, with no effect on DNA binding or protein stability. There was no evidence of a dominant negative effect of the mutant protein. The impact of the G319S mutation at the population level was assessed by classifying subjects with type 2 diabetes according to HNF1A genotype and plotting the cumulative age of onset of diabetes. Disease onset was modeled satisfactorily by two-parameter sigmoidal functions for all diabetic subjects and all three HNF1A genotypes. Pairwise statistical comparisons showed significant between-genotype differences in t50 (all P < 0.00001), corresponding to the age at which half the subjects had become diabetic. Each dose of G319S accelerated median disease onset by approximately 7 years. Thus, the transactivation-deficient HNF1A G319S mutation affects the dynamics of disease onset. The demonstration of a functional consequence for HNF1A G319S provides a mechanistic basis for its strong association with Oji-Cree type 2 diabetes and its unparalleled specificity for diabetes prediction in these people, in whom diabetes presents a significant public health dilemma. The findings also show that HNF1A mutations can be associated with typical adult-onset insulin-resistant obesity-related diabetes in addition to maturity-onset diabetes of the young.

Adult↗
PubMed2002

The impact of diabetes on cardiovascular risk factors and outcomes in a native Canadian population.

We measured cardiovascular disease (CVD) risk factors and their relationship to glucose intolerance in a Native Canadian population with very high rates of Type 2 diabetes mellitus. Five hundred and twenty five study-eligible Ojibwa-Cree individuals age 18 and over in the community of Sandy Lake, Canada who had participated in a population-based survey were studied. Diabetes status, plasma concentrations of total cholesterol (TC), triglycerides (TG), high density lipoprotein cholesterol (HDL-C), calculated low density lipoprotein-cholesterol (LDL-C), waist/hip ratio (WHR), BMI, systolic and diastolic BP, and history of smoking were compared to a standard national population. Extremely high rates of obesity (BMI and WHR) were identified in the study population and were associated with increasing glucose intolerance for both males and females. Rates of smoking exceeded 70 and 80% in females and males, respectively. Interestingly, despite obesity individuals who had normal glucose tolerance had significantly lower rates of high risk TC, TG, LDL-C, and HDL-C levels compared to a national Canadian population survey. However, with worsening glucose intolerance, TC, TG, LDL-C and HDL-C dramatically deteriorated in comparison to nationally published levels. These changes in cardiovascular risk factors, as a consequence of diabetes, appear to result in increased clinical outcomes. Admission to hospital for Ischemic Heart Disease (IHD) for Sandy Lake residents increased from a rate of 34.8/10,000 to 109.1/10,000 in 15 years. Although this and similar populations have historically reported low rates of CVD, the impact of diabetes on lipid risk factor is having devastating consequences on cardiovascular outcomes. This trend is expected to continue unless the high rates of diabetes can be modified.

Adult↗
PubMed2002

Pedometer-determined ambulatory activity in individuals with type 2 diabetes.

This cross-sectional study presents the first normative data on pedometer-determined ambulatory activity, defined as steps/day, in 160 (98 males, 62 females; age=52.4 +/- 5.3 years; BMI=32.3 +/- 5.7) free-living individuals with type 2 diabetes. Participants took 6662 +/- 3077 steps per day, less than that reported in nondiabetic samples and more than that reported for samples living with more restrictive chronic conditions including claudication, joint replacement, chronic obstructive lung disease, and chronic heart failure. Steps/day and BMI were inversely and significantly correlated (r=-0.27, P<0.01). Further, there was a significant difference between BMI categories (from normal weight to obesity class III) with regard to steps/day (F=2.96, P<0.05). The difference was most apparent between the highest obesity classes (II and III) and normal weight categories. This data is useful for sample comparison purposes. In addition the standard deviation or variance estimates can be used to calculate samples sizes for intervention efforts. Objective quantification of ambulatory activity via simple and inexpensive pedometers permits researchers and practitioners to easily screen for level of activity along a continuum. This study opens the door for future research and clinical applications including identifying threshold values related to important health outcomes and evaluating incremental change due to various interventions in this population.

Body Mass Index↗
PubMed2002

Preliminary outcome evaluation of the First Step Program: a daily physical activity intervention for individuals with type 2 diabetes.

The First Step Program uses simple and inexpensive pedometers to incrementally increase walking behaviors in sedentary individuals with type 2 diabetes. The pilot sample consisted of nine individuals (six women, three men; group mean age 53+/-6; group mean body mass index=32.9+/-3.4kg/m(2)). A timed self-paced walk while wearing the pedometer allowed for the conversion of changes in pedometer steps per day to time in minutes per day. There was an immediate and dramatic increase in walking behavior (an average of 34.3min of walking a day) that was sustained even 2 months post-intervention and after withdrawal of contact (an average of 22.6min of walking a day). Improvements in other outcomes (systolic blood pressure and waist girth) support a valid change in behavior. Although preliminary, these results warrant further investigation of such approaches.

Analysis of Variance↗
PubMed2002

The role of patient, physician and systemic factors in the management of type 2 diabetes mellitus.

BACKGROUND: Few studies have explored the contextual dimensions and subsequent interactions that contribute to a lack of adherence in the application of guidelines for diabetes management. OBJECTIVE: The purpose of this qualitative study was to explore family physicians' issues and perceptions regarding the barriers to and facilitators of the management of patients with type 2 diabetes mellitus (DM). METHODS: Four focus groups composed of family physicians (n= 30) explored the participants' experiences in the management of patients with type 2 DM. A semi-structured interview guide began with questions on family physicians' experience of providing care and included specific probes to stimulate discussion about the various barriers to and facilitators of the management of type 2 DM in family practice. RESULTS: Participants clearly identified type 2 DM as a chronic disease most often managed by family physicians. The findings revealed distinct barriers and facilitators in managing patients with type 2 DM which fell into three domains: patient factors; physician factors; and systemic factors. There was a dynamic interplay among the three factors. The important role of education was common to each. CONCLUSIONS: The interactions of patient, physician and systemic factors have implications for the implementation of a diabetes management model. The care of patients with type 2 DM exemplifies the ongoing challenges of caring for patients with a chronic disease in family practice. The findings, while specific to the management of type 2 DM, have potential transferability to other chronic illnesses managed by family physicians.

Clinical Competence↗
PubMed2002

Cross-sectional and prospective associations between abdominal adiposity and proinsulin concentration.

The objective of this study was to investigate the associations of total and abdominal obesity with variation in proinsulin concentration in a Native Canadian population experiencing an epidemic of type 2 diabetes mellitus (DM). Between 1993 and 1995, 728 members of a Native Canadian community participated in a population-based survey to determine the prevalence and risk factors for type 2 DM. Samples for glucose, C-peptide, and proinsulin were drawn after an overnight fast, and a 75-g oral glucose tolerance test was administered. Type 2 DM and impaired glucose tolerance (IGT) were diagnosed using World Health Organization criteria. Height, weight, waist circumference, and percent body fat were measured. In 1998, 95 individuals who, at baseline, had IGT or normal glucose tolerance with an elevated 2-h glucose level (> or = 7.0 mM) participated in a follow-up evaluation using the same protocol. After adjustment for age, sex, C-peptide concentration, per cent body fat, and waist circumference, proinsulin was found to be significantly elevated in diabetic subjects, relative to subjects with both impaired and normal glucose tolerance (both P < 0.0001); and the concentration in those with IGT was higher, compared with normals (P < 0.0001). Among nondiabetic subjects, proinsulin showed significant univariate associations with percent body fat, body mass index, and waist circumference (r = 0.34, 0.45, 0.41, respectively, all P < 0.0001). After adjustment for body fat and other covariates, waist circumference remained significantly associated with proinsulin concentration in nondiabetic subjects (r = 0.20, P < 0.0001). In prospective analysis, adjusted for covariates (including baseline IGT and follow-up glucose tolerance status), baseline waist circumference was positively associated with both follow-up and change in proinsulin concentration (r = 0.27, P = 0.01; r = 0.24, P = 0.03, respectively). These data highlight the detrimental effects of abdominal obesity on beta-cell function, and support the hypothesis that beta-cell dysfunction occurs early in the natural history of glucose intolerance.

Abdomen↗
PubMed2002

A single nucleotide polymorphism in protein tyrosine phosphatase PTP-1B is associated with protection from diabetes or impaired glucose tolerance in Oji-Cree.

Several lines of evidence support a role for protein tyrosine phosphatase 1B (PTP-1B) in metabolism, and specifically in insulin sensitivity and obesity. We report the development of reagents for the amplification and sequencing of the PTP-1B gene, which has resulted in the identification of a novel single nucleotide polymorphism (SNP), designated 981C-->T. We found a significant association between this SNP and the risk of either impaired glucose tolerance (IGT) or type 2 diabetes in the Oji-Cree of Sandy Lake, Ontario, Canada. Six hundred and fifty-three subjects were genotyped using PCR amplification of exon 8, followed by digestion with the restriction enzyme AvaI. Sixty-eight subjects were heterozygotes, and none was a homozygote. Thus, the overall frequencies of the C allele and the T allele were 0.948 and 0.052, respectively. Subjects with the PTP-1B 981T/981C genotype were approximately 40% less likely to have IGT or diabetes as subjects with the 981C/981C genotype (P = 0.040). There was no difference in quantitative traits among subjects grouped according to the PTP-1B 981C-->T SNP genotype. These very preliminary findings suggest that genomic variation in PTP-1B is associated with a reduced risk of diabetes and are consistent with the idea that this protein is important in metabolism.

Adult↗
PubMed2002

Association of parity with risk of type 2 diabetes and related metabolic disorders.

OBJECTIVE: The relationship between parity and risk of diabetes is controversial, and little information is available regarding associations between parity and measures of insulin resistance and beta-cell function. The objective of this study was to investigate the association between parity and risk of glucose intolerance and related metabolic disorders using data from a population-based study in a Native Canadian community. RESEARCH DESIGN AND METHODS: Female participants (n = 383, aged 12-79 years) provided fasting blood samples for the determination of glucose, insulin, C-peptide, and proinsulin concentrations. A 75-g oral glucose tolerance test was administered, and diabetes and impaired glucose tolerance were diagnosed according to World Health Organization criteria. Waist circumference and percent body fat were determined. Information regarding occurrence of live births and previously diagnosed diabetes was obtained from interviewer-administered questionnaires. RESULTS: Parity was associated with a significantly reduced risk of diabetes (nulliparous vs. >or=1 birth, odds ratio 0.43, 95% CI 0.19- 0.94, P < 0.05) after adjustment for age and waist circumference. In addition, nondiabetic nulliparous women had significantly elevated concentrations of fasting insulin and proinsulin relative to nondiabetic parous women (all P < 0.05) in analyses adjusted for age and waist circumference. CONCLUSIONS: Our results are consistent with those from other populations experiencing high rates of diabetes and suggest the presence of a diabetes-prone phenotype within the nulliparous subcohort of this population, which may contribute to infertility.

Adipose Tissue↗