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

Outcomes of out of hospital cardiac arrest in First Nations and non-First Nations patients in Saskatoon

INTRODUCTION

One in nine (11.7%) people in Saskatchewan identify as First Nations. It is known that First Nations people have a higher burden of cardiovascular disease, but not whether outcomes of out of hospital cardiac arrest are different.

METHODS/METHODOLOGY

We reviewed pre-hospital and inpatient records of patients with out of hospital cardiac arrest between January 1st, 2015 and December 31st, 2017. The population consisted of patients aged 18 years or older with out of hospital cardiac arrest of presumed cardiac origin occurring in the catchment area of Saskatoon's emergency medical services (EMS). Variables of interest included age, gender, First Nations status, EMS response times, bystander cardiopulmonary resuscitation (CPR), and shockable rhythm. Outcomes of interest included return of spontaneous circulation (ROSC), survival to hospital admission, and survival to hospital discharge.

RESULTS

In all, 372 patients sustained out of hospital cardiac arrest, of which 27 were status First Nations. There were no differences between First Nations and non-First Nations patients in terms of shockable rhythms (24% vs 26%; p = 0.80), ROSC (42% vs 41%; p = 0.87), survival to hospital admission (27% vs 33%; p = 0.53), and survival to hospital discharge (15% vs 12%; p = 0.54). First Nations patients with out of hospital cardiac arrest were significantly younger (mean age 46 vs. 65 years; p < 0.0001) and had shorter EMS response times (median times 5.3 vs. 6.2 min; p = 0.01) when compared to non-First Nations patients.

CONCLUSIONS

In Saskatoon, First Nations patients with out of hospital cardiac arrest appear to have similar survival rates when compared with non-First Nations patients. However, First Nations patients sustaining out of hospital cardiac arrest were significantly younger than their non-First Nations counterparts. This highlights a significant public health issue.

Influence of Preexisting Diabetes on Survival After a Breast Cancer Diagnosis in First Nations Women in Ontario, Canada

PURPOSE

Survival after a breast cancer diagnosis is poorer in First Nations women with a preexisting comorbidity compared with comorbidity-free First Nations women in Ontario, Canada. Given the high prevalence of diabetes in this population, it is important to determine whether preexisting diabetes is related to poorer survival after a breast cancer diagnosis.

METHODS

All First Nations women were identified from a cohort of First Nations people diagnosed with breast cancer in diagnostic periods-1995 to 1999 and 2000 to 2004-and seen at a regional cancer program (RCP) in Ontario. Preexisting diabetes status and other factors, such as age at diagnosis, body mass index, and stage at diagnosis, were collected from medical charts at the regional cancer programs. The association between preexisting diabetes and First Nations status was examined by each of the demographic, personal, tumor, and treatment factors using logistic regression models. Survival was compared between First Nations women with (n = 67) and without (n = 215) preexisting diabetes, adjusted by significant study factors using a Cox proportional hazards regression model.

RESULTS

The 5-year survival rate among First Nations women with diabetes was 59.8% versus 78.7% among those without diabetes (P < .01). Preexisting diabetes significantly increased the risk of death among First Nations women with breast cancer (hazard ratio, 1.87; 95% CI, 1.12 to 3.13) after adjustment for age group, period of diagnosis, body mass index, other comorbidities at diagnosis, and stage.

CONCLUSION

This study recommends awareness of this survival discrepancy among the treatment team for First Nations patients with breast cancer with preexisting diabetes.

Cultural connectedness as a determinant of physical activity among Indigenous adults in Saskatchewan

Cultural connectedness has been associated with increased self-esteem and mental health among Indigenous Peoples. Physical activity is an important contributor to health, although the importance of culture as a determinant of physical activity for Indigenous Peoples in Canada is unclear. The purpose of this study is to evaluate differences in cultural connectedness between Indigenous adults in Canada achieving high and low physical activity levels. Questionnaires evaluated cultural connectedness and physical activity. Indigenous adults were classified into high and low physical activity groups at the specific group mean and as meeting or not meeting musculoskeletal activity guidelines of twice per week. First Nations and specifically Cree/Nehiyaw First Nations adults who were more physically active reported greater identity, spirituality, traditions, exploration, commitment, affirmation/belonging, and overall cultural connectedness. Cultural connectedness elements of commitment, exploration, identity, affirmation/belonging, traditions, spirituality, and overall cultural connectedness were not different between high and low physical activity Métis adults. Musculoskeletal activity was not associated with any elements of cultural connectedness among any Indigenous identity. Cultural connectedness is a protective factor for physical activity among First Nations and Cree/Nehiyaw First Nations adults, but not among Métis adults in Canada. Novelty Musculoskeletal activity was not associated with cultural connectedness. Cultural connectedness is a protective factor of physical activity for First Nations adults. Moving away from one's home community was associated with lower cultural connectedness for Indigenous Peoples.

Trends in cardiovascular care and event rates among First Nations and other people with diabetes in Ontario, Canada, 1996-2015

BACKGROUND

Rates of cardiovascular disease among people with diabetes have declined over the last 20-30 years. To determine whether First Nations people have experienced similar declines, we compared time trends in rates of cardiac event and disease management among First Nations people with diabetes and other people with diabetes in Ontario, Canada.

METHODS

We conducted a retrospective cohort study of patients aged 20 to 105 years with diabetes between 1996 and 2015, using linked health administrative databases. Outcomes compared were the annual incidence of each admission to hospital for myocardial infarction and heart failure, and death owing to ischemic heart disease. Management indicators were coronary revascularization and prescription rates for cardioprotective medications. Overall rates and annual percent changes were compared using Poisson regression.

RESULTS

Incidence rates for all cardiac outcomes decreased over the study period. The greatest relative annual decline among First Nations men and women were observed in ischemic heart disease death (4.4%, 95% confidence interval [CI] 3.0 to 5.9) and heart failure (5.4%, 95% CI 4.5 to 6.4), respectively. Among other men and women, the greatest annual declines were seen in ischemic heart disease death (6.3%, 95% CI 6.1 to 6.5 and 7.3%, 95% CI 7.1 to 7.6, respectively). However, all absolute cardiac event rates were higher among First Nations people (p < 0.001). Coronary artery revascularization procedures and prescriptions for cardioprotective medications increased among First Nations people, while only prescriptions increased among other people.

INTERPRETATION

Over the last 20 years, the incidence of cardiac events has declined among First Nations people with diabetes, but remains higher than other people with diabetes in Ontario. For continued reductions in incidence, future efforts need to recognize First Nations people's unique social and cultural determinants of health.

A Global Perspective on Cardiovascular Disease in Vulnerable Populations

Cardiovascular disease (CVD) is a major contributor to the growing public health epidemic in chronic diseases. Much of the disease and disability burden from CVDs are in people younger than the age of 70 years in low- and middle-income countries, formerly "the developing world." The risk of CVD is heavily influenced by environmental conditions and lifestyle variables. In this article we review the scope of the CVD problem in low- and middle-income countries, including economic factors, risk factors, at-risk groups, and explanatory frameworks that hypothesize the multifactorial drivers. Finally, we discuss current and potential interventions to reduce the burden of CVD in vulnerable populations including research needed to evaluate and implement promising solutions for those most at risk.

Differential mortality and the excess burden of end-stage renal disease among First Nations people with diabetes mellitus: a competing-risks analysis

BACKGROUND

Diabetes-related end-stage renal disease disproportionately affects indigenous peoples. We explored the role of differential mortality in this disparity.

METHODS

In this retrospective cohort study, we examined the competing risks of end-stage renal disease and death without end-stage renal disease among Saskatchewan adults with diabetes mellitus, both First Nations and non-First Nations, from 1980 to 2005. Using administrative databases of the Saskatchewan Ministry of Health, we developed Fine and Gray subdistribution hazards models and cumulative incidence functions.

RESULTS

Of the 90 429 incident cases of diabetes, 8254 (8.9%) occurred among First Nations adults and 82,175 (90.9%) among non-First Nations adults. Mean age at the time that diabetes was diagnosed was 47.2 and 61.6 years, respectively (p<0.001). After adjustment for sex and age at the time of diabetes diagnosis, the risk of end-stage renal disease was 2.66 times higher for First Nations than non-First Nations adults (95% confidence interval [CI] 2.24-3.16). Multivariable analysis with adjustment for sex showed a higher risk of death among First Nations adults, which declined with increasing age at the time of diabetes diagnosis. Cumulative incidence function curves stratified by age at the time of diabetes diagnosis showed greatest risk for end-stage renal disease among those with onset of diabetes at younger ages and greatest risk of death among those with onset of diabetes at older ages.

INTERPRETATION

Because they are typically younger when diabetes is diagnosed, First Nations adults with this condition are more likely than their non-First Nations counterparts to survive long enough for end-stage renal disease to develop. Differential mortality contributes substantially to ethnicity-based disparities in diabetes-related end-stage renal disease and possibly to chronic diabetes complications. Understanding the mechanisms underlying these disparities is vital in developing more effective prevention and management initiatives.

A systematic review of physical activity levels in Native American populations in Canada and the United States in the last 50 years

Physical activity is beneficial for many chronic conditions. However, activity levels of Native Americans are not well known. This systematic review investigated if Native American populations achieve the recommended physical activity levels, compared current and past activity levels, and assessed the ability of exercise training programmes to improve health outcomes among this population. Electronic databases (e.g. MEDLINE, EMBASE) were searched and citations were cross-referenced. Included articles reported physical activity levels or investigations among Native Americans. This search identified 89 articles: self-report (n = 61), accelerometry and pedometry (n = 10), metabolic monitoring (n = 10) and physical activity interventions (n = 17). Few adults were found to meet the physical activity recommendations (27.2% [95% confidence interval = 26.9-27.5%] self-report, 9% [4-14%] accelerometry). Among children/youth, 26.5% (24.6-28.4%) (self-report) to 45.7% (42.3-49.1%) (pedometry/accelerometry) met the recommendations. Adults and children/youth were generally identified as physically inactive (via doubly labelled water). Overall, Native American adults reported lower activity levels since 2000, compared to 1990s, although similar to 1980s. Few physical activity interventions employed strong methodologies, large sample sizes and objective outcome measures. There is a clear need to increase Native American populations' physical activity. Additional research is required to evaluate exercise training programmes among this population.

Utility of non-high-density lipoprotein cholesterol in assessing incident type 2 diabetes risk

AIMS

Traditional lipid indices have been associated with type 2 diabetes, but limited data are available regarding non-high-density lipoprotein (non-HDL) cholesterol. In view of recent guidelines for the clinical management of dyslipidemia recommending the monitoring of non-HDL cholesterol as a secondary target after achieving the low-density lipoprotein (LDL) cholesterol goal, we aimed to assess the association of non-HDL cholesterol with incident type 2 diabetes and compare its utility as a risk predictor with traditional lipid variables in Aboriginal Canadians.

METHODS

Of 606 diabetes-free participants at baseline, 540 (89.1%) returned for 10-year follow-up assessments. Baseline anthropometry, blood pressure, fasting insulin and serum lipids were measured. Fasting and 2-h postload glucose were obtained at baseline and follow-up to determine the incidence of type 2 diabetes.

RESULTS

The cumulative incidence of type 2 diabetes was 17.5%. Higher non-HDL cholesterol, total-to-HDL cholesterol ratio, apolipoprotein B, triglyceride and LDL cholesterol and lower HDL cholesterol concentrations were individually associated with incident type 2 diabetes in univariate analyses (all p < 0.05). Non-HDL cholesterol was a superior determinant of incident diabetes compared with LDL cholesterol (comparing C-statistics of univariate models p = 0.01) or HDL cholesterol (p = 0.004). With multivariate adjustment including waist circumference, non-HDL cholesterol remained associated with incident diabetes [odds ratio (OR) 1.42 (95% confidence interval, CI 1.07-1.88)], while LDL cholesterol and HDL cholesterol became non-significant.

CONCLUSIONS

Non-HDL cholesterol was associated with incident type 2 diabetes and was superior to LDL cholesterol as a risk predictor in this population. Further studies are required to establish the utility of non-HDL cholesterol in non-Aboriginal populations.

Prevalence, determinants and co-morbidities of chronic kidney disease among First Nations adults with diabetes: results from the CIRCLE study

BACKGROUND

Indigenous peoples worldwide are experiencing elevated rates of type 2 diabetes and its complications. To better understand the disproportionate burden of diabetic end stage renal disease (ESRD) among Canadian First Nations people (FN), we examined prevalence, determinants, and co-morbidities of chronic kidney disease (CKD) within this population.

METHODS

The 2007 Canadian FN Diabetes Clinical Management and Epidemiologic (CIRCLE) study conducted a cross-sectional national medical chart audit of 885 FN adults with type 2 diabetes to assess quality of diabetes care. In this sub-study, participants were divided by estimated glomerular filtration rate (eGFR in ml/min/1.73 m2), as well as by albuminuria level in those with eGFRs = > 60. Those with eGFRs = > 60 and negative albuminuria were considered to have normal/near normal kidney function (non-CKD). Using univariate and logistic regression analysis, they were compared with participants having eGFRs = > 60 plus albuminuria (CKD-alb) and with participants having eGFRs <60 (CKD-eGFR <60).

RESULTS

While 84.5% of total CIRCLE participants had eGFRs = > 60, almost 60% of the latter had CKD-alb. Of the 15.5% of total participants with CKD-eGFR <60, 80% had eGFRs 30-60 (Stage 3 CKD) but over 10% (1.6% of total participants) had ESRD. Independent determinants of CKD-alb were male gender and increasing diabetes duration, systolic BP, A1C and total cholesterol. These plus smoking rates also discriminated between FN with micro- and macro-albuminuria. Independent determinants of CKD-eGFR <60 were increasing age at diabetes diagnosis, diabetes duration, total cholesterol and systolic BP. However, participants with CKD-eGFR <60 also displayed a decreasing mean age of diabetes diagnosis as eGFR declined. Micro-vascular co-morbidities were significantly associated with CKD-alb but both micro- and macro-vascular co-morbidities were associated with CKD-eGFR <60. Only 35-40% of participants with CKD used insulin.

CONCLUSIONS

High prevalences of CKD-alb and early CKD-eGFR <60 among diabetic FN were largely related to modifiable and treatable risk factors. However, an earlier age of diabetes diagnosis and longer duration of diabetes characterized those with ESRD. These findings suggest that a failure to meet current standards of diabetes care interacting with an age-related survival benefit contribute to the disproportionate burden of ESRD among FN and possibly other Indigenous peoples.

An evaluation of the physical activity and health status of British Columbian Aboriginal populations

Aboriginal people have experienced elevated rates of obesity, diabetes, cardiovascular disease, and other chronic conditions that are disproportionate to the general Canadian population. We sampled British Columbian Aboriginal populations to determine the current health status of this population. A total of 882 Aboriginal adults ≥16 years of age from 25 locations around the province were sampled from 2007–2011. Health measurements evaluated included body mass index, waist circumference, physical activity, smoking behaviours, and resting blood pressure as well as histories of diabetes, cardiovascular disease, and hypertension. Nonfasting measures of blood sugar, total cholesterol, and high-density lipoprotein cholesterol were also recorded. We used logistical regression to quantify variations in diabetes and cardiovascular disease risk factors with age, gender, geographic location, on- and off-reserve and urban–rural areas of residence, smoking, and physical activity behaviour. The prevalence of diabetes, hypertension, and high total cholesterol were found to be greater among males, while females experienced greater rates of abdominal obesity and physical inactivity. Rates of chronic conditions were similar across on- and off-reserve, urban–rural areas, and geographic region residences, though rural, on-reserve, and northern residents experienced greater risk of poor health status. Larger proportions of on-reserve, rural, and interior individuals were found to be more physically inactive. Aboriginal populations still experience substantially poorer health status in comparison with the general population. Initiatives to improve the health of this population are urgently needed addressing all sectors of the Aboriginal population, all geographic regions, and all areas of residence, with special emphasis on rural, on-reserve, and northern populations.

The effectiveness of community based physical activity interventions with Aboriginal peoples

Though historically rare, Aboriginal individuals continue to experience greater levels of cardiovascular disease than the general Canadian population. Increasing evidence indicates rising sedentary behaviors from the traditional healthy and active lifestyles of this population.

OBJECTIVE

This investigation aimed to examine the health benefits of a community-based physical activity intervention for Aboriginal Canadians.

METHODS

From 2007-2010, 273 participants from the province of British Columbia, Canada were recruited through 21 Aboriginal communities representing male and females of wide ranging ages and health statuses. Participants attended identical testing of body composition, blood pressure, total and high density lipoprotein cholesterols, and physical activity behavior pre-and post-training. Participants completed one of three self-selected 13 week interventions: walking (n=149), walk/running (n=86), or running (n=27).

RESULTS

Improvements in health measures were observed for both male and female participants of all age groups and all three training programs. Male and female participants' improvements included waist circumference: 2.7 cm and 2.2 cm, total cholesterol: 0.18 mmol/L and 0.12 mmol/L, and systolic blood pressure: 2.6mm Hg and 1.5mm Hg, respectively.

CONCLUSIONS

The self-selected intensities program was successful in improving health status and physical activity for Aboriginal adults of all ages, genders and activity programs.

The prevalence of overweight and obesity in British Columbian Aboriginal adults

Overweight and obesity among Aboriginal populations has been a growing challenge within Canada. This investigation aimed to identify the prevalence of overweight and obesity within British Columbian adult Aboriginal populations including both on and off reserve individuals through direct measurement. Further, this study stratified the variations in these rates according to age, gender and geographic region. Weight, height and waist circumference (WC) were measured via standardized procedures, and body mass index (BMI) was calculated. The mean body composition indicators were above recommended for men (BMI = 30.3 ± 5.6 kg m(-2) ; WC = 104.2 ± 14.7 cm) and women (BMI = 30.9 ± 7.2 kg m(-2); WC= 99.3 ± 17.1 cm), respectively. Rates of obesity for men and women were similar, 48.4% and 48.7%, respectively, and showed significant increases with age. Abdominal obesity (AO) was significantly greater among female participants, 69.0% compared with 52.7% in men, while both genders also demonstrated significant increases in AO with age. Both obesity and AO rates were found to be significantly greater in the Northern and Interior regions of the province in comparison to the Vancouver/Lower Mainland region. Alarmingly high rates of obesity and AO were observed in this population in men and women at every age and geographic region.

Obesity and type 2 diabetes in Northern Canada's remote First Nations communities: the dietary dilemma

First Nations populations in Northwestern Ontario have undergone profound dietary and lifestyle transformations in less than 50 years, which have contributed to the alarming rise in obesity and obesity-related diseases, in particular type 2 diabetes mellitus. Even though the genetic background of First Nations peoples differs from that of the Caucasians, genetics alone cannot explain such a high prevalence in obesity and type 2 diabetes. Modifications in lifestyle and diet are major contributors for the high prevalence of chronic diseases. What remains constant in the literature is the persistent view that locally harvested and prepared foods are of tremendous value to First Nations peoples providing important health and cultural benefits that are increasingly being undermined by western-based food habits. However, the complexities of maintaining a traditional diet require a multifaceted approach, which acknowledges the relationship between benefits, risks and viability that cannot be achieved using purely conventional medical and biological approaches. This brief review explores the biological predispositions and potential environmental factors that contribute to the development of the high incidence of obesity and obesity-related diseases in First Nations communities in Northern Canada. It also highlights some of the complexities of establishing exact physiological causes and providing effective solutions.

HNF1A G319S variant, active cigarette smoking and incident type 2 diabetes in Aboriginal Canadians: a population-based epidemiological study

Background

In a recent report of large-scale association analysis, a type 2 diabetes susceptibility locus near HNF1A was identified in predominantly European descent populations. A population-specific G319S polymorphism in HNF1A was previously identified in Aboriginal Canadians who have a high prevalence of type 2 diabetes. We aimed to investigate the association of the HNF1A G319S polymorphism with incident type 2 diabetes and to assess whether clinical risk variables for type 2 diabetes influence the association in an Aboriginal population.

Methods

Of 606 participants who were free of diabetes at baseline in 1993-1995, 540 (89.1%) participated in 10-year follow-up assessments in 2003-2005. Fasting glucose and a 75-g oral glucose tolerance test were obtained to determine incident type 2 diabetes. Participants were genotyped for the HNF1A G319S polymorphism. Interviewers administered questionnaires on smoking behavior.

Results

The incidence rates of type 2 diabetes were 14.2% (55/388) in major allele homozygotes and 31.2% (29/93) in minor allele carriers (p < 0.001). The HNF1A G319S carrier status was associated with incident type 2 diabetes (odds ratio [OR] 3.78 [95% CI 2.13-6.69]) after adjustment for age, sex, hypertension, triglyceride, HDL cholesterol, and waist circumference. A statistical interaction was observed between HNF1A G319S and baseline active cigarette smoking on the development of type 2 diabetes with similar adjustment (p = 0.006). When participants were stratified by baseline smoking status, HNF1A G319S carriers who were active smokers had increased risk of developing diabetes (OR 6.91 [95% CI 3.38-14.12]), while the association was attenuated to non-significance among non-smokers (1.11 [0.40-3.08]).

Conclusions

The HNF1A G319S variant is associated with incident type 2 diabetes in Aboriginal Canadians. Furthermore, cigarette smoking appears to amplify incident diabetes risk in carriers of HNF1A G319S.

Measuring quality of diabetes care by linking health care system administrative databases with laboratory data

BACKGROUND

Chronic complications of diabetes can be reduced through optimal glycemic and lipid control as evaluated through measurement of glycosylated hemoglobin (A1C) and low-density lipoprotein cholesterol (LDL-C). We aimed to produce measures of quality of diabetes care in Saskatchewan and to identify sub-groups at particular risk of developing complications.

FINDINGS

Prevalent adult cases of diabetes in 2005/06 were identified from administrative databases and linked with A1C and LDL-C tests measured in centralized laboratories. A1C results were performed in 33,927 of 50,713 (66.9%) diabetes cases identified in Saskatchewan, and LDL-C results were performed in 12,031 of 24,207 (49.7%) cases identified within the province's two largest health regions. The target A1C of <= 7.0% and the target LDL-C of <2.5 mmol/L were achieved in 48.3% and 45.1% of diabetes cases respectively. The proportions were lower among those who were female, First Nations, non-urban, younger and in lower income quintiles. The same groups experienced poorer glycemic control (exception females), and poorer lipid control (exception First Nations people). Among non-Aboriginal people, younger diabetic females were least likely to receive lipid lowering agents.

CONCLUSIONS

Linkage of laboratory with administrative data is an effective method of assessing quality of diabetes care on a population basis and to identify sub-groups requiring particular attention. We found that less than 50% of Saskatchewan people with diabetes achieved optimal glycemic and lipid control. Disparities were most evident among First Nations people and young women. The indicators described can be used to provide standardized information that would support quality improvement initiatives.

APOC1 T45S polymorphism is associated with reduced obesity indices and lower plasma concentrations of leptin and apolipoprotein C-I in aboriginal Canadians

Apolipoprotein (apo) C-I is a constituent of chylomicrons, very low density lipoprotein, and high density lipoprotein. The role of apo C-I in human metabolism is incompletely defined. We took advantage of a naturally occurring amino acid polymorphism that is present in aboriginal North Americans, namely apo C-I T45S. We assessed the hypothesis that metabolic traits, including obesity-related and lipoprotein-related traits, would differ between carriers and noncarriers of apo C-I T45S. A genotyping assay was developed for APOC1 T45S and genotypes were determined in a sample of 410 Canadian Oji-Cree subjects. The allele frequency of the apo C-I S45 allele was approximately 8% in this sample. We observed the apo C-I S45 allele was significantly associated with 1) lower percent body fat (P < 0.05), 2) lower waist circumference (P = 0.058), 3) lower serum leptin levels (P < 0.05), and 4) lower plasma apo C-I levels (P < 0.0001), using a newly developed ELISA-based method. Taken together, these results suggest that at the whole human phenotype level, apo C-I is associated with the complex metabolic trait of obesity as well as with serum leptin levels.

Blood lipid levels in relation to glucose status in seven populations of Asian origin without a prior history of diabetes: the DECODA study

BACKGROUND

Dyslipidaemia commonly coexists with diabetes. We investigated the association of lipid profiles with glucose levels in populations of Asian origin without a prior history of diabetes.

METHODS

Cross-sectional data of 10,374 men and 12,552 women aged 30-74 years from 14 cohorts, representing seven populations of Asian origin were jointly analysed. Multivariable adjusted linear regression analyses with standardized regression coefficients (beta) were performed to estimate relationships between lipids and plasma glucose.

RESULTS

Within each glucose category, fasting plasma glucose (FPG) levels were correlated with increasing levels of triglycerides (TGs), total cholesterol (TC), TC to high-density lipoprotein (HDL) ratio and non-HDL cholesterol (non-HDL-C) (p < 0.05 in most of the ethnic groups) and inversely associated with HDL-C (p < 0.05 in some, but not all, of the populations). The association of lipids with 2-h plasma glucose (2hPG) followed a similar pattern as that for the FPG, except that an inverse relationship between HDL-C and glucose was more commonly observed for 2hPG than for FPG among different ethnic groups.

CONCLUSIONS

Hyperglycaemia is associated with adverse lipid profiles in Asians without a prior history of diabetes. The 2hPG appears to be more closely associated with lipid profiles than does FPG. When assessing the risk of cardiovascular disease, the association of the dyslipidaemia with intermediate hyperglycaemia needs to be considered.

Metabolic syndrome and its components as predictors of incident type 2 diabetes mellitus in an Aboriginal community

BACKGROUND

Risk factors for type 2 diabetes remain poorly characterized among Aboriginal Canadians. We aimed to determine the incidence of type 2 diabetes in an Aboriginal community and to evaluate prospective associations with metabolic syndrome and its components.

METHODS

Of 606 participants in the Sandy Lake Health and Diabetes Project from 1993 to 1995 who were free of diabetes at baseline, 540 (89.1%) participated in 10-year follow-up assessments. Baseline anthropometry, blood pressure, fasting insulin and serum lipid levels were measured. Fasting and 2-hour postload glucose levels were obtained at follow-up to determine incident cases of type 2 diabetes.

RESULTS

The 10-year cumulative incidence of diabetes was 17.5%. High adiposity, dyslipidemia, hyperglycemia, hyperinsulinemia and hypertension at baseline were associated with an increased risk of diabetes after adjustment for age and sex (all p < or = 0.03). Metabolic syndrome had high specificity (75%-88%) and high negative predictive value (85%-87%) to correctly detect diabetes-free individuals at follow-up. It had low sensitivity (26%-48%) and low positive predictive value (29%-32%) to detect future diabetes. Metabolic syndrome at baseline was associated with incident diabetes after adjustment for age and sex, regardless of whether the syndrome was defined using the National Cholesterol Education Program criteria (odds ratio [OR] 2.03, 95% confidence interval [CI] 1.10-3.75) or the International Diabetes Federation criteria (OR 2.14, 95% CI 1.29-3.55). The association was to the same degree as that for impaired glucose tolerance assessed using the oral glucose tolerance test (OR 2.87, 95% CI 1.52-5.40; p > 0.05 for comparison of C statistics).

INTERPRETATION

Metabolic syndrome and its components can be identified with readily available clinical measures. As such, the syndrome may be useful for identifying individuals at risk of type 2 diabetes in remote Aboriginal communities.

The relationship of the burbot (Lota lota L.) to the reintroduction of off-the-land foods in the Sandy Lake First Nation Community

This article is based on a study of traditional lifestyle practices in the Sandy Lake First Nation community in northwestern Ontario, considering some of the benefits and risks of reintroducing off-the-land food sources, specifically as they relate to the burbot (Lota lota L). This article concentrates, therefore, on four avenues of exploration: (1) the "nutrition transition" in the First Nations population, (2) the meaning of a traditional diet in the Sandy Lake First Nation, (3) a nutritional value analysis of the burbot to determine its energy content and medicinal properties, and (4) the plausibility of reintroducing off-the-land food sources into the Sandy Lake First Nation community. We argue that though there may be health advantages to the reintroduction of off-the land food sources into First Nations contemporary diets, these benefits will be realized only if practiced according to historical dietary traditions drawing from critical parts of animal tissues to maximize nutrient intake.

Blood lipid levels in relation to glucose status in European men and women without a prior history of diabetes: the DECODE Study

OBJECTIVE

Dyslipidaemia is present not only in diabetic but also in prediabetic subjects. The purpose of this study is to investigate the relationship between lipid and glucose levels in a large European population without a prior history of diabetes.

RESEARCH DESIGN AND METHODS

Data from the population-based studies of 8960 men and 10,516 women aged 35-74 years representing 15 cohorts in 8 European countries were jointly analyzed. Multivariate adjusted linear regression analyses with standardized coefficients (beta) were performed to estimate the relationship between lipid and plasma glucose.

RESULTS

In subjects without a prior history of diabetes, positive relationships were shown between fasting plasma glucose (FPG) and total cholesterol (TC) (beta=0.06 and 0.03, respectively for men and women, p<0.01), triglycerides (TG) (beta=0.14 and 0.12, p<0.001), non-high-density lipoprotein cholesterol (non-HDL-C) (beta=0.06 and 0.03, p<0.01) and TC to HDL ratio (beta=0.06 and 0.05, p<0.001) but a negative trend between FPG and HDL-C (beta=-0.02, p>0.05 in men and beta=-0.03, p<0.05 in women). The relationship between lipid and 2-h plasma glucose (2hPG) followed a similar pattern as that for FPG, except that TC was not increased and HDL-C was reduced in both sexes in subjects with impaired glucose tolerance (IGT).

CONCLUSIONS

For cardiovascular prevention, the different lipid patterns between impaired fasting glucose (IFG) and IGT may deserve further attention to evaluate the combined risks of dyslipidaemia and elevated glucose levels below the diagnostic threshold of diabetes.

Global complication rates of type 2 diabetes in Indigenous peoples: A comprehensive review

INTRODUCTION AND OBJECTIVE

The world's Indigenous peoples are experiencing an unprecedented epidemic of type 2 diabetes [T2DM] but little has been published describing the complications burden. The objective of this paper was to conduct a systematic review of T2DM complications in Indigenous populations worldwide.

METHODS

A literature review was conducted using PubMed and EMBASE to examine available complications data. Country, Indigenous population, authors, publication year, total sample size, Indigenous sample size, age, methodology, and prevalence of nephropathy, end-stage renal disease, retinopathy, neuropathy, lower extremity amputations, cardiovascular disease, hospitalizations and mortality due to diabetes were recorded.

RESULTS

One-hundred and eleven studies were selected. Results revealed a disproportionate burden of disease complications among all Indigenous peoples regardless of their geographic location. Complication rates were seen to vary widely across Indigenous groups.

DISCUSSION

Gaps were found in the published literature on complications among Indigenous populations, especially those living in underdeveloped countries. These gaps may be in part due to the challenges caused by varying operational practices, research methodologies, and definitions of the term Indigenous, making documentation of rates among these peoples problematic. Comprehensive surveillance applying standardized definitions and methodologies is needed to design targeted prevention and disease management strategies for Indigenous peoples with T2DM.

Dietary intake and development of a quantitative food-frequency questionnaire for a lifestyle intervention to reduce the risk of chronic diseases in Canadian First Nations in north-western Ontario

Objectives

To characterise the diet of First Nations in north-western Ontario, highlight foods for a lifestyle intervention and develop a quantitative food-frequency questionnaire (QFFQ).

Design

Cross-sectional survey using single 24 h dietary recalls.

Setting

Eight remote and semi-remote First Nations reserves in north-western Ontario.

Subjects

129 First Nations (Oji-Cree and Ojibway) men and women aged between 18 and 80 years.

Results

The greatest contributors to energy were breads, pasta dishes and chips (contributing over 20 % to total energy intake). ‘Added fats’ such as butter and margarine added to breads and vegetables made up the single largest source of total fat intake (8·4 %). The largest contributors to sugar were sugar itself, soda and other sweetened beverages (contributing over 45 % combined). The mean number of servings consumed of fruits, vegetables and dairy products were much lower than recommended. The mean daily meat intake was more than twice that recommended. A 119-item QFFQ was developed including seven bread items, five soups or stews, 24 meat- or fish-based dishes, eight rice or pasta dishes, nine fruits and 14 vegetables. Frequency of consumption was assessed by eight categories ranging from ‘Never or less than one time in one month’ to ‘two or more times a day’.

Conclusion

We were able to highlight foods for intervention to improve dietary intake based on the major sources of energy, fat and sugar and the low consumption of fruit and vegetable items. The QFFQ is being used to evaluate a diet and lifestyle intervention in First Nations in north-western Ontario.

Diabetic retinopathy in native and nonnative Canadians

High prevalence rates of type 2 diabetes are being observed in native Canadian communities. It is believed that native populations have a higher prevalence rate of vascular complications than nonnatives. The Southern Alberta Study of Diabetic Retinopathy (DR) examined the prevalence and incidence of DR and associated metabolic abnormalities in native and nonnative subjects. Prevalence rates of DR in type 2 diabetic native and nonnative subjects were identical, with a prevalence rate of 40%. Native subjects with retinopathy, however, tended to have more advanced changes of retinopathy compared to the nonnative subjects. Key factors such as A1c, blood pressure, duration of diabetes, and lipid values were not significantly different between the two cohorts. These data indicate that ethnicity does play a role in the development and severity of DR but potential risk factors that may affect the development of retinopathy are not significantly different between native and nonnative groups.

Elevated C-reactive protein in Native Canadian children: an ominous early complication of childhood obesity

AIM

Subclinical inflammation has been proposed as a pathophysiologic mechanism linking obesity with vascular and metabolic disease. Native North American populations are experiencing high prevalence rates of both (i) childhood obesity and (ii) adult cardiovascular disease (CVD) and type 2 diabetes. Thus, we sought to determine whether subclinical inflammation is an early complication of obesity in Native children.

METHODS

Serum concentrations of the inflammatory biomarker C-reactive protein (CRP) were assessed in a population-based, cross-sectional study of the Sandy Lake Oji-Cree community of Northern Ontario, Canada, involving 228 children aged 10-19 years (mean age 14.8).

RESULTS

Median CRP in this population was 0.5 mg/l (interquartile range 0.18-1.79 mg/l). CRP levels were higher than age-matched reference data from the Third National Health and Nutrition Examination Survey (NHANES III). Importantly, fully 15.8% of the children of this community had CRP concentrations between 3 and 10 mg/l, a range that identifies adults at high risk of CVD. Moreover, increasing CRP concentration in this paediatric population was associated with an enhanced CV risk profile, consisting of increased adiposity, higher insulin resistance, worsening lipid profile (higher total cholesterol, triglycerides, low-density lipoprotein cholesterol, apolipoprotein B and total cholesterol : high-density-lipoprotein cholesterol ratio), increased leptin and decreased adiponectin. On multivariate analysis, waist circumference and interleukin-6 (IL-6) emerged as independent determinants of CRP concentration.

CONCLUSION

Subclinical inflammation is an early complication of childhood obesity in Native children and may foreshadow an increased burden of CVD and type 2 diabetes in the future.

Relationship of the metabolic syndrome to carotid ultrasound traits

Background

The metabolic syndrome is associated with increased vascular disease risk. We evaluated two carotid ultrasound measurements, namely intima media thickness and total plaque volume, in a Canadian Oji-Cree population with a high metabolic syndrome prevalence rate.

Methods

As part of the Sandy Lake Complications Prevalence and Risk Factor Study, 166 Oji-Cree subjects (baseline metabolic syndrome prevalence, 44.0%, according to the National Cholesterol Education Program Adult Treatment Panel III guidelines) were examined using a high-resolution duplex ultrasound scanner.

Results

Image analysis showed that mean intima media thickness was elevated in subjects with the metabolic syndrome (818 ± 18 vs 746 ± 20 μm), as was total plaque volume (125 ± 26 vs 77.3 ± 17.0 mm³). However, after adjustment for age and sex, the differences were significant only for intima media thickness (P = 0.039). Furthermore, a significant trend towards increased intima media thickness was observed with increasing numbers of metabolic syndrome components: mean intima media thickness was highest among individuals with all five metabolic syndrome components compared to those with none (866 ± 55 vs 619 ± 23 μm, P = 0.0014). A similar, but non-significant trend was observed for total plaque volume.

Conclusion

This is the first study of the relationship between the metabolic syndrome and two distinct carotid ultrasound traits measured in the same individuals. The results suggest that standard intima media thickness measurement shows a more consistent and stronger association with the metabolic syndrome than does total plaque volume.

Metabolic syndrome in aboriginal Canadians: prevalence and genetic associations

OBJECTIVES

The prevalence rates of type 2 diabetes (T2DM) and coronary heart disease (CHD) in Ontario Oji-Cree are among the world's highest. Since metabolic syndrome (MetS) increases risk of T2DM and CHD, we characterized prevalence and putative genetic determinants of MetS in Oji-Cree.

METHODS AND RESULTS

In 515 adult (> or = 18 years old) and 115 adolescent (< 18 years old) Oji-Cree subjects, using the National Cholesterol Education Program Adult Treatment Panel III (NCEP ATP III) criteria, we determined that 29.9% of Oji-Cree adults, and 43.4% of adults > or = 35 years of age, had MetS. Furthermore, 33.9 and 8.7% of female Oji-Cree adults and adolescents, respectively, had MetS. Increased waist girth and depressed HDL cholesterol were the most prevalent individual MetS components, while increased blood pressure was least prevalent. AGT T174M, GNB3 825C>T, and APOC3 -455T>C genotypes were significantly associated with MetS (P = 0.018, 0.0056, and 0.029, respectively) for female adults, whereas FABP2 A54T genotype was associated with MetS (P = 0.040) for female adolescents.

CONCLUSIONS

The high MetS prevalence in Oji-Cree adults, especially women, is consistent with their high risk of T2DM and CHD. Functional polymorphisms in three candidate genes for plasma lipoproteins and blood pressure were associated with MetS in adult Oji-Cree. Furthermore, several female adolescents met the adult MetS criteria, suggesting that the genesis of MetS begins in youth, especially among aboriginal females.

Development, adaptation, and implementation of a cardiovascular health program for Alaska native women

Southcentral Foundation's Traditions of the Heart program is an innovative cardiovascular disease prevention program for women designed to build on the strengths of the Alaska Native culture as a way to support and encourage positive lifestyle behaviors that focus on healthy eating, active living, stress management, and tobacco cessation. After conducting assessments of existing intervention programs and formative data collection, we adapted two existing programs, Native Nutrition Circles and A New Leaf... Choices for Healthy Living, to develop the Traditions of the Heart program. We implemented and evaluated a pilot intervention study to determine the program's acceptance among Alaska Native women. We used the evaluation results to further refine our study protocol. This article describes the adaptation of these programs to the cultural needs and strengths of Alaska Native women and the results of the formative evaluation used to improve the program design. The complete pilot study outcomes will be published separately.

Diabetes and ethnic minorities

The global prevalence of diabetes for all age groups is estimated to be 2.8%. Type 2 diabetes accounts for at least 90% of diabetes worldwide. Diabetes incidence, prevalence, and disease progression varies by ethnic group. This review highlights unique aspects of the risk of developing diabetes, its overwhelming vascular complications, and their management mainly using data among South Asians and African-Caribbeans in the UK but also using non-UK data. It is concluded that although the origin of the ethnic differences in incidence need further clarification, many factors should be amenable to prevention and treatment in all ethnic groups worldwide.

Synergism between mutant HNF1A and the metabolic syndrome in Oji-Cree Type 2 diabetes

AIMS

To determine the prevalence of the metabolic syndrome in the Sandy Lake Oji-Cree and to examine its interaction with HNF1A in association with impaired glucose tolerance and Type 2 diabetes.

METHODS

Using data collected from the Sandy Lake Health and Diabetes Project (1993-1995), the presence or absence of the metabolic syndrome was determined in 515 Oji-Cree subjects, > or = 18 years of age. In the original study, fasting plasma analytes were measured, a 75-g oral glucose tolerance test was administered, and subjects were genotyped for HNF1A G319S.

RESULTS

The unadjusted prevalence of the metabolic syndrome in the Oji-Cree adults was 29.9%. The adjusted odds ratio (OR) and 95% confidence interval for Type 2 diabetes among subjects who carried the HNF1A G319S mutation and had the modified metabolic syndrome (excluding hyperglycaemia) was 20.3 (6.94, 59.6). Adjusted ORs for Type 2 diabetes for subjects with either the HNF1A G319S mutation alone or the modified metabolic syndrome alone were 5.56 (2.85, 10.9) and 4.84 (2.53, 9.27), respectively. The risk of having impaired glucose tolerance was not influenced by the presence of either factor.

CONCLUSIONS

The risk of Type 2 diabetes was similar (approximately five-fold increased) for subjects with either the presence of the modified metabolic syndrome or the private HNF1A G319S mutation. Interestingly, when present in combination, the two independent risk factors appeared to act synergistically to confer an even greater increased risk of Type 2 diabetes.

Cigarette smoking and cardiovascular risk factors among Aboriginal Canadian youths

BACKGROUND

Aboriginal populations in North America are exhibiting an increased prevalence of cardiovascular disease and associated traditional and nontraditional cardiovascular risk factors, trends believed to be due to the influence of Western lifestyle habits. Because these influences are present at an early age, we sought to study the patterns of one such habit, cigarette smoking, among Aboriginal Canadian youths and to assess the associated accrual of cardiovascular risk factors at an early age.

METHODS

Patterns of cigarette smoking were assessed in a population-based, cross-sectional study involving 236 youths aged 10-19 (mean 14.9) years in the Oji-Cree community of Sandy lake, in northwestern Ontario. Participants underwent clinical and metabolic evaluation with assessment of cardiovascular risk factors.

RESULTS

The prevalence of cigarette smoking among the study participants was considerably higher than age-specific national averages, with fully 50% of the participants overall and 82% of the adolescent participants (aged 15-19) being current smokers. Compared with their peers, children smoking 6 or more cigarettes per day had an enhanced cardiovascular risk profile consisting of a higher mean systolic blood pressure (111 v. 107.5 mm Hg, p = 0.036), a higher mean plasma homocysteine level (8.7 v. 7.6 micromol/L, p = 0.008) and a lower mean serum folate level (4.5 v. 5.4 mmol/L, p = 0.007), after adjustment for age, sex and body mass index. In separate multiple linear regression analyses, current cigarette exposure (number of cigarettes smoked per day) emerged as an independent determinant of both systolic blood pressure and plasma homocysteine level.

INTERPRETATION

In this Aboriginal community with remarkably high rates of cigarette smoking among its youth, an independent dose-response relation was found between current smoking exposure and both traditional (systolic blood pressure) and nontraditional (homocysteine level) cardiovascular risk factors. The association of cigarette smoking with an enhanced cardiovascular risk profile at an early age may be a factor contributing to the high prevalence of cardiovascular disease in this Aboriginal population.

A comparison of ultrasound measurements to assess carotid atherosclerosis development in subjects with and without type 2 diabetes

BACKGROUND

Subjects with type 2 diabetes are at an increased risk of vascular complications. The use of carotid ultrasound remains an attractive, non-invasive method to monitor atherosclerotic disease progression and/or response to treatment in patients with type 2 diabetes, with intima-media thickness routinely used as the gold standard to detect pathology. However, alternative measurements, such as plaque area or volume, may represent a potentially more powerful approach. Thus, the objective of this study was to compare the traditional intima-media thickness measurement against the novel total plaque volume measurement in analyzing carotid atherosclerosis development in individuals with type 2 diabetes.

METHODS

The case-control study included 49 Oji-Cree adults with diabetes or impaired glucose tolerance, aged 21-69, and 49 sex- and age-matched normoglycemic subjects. At baseline, metabolic variables were measured, including body mass index, waist circumference, total cholesterol: high density lipoprotein ratio, plasma triglycerides, plasma glucose, and serum insulin. Carotid ultrasound measurements, 7 years later, assessed carotid arterial intima-media thickness and total plaque volume.

RESULTS

At baseline, the two groups were well matched for smoking habits, hypertension, body mass index, and waist circumference. Differences were noted in baseline measurements of total cholesterol:high density lipoprotein (P = 0.0006), plasma triglycerides (P < 0.0001) and fasting glucose (P < 0.0001). After seven years, carotid ultrasound scans revealed that total plaque volume measurements (P = 0.037), but not intima-media thickness measurements, were higher in subjects with diabetes/impaired glucose tolerance compared to the normoglycemic controls. Correlation between intima-media thickness and total plaque volume was moderate. Based on our study findings, to achieve power levels > 0.70 when comparing intima-media thickness measurements for diabetics versus non-diabetics, thousands of study subjects are required. For comparing total plaque volume measurements, only hundreds of study subjects are required.

CONCLUSION

The development of atherosclerotic plaque is greater in subjects with diabetes/impaired glucose tolerance. Total plaque volume appears to capture the atherosclerotic disease burden more effectively in subjects with type 2 diabetes, and would be an appropriate outcome measure for studies aimed at changing the diabetic milieu.

Genetic and physiological insights into the metabolic syndrome

The metabolic syndrome (MetS) is a common phenotype that is clinically defined by threshold values applied to measures of central obesity, dysglycemia, dyslipidemia, and/or elevated blood pressure, which must be present concurrently in any one of a variety of combinations. Insulin resistance, although not a defining component of the MetS, is nonetheless considered to be a core feature. MetS is important because it is rapidly growing in prevalence and is strongly related to the development of cardiovascular disease. To define etiology, pathogenesis and expression of MetS, we have studied patients, specifically Canadian families and communities. One example is familial partial lipodystrophy (FPLD), a rare monogenic form of insulin resistance caused by mutations in either LMNA, encoding nuclear lamin A/C (subtype FPLD2), or in PPARG, encoding peroxisomal proliferator-activated receptor-gamma (subtype FPLD3). Because it evolves slowly and recapitulates key clinical and biochemical attributes, FPLD seems to be a useful monogenic model of MetS. A second example is the disparate MetS prevalence between two Canadian aboriginal groups that is mirrored by disparate prevalence of diabetes and cardiovascular disease. Careful phenotypic evaluation of such special cases of human MetS by using a wide range of diagnostic methods, an approach called "phenomics," may help uncover early presymptomatic disease biomarkers, which in turn might reveal new pathways and targets for interventions for MetS, diabetes, and atherosclerosis.

Diabetes in Montana's Indians: the epidemiology of diabetes in the Indians of the Northern Plains and Canada

The prevalence of diabetes is two- to threefold higher in American Indians in Montana compared with the non-Indian population. High rates of diabetes have also been described in Canadian aboriginal populations closely related to the tribes in Montana. Diabetes in pregnancy has increased among Indian mothers and high-birth-weight babies are increasingly likely to be born to Indian mothers with diabetes in pregnancy. Over 70% of the incident cases of diabetes in youth less than 20 years of age on the reservations have the clinical characteristics of type 2 diabetes. Cardiovascular disease mortality rates are high among Indians in Montana, and the prevalence of smoking in the Indian populations of Montana and the neighboring tribes in Canada is remarkably high. Indians in Montana are more likely than non-Indians of similar age to believe that diabetes is preventable and to recall advice about diabetes risk.

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.

Relation of waist circumference and glycemic status to C-reactive protein in the Sandy Lake Oji-Cree

OBJECTIVE

To determine the prevalence of elevated C-reactive protein (CRP) in the Sandy Lake Oji-Cree, an aboriginal community residing in the Sioux Lookout zone of Northwestern Ontario, Canada, and to determine the associations of obesity and diabetes with CRP in a community with a very high prevalence of type II diabetes.

DESIGN

We surveyed 512 community members aged 18 y and older to determine the prevalence and the determinants of elevated CRP in Sandy Lake.

MEASUREMENTS

Clinical variables, indices of obesity and serum concentrations of CRP, insulin, serum amyloid A (SAA) and interleukin-6 (IL-6).

RESULTS

The prevalence of CRP >or=3.8 mg/l was significantly higher in women than in men (51% vs. 32%, P<0.0001). Regression analysis determined that body mass index and IL-6 were independent determinants of CRP concentration in women and waist circumference and IL-6 were independent determinants of CRP concentration in men. Diabetes was associated with elevated CRP in both sexes, but was only a moderate strong determinant in CRP concentration in multivariate regression analysis.

CONCLUSIONS

The prevalence of elevated CRP in this aboriginal community is remarkably high. These data further demonstrate that the association between CRP and specific indices of obesity and metabolism vary according to gender and glycemic status.

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.