Ethnic Variation in Prediabetes Incidence and Outcomes among Immigrants and Long-Term Residents

Type 2 diabetes is rapidly increasing worldwide, particularly in low and middle-income countries. In Canada, the estimated prevalence of diabetes is projected to increase from 9.3% to 12.1% by 2025. Previous studies have shown that some ethnoracial populations of non-European descent have a higher risk of developing diabetes, however, evidence on the onset of prediabetes across different ethnoracial groups in Canada is not available. Although, 5-10% of people with prediabetes convert to diabetes, there is no knowledge on the risk of conversion to diabetes among immigrants of different ethnic origins in Canada. Therefore, the purpose of this thesis was to investigate the epidemiology of prediabetes within an immigrant cohort across different ethnicities, compared with long-term Canadian residents to inform future research and policy. The main findings from this thesis conclude that: 1) Ethnicity is an important risk factor for the development of prediabetes and its progression to diabetes 2) Non-European populations, especially, people of South Asian, Sub-Saharan African and Caribbean, and South-East Asians at young ages have an elevated risk of developing prediabetes, in comparison to Western Europeans 3) Generally, South Asians, Sub-Saharan African and Caribbeans, and West Asian and Arabs, have a nearly twofold risk of converting to diabetes relative to Western Europeans 4) Relative to Western Europeans, the incidence of prediabetes and its conversion to diabetes was elevated for both women and men of non-European descents 5) Neighbourhood walkability amplified the effects of ethnicity such that non-European populations living in low walkability neighbourhoods had an increased risk of prediabetes, but those living in high walkability neighbourhoods did not. This was particularly evident among West Asian and Arabs, and Latin Americans. These findings highlight the need for population health interventions that will address the rapidly rising rates of prediabetes and conversion to diabetes among immigrant populations of different ethnicities. Future research and policy steps may involve establishing age/ethnic specific cut offs for diabetes screening and monitoring prediabetes risk within health care settings; designing diabetes prevention programs tailored to high risk groups and tackling upstream determinants such as neighbourhood designs that promote healthier lifestyles and support the prevention of diabetes.Ph.D

Neighborhood walkability and pre-diabetes incidence in a multiethnic population

Introduction We examined whether adults living in highly walkable areas are less likely to develop pre-diabetes and if so, whether this association is consistent according to immigration status and ethnicity.Research design and methods Population-level health, immigration, and administrative databases were used to identify adults aged 20–64 (n=1 128 181) who had normoglycemia between January 2011 and December 2011 and lived in one of 15 cities in Southern Ontario, Canada. Individuals were assigned to one of ten deciles (D) of neighborhood walkability (from lowest (D1) to highest (D10)) and followed until December 2013 for the development of pre-diabetes.Results Overall, 220 225 individuals in our sample developed pre-diabetes during a median follow-up of 8.4 years. Pre-diabetes incidence was 20% higher among immigrants living in the least (D1) (adjusted HR 1.20, 95% CI 1.15 to 1.25, p<0.0001) versus most (D10, referent) walkable neighborhoods after accounting for age, sex, and area income. Findings were similar among long-term residents and across sexes. However, susceptibility to walkability varied by ethnicity where D1 versus D10 adjusted HRs ranged from 1.17 (95% CI 1.02 to 1.35, p=0.03) among West Asian and Arab immigrants to 1.32 (95% CI 1.19 to 1.47, p<0.0001) in Southeast Asians. Ethnic variation in pre-diabetes incidence was more marked in low walkability settings. Relative to Western Europeans, the adjusted HR for pre-diabetes incidence was 2.11 (95% CI 1.81 to 2.46, p<0.0001) and 1.50 (95% CI 1.27 to 1.77, p<0.0001) among Sub-Saharan African and the Carribean and Latin American immigrants, respectively, living in the least walkable (D1) neighborhoods, but only 1.24 (95% CI 1.08 to 1.42, p=0.002) and 1.00 (95% CI 0.87 to 1.15, p=0.99) for these same groups living in the most walkable (D10) neighborhoods.Conclusions Pre-diabetes incidence was reduced in highly walkable areas for most groups living in Southern Ontario cities. These findings suggest a potential role for walkable urban design in diabetes prevention

Ethnic variation in the conversion of prediabetes to diabetes among immigrant populations relative to Canadian-born residents: a population-based cohort study

ObjectiveThe aim of this study was to compare absolute and relative rates of conversion from prediabetes to diabetes among non-European immigrants to Europeans and Canadian-born residents, overall, and by age and level of glycemia.Research design and methodsWe conducted a retrospective cohort population-based study using administrative health databases from Ontario, Canada, to identify immigrants (n=23 465) and Canadian born (n=1 11 085) aged ≥20 years with prediabetes based on laboratory tests conducted between 2002 and 2011. Individuals were followed until 31 December 2013 for the development of diabetes using a validated algorithm. Immigration data was used to assign ethnicity based on country of origin, mother tongue, and surname. Fine and Gray’s survival models were used to compare diabetes incidence across ethnic groups overall and by age and glucose category.ResultsOver a median follow-up of 5.2 years, 8186 immigrants and 39 722 Canadian-born residents developed diabetes (7.1 vs 6.1 per 100 person-years, respectively). High-risk immigrant populations such as South Asians (HR: 1.72, 95% CI 1.55 to 1.99) and Southeast Asians (HR: 1.65, 95% CI 1.46 to 1.86) had highest risk of converting to diabetes compared with Western Europeans (referent). Among immigrants aged 20–34 years, the adjusted cumulative incidence ranged from 18.4% among Eastern Europeans to 52.3% among Southeast Asians. Conversion rates increased with age in all groups but were consistently high among South Asians, Southeast Asians and Sub-Saharan African/Caribbeans after the age of 35 years. On average, South Asians converted to diabetes 3.1–4.6 years earlier than Western Europeans and at an equivalent rate of conversion to Western Europeans who had a 0.5 mmol/L higher baseline fasting glucose value.ConclusionsHigh-risk ethnic groups converted to diabetes more rapidly, at younger ages, and at lower fasting glucose values than European populations, leading to a shorter window for diabetes prevention

Forecasting Diabetes Cases Prevented and Cost Savings Associated with Population Increases of Walking in the Greater Toronto and Hamilton Area, Canada

Promoting adequate levels of physical activity in the population is important for diabetes prevention. However, the scale needed to achieve tangible population benefits is unclear. We aimed to estimate the public health impact of increases in walking as a means of diabetes prevention and health care cost savings attributable to diabetes. We applied the validated Diabetes Population Risk Tool (DPoRT) to the 2015/16 Canadian Community Health Survey for adults aged 18–64, living in the Greater Toronto and Hamilton area, Ontario, Canada. DPoRT was used to generate three population-level scenarios involving increases in walking among individuals with low physical activity levels, low daily step counts and high dependency on non-active forms of travel, compared to a baseline scenario (no change in walking rates). We estimated number of diabetes cases prevented and health care costs saved in each scenario compared with the baseline. Each of the three scenarios predicted a considerable reduction in diabetes and related health care cost savings. In order of impact, the largest population benefits were predicted from targeting populations with low physical activity levels, low daily step counts, and non active transport use. Population increases of walking by 25 min each week was predicted to prevent up to 10.4 thousand diabetes cases and generate CAD 74.4 million in health care cost savings in 10 years. Diabetes reductions and cost savings were projected to be higher if increases of 150 min of walking per week could be achieved at the population-level (up to 54.3 thousand diabetes cases prevented and CAD 386.9 million in health care cost savings). Policy, programming, and community designs that achieve modest increases in population walking could translate to meaningful reductions in the diabetes burden and cost savings to the health care system

Ethnic differences in prediabetes incidence among immigrants to Canada: a population-based cohort study

Abstract Background Prediabetes appears to be increasing worldwide. This study examined the incidence of prediabetes among immigrants to Canada of different ethnic origins and the age at which ethnic differences emerged. Methods We assembled a cohort of Ontario adults (≥ 20 years) with normoglycemia based on glucose testing performed between 2002 and 2011 through a single commercial laboratory database (N = 1,772,180). Immigration data were used to assign ethnicity based on country of origin, mother tongue, and surname. Individuals were followed until December 2013 for the development of prediabetes, defined using either the World Health Organization/Diabetes Canada (WHO/DC) or American Diabetes Association (ADA) thresholds. Multivariate competing risk regression models were derived to examine the effect of ethnicity and immigration status on prediabetes incidence. Results After a median follow-up of 8.0 years, 337,608 individuals developed prediabetes. Using definitions based on WHO/DC, the adjusted cumulative incidence of prediabetes was 40% (HR 1.40, CI 1.38–1.41) higher for immigrants relative to long-term Canadian residents (21.2% vs 16.0%, p < 0.001) and nearly twofold higher among South Asian than Western European immigrants (23.6%; HR 1.95, CI1.87–2.03 vs 13.1%; referent). Cumulative incidence rates based on ADA thresholds were considerably higher (47.1% and 32.3% among South Asians and Western Europeans, respectively). Ethnic differences emerged at young ages. South Asians aged 20–34 years had a similar prediabetes incidence as Europeans who were 15 years older (35–49 years), regardless of which prediabetes definition was used (WHO/DC 14.4% vs 15.7%; ADA 38.0% vs 33.0%). Conclusion Prediabetes incidence was substantially higher among non-European immigrants to Canada, highlighting the need for early prevention strategies in these populations

The evidence base of primary research in public health emergency preparedness: a scoping review and stakeholder consultation

Abstract Background Effective public health emergency preparedness and response systems are important in mitigating the impact of all-hazards emergencies on population health. The evidence base for public health emergency preparedness (PHEP) is weak, however, and previous reviews have noted a substantial proportion of anecdotal event reports. To investigate the body of research excluding the anecdotal reports and better understand primary and analytical research for PHEP, a scoping review was conducted with two objectives: first, to develop a thematic map focused on primary research; and second, to use this map to inform and guide an understanding of knowledge gaps relevant to research and practice in PHEP. Methods A scoping review was conducted based on established methodology. Multiple databases of indexed and grey literature were searched based on concepts of public health, emergency, emergency management/preparedness and evaluation/evidence. Inclusion and exclusion criteria were applied iteratively. Primary research studies that were evidence-based or evaluative in nature were included in the final group of selected studies. Thematic analysis was conducted for this group. Stakeholder consultation was undertaken for the purpose of validating themes and identifying knowledge gaps. To accomplish this, a purposive sample of researchers and practicing professionals in PHEP or closely related fields was asked to complete an online survey and participate in an in-person meeting. Final themes and knowledge gaps were synthesized after stakeholder consultation. Results Database searching yielded 3015 citations and article selection resulted in a final group of 58 articles. A list of ten themes from this group of articles was disseminated to stakeholders with the survey questions. Survey findings resulted in four cross-cutting themes and twelve stand-alone themes. Several key knowledge gaps were identified in the following themes: attitudes and beliefs; collaboration and system integration; communication; quality improvement and performance standards; and resilience. Resilience emerged as both a gap and a cross-cutting theme. Additional cross-cutting themes included equity, gender considerations, and high risk or at-risk populations. Conclusions In this scoping review of the literature enhanced by stakeholder consultation, key themes and knowledge gaps in the PHEP evidence base were identified which can be used to inform future practice-oriented research in PHEP

Identifying mechanisms for facilitating knowledge to action strategies targeting the built environment

Abstract Background In recent years, obesity-related diseases have been on the rise globally resulting in major challenges for health systems and society as a whole. Emerging research in population health suggests that interventions targeting the built environment may help reduce the burden of obesity and type 2 diabetes. However, translation of the evidence on the built environment into effective policy and planning changes requires engagement and collaboration between multiple sectors and government agencies for designing neighborhoods that are more conducive to healthy and active living. In this study, we identified knowledge gaps and other barriers to evidence-based decision-making and policy development related to the built environment; as well as the infrastructure, processes, and mechanisms needed to drive policy changes in this area. Methods We conducted a qualitative thematic analysis of data collected through consultations with a broad group of stakeholders (N = 42) from Southern Ontario, Canada, within various sectors (public health, urban planning, and transportation) and levels of government (federal, provincial, and municipalities). Relevant themes were classified based on the specific phase of the knowledge-to-action cycle (research, translation, and implementation) in which they were most closely aligned. Results We identified 5 themes including: 1) the need for policy-informed and actionable research (e.g. health economic analyses and policy evaluations); 2) impactful messaging that targets all relevant sectors to create the political will necessary to drive policy change; 3) common measures and tools to increase capacity for monitoring and surveillance of built environment changes; (4) intersectoral collaboration and alignment within and between levels of government to enable collective actions and provide mechanisms for sharing of resources and expertise, (5) aligning public and private sector priorities to generate public demand and support for community action; and, (6) solution-focused implementation of research that will be tailored to meet the needs of policymakers and planners. Additional research priorities and key policy and planning actions were also noted. Conclusion Our research highlights the necessity of involving stakeholders in identifying inter-sectoral solutions to develop and translate actionable research on the built environment into effective policy and planning initiatives

Development of a neighborhood drivability index and its association with transportation behavior in Toronto.

Background: Car driving is a form of passive transport that is associated with an increase in physical inactivity, obesity, air pollution and noise. Built environment characteristics may influence transport mode choice, but comprehensive indices for built environment characteristics that drive car use are still lacking, while such an index could provide tangible policy entry points. Objective: We developed and validated a neighbourhood drivability index, capturing combined dimensions of the neighbourhood environment in the City of Toronto, and investigated its association with transportation choices (car, public transit or active transport), overall, by trip length, and combined for residential neighbourhood and workplace drivability. Methods: We used exploratory factor analysis to derive distinct factors (clusters of one or more environmental characteristics) that reflect the degree of car dependency in each neighbourhood, drawing from candidate variables that capture density, diversity, design, destination accessibility, distance to transit, and demand management. Area-level factor scores were then combined into a single composite score, reflecting neighbourhood drivability. Negative binomial generalized estimating equations were used to test the association between driveability quintiles (Q) and primary travel mode (>50% of trips by car, public transit, or walking/cycling) in a population-based sample of 63,766 Toronto residents enrolled in the Transportation Tomorrow Survey (TTS) wave 2016, adjusting for individual and household characteristics, and accounting for clustering of respondents within households. Results: The drivability index consisted of three factors: Urban sprawl, pedestrian facilities and parking availability. Relative to those living in the least drivable neighbourhoods (Q1), those in high drivability areas (Q5) had a significantly higher rate of car travel (adjusted Risk Ratio (RR): 1.80, 95%CI: 1.77–1.88), and lower rate of public transit use (RR: 0.90, 95%CI: 0.85–0.94) and walking/cycling (RR: 0.22, 95%CI: 0.19–0.25). Associations were strongest for short trips (<3 km) (RR: 2.72, 95%CI: 2.48–2.92), and in analyses where both residential and workplace drivability was considered (RR for car use in high/high vs. low/low residential/workplace drivability: 2.18, 95%CI: 2.08–2.29). Conclusion: This novel neighbourhood drivability index predicted whether local residents drive or use active modes of transportation and can be used to investigate the association between drivability, physical activity, and chronic disease risk