Gillian L. Booth

Relation between age and cardiovascular disease in men and women with diabetes compared with non-diabetic people: a population-based retrospective cohort study

BACKGROUND Adults with diabetes are thought to have a high risk of cardiovascular disease (CVD), irrespective of their age. The main aim of this study was to find out the age at which people with diabetes develop a high risk of CVD, as defined by: an event rate equivalent to a 10-year risk of 20% or more; or an event rate equivalent to that associated with previous myocardial infarction. METHODS We did a population-based retrospective cohort study using provincial health claims to identify all adults with (n=379,003) and (n=9,018,082) without diabetes mellitus living in Ontario, Canada, on April 1, 1994. Individuals were followed up to record CVD events until March 31, 2000. FINDINGS The transition to a high-risk category occurred at a younger age for men and women with diabetes than for those without diabetes (mean difference 14.6 years). For the outcome of acute myocardial infarction (AMI), stroke, or death from any cause, diabetic men and women entered the high-risk category at ages 47.9 and 54.3 years respectively. When we used a broader definition of CVD that also included coronary or carotid revascularisation, the ages were 41.3 and 47.7 years for men and women with diabetes respectively. INTERPRETATION Diabetes confers an equivalent risk to ageing 15 years. However, in general, younger people with diabetes (age 40 or younger) do not seem to be at high risk of CVD. Age should be taken into account in targeting of risk reduction in people with diabetes.

Effect of a Low–Glycemic Index or a High–Cereal Fiber Diet on Type 2 Diabetes: A Randomized Trial

CONTEXT Clinical trials using antihyperglycemic medications to improve glycemic control have not demonstrated the anticipated cardiovascular benefits. Low-glycemic index diets may improve both glycemic control and cardiovascular risk factors for patients with type 2 diabetes but debate over their effectiveness continues due to trial limitations. OBJECTIVE To test the effects of low-glycemic index diets on glycemic control and cardiovascular risk factors in patients with type 2 diabetes. DESIGN, SETTING, AND PARTICIPANTS A randomized, parallel study design at a Canadian university hospital research center of 210 participants with type 2 diabetes treated with antihyperglycemic medications who were recruited by newspaper advertisement and randomly assigned to receive 1 of 2 diet treatments each for 6 months between September 16, 2004, and May 22, 2007. INTERVENTION High-cereal fiber or low-glycemic index dietary advice. MAIN OUTCOME MEASURES Absolute change in glycated hemoglobin A(1c) (HbA(1c)), with fasting blood glucose and cardiovascular disease risk factors as secondary measures. RESULTS In the intention-to-treat analysis, HbA(1c) decreased by -0.18% absolute HbA(1c) units (95% confidence interval [CI], -0.29% to -0.07%) in the high-cereal fiber diet compared with -0.50% absolute HbA(1c) units (95% CI, -0.61% to -0.39%) in the low-glycemic index diet (P < .001). There was also an increase of high-density lipoprotein cholesterol in the low-glycemic index diet by 1.7 mg/dL (95% CI, 0.8-2.6 mg/dL) compared with a decrease of high-density lipoprotein cholesterol by -0.2 mg/dL (95% CI, -0.9 to 0.5 mg/dL) in the high-cereal fiber diet (P = .005). The reduction in dietary glycemic index related positively to the reduction in HbA(1c) concentration (r = 0.35, P < .001) and negatively to the increase in high-density lipoprotein cholesterol (r = -0.19, P = .009). CONCLUSION In patients with type 2 diabetes, 6-month treatment with a low-glycemic index diet resulted in moderately lower HbA(1c) levels compared with a high-cereal fiber diet. Trial Registration clinicaltrials.gov identifier: NCT00438698.

Increased Risk of Cardiovascular Disease in Young Women Following Gestational Diabetes Mellitus

OBJECTIVE—To determine whether women with gestational diabetes mellitus (GDM) have an increased risk of cardiovascular disease (CVD) following pregnancy. RESEARCH DESIGN AND METHODS—All women aged 20–49 years with live births between April 1994 and March 1997 in Ontario, Canada, were identified. Women with GDM were matched with 10 women without GDM and were followed for CVD. RESULTS—The matched cohorts included 8,191 women with GDM and 81,262 women without GDM. Mean age at entry was 31 years, and median follow-up was 11.5 years. The hazard ratio for CVD events was 1.71 (95% CI 1.08–2.69). After adjustment for subsequent type 2 diabetes, the hazard ratio was attenuated (1.13 [95% CI 0.67–1.89]). CONCLUSIONS—Young women with GDM had a substantially increased risk for CVD compared with women without GDM. Much of this increased risk was attributable to subsequent development of type 2 diabetes.

Age- and sex-related prevalence of diabetes mellitus among immigrants to Ontario, Canada

Background: The majority of immigrants to Canada originate from the developing world, where the most rapid increase in prevalence of diabetes mellitus is occurring. We undertook a population-based study involving immigrants to Ontario, Canada, to evaluate the distribution of risk for diabetes in this population. Methods: We used linked administrative health and immigration records to calculate age-specific and age-adjusted prevalence rates among men and women aged 20 years or older in 2005. We compared rates among 1 122 771 immigrants to Ontario by country and region of birth to rates among long-term residents of the province. We used logistic regression to identify and quantify risk factors for diabetes in the immigrant population. Results: After controlling for age, immigration category, level of education, level of income and time since arrival, we found that, as compared with immigrants from western Europe and North America, risk for diabetes was elevated among immigrants from South Asia (odds ratio [OR] for men 4.01, 95% CI 3.82–4.21; OR for women 3.22, 95% CI 3.07–3.37), Latin America and the Caribbean (OR for men 2.18, 95% CI 2.08–2.30; OR for women 2.40, 95% CI: 2.29–2.52), and sub-Saharan Africa (OR for men 2.31, 95% CI 2.17–2.45; OR for women 1.83, 95% CI 1.72–1.95). Increased risk became evident at an early age (35–49 years) and was equally high or higher among women as compared with men. Lower socio-economic status and greater time living in Canada were also associated with increased risk for diabetes. Interpretation: Recent immigrants, particularly women and immigrants of South Asian and African origin, are at high risk for diabetes compared with long-term residents of Ontario. This risk becomes evident at an early age, suggesting that effective programs for prevention of diabetes should be developed and targeted to immigrants in all age groups.

The risk of hip fractures in older individuals with diabetes: a population-based study.

OBJECTIVE—Compared with men and women without diabetes, individuals with type 2 diabetes have higher bone mineral density (BMD). However, they may still be at increased risk for hip fractures. Using population-based Ontario health care data, we compared the risk of hip fractures among men and women with and without diabetes. RESEARCH DESIGN AND METHODS—Using a retrospective cohort design, we identified Ontario residents aged ≥66 years with diabetes from a validated registry from 1994 to 1995 (n = 197,412) and followed them for their first hip fracture until 31 March 2003 (mean 6.1-year follow-up). Hip fracture rates were compared with those of age-matched Ontario residents without diabetes (n = 401,400), and results were stratified by sex and adjusted for age and other covariates. RESULTS—Compared with individuals without diabetes, individuals with diabetes had greater comorbidity, were less likely to have had a BMD test, and were more likely to be taking medications that increase risk of falling and decrease BMD. After adjusting for these differences and age, we found that diabetes increased fracture risk in both men (hazard ratio 1.18 [95% CI 1.12–1.24], P < 0.0001) and women (1.11 [1.08–1.15], P < 0.0001). CONCLUSIONS—Men and women with diabetes have a higher risk of hip fractures compared with individuals without diabetes. Further research to elucidate the mechanisms underlying this increased risk of fracture is needed, as well as increased attention to fracture prevention strategies in patients with diabetes.

Type 2 Diabetes, Medication-Induced Diabetes, and Monogenic Diabetes in Canadian Children: A Prospective National Surveillance Study

OBJECTIVE To determine in Canadian children aged <18 years the 1) incidence of type 2 diabetes, medication-induced diabetes, and monogenic diabetes; 2) clinical features of type 2 diabetes; and 3) coexisting morbidity associated with type 2 diabetes at diagnosis. RESEARCH DESIGN AND METHODS This Canadian prospective national surveillance study involved a network of pediatricians, pediatric endocrinologists, family physicians, and adult endocrinologists. Incidence rates were calculated using Canadian Census population data. Descriptive statistics were used to illustrate demographic and clinical features. RESULTS From a population of 7.3 million children, 345 cases of non–type 1 diabetes were reported. The observed minimum incidence rates of type 2, medication-induced, and monogenic diabetes were 1.54, 0.4, and 0.2 cases per 100,000 children aged <18 years per year, respectively. On average, children with type 2 diabetes were aged 13.7 years and 8% (19 of 227) presented before 10 years. Ethnic minorities were overrepresented, but 25% (57 of 227) of children with type 2 diabetes were Caucasian. Of children with type 2 diabetes, 95% (206 of 216) were obese and 37% (43 of 115) had at least one comorbidity at diagnosis. CONCLUSIONS This is the first prospective national surveillance study in Canada to report the incidence of type 2 diabetes in children and also the first in the world to report the incidence of medication-induced and monogenic diabetes. Rates of type 2 diabetes were higher than expected with important regional variation. These results support recommendations that screening for comorbidity should occur at diagnosis of type 2 diabetes.

Risk Factors for Cardiovascular Disease in Homeless Adults

Background—Homeless people represent an extremely disadvantaged group in North America. Among older homeless men, cardiovascular disease (CVD) is the leading cause of death. The objective of this study was to examine cardiovascular risk factors in a representative sample of homeless adults and identify opportunities for improved risk factor modification. Methods and Results—Homeless persons were randomly selected at shelters for single adults in Toronto. Response rate was 79%. Participants (n=202) underwent interviews, physical measurements, and blood sampling. The mean age of participants was 42 years, and 89% were men. The prevalence of smoking among homeless subjects (78%; 95% confidence interval [CI], 72% to 84%) was significantly higher than in the general population (standardized morbidity ratio [SMR], 254; 95% CI, 216 to 297). Hypertension, high cholesterol, and diabetes were not more prevalent than in the general population but were often poorly controlled. Homeless men were significantly less likely to be overweight or obese than men in the general population (SMR, 79; 95% CI, 63 to 98). Cocaine use in the last year was reported by 29% of subjects (95% CI, 23% to 36%). CVD was reported by 15% of subjects, fewer than one third of whom reported taking aspirin or cholesterol-lowering medication. According to multiple-risk-factor equations, the median estimated 10-year absolute risk of myocardial infarction or coronary death among homeless men aged 30 to 74 years was 5% (interquartile range, 3% to 9%). Conclusions—Cardiovascular risk factor modification is suboptimal among homeless adults in Toronto, despite universal health insurance. Multiple risk factor equations may underestimate true risk in this population because of inadequate accounting for factors such as cocaine use and heavy smoking.

Effects of intensive glycaemic control on ischaemic heart disease: Analysis of data from the randomised, controlled ACCORD trial

BACKGROUND Hyperglycaemia could substantially increase the risk of ischaemic heart disease in patients with type 2 diabetes. We investigated whether intensive lowering of glucose concentrations affects risk. METHODS We assessed 10,251 adults aged 40-79 years with established type 2 diabetes, mean glycated haemoglobin A1c (HbA1c) concentration of 67 mmol/mol (8·3%), and risk factors for ischaemic heart disease enrolled in the ACCORD trial. Participants were assigned to intensive or standard therapy (target HbA1c less than 42 or 53-63 mmol/mol [less than 6·0% or 7·0-7·9%], respectively). We assessed fatal or non-fatal myocardial infarction, coronary revascularisation, unstable angina, and new angina during active treatment (mean 3·7 years) plus a further mean 1·2 years. This trial is registered with ClinicalTrials.gov, number NCT00000620. FINDINGS Myocardial infarction was less frequent in the intensive than in the standard therapy group during active treatment (hazard ratio [HR] 0·80, 95% CI 0·67-0·96; p=0·015) and overall (0·84, 0·72-0·97; p=0·02). Findings were similar for combined myocardial infarction, coronary revascularisation, and unstable angina (active treatment HR 0·89, 95% CI 0·79-0·99, overall 0·87 0·79-0·96) and for coronary revascularisation alone (0·84, 0·75-0·94) and unstable angina alone (0·81, 0·67-0·97) during full follow-up. With lowest achieved HbA1C concentrations included as a time-dependent covariate, all hazards became non-significant. INTERPRETATION Raised glucose concentration is a modifiable risk factor for ischaemic heart disease in middle-aged people with type 2 diabetes and other cardiovascular risk factors. FUNDING National Heart, Lung, and Blood Institute, National Institute of Diabetes and Digestive and Kidney Diseases, National Institute on Aging, National Eye Intitute, and Centers for Disease Control and Prevention.

Newly diagnosed diabetes mellitus as a risk factor for serious liver disease

Background: The negative impact of diabetes mellitus is well recognized, yet little is known about the effect of this disease on the liver, an organ susceptible to nonalcoholic fatty liver disease related to insulin resistance. We evaluated whether adults with newly diagnosed diabetes were at increased risk of serious liver disease. Methods: We used administrative health databases for the province of Ontario (1994–2006) to perform a population-based matched retrospective cohort study. The exposed group comprised 438 069 adults with newly diagnosed diabetes. The unexposed comparison group — those without known diabetes — consisted of 2 059 708 individuals, matched 5:1 to exposed persons, by birth year, sex and local health region. We excluded individuals with pre-existing liver or alcohol-related disease. The primary study outcome was the subsequent development of serious liver disease, namely, liver cirrhosis, liver failure and its sequelae, or receipt of a liver transplant. Results: The incidence rate of serious liver disease was 8.19 per 10 000 person-years among those with newly diagnosed diabetes and 4.17 per 10 000 person-years among those without diabetes. The unadjusted hazard ratio was 1.92 (95% confidence interval [CI] 1.83–2.01). After adjustment for age, income, urban residence, health care utilization and pre-existing hypertension, dyslipidemia, obesity and cardiovascular disease, the hazard ratio was 1.77 (95% CI 1.68–1.86). Interpretation: Adults with newly diagnosed diabetes appeared to be at higher risk of advanced liver disease, also known as diabetic hepatopathy. Whether this reflects nonalcoholic fatty liver disease or direct glycemic injury of the liver remains to be determined.

Density, Destinations or Both? A Comparison of Measures of Walkability in Relation to Transportation Behaviors, Obesity and Diabetes in Toronto, Canada

The design of suburban communities encourages car dependency and discourages walking, characteristics that have been implicated in the rise of obesity. Walkability measures have been developed to capture these features of urban built environments. Our objective was to examine the individual and combined associations of residential density and the presence of walkable destinations, two of the most commonly used and potentially modifiable components of walkability measures, with transportation, overweight, obesity, and diabetes. We examined associations between a previously published walkability measure and transportation behaviors and health outcomes in Toronto, Canada, a city of 2.6 million people in 2011. Data sources included the Canada census, a transportation survey, a national health survey and a validated administrative diabetes database. We depicted interactions between residential density and the availability of walkable destinations graphically and examined them statistically using general linear modeling. Individuals living in more walkable areas were more than twice as likely to walk, bicycle or use public transit and were significantly less likely to drive or own a vehicle compared with those living in less walkable areas. Individuals in less walkable areas were up to one-third more likely to be obese or to have diabetes. Residential density and the availability of walkable destinations were each significantly associated with transportation and health outcomes. The combination of high levels of both measures was associated with the highest levels of walking or bicycling (p<0.0001) and public transit use (p<0.0026) and the lowest levels of automobile trips (p<0.0001), and diabetes prevalence (p<0.0001). We conclude that both residential density and the availability of walkable destinations are good measures of urban walkability and can be recommended for use by policy-makers, planners and public health officials. In our setting, the combination of both factors provided additional explanatory power.