Rigid versus non-rigid fixation for bilateral mandibular angle fractures: a retrospective multicentre review

BACKGROUND

Fractures involving the bilateral mandibular angle are an uncommon occurrence with limited evidence to inform the ideal fixation requirements for adequate treatment. The aim of this study was to evaluate the outcomes of managing bilateral mandibular angle fractures and determine if rigid fixation on one side improves outcomes compared to bilateral non-rigid fixation.

METHODS

Patients with isolated bilateral mandibular angle fractures surgically treated at the Royal Brisbane and Women's Hospital, Princess Alexandra Hospital, Gold Coast University Hospital and Townsville University Hospital between January 1, 2010 and December 31, 2022 were retrospectively identified. Data collected included patient demographics, mechanism of injury, fixation scheme, postoperative occlusion and the occurrence of postoperative complications and subsequent management.

RESULTS

Eighty-four patients met the inclusion criteria. Fifty-two patients had non-rigid fixation applied to both fractures, and thirty-two had rigid fixation placed on at least one side. All cases proceeded to union. There was no statistically significant difference between the groups for occlusal outcomes, wound dehiscence, infection or plate or screw loosening.

CONCLUSION

Our results suggest that bilateral non-rigid fixation can be used to treat bilateral mandibular angle fractures in the appropriate clinical context.

Patient transportation in Canada's northern territories: patterns, costs and providers' perspectives

INTRODUCTION

Canada's northern territories are characterized by small, scattered populations separated by long distances. A major challenge to healthcare delivery is the reliance on costly patient transportation, especially emergency air evacuations (medevacs). The purpose of this study was to describe the patterns, costs and providers' perspectives on patient transportation, and identify potential factors associated with utilization and performance.

METHODS

Secondary analyses of medical travel databases and an online survey of nurses in the communities and physicians in regional centers were undertaken.

RESULTS

The proportion of the population living within 100 km of a hospital was 83% in Yukon, 63% in Northwest Territories (NWT) and 21% in Nunavut. In Nunavut and NWT, road access to a hospital was limited to residents of the cities where the hospitals were located, with the rest relying exclusively on air travel. Medevac rates varied among the three territories: 0.9 trips/1000 residents/year in Yukon, 32/1000 in NWT and 53/1000 in Nunavut. In Yukon, all communities except one are road-accessible whereas in Nunavut no communities are connected by roads. The relative absence of roads is a major reason why the patient transportation costs are high in Nunavut and NWT. The rate of medevacs originating from the remote, air-accessible-only communities varied greatly, which cannot be explained by the air distance from the nearest hospital, population size or frequency of health center visits. Medical travel accounts for 5% of the health expenditures in NWT and 20% in Nunavut. A medevac on average costs $218 per person per year in NWT and $700 in Nunavut. The providers survey detected only 66% or less in support of statements that nurses in the communities received timely access to clinical advice, whereas only 50% of physicians agreed with statements that the clinical information provided by the nurses was clear.

CONCLUSION

Patient transportation, especially emergency air evacuations, is an essential but costly component of the healthcare system serving Canada's north. It is the 'glue' that binds an extensive network of facilities staffed by different categories of health professionals. While system design is largely dictated by geography, addressing human factors such as interprofessional communication is important for improving the system's effectiveness. This study is primarily descriptive and it points to additional areas for improved understanding of the performance of the system.

How we identify and count Aboriginal people--does it make a difference in estimating their disease burden?

INTRODUCTION

We examined the concordance between the Canadian Community Health Survey (CCHS) "identity" and "ancestry" questions used to estimate the size of the Aboriginal population in Canada and whether the different definitions affect the prevalence of selected chronic diseases.

METHODS

Based on responses to the "identity" and "ancestry" questions in the CCHS combined 2009-2010 microdata file, Aboriginal participants were divided into 4 groups: (A) identity only; (B) ancestry only; (C) either ancestry or identity; and (D) both ancestry and identity. Prevalence of diabetes, arthritis and hypertension was estimated based on participants reporting that a health professional had told them that they have the condition(s).

RESULTS

Of participants who identified themselves as Aboriginal, only 63% reported having an Aboriginal ancestor; of those who claimed Aboriginal ancestry, only 57% identified themselves as Aboriginal. The lack of concordance also differs according to whether the individual was First Nation, Métis or Inuit. The different method of estimating the Aboriginal population, however, does not significantly affect the prevalence of the three selected chronic diseases.

CONCLUSION

The lack of concordance requires further investigation by combining more cycles of CCHS to compare discrepancy across regions, genders and socio-economic status. Its impact on a broader list of health conditions should be examined.

Compound heterozygote myocilin mutations in a pedigree with high prevalence of primary open-angle glaucoma

PURPOSE

To describe the phenotype of ocular hypertension and primary open-angle glaucoma in a family with individuals compound heterozygote for Gln368STOP and Thr377Met myocilin (MYOC) mutations.

METHODS

Family members of the proband underwent comprehensive ocular clinical examination and DNA sequencing for MYOC mutations.

RESULTS

A 34-year-old woman with marked ocular hypertension was found to carry Gln368STOP and Thr377Met MYOC mutations. Three other siblings carried both mutations, while one carried Gln368STOP alone. Three of five siblings had received treatment for ocular hypertension or early glaucoma, with the average age of diagnosis 28 years; one required trabeculectomy at age 27. The mother of the proband was found to be a carrier for Gln368STOP alone, which indicates that her offspring with both Gln368STOP and Thr377Met carry variants on opposing alleles.

CONCLUSIONS

This pedigree is the first report with individuals compound heterozygote for the two most common glaucoma-causing MYOC variants. The combination of mutations manifests a more severe phenotype than either alone. Identification of gene changes associated with glaucoma within the family has enabled unaffected members to stratify their risk of future disease and institute closer monitoring and early treatment.

Obesity and obesity-related comorbidities in a Canadian First Nation population

Introduction

Rates of obesity are higher among Canada's Aboriginal First Nations populations than among non-First Nations populations. We studied obesity and obesity-related illness in a Manitoba First Nation community.

Methods

We conducted a screening study of diabetes and diabetes complications in 2003, from which we drew a representative sample of Manitoba First Nation adults (N = 483). We assessed chronic disease and chronic disease risk factors.

Results

Prevalence of obesity and associated comorbidities was higher among women than men. By using multivariate analysis, we found that factors significantly associated with obesity among women were diastolic blood pressure, insulin resistance, and employment status. Among men, factors were age, apolipoprotein A1 level, apolipoprotein B level, and insulin resistance. Seventy-five percent of study participants had at least 1 of the following conditions: obesity, dyslipidemia, hypertension, or diabetes. Comorbidity was high even among the youngest age groups; 22% of men and 43% of women aged 18 to 29 had 2 or more chronic conditions. Twenty-two percent of participants had undiagnosed hypertension. Participants with undiagnosed hypertension had significantly more chronic conditions and were more likely to have microalbuminuria than were those without hypertension. The number of chronic conditions was not significantly different for participants with newly diagnosed hypertension than for those with previously diagnosed hypertension.

Conclusion

The prevalence of obesity and other chronic conditions in the study community is high, especially considering the number of young people. Community-based interventions are being undertaken to reduce the excessive rate of illness.

Cardiovascular risk according to plasma apolipoprotein and lipid profiles in a Canadian First Nation

Introduction

Despite high diabetes rates among Canadian First Nations people, little is known about their cardiovascular disease risk. Our aim was to describe the apolipoprotein profile with respect to cardiovascular risk in a Canadian First Nation community.

Methods

In 2003, a representative sample of adult members of a Manitoba First Nation (N = 483) participated in a screening study for diabetes and diabetes complications. We assessed their cardiovascular risk factors.

Results

Sixty percent of women were at increased cardiovascular risk because of low apolipoprotein A1 (apoA1) levels, compared with 35% of men. The proportion of women with low apoA1 levels decreased with age, but the proportion with low high-density lipoprotein levels remained stable across age groups. Both apoB and apoA1 were significantly associated with obesity when age, sex, diastolic blood pressure, homocysteine, diabetes, and insulin resistance were controlled for.

Conclusion

Apolipoprotein and lipid profiles in this First Nation population suggest high cardiovascular risk. Future research should characterize the lipoprotein particle size in this population.

Obesity and obesity-related comorbidities in a Canadian First Nation population

INTRODUCTION

Rates of obesity are higher among Canada's Aboriginal First Nations populations than among non-First Nations populations. We studied obesity and obesity-related illness in a Manitoba First Nation community.

METHODS

We conducted a screening study of diabetes and diabetes complications in 2003, from which we drew a representative sample of Manitoba First Nation adults (N = 483). We assessed chronic disease and chronic disease risk factors.

RESULTS

Prevalence of obesity and associated comorbidities was higher among women than men. By using multivariate analysis, we found that factors significantly associated with obesity among women were diastolic blood pressure, insulin resistance, and employment status. Among men, factors were age, apolipoprotein A1 level, apolipoprotein B level, and insulin resistance. Seventy-five percent of study participants had at least 1 of the following conditions: obesity, dyslipidemia, hypertension, or diabetes. Comorbidity was high even among the youngest age groups; 22% of men and 43% of women aged 18 to 29 had 2 or more chronic conditions. Twenty-two percent of participants had undiagnosed hypertension. Participants with undiagnosed hypertension had significantly more chronic conditions and were more likely to have microalbuminuria than were those without hypertension. The number of chronic conditions was not significantly different for participants with newly diagnosed hypertension than for those with previously diagnosed hypertension.

CONCLUSION

The prevalence of obesity and other chronic conditions in the study community is high, especially considering the number of young people. Community-based interventions are being undertaken to reduce the excessive rate of illness.

Arthritis in the Canadian Aboriginal population: north-south differences in prevalence and correlates

Background

Information on arthritis and other musculoskeletal disorders among Aboriginal people is sparse. Survey data show that arthritis and rheumatism are among the most commonly reported chronic conditions and their prevalence is higher than among non-Aboriginal people.

Objective

To describe the burden of arthritis among Aboriginal people in northern Canada and demonstrate the public health significance and social impact of the disease.

Methods

Using cross-sectional data from more than 29 000 Aboriginal people aged 15 years and over who participated in the Aboriginal Peoples Survey 2006, we assessed regional differences in the prevalence of arthritis and its association with other risk factors, co-morbidity and health care use.

Results

The prevalence of arthritis in the three northern territories ("North") is 12.7% compared to 20.1% in the provinces ("South") and is higher among females than males in both the North and South. The prevalence among Inuit is lower than among other Aboriginal groups. Individuals with arthritis are more likely to smoke, be obese, have concurrent chronic diseases, and are less likely to be employed. Aboriginal people with arthritis utilized the health care system more often than those without the disease.

Conclusion

Aboriginal-specific findings on arthritis and other chronic diseases as well as recognition of regional differences between North and South will enhance program planning and help identify new priorities in health promotion.

Arthritis in the Canadian Aboriginal population: North-South differences in prevalence and correlates

BACKGROUND

Information on arthritis and other musculoskeletal disorders among Aboriginal people is sparse. Survey data show that arthritis and rheumatism are among the most commonly reported chronic conditions and their prevalence is higher than among non-Aboriginal people.

OBJECTIVE

To describe the burden of arthritis among Aboriginal people in northern Canada and demonstrate the public health significance and social impact of the disease.

METHODS

Using cross-sectional data from more than 29 000 Aboriginal people aged 15 years and over who participated in the Aboriginal Peoples Survey 2006, we assessed regional differences in the prevalence of arthritis and its association with other risk factors, co-morbidity and health care use.

RESULTS

The prevalence of arthritis in the three northern territories ("North") is 12.7% compared to 20.1% in the provinces ("South") and is higher among females than males in both the North and South. The prevalence among Inuit is lower than among other Aboriginal groups. Individuals with arthritis are more likely to smoke, be obese, have concurrent chronic diseases, and are less likely to be employed. Aboriginal people with arthritis utilized the health care system more often than those without the disease.

CONCLUSION

Aboriginal-specific findings on arthritis and other chronic diseases as well as recognition of regional differences between North and South will enhance program planning and help identify new priorities in health promotion.

Cardiovascular risk according to plasma apolipoprotein and lipid profiles in a Canadian First Nation

INTRODUCTION

Despite high diabetes rates among Canadian First Nations people, little is known about their cardiovascular disease risk. Our aim was to describe the apolipoprotein profile with respect to cardiovascular risk in a Canadian First Nation community.

METHODS

In 2003, a representative sample of adult members of a Manitoba First Nation (N = 483) participated in a screening study for diabetes and diabetes complications. We assessed their cardiovascular risk factors.

RESULTS

Sixty percent of women were at increased cardiovascular risk because of low apolipoprotein A1 (apoA1) levels, compared with 35% of men. The proportion of women with low apoA1 levels decreased with age, but the proportion with low high-density lipoprotein levels remained stable across age groups. Both apoB and apoA1 were significantly associated with obesity when age, sex, diastolic blood pressure, homocysteine, diabetes, and insulin resistance were controlled for.

CONCLUSION

Apolipoprotein and lipid profiles in this First Nation population suggest high cardiovascular risk. Future research should characterize the lipoprotein particle size in this population.

Carotid atherosclerosis and a reduced likelihood for lowered cognitive performance in a Canadian First Nations population

BACKGROUND

We investigated the associations among cardiovascular risk factors, carotid atherosclerosis and cognitive function in a Canadian First Nations population.

METHODS

Individuals aged > or = 18 years, without stroke, nonpregnant and with First Nations status were assessed by the Trail Making Test Parts A and B. Results were combined into a Trail Making Test executive function score (TMT-exec). Doppler ultrasonography assessed carotid stenosis and plaque volume. Anthropometric, vascular and metabolic risk factors were assessed by interview, clinical examinations and blood tests.

RESULTS

For 190 individuals with TMT-exec scores, the median age of the population was 39 years. Compared to the reference group, individuals with elevated levels of left carotid stenosis (LCS) and total carotid stenosis (TCS) were less likely to demonstrate lowered cognitive performance [LCS, odds ratio (OR): 0.47, 95% confidence interval (CI): 0.24-0.96; TCS, OR: 0.40, 95% CI: 0.20-0.80]. No effect was shown for plaque volume. In structural equation modeling, we found that for every 1-unit change in the anthropometric factor in kg/m(2), there was a 0.86-fold decrease in the percent of TCS (p < 0.05).

CONCLUSIONS

Individuals with elevated levels of LCS and TCS were less likely to demonstrate lowered performance. There was some suggestion that TCS mediates the effect of anthropometric risk factors on cognitive function.

Design and Synthesis of Binucleating Macrocyclic Clefts Derived from Schiff-Base Calixpyrroles

The syntheses, characterisation and complexation reactions of a series of binucleating Schiff-base calixpyrrole macrocycles are described. The acid-templated [2+2] condensations between meso-disubstituted diformyldipyrromethanes and o-phenylenediamines generate the Schiff-base pyrrolic macrocycles H(4)L(1) to H(4)L(6) upon basic workup. The single-crystal X-ray structures of both H(4)L(3).2 EtOH and H(4)L(6).H2O confirm that [2+2] cyclisation has occurred, with either EtOH or H2O hydrogen-bonded within the macrocyclic cleft. A series of complexation reactions generate the dipalladium [Pd2(L)] (L=L(1) to L(5)), dinickel [Ni2(L(1))] and dicopper [Cu2(L)] (L=L(1) to L(3)) complexes. All of these complexes have been structurally characterised in the solid state and are found to adopt wedged structures that are enforced by the rigidity of the aryl backbone to give a cleft reminiscent of the structures of Pacman porphyrins. The binuclear nickel complexes [Ni2(mu-OMe)2Cl2(HOMe)2(H(4)L(1))] and [Ni2(mu-OH)2Cl2(HOMe)(H(4)L(5))] have also been prepared, although in these cases the solid-state structures show that the macrocyclic ligand remains protonated at the pyrrolic nitrogen atoms, and the Ni(II) cations are therefore co-ordinated by the imine nitrogen atoms only to give an open conformation for the complex. The dicopper complex [Cu2(L(3))] was crystallised in the presence of pyridine to form the adduct [Cu2(py)(L(3))], in which, in the solid state, the pyridine ligand is bound within the binuclear molecular cleft. Reaction between H(4)L(1) and [Mn(thf){N(SiMe(3))2}2] results in clean formation of the dimanganese complex [Mn2(L(1))], which, upon crystallisation, formed the mixed-valent complex [Mn2(mu-OH)(L(1))] in which the hydroxo ligand bridges the metal centres within the molecular cleft.

Are the circumpolar Inuit becoming obese?

This paper reviews the ethnographic, historical, and recent epidemiological evidence of obesity among the Inuit/Eskimo in the circumpolar region. The Inuit are clearly at higher risk for obesity than other populations globally, if "universal" measures based on body mass index (BMI) and waist circumference and criteria such as those of WHO are used. Inuit women in particular have very high mean waist circumference levels in international comparisons. Given the limited trend data, BMI-defined obesity is more common today than even as recently as three decades ago. Inuit are not immune from the health hazards associated with obesity. However, the "dose-response" curves for the impact of obesity on metabolic indicators such as plasma lipids and blood pressure are lower than in other populations. Long-term, follow-up studies are needed to determine the metabolic consequences and disease risks of different categories of obesity. At least in one respect, the higher relative sitting height among Inuit, obesity measures based on BMI may not be appropriate for the Inuit. Ultimately, it is important to go beyond simple anthropometry to more accurate determination of body composition studies, and also localization of body fat using imaging techniques such as ultrasound and computed tomography. Internationally, there is increasing recognition of the need for ethnospecific obesity criteria. Notwithstanding the need for better quality epidemiological data, there is already an urgent need for action in the design and evaluation of community-based health interventions, if the emerging epidemic of obesity and other chronic diseases are to be averted.

Preventing type 2 diabetes using combination therapy: design and methods of the CAnadian Normoglycaemia Outcomes Evaluation (CANOE) trial

Several studies have demonstrated that type 2 diabetes mellitus (DM) can be prevented/delayed in subjects with impaired glucose tolerance (IGT) by using pharmacologic agents and/or lifestyle interventions. However, a number of challenges remain, including the translation of lifestyle programmes to the general population and the need to achieve greater risk reductions by using pharmacologic approaches. IGT, like DM, is characterized by insulin resistance, beta-cell dysfunction and increased hepatic glucose production. We believe that the use of combination diabetes therapy would be a particularly effective diabetes prevention strategy. In this context, we initiated the Canadian Normoglycemia Outcomes Evaluation (CANOE) study, a moderately sized, randomized, double-blind, controlled trial. The primary objective of CANOE is to determine whether treatment with metformin plus rosiglitazone, in addition to a healthy living lifestyle programme, will prevent the development of DM. The secondary objective of CANOE is to determine whether this treatment approach will improve cardiovascular risk factors associated with IGT. A total of 200 patients will be recruited in Toronto and London, Ontario, and followed for an average of 4 years (range 3-5 years). Active treatment with metformin (500 mg) plus rosiglitazone (2 mg), administered as one capsule twice daily, will be compared to matched placebo. Subjects will be eligible for randomization if they have IGT and are between the ages of 30-75 years. The primary outcome will be the development of new-onset DM, diagnosed by either two fasting plasma glucose values of >or=7 mmol/l or one positive oral glucose tolerance test with a 2-h plasma glucose value of >11.0 mmol/l during the active drug phase of the trial. With a sample size of 100 participants per group, we will be able to detect a relative risk reduction of 45%, with a two-sided log-rank test with a significance level of 0.05 and 80% power, assuming that the median time to progression is 8 years in the control group and that participants will be recruited over 2 years and followed for an average of 4 years. In conclusion, the CANOE study will determine whether combination pharmacological therapy combined with a lifestyle intervention programme can significantly modify the development of diabetes in high-risk Canadians.

Characteristics and prevalence of the metabolic syndrome among three ethnic groups in Canada

OBJECTIVE

To compare the characteristics and prevalence of the metabolic syndrome (MetS) among Native Indians, Inuit, and non-Aboriginal Canadians.

METHODS

The study was based on four cross-sectional studies conducted in the late 1980s and early 1990s involving three ethnic groups living in contiguous regions in central Canada: Oji-Cree Indians from several reserves in northern Ontario and Manitoba, Inuit from the Keewatin region of the Northwest Territories, and non-Aboriginal Canadians (predominantly of European heritage) in the province of Manitoba. The MetS was identified among adult subjects according to the National Cholesterol Education Program (NCEP) definition. Prevalence rates were standardized to the 1991 Canadian national population.

RESULTS

The age-standardized prevalence of the MetS varied by ethnic group, ranging from as high as 45% among Native Indian women to as low as 8% among Inuit men. Compared with Canadians of European origin, Indians had a worse metabolic profile, while Inuit had a better metabolic profile except for a high rate of abdominal obesity. The NCEP criteria in identifying individuals with the MetS were compared to those of the World Health Organization (WHO) in a subset of subjects with the requisite laboratory data. There was moderate agreement between the NCEP and WHO definitions, with a kappa value of 0.63 (95% confidence interval 0.56-0.70).

CONCLUSIONS

The results indicate that the MetS is prevalent in diverse ethnic groups in Canada but varies in the pattern of phenotypic expression. Given the diverse nature of these populations, careful consideration should be given to developing culturally appropriate community-based prevention strategies aimed at reducing the frequency of this syndrome.

35 years of ICCH: evolution or stagnation of circumpolar health research?

The first Circumpolar Health symposium took place in Fairbanks in 1967. Approximately every three years since, an increasing number of researchers have met to present and discuss the health conditions of the North. We analysed the proceedings from the 11 congresses and the abstracts from the 12th congress in 2003 and found a shift of focus from biology to sociology of health. Today, circumpolar health research is primarily focused on three major topics: 1. epidemiology of indigenous peoples of the North; 2. health care delivery in the North; and 3. the effect of physical factors on human physiology and health. Despite the diverse research interests, it is remarkable how a community of circumpolar scientists and practitioners has emerged over the past 35 years.

On prediction of the cesarean delivery risk in a large private practice

OBJECTIVE

This study was undertaken to develop an easily usable integrated formula for predicting the probability of cephalopelvic disproportion/failure to progress (CPD) and cesarean delivery (CS) as a function of demographic factors in a middle-class private practice, and to evaluate risk factors for CS in a low-risk primiparous population.

METHODS

We studied 3355 primiparous women who delivered singleton births between February 1993 and July 2001 in a large private practice. We calculated body mass index (BMI) and weight gain during pregnancy by using clinical data from a comprehensive clinical database. Multivariable logistic regression analysis was used to estimate the relationship between the probability of CS and CS carried out for CPD and 6 demographic factors: maternal age, maternal height, initial pregnancy BMI, pregnancy weight gain, gestational age, and birth weight. Three methods were used to assess the accuracy of the model: the Hosmer-Lemeshow goodness-of-fit statistic, association of predicted probabilities, and direct comparison of the formula to the actual data. Odds ratios with a 95% CI are also calculated for each of these factors.

RESULTS

The overall rate of primiparous CS for the practice is 21.7%, with 11.7% carried out for CPD. Formulas were developed to predict the probability of CS and the probability of CS caused by CPD. Our analysis shows that both the risk of CS and the risk of CS caused by CPD are significantly associated with all 6 demographic factors. We also develop an easily usable Web page-based calculator to instantly estimate any woman's probability of a CS or CPD at the beginning or at the end of her pregnancy.

CONCLUSION

The probability of CS and CS performed for CPD is higher for shorter, older, more obese women with large pregnancy weight gains, larger fetal birth weights, and longer gestation ages. Accurate formulas that predict the probabilities of CS and CS performed for CPD in this large private practice have been developed.

Factors that are associated with cesarean delivery in a large private practice: the importance of prepregnancy body mass index and weight gain

OBJECTIVE

The purpose of this study was to examine body mass index and pregnancy weight gain as risk factors for primary cesarean delivery in nulliparous women in a middle-class private practice.

STUDY DESIGN

Primiparous women who delivered in a private practice setting between February 1993 and July 13, 2001, were included. CIs along with Z statistics for paired count data were used to assess the statistical significance and relative importance of the relationships of body mass index and maternal weight gain to cesarean delivery. The effect of body mass index was examined as related to known confounders such as gestational age, birth weight, maternal age, and maternal height.

RESULTS

The overall cesarean delivery rate for primiparous women was 21.76%. Risk of cesarean delivery increased consistently and significantly (P <.0001) with increasing body mass index. This effect was primarily mediated through an increase in cesarean delivery carried out for cephalopelvic disproportion/failure to progress. In our practice, the primiparous woman whose body mass index is >30 kg/m(2) is six times more likely to have a cesarean delivery for the diagnosis of cephalopelvic disproportion/failure to progress than the primiparous woman whose body mass index is <20 kg/m(2). This differential in cesarean delivery rate persisted when controlled for birth weight and gestational age and continues to persist when maternal age and height are also controlled. Excessive pregnancy weight gain exerted a statistically significant effect on cesarean delivery rate. This increase was primarily related to cephalopelvic disproportion/failure to progress among the nonobese women.

CONCLUSION

Maternal body mass index is related strongly to the ability of primiparous women to be delivered vaginally without great difficulty. In fact, lean patients are excellent labor performers, particularly in contrast with obese patients. The relationship of increased body mass index to increased cesarean delivery is due to an increased rate of cephalopelvic disproportion/failure to progress. Excessive pregnancy weight gain is associated with a doubling of cephalopelvic disproportion/failure to progress rate in nonobese patients.

The evaluation of transferred health care services in Wunnimin Lake, Wapekeka and Kingfisher Lake First Nations: a nursing perspective

The Canadian federal government initiated the policy to transfer administrative control of health services to First Nations communities in the late 1980s. While there are outstanding issues concerning the implementation of the policy, many communities consider this an opportunity to improve the health of First Nations people and the work environment of health care providers. This paper reports on the evaluation of the process of transfer of health services experienced by three communities in northwestern Ontario, Canada, focusing on nursing services. Based on interviews with health care providers and community members, the overall assessment was that transfer had successfully addressed chronic issues relating to the working conditions of nurses and problems of recruitment and retention.

Possible site of decreased intestinal zinc absorption in chronic uremic rats

BACKGROUND/AIMS

Previous zinc tolerance tests in uremic patients indicated decreased intestinal zinc absorption. In the present study, a zinc tolerance test was initially applied to a uremic rat model and subsequently the possible site of malabsorption investigated.

METHODS

Chronic uremia was induced by five-sixths nephrectomy. Both control and nephrectomized rats were divided into three groups including animals with intact intestine, removal of the jejunum, and removal of the ileum. Each rat was orally loaded with zinc sulfate (80 mg/kg) in conscious state. Blood samples were drawn before and after zinc load at different intervals during 6 h for zinc analysis. The area under the plasma zinc curve (AUC) and the maximal increase of plasma zinc level (C(max)) were calculated.

RESULTS

Jejunectomy decreased both AUC and C(max) in control and nephrectomized rats, whereas ilectomized animals remained, interestingly, unchanged with regard to these two parameters. Significant decreases in both AUC and C(max) were observed in nephrectomized rats as compared with the control rats.

CONCLUSIONS

The jejunum is the main site of zinc absorption in response to a large oral load of zinc sulfate in both normal and uremic rats. The data further suggest that five-sixths nephrectomy reduces gastrointestinal zinc absorption in rats predominantly by the ileum.

Gastric emptying and intestinal transit of liquid and solid markers in rats with chronic uremia

Gastrointestinal motor abnormalities may account for dyspeptic symptoms of chronic uremia patients. However, the data on gastric emptying are conflicting in human studies. We, therefore, assessed gastric emptying and gastrointestinal transit in a rat uremia model. Chronic uremia was induced by five-sixths nephrectomy in the rats. After 20-hour fasting, the rats were loaded with 70 glass beads as solid markers through a gastric catheter. Two hours later, the stomach was exposed and the small intestine was equally divided into 10 segments. The glass beads in the stomach and in each intestinal segment were counted. The gastric emptying was expressed as the ratio of the number of glass beads in the small intestine to that counted from the entire gastrointestinal tract. The intestinal transit was assessed by analyzing the geometric center of the distribution of glass beads in the intestinal segments. Two conventional nonabsorbable markers, radioactive chromate and charcoal, were also used to evaluate gastric emptying and intestinal transit in the fasted state. Additionally, similar experiments of glass beads were performed in the fed state. It was found that, in the fasted state, the gastric emptying and the intestinal transit of liquid or solid markers were little affected by uremia. In the fed state, however, chronic uremia significantly decreased the intestinal transit but hardly affected the gastric emptying. We conclude that the postprandial intestinal transit, but not the gastric emptying, of solid markers may be decreased in the fed state by chronic uremia in a severity-dependent manner of a rat model, which resembles the findings in uremic patients.

Common genomic variation in LMNA modulates indexes of obesity in Inuit

We discovered that rare mutations in LMNA, which encodes lamins A and C, underlie autosomal dominant Dunnigan-type familial partial lipodystrophy. Because familial partial lipodystrophy is an extreme example of genetically disturbed adipocyte differentiation, it is possible that common variation in LMNA is associated with obesity-related phenotypes. We subsequently discovered a common single nucleotide polymorphism (SNP) in LMNA, namely 1908C/T, which was associated with obesity-related traits in Canadian Oji-Cree. We now report association of this LMNA SNP with anthropometric indexes in 186 nondiabetic Canadian Inuit. We found that physical indexes of obesity, such as body mass index, waist circumference, waist to hip circumference ratio, subscapular skinfold thickness, and subscapular to triceps skinfold thickness ratio were each significantly higher among Inuit subjects with the LMNA 1908T allele than in subjects with the 1908C/1908C genotype. For each significantly associated obesity-related trait, the LMNA 1908C/T SNP genotype accounted for between approximately 10--100% of the attributable variation. The results indicate that common genetic variation in LMNA is an important determinant of obesity-related quantitative traits.

Variable association between genetic variation in the CYP7 gene promoter and plasma lipoproteins in three Canadian populations

The promoter sequence variant -278A in the CYP7 gene, which encodes cholesterol 7-alpha hydroxylase, was previously reported to be associated with reduced plasma low density lipoprotein (LDL) cholesterol concentration. We tested for association of CYP7-278A with plasma lipoprotein traits in samples taken from three distinct Canadian populations: 594 Alberta Hutterites, 325 Ontario Oji-Cree and 190 Keewatin Inuit. The CYP7-278A allele frequencies in these three groups were 0.708, 0.466 and 0.490, respectively. The frequencies of CYP7-278A/A homozygotes were 0.481, 0.215 and 0.247, respectively. In the Hutterites, CYP7-278A was associated with reduced plasma HDL-cholesterol and apolipoprotein AI concentration. In the Oji-Cree, CYP7-278A was not significantly associated with any plasma lipoprotein trait. In the Inuit CYP7-278A was associated with elevated plasma total and LDL-cholesterol. There was no consistent relationship between the population mean plasma LDL-cholesterol concentration and the population CYP7-278A frequency. Our findings suggest that the common -278A promoter variant of CYP7 was inconsistently associated with variation in plasma LDL- and HDL-cholesterol in samples from three independent populations. The inconsistencies could be due to differences in genetic background or to unspecified environmental or genetic factors.

Undiagnosed diabetes: does it matter?

BACKGROUND

The 1998 Canadian clinical practice guidelines for the management of diabetes lowered the cutoff point for diagnosing diabetes mellitus from a fasting plasma glucose (FPG) level of 7.8 to 7.0 mmol/L. We studied the prevalence and clinical outcomes of undiagnosed and diagnosed diabetes within specific ranges of FPG among a cohort of subjects recruited in 1990.

METHODS

In 1990 a representative sample of 2792 adult residents of Manitoba participated in the Manitoba Heart Health Survey, which included measurement of FPG and a question about each participant's past history of diabetes. Individuals who would now be classified as having undiagnosed diabetes under the new criteria were not considered as such in 1990. Through data linkage with the provincial health care utilization database, the use of health care by these individuals was tracked and compared with that of individuals whose diabetes had been diagnosed and with that of normoglycemic individuals over an 8-year period subsequent to the survey.

RESULTS

The prevalence of undiagnosed diabetes in the adult population of Manitoba was 2.2%. Undiagnosed cases accounted for about one-third of all diabetes cases. Individuals with undiagnosed diabetes had an unfavourable lipid profile and higher blood pressure and obesity indices than normoglycemic individuals. Individuals who satisfied the new criteria for diabetes but remained undiagnosed had an additional 1.35 physician visits per year (95% confidence interval [95% CI] 0.93-1.96) and were more likely to be admitted to hospital at least once (odds ratio 1.23, 95% CI 0.40-3.79), compared with normoglycemic individuals.

INTERPRETATION

Undiagnosed cases represent the unseen but clinically important burden of diabetes, with significant concurrent metabolic derangements and a long-term impact on health care use.

Type 2 diabetes mellitus in Canada's first nations: status of an epidemic in progress

This review provides a status report on the epidemic of type 2 diabetes mellitus that is affecting many of Canada's First Nations. We focus on the published literature, especially reports published in the past 2 decades, and incorporate data from the Aboriginal Peoples Survey and the First Nations and Inuit Regional Health Survey. We look at the extent and magnitude of the problem, the causes and risk factors, primary prevention and screening, clinical care and education, and cultural concepts and traditional knowledge. The epidemic of type 2 diabetes is still on the upswing, with a trend toward earlier age at onset. Genetic-environmental interactions are the likely cause. Scattered intervention projects have been implemented and evaluated, and some show promise. The current health and social repercussions of the disease are considerable, and the long-term outlook remains guarded. A national Aboriginal diabetes strategy is urgently needed.

Monitoring disease burden and preventive behavior with data linkage: cervical cancer among aboriginal people in Manitoba, Canada

OBJECTIVES

This study sought to estimate rates of cervical cancer and Papanicolaou testing among Aboriginal and non-Aboriginal women in Manitoba, Canada.

METHODS

Data were derived through linking of administrative databases.

RESULTS

In comparison with non-Aboriginal women, Aboriginal women had 1.8 and 3.6 times the age-standardized incidence rates of in situ and invasive cervical cancer, respectively. With the exception of those aged 15 to 19 years, Aboriginal women were less likely to have had at least 1 Papanicolaou test in the preceding 3 years.

CONCLUSIONS

Data linkage provides a rapid and inexpensive means to estimate disease burden and preventive behavior in the absence of registries. There is an urgent need for an organized Papanicolaou test screening program in the Aboriginal population.

Health care seeking behavior following a health survey: impact on prevalence estimates of chronic diseases

This article addresses the time sequence between a population health survey and subsequent health care use and how this changes the incidence estimates of selected chronic diseases. A cardiovascular survey of a representative sample of the adult population of Manitoba, Canada was linked with the health insurance claims database. Of the 2792 subjects in the survey, 98% were linked successfully, using an encrypted personal health insurance number. Five years of physician claims data for the survey participants were reviewed including 18 months prior to and 42 months following the survey. Survey participants started seeking confirmation of possible hypertension as soon as they received blood pressure information at the interview. Confirmation of diabetes and elevated cholesterol were not completed until 3-4 months after participants had received the laboratory test results. As many as 4.6 times more new cases of hypertension per month, 5.1 times more cases of elevated cholesterol, and 3.3 times more cases of diabetes were diagnosed following the survey. Surveys designed to determine the prevalence of specific chronic diseases generate new cases within a short time afterwards, thus affecting the original prevalence estimates. The process of assessing the burden of disease in a population is dynamic rather than static, and comparisons across populations need to take into account the frequency and recency of past surveys.

Association between PON1 L/M55 polymorphism and plasma lipoproteins in two Canadian aboriginal populations

Serum paraoxonase circulates on a subfraction of high density lipoproteins and appears to use phospholipids on both low and high density lipoprotein particles as a physiological substrate. This functional relationship could explain the reported associations between common variation in the PON1 gene--at codons 55 and 192--and phenotypes related to atherosclerosis and lipoprotein metabolism. We evaluated associations between plasma lipoproteins and PON1 L/M55, PON1 Q/R192 and PON2 A/G148 polymorphisms in samples from two Canadian aboriginal populations, namely the Oji-Cree and the Inuit. In diabetic Oji-Cree, we found that carriers of PON1 M55 had a higher mean plasma triglyceride concentration than non-carriers. In non-diabetic Oji-Cree, we found that carriers of PON1 M55 had higher mean plasma concentrations of total and low density lipoporetein cholesterol and apo B than non-carriers. In Inuit, we found that carriers of PON1 M55 had higher mean plasma concentrations of total and low density lipoprotein cholesterol than non-carriers. The other polymorphic markers were not associated with variation in any plasma lipoprotein trait. Thus, the PON1 M55 allele appeared to be associated with deleterious changes in the plasma lipoprotein profile from two independent Canadian aboriginal samples. These results suggest that common variation in PON1 codon 55 is associated with variation of intermediate traits in plasma lipoprotein metabolism in aboriginal Canadians.

Diabetes-associated autoantibodies in aboriginal children

Type-2 diabetes is increasing in aboriginal children and adolescents and must be distinguished from type-1 diabetes in this population. The absence of diabetes-associated autoantibodies supports the clinical impression of type-2 diabetes in the affected members of this population.

Childhood obesity in a population at high risk for type 2 diabetes

OBJECTIVES

To determine the prevalence of obesity and investigate its association with fasting glucose and insulin among children and adolescents in a population at high risk for type 2 diabetes.

DESIGN

A cross-sectional screening survey involving anthropometry and fasting serum levels of glucose and insulin.

SETTING

A remote aboriginal (Ojibwa-Cree) community in northern Manitoba, Canada.

PARTICIPANTS

All children aged 4 to 19 years in the community were invited to participate, with a response rate of 82% (n = 719).

MAIN OUTCOME MEASURES

Obesity is defined as body mass index exceeding the 85th percentile of the National Center for Health Statistics reference data. The diagnosis of diabetes and impaired fasting glucose is based on the new criteria of the American Diabetes Association.

RESULTS

There is a high prevalence of obesity, with 64% (female) and 60% (male) exceeding the 85th percentile and 40% (female) and 34% (male) exceeding the 95th percentile. Body mass index is a significant predictor of both glucose and insulin in both sexes, independent of age. Obese children are at increased risk of being classified as having diabetes or impaired fasting glucose (odds ratio 5.1, 95% CI 1.51, 17.0).

CONCLUSIONS

The early onset of type 2 diabetes in childhood is increasingly observed in many populations. Childhood obesity is a strong risk factor. Early detection and intervention directed at obesity are potential strategies to avert the long-term consequences of type 2 diabetes.

G-protein beta3 subunit gene splice variant and body fat distribution in Nunavut Inuit

The GNB3 825T allele encodes a product that has enhanced activation of heterotrimeric G proteins in vitro and could play a role in adipogenesis. We therefore evaluated the possibility that the GNB3 825T allele was associated with obesity in a sample of 213 healthy Canadian Inuit. We found that body weight, body mass index, waist girth, hip girth, subscapular skinfold thickness, and triceps skinfold thickness were significantly higher in subjects with the GNB3 825T/T genotype than in subjects with other genotypes. Furthermore, two anthropometric ratios, namely that of waist to hip circumference and that of subscapular to triceps skinfold thickness, were not significantly different across genotypes. This suggested that the increased deposition of fat in subjects with the GNB3 825T/T genotype was generalized and not localized to particular subregions. There was no association of this genetic variation with blood pressure. The GNB3 825T/T genotype accounted for between 1.6% and 3.3% of the total variation (< or =13% of attributable variation) of the obesity-related traits. The potential for a genetic marker of obesity creates opportunities for future studies in the Inuit, not just to confirm the associations, but also to examine prospectively the influence of interventions and possible relationships between GNB3 825T and longer term complications of obesity.

Absence of association between genetic variation in the LIPC gene promoter and plasma lipoproteins in three Canadian populations

The promoter sequence variant -480T in the hepatic lipase gene (LIPC) has been shown to be significantly associated with low post-heparin hepatic lipase activity. Some studies have also found that the -480T variant is associated with elevation in plasma HDL cholesterol. We tested for associations of LIPC -480T with plasma lipoprotein traits in samples taken from three distinct Canadian populations: 657 Alberta Hutterites, 328 Ontario Oji-Cree and 210 Keewatin Inuit. Plasma HL activity was not available for analyses. The LIPC -480T allele frequencies in these three groups, respectively, were 0.219, 0.527 and 0.383, and the prevalence of LIPC -480T/T homozygotes was, respectively, 0.042, 0.274 and 0.167. No significant association was found between LIPC -480T and plasma HDL cholesterol or apolipoprotein AI concentration, after adjusting for covariates including gender and body mass index. There was no consistent relationship between the population mean plasma HDL cholesterol concentration and the population LIPC -480T frequency. Our findings are consistent with the idea that the common promoter variation in LIPC, which has been reported to be associated with variation in post heparin HL activity and HDL triglyceride concentration, is not always associated with variation in plasma HDL cholesterol concentration, possibly due to yet unspecified environmental or genetic factors.

Plasma phospholipid fatty acids in the central Canadian arctic: biocultural explanations for ethnic differences

As part of the Keewatin Health Assessment Study, a comprehensive health interview and examination survey of Inuit and non-Inuit in the central Canadian Arctic during 1990-91, plasma samples were analyzed for phospholipid fatty acid composition. Compared to non-Inuit, the Inuit have reduced levels of dihomo-gamma-linoleic (DGLA) and arachidonic acid (ratios of 0.41 and 0.46) and the sum of all n-6 fatty acids (ratio of 0.65), but increased level of eicosapentaenoic (EPA) acid (ratio of 1.37). These trends are consistent with those reported from other circumpolar Inuit populations, especially the reduced arachidonic acid and increased EPA, although the Inuit excess in EPA is much less pronounced due to the greater importance of caribou rather than sea mammals in most of the Keewatin communities. The high linoleic/arachidonic acid ratio suggests increased inhibition of the metabolic pathway regulated by the enzyme delta-5 desaturase, which can be explained by the presence of high levels of highly unsaturated fatty acids of dietary origin, and/or a genetic deficiency. In multiple linear regression models with the independent variable list consisting of Inuit status, age, sex, education, physical activity, spending time on the land and consumption of wild meat and local fish, Inuit status is independently associated with lower levels of the n-6 acids but not the n-3 acids. This indicates that factors other than diet and lifestyle, perhaps genetic ones, may account for the observed "ethnic" differences. However, for those fatty acids in which Inuit differ from non-Inuit, there is no dose-response relationship in terms of self-reported degree ofnon-Inuit admixture. Dietary fatty acids play an important role in the risk of cardiovascular diseases and diabetes, diseases of increasing importance in the health transition experienced by the Inuit. Association studies of plasma fatty acids and DNA markers of candidate genes for atherosclerosis and insulin resistance may provide a clearer picture of the genetic basis for the observed differences in plasma fatty acid composition between Inuit and non-Inuit.

Effects of zinc deficiency on endogenous antioxidant enzymes and lipid peroxidation in glomerular cells of normal and five-sixths nephrectomized rats

We evaluated the effects of zinc deficiency on the activities of endogenous antioxidant enzymes and lipid peroxidation in rat glomerular cells (GCs). Male Sprague-Dawley rats (n = 48) were fed a zinc-deficient diet and deionized distilled water for 1 week to induce zinc deficiency. Half of the rats (zinc-deficient group) continued on this diet for 4 weeks, and the other half (zinc-replete group) were maintained on the same diet but with zinc-supplemented water (150 mg/Lzinc sulfate solution). Half of each group underwent five-sixths nephrectomy, while the other half underwent a sham operation. Another 12 normal rats (controls) were fed standard rat chow (containing 23.4% protein and 70 ppm zinc) and drank deionized distilled water. The zinc-deficient rats, including sham and five-sixths nephrectomized rats, showed severe growth retardation and poor appetite. Their mean plasma zinc concentrations were half that of normal control rats, but their plasma copper concentration was significantly higher than that of the control rats. Zinc supplementation corrected the abnormality of plasma zinc and copper concentrations and the loss of body weight in zinc-deficient rats. Zinc-deficient rats exhibited lower renal creatinine clearance and higher GC-malondialdehyde (GC-MDA) than zinc-replete rats. The remnant kidney of all five-sixths nephrectomized rats, including zinc-deficient and zinc-replete rats, showed a compensatory elevation in renal creatinine clearance and increased GC-MDA concentrations. Zinc concentrations in the renal cortex were decreased in zinc-deficient rats and the activities of GC-superoxide dismutase and GC-glutathione peroxidase were increased, while zinc-replete rats exhibited normal activities of GC-superoxide dismutase and GC-glutathione peroxidase. We suggest that zinc deficiency enhances the formation of reactive oxygen species but does not affect the activities of endogenous antioxidant enzymes in glomerular cells.

Survivors of sexual abuse: clinical, lifestyle and reproductive consequences

BACKGROUND

In recent years, an increase in the prevalence of sexual abuse of women has been reported in Canada and elsewhere. However, there are few empirical data on the extent of the problem in Canadian aboriginal populations. The authors investigated the presence of a reported history of sexual abuse and other health determinants in a sample of women attending a community health centre with a substantial aboriginal population. This allowed determination of whether reported sexual abuse and its associated demographic and health-related effects were different for aboriginal and non-aboriginal women.

METHODS

A sample of 1696 women was selected from women attending a community health centre in a predominantly low-income inner-city area of Winnipeg for a cross-sectional survey designed to study the association between sexual behavior and cervical infections. The survey was conducted between November 1992 and March 1995 and involved a clinical examination, laboratory tests and an interviewer-administered questionnaire. A substudy was conducted among 1003 women who were asked 2 questions about sexual abuse.

RESULTS

The overall response rate for the main study was 87%. Of the 1003 women who were asked the questions about sexual abuse, 843 (84.0%) responded. Among the respondents, 368 (43.6%) were aboriginal. Overall, 308 (36.5%) of the respondents reported having been sexually abused, 74.0% of the incidents having occurred during childhood. The prevalence was higher among aboriginal women than among non-aboriginal women (44.8% v. 30.1%, p < 0.001). Women who had been sexually abused were younger when they first had sexual intercourse, they had multiple partners, and they had a history of sexually transmitted diseases. In addition, non-aboriginal women who had been sexually abused were more likely than those who had not been abused to have been separated or divorced, unemployed and multiparous and to have used an intrauterine device rather than oral contraceptives. Aboriginal women who had been sexually abused were more likely than those who had not been abused to have been separated or divorced, unemployed and multiparous and to have used an intrauterine device rather than oral contraceptives. Aboriginal women who had been sexually abused were more likely than those who had not been abused to have had abnormal Papanicolaou smears. The proportion of smokers was higher among the abused women than among the non-abused women in both ethnic groups.

INTERPRETATION

A history of sexual abuse was associated with other clinical, lifestyle and reproductive factors. This suggests that sexual abuse may be associated with subsequent health behaviors, beyond specific physical and psychosocial disorders. Aboriginal and non-aboriginal women who have suffered sexual abuse showed substantial differences in their subsequent health and health-related behaviours.

Factors associated with adult periodontitis in a dental teaching clinic population

Exposure to a number of environmental, behavioral and sociodemographic variables has been associated with increased prevalence and severity of adult periodontitis. However, it is not possible easily to identify the individuals most susceptible to this chronic disease. A case control study was conducted among a population of adults to determine what factors were associated with increased prevalence of moderate to advanced periodontitis. Clinical and radiographic data were obtained from dental charts and structured interviews were conducted by telephone to collect sociodemographic and behavioral data. Statistical modeling was completed for the total study population (35-87-year-olds) and for two age-stratified subpopulations. Significant crude disease associations were observed between periodontitis and numerous explanatory variables. However, after adjustment for age and gender, few variables remained significant. Age stratification indicated that young adults (35-54 years) were affected differently from older adults (> or =55 years) by exposures to certain variables. Young moderate smokers had a 3.15 times increased risk of periodontitis and young heavy smokers had a 7.33 times increased risk compared to never-smokers. Older single adults had a 3.07 times increased risk compared to those with partners.

Effects of parathyroid hormone infusion on glucose tolerance and glucose-stimulated insulin secretion in normal and uremic rats

We used thyroparathyroidectomized (TPTX) rats with hypocalcemia to evaluate the effects of parathyroid hormone (PTH) infusion on glucose tolerance and glucose-stimulated insulin secretion in normal and uremic rats. Animals were subjected to oral glucose tolerance test (OGTT) and glucose-stimulated insulin secretion before and after TPTX or after their plasma calcium level was normalized by PTH infusion, vitamin D injection or calcium load. In both normal and uremic groups, TPTX produced a significant increase in area under the cure (AUC) of plasma glucose from 0 to 6 h in response to an oral glucose challenge and decrease plasma insulin level in response to glucose-stimulated insulin secretion. Before TPTX, uremic animals have a normal basal plasma insulin level (29 +/- 3 versus 31 +/- 2 microU/ml) and a normal glucose-stimulated insulin secretion, but significantly increase plasma glucose AUC in response to OGTT as compared with normal rats. TPTX worsen the response of glucose intolerance in uremic rats. After PTH infusion, vitamin D injection or calcium load, all rats in the response of OGTT and glucose-stimulated insulin secretion are recovered to the level before TPTX including normal and uremic rats, but uremic rats still have an abnormal glucose tolerance in response to OGTT. Uremic rats have a low basal plasma glucose level as compared with normal rats. TPTX significantly increase basal plasma glucose level in normal and uremic rats, but the uremic rats with TPTX have been found to elevate basal plasma glucose level to the range of normal rats. The basal plasma glucose level of normal rats with TPTX was recovered to the range before TPTX by PTH infusion, vitamin D injection or calcium load, but PTH infusion, vitamin D injection or calcium load did not decrease the level of basal plasma glucose in uremic rats with TPTX. All TPTX rats, including intact kidney or five-sixths Nx rats, were treated three times weekly by subcutaneous injection of 8 micrograms/kg L-thyroxin. These results indicate that uremia may produce thyroid dysfunction and PTH infusion did not affect the glucose tolerance in OGTT and glucose-stimulated insulin secretion in normal and uremic rats. In addition to PTH, other uremic toxins may be responsible for the glucose intolerance of uremia.

F5 Q506 mutation and the low prevalence of cardiovascular disease in Canadian Inuit

BACKGROUND

The Keewatin Inuit have a very low age-adjusted mortality rate from vascular diseases compared to the general population of Canada. Interethnic differences in both genetic and lifestyle factors have been offered as explanations for this observation. We previously found that compared to white subjects, the Inuit had a significantly increased prevalence of 4 candidate alleles for atherosclerosis-related phenotypes, namely AGT T235, FABP2 T54, PONI R192, and APOE E4, and a significantly decreased prevalence of 2 candidate alleles for atherosclerosis-related phenotypes, namely ACE D and MTHFR 677T.

METHODS

We tested the hypothesis that 165 Canadian Inuit would have a significantly different frequency of the thrombosis-associated F5 Q506 allele compared with reference controls.

RESULTS

We found a complete absence of F5 Q506 in 165 Inuit, which was significantly different from the frequency of 3.92% observed in regional control White subjects.

CONCLUSIONS

The aggregate of results from our studies in Inuit to date suggests that the beneficial influence of the low prevalence of any or all of the ACE D, MTHFR 677T and F5 Q506 outweighs the deleterious influence of the high prevalence of any or all of the other disease-associated alleles. However, it remains possible that other genetic and/or environmental factors determine the low susceptibility to vascular disease in the Inuit.

The health of Canadians with diabetes

OBJECTIVES

This article focuses on the prevalence of diabetes mellitus among Canadians, the health status of those with the disease, their socioeconomic characteristics, personal health behaviours, and use of health services.

DATA SOURCE

The data are from the 1994/95 National Population Health Survey.

ANALYTICAL TECHNIQUES

Weighted counts were used in computing the prevalence of diabetes and the proportions of people with the characteristics and health behaviours considered.

MAIN RESULTS

In 1994/95, 3% of Canadians aged 12 and older--over 722,000 people--reported having diabetes that had been diagnosed by a health care professional. The prevalence of diabetes increases with age and is associated with low income. A higher percentage of adults with diabetes were overweight compared to those without the disease.

Estimating the burden of disease. Comparing administrative data and self-reports

OBJECTIVES

A cardiovascular health survey of a representative sample of the adult population of Manitoba, Canada was combined with the provincial health insurance claims database to determine the accuracy of survey questions in detecting cases of diabetes, hypertension, ischemic heart disease, stroke, and hypercholesterolemia.

METHODS

Of 2,792 subjects in the survey, 97.7% were linked successfully using a scrambled personal health insurance number. Hospital and physician claims were extracted for these individuals for the 3-year period before the survey.

RESULTS

The authors found no benefits to using restrictive criteria for entrance into the study (ie, requiring more than one diagnosis to define a case). Using additional years of data increased agreement between data sources. Kappa values indicated high levels of agreement between administrative data and self-reports for diabetes (0.72) and hypertension (0.59); kappa values were approximately 0.4 for the other conditions. Using administrative data as the "gold standard," specificity was generally very high, although cases with hypertension and hypercholesterolemia (diagnosed primarily by laboratory or physical measurement) were associated with a lower specificity than the other conditions. Sensitivity varied markedly and was lowest for "other heart disease" and "stroke". For diabetes and hypertension, inclusion criteria calling for more than one diagnosis reduced the accuracy of case identification, whereas increasing the number of years of data increased accuracy of identification. For diabetes and hypertension, self-reports were fairly accurate in detecting "true" past history of the illness based on physician diagnosis recorded on insurance claims.

CONCLUSIONS

This study demonstrates the feasibility of linking a large health survey with administrative data and the validity of self-reports in estimating the prevalence of chronic diseases, especially diabetes and hypertension. A linked data set offers unusual opportunities for epidemiologic and health services research in a defined population.

Comparison of survey and physician claims data for detecting hypertension

Using linked data from the Manitoba (Canada) Heart Health Survey (MHHS) and physician service claims files we assessed the degree to which self-reported hypertension and clinically measured hypetension agreed with physician claims hypertension, and examined the likely sources of disagreement. The overall agreement between survey and claims data for hypertension detection was moderate to high: 82% (kappa = 0.56) for self-reported and physician claims hypertension, and 85% (kappa = 0.60) for clinically measured and physician claims hypertension. In the comparison between self-report and physician claims, those who were classified as obese, diabetic, or a homemaker were significantly more likely to have a hypertension measure not confirmed by the other. Disagreement between clinically measured and physician claims was also more common among the obese and homemakers, as well as those on medication for heart diseases, elevated cholesterol levels (LDL), and 35 years of age and older. The high overall level of agreement among these three measures suggest that each may be used with confidence as an indication of hypertension; however, the agreement appears lower among individuals presenting a more complicated clinical profile.

Are Canadian Inuit at increased genetic risk for coronary heart disease?

The Keewatin Inuit of the Northwest Territories of Canada have a very low age-adjusted mortality rate from coronary heart disease. We hypothesized that this apparent protection from disease has a genetic basis. We determined the prevalence of the disease-associated alleles of five candidate genes for atherosclerosis-related phenotypes. Surprisingly, four of the five alleles studied, namely AGT T235, FABP2 T54, PON R192 and APOE E4, were significantly more frequent in a sample of 175 Keewatin Inuit than among a representative control sample of whites living in the region. The high frequencies of these disease-associated alleles suggests either that they have no relationship with disease susceptibility in the Inuit, or that some unmeasured genetic and/or environmental factors mitigate disease susceptibility that is associated with these alleles. This highlights the difficulty in extrapolating findings from one population to another. Also, very modest genotype-phenotype associations were observed between APOE genotype (P = 0.016) and plasma low-density lipoprotein cholesterol concentration and between FABP2 genotype and plasma 2-h postprandial, glucose concentration (P = 0.048). The relationship between APOE alleles and plasma low-density lipoprotein cholesterol was the same as has been previously reported in many study samples. However, the relationship between FABP2 alleles and plasma 2-h postprandial glucose concentrations was the opposite to that reported in other studies. This suggests that differences in environment, such as the type of fatty acid consumed, interacts with functional differences in gene products involved in candidate metabolic pathways to produce phenotypic differences.

Factors associated with human papillomavirus infection detected by polymerase chain reaction among urban Canadian aboriginal and non-aboriginal women

OBJECTIVES

To determine the prevalence and correlates of human papillomavirus (HPV) infection among women attending an ethnically mixed, predominantly low-income, inner-city primary care clinic.

STUDY DESIGN

Cross-sectional survey (N = 1,477). Demographic, behavioral, and reproductive history data were collected by questionnaire. Cervical swabs were analyzed for gonorrhea and chlamydial infections, abnormal cytology, and HPV infection assessed by PCR followed by hybridization for types 6, 11, 16, 18, 31, 33, and 35.

RESULTS

Human papillomavirus was detected in 33% of specimens, with no significant difference between Aboriginal (AB) and non-Aboriginal women. Adjusting for AB status, HPV infection was associated with marital status, condom use, number of sexual partners (last year and lifetime), age at first sexual intercourse, a history of sexual abuse, and current abnormal Papanicolaou (Pap) smear. In multivariate analyses excluding abnormal Pap smear as an independent variable, marital status and the number of lifetime sexual partners were found to be significant independent predictors of HPV infection. Comparing individuals with 20+ lifetime sexual partners and those with 1 or fewer partners, the odds ratio (OR) for HPV infection was 1.90 (95% confidence interval [CI] 1.66-2.17) among AB women and 1.54 among non-AB women (95% CI 1.36-1.73). The OR for infection with HPV types 6 and 11 was 1.39 (95% CI 1.22-1.58), whereas for the high oncogenic risk types of 16, 18, 31, 33, and 35, the OR was 1.82 (95% CI 1.65-2.01).

CONCLUSIONS

No differences were found between AB and non-AB women in the detection of HPV DNA, despite the higher risk for cervical cancer and the prevalence of recognized behavioral and reproductive risk factors among AB women. This study also indicates that the association of sexual activity with HPV infection holds true for both high- and low-oncogenic HPV types.