Multimorbidity at time of death among persons with type 2 diabetes: a population-based study in Ontario, Canada.

OBJECTIVE: Individuals with Type 2 Diabetes are likely to experience multimorbidity and accumulate multiple chronic conditions over their life. We aimed to identify causes of death and chronic conditions at the time of death in a population-based cohort, and to analyze variations in the presence of diabetes at the time of death overall and across income and immigrant status. RESEARCH DESIGN AND METHODS: We conducted a retrospective cohort study of 2,199,801 adult deaths from 1992 to 2017 in Ontario, Canada. We calculated the proportion of decedents with chronic conditions at time of death and causes of death. The risk of diabetes at the time of death was modeled across sociodemographic variables with a log binomial regression adjusting for sex, age, immigrant status, area-level income. comorbiditiesand time. RESULTS: The leading causes of death in the cohort were cardiovascular and cancer. Decedents with diabetes had a higher prevalence of most chronic conditions than decedents without diabetes, including hypertension, osteo and other arthritis, chronic coronary syndrome, mood disorder, and congestive heart failure. The risk of diabetes at the time of death was 19% higher in immigrants (95%CI 1.18-1.20) and 15% higher in refugees (95%CI 1.12-1.18) compared to long-term residents, and 19% higher in the lowest income quintile (95%CI 1.18-1.20) relative to the highest income quintile, after adjusting for other covariates. CONCLUSIONS: Individuals with diabetes have a greater multimorbidity burden at the time of death, underscoring the importance of multiple chronic disease management among those living with diabetes and further considerations of the social determinants of health.

The Economic and Long-Term Health Consequences of Canadian COVID-19 Lockdowns.

To prevent exponential spread of COVID-19, many governments restricted economic activity through lockdowns. We model these restrictions as shocks to productivity by sector and trace total equilibrium effects across the economy using techniques from production network economics. We combine this economic model with an epidemiological model of income shocks to long-term health. On both long-run health and economic grounds, it is better to keep upstream sectors such as transportation, manufacturing, and wholesale open than consumer-facing sectors such as retail and restaurants.

Pour enrayer la propagation exponentielle de la COVID­19, maints gouvernements ont restreint l'activité économique en procédant à des confinements d'activité. Nous modélisons ces restrictions comme des chocs subis par la productivité dans différents secteurs d'activité et en suivons les répercussions sur l'équilibre économique global, grâce à des techniques inspirées de l'économie des réseaux de production. Nous associons ce modèle économique à un modèle épidémiologique d'incidence des chocs de revenu sur la santé à long terme. Tant sur le plan de la santé à long terme que sur le plan économique, il est plus avantageux de maintenir en activité les secteurs en amont, comme le transport, la fabrication et le commerce de gros, que les secteurs de la consommation directe, comme le commerce de détail et la restauration.

Death and Chronic Disease Risk Associated With Poor Life Satisfaction: A Population-Based Cohort Study.

Life satisfaction is increasingly recognized as an important determinant of health; however, prospective population-based studies on this topic are limited. We estimated the risk of chronic disease and death according to life satisfaction among a population-based cohort in Ontario, Canada (n = 73,904). The cohort included 3 pooled cycles of the Canadian Community Health Survey (2003-2008) linked to 6 years of follow-up (to 2015), using population-based health databases and validated disease-specific registries. The databases capture incident and prevalent cases of diabetes, cancer, chronic obstructive pulmonary disease, heart disease, and death. Multivariable Cox proportional hazard models were used to estimate hazards of incident chronic disease and death, and were adjusted for sociodemographic, behavioral, and clinical confounders, including age, sex, comorbidity, mood disorder, smoking, alcohol consumption, physical activity, body mass index, immigrant status, education, and income. In the fully adjusted models, risk of both death and incident chronic disease was highest for those most dissatisfied with life (for mortality, hazard ratio = 1.59, 95% confidence interval: 1.15, 2.19; for chronic disease, hazard ratio = 1.70, 95% confidence interval: 1.16, 2.51). In this population-based cohort, poor life satisfaction was an independent risk factor for incident chronic disease and death, supporting the idea that interventions and programs that improve life satisfaction will affect population health.

Regional variation of premature mortality in Ontario, Canada: a spatial analysis.

BACKGROUND: Premature mortality is a meaningful indicator of both population health and health system performance, which varies by geography in Ontario. We used the Local Health Integration Network (LHIN) sub-regions to conduct a spatial analysis of premature mortality, adjusting for key population-level demographic and behavioural characteristics. METHODS: We used linked vital statistics data to identify 163,920 adult premature deaths (deaths between ages 18 and 74) registered in Ontario between 2011 and 2015. We compared premature mortality rates, population demographics, and prevalence of health-relevant behaviours across 76 LHIN sub-regions. We used Bayesian hierarchical spatial models to quantify the contribution of these population characteristics to geographic disparities in premature mortality. RESULTS: LHIN sub-region premature mortality rates ranged from 1.7 to 6.6 deaths per 1000 per year in males and 1.2 to 4.8 deaths per 1000 per year in females. Regions with higher premature mortality had fewer immigrants and higher prevalence of material deprivation, excess body weight, inadequate fruit and vegetable consumption, sedentary behaviour, and ever-smoked status. Adjusting for all variables eliminated close to 90% of geographic variation in premature mortality, but did not fully explain the spatial pattern of premature mortality in Ontario. CONCLUSIONS: We conducted the first spatial analysis of mortality in Ontario, revealing large geographic variations. We demonstrate that well-known risk factors explain most of the observed variation in premature mortality. The result emphasizes the importance of population health efforts to reduce the burden of well-known risk factors to reduce variation in premature mortality.

Risk of premature mortality due to smoking, alcohol use, obesity and physical activity varies by income: A population-based cohort study.

Background: Premature deaths are a strong population health indicator. There is a persistent and widening pattern of income inequities for premature mortality. We sought to understand the combined effect of health behaviours and income on premature mortality in a large population-based cohort. Methods: We analyzed a cohort of 121,197 adults in the 2005-2014 Canadian Community Health Surveys, linked to vital statistics data to ascertain deaths for up to 5 years following baseline. Information on household income quintile and mortality-relevant risk factors (smoking status, alcohol use, body mass index (BMI), and physical activity) was captured from the survey. Hazard ratios (HR) for combined income-risk factor groups were estimated using Cox proportional hazards models. Stratified Cox models were used to identify quintile-specific HR for each risk factor. Results: For each risk factor, HR of premature mortality was highest in the lowest-income, highest-risk group. Additionally, an income gradient was seen for premature mortality HR for every exposure level of each risk factor. In the stratified models, risk factor HRs did not vary meaningfully between income groups. All findings were consistent in the unadjusted and adjusted models. Conclusion: These findings highlight the need for targeted strategies to reduce health inequities and more careful attention to how policies and interventions are distributed at the population level. This includes targeting and tailoring resources to those in lower income groups who disproportionately experience premature mortality risk to prevent further widening health inequities.

Neighbourhood socioeconomic improvement, residential mobility and premature death: a population-based cohort study and inverse probability of treatment weighting analysis.

BACKGROUND: Causal inference using area-level socioeconomic measures is challenging due to risks of residual confounding and imprecise specification of the neighbourhood-level social exposure. By using multi-linked longitudinal data to address these common limitations, our study aimed to identify protective effects of neighbourhood socioeconomic improvement on premature mortality risk. METHODS: We used data from the Canadian Community Health Survey, linked to health administrative data, including longitudinal residential history. Individuals aged 25-69, living in low-socioeconomic status (SES) areas at survey date (n = 8335), were followed up for neighbourhood socioeconomic improvement within 5 years. We captured premature mortality (death before age 75) until 2016. We estimated protective effects of neighbourhood socioeconomic improvement exposures using Cox proportional hazards models. Stabilized inverse probability of treatment weights (IPTW) were used to account for confounding by baseline health, social and behavioural characteristics. Separate analyses were carried out for three exposure specifications: any improvement, improvement by residential mobility (i.e. movers) or improvement in place (non-movers). RESULTS: Overall, 36.9% of the study cohort experienced neighbourhood socioeconomic improvement either by residential mobility or improvement in place. There were noted differences in baseline health status, demographics and individual SES between exposure groups. IPTW survival models showed a modest protective effect on premature mortality risk of socioeconomic improvement overall (HR = 0.86; 95% CI 0.63, 1.18). Effects were stronger for improvement in place (HR = 0.67; 95% CI 0.48, 0.93) than for improvement by residential mobility (HR = 1.07, 95% 0.67, 1.51). CONCLUSIONS: Our study provides robust evidence that specific neighbourhood socioeconomic improvement exposures are important for determining mortality risks.

Socioeconomic status influences participation in cancer prehabilitation and preparation for surgical recovery: A pooled retrospective analysis using a validated area-level socioeconomic status metric.

BACKGROUND: Prehabilitation employs exercise, nutrition, and psychological interventions to optimize physiological status in preparation for surgery. First, we described the extent to which material deprivation index score (MDIS) influenced prehabilitation participation. Second, we evaluated the extent to which prehabilitation influenced recovery as compared to control. METHODS: Pooled patient records from prospective multimodal prehabilitation studies in oncologic surgery were retrospectively examined. Patient postal codes were linked to their MDIS, a validated area-level socioeconomic status (SES) metric, as quintiles 1-5 (1 = highest SES). Functional capacity was evaluated with the 6-min walking test (6MWT) at baseline, before, and 8 weeks post-surgery. Influence of prehabilitation on length of hospital stay (LOS) was explored using generalized linear models with a negative binomial distribution adjusted for age, sex, surgical population, and MDIS. RESULTS: Recruitment records were available from 2014 onwards, yielding 1013 eligible patients for prehabilitation participation with MDIS data. Fewer patients with a low SES enrolled (Q1:62% vs. Q5:47%; P = 0.01) and remained in prehabilitation studies (Q1: 59% vs. Q5: 45%; P = 0.07). Prehabilitation study records were available from 2008 onward, yielding 886 enrolled patients with MDIS data (n = 510 prehabilitation, n = 376 control). Preoperative 6MWT similarly improved by > 20 m in response to prehabilitation across SES strata (P < 0.05). Postoperative 6MWT could not be evaluated due to substantial missing data. Prehabilitation had a significant protective influence on LOS, as compared to control, in unadjusted and adjusted models [adjusted IRR:0.77 (95% CI:0.68 to 0.87; P < 0.001]. CONCLUSION: Findings suggest that prehabilitation is effective across all SES; however, participation across SES quintiles was not equal. Barriers to participation must be identified and addressed. Once these barriers are addressed, prehabilitation may reduce surgical disparities among SES.

Clarifying rural-urban disparities in alcohol-related emergency department visits and hospitalizations in Ontario, Canada: A spatial analysis.

PURPOSE: Rates of alcohol-related harm are higher in rural versus urban Canada. This study characterized the spatial distribution and regional determinants of alcohol-related emergency department (ED) visits and hospitalizations in Ontario to better understand this rural-urban disparity. METHODS: This was a cross-sectional spatial analysis of rates of alcohol-related ED visits and hospitalizations by Ministry of Health subregion (n = 76) in Ontario, Canada between 2016 and 2019. Regional hot- and cold-spots of alcohol-related harm were identified using spatial autocorrelation methods. Rurality was measured as the population weighted geographic remoteness of a subregion. The associations between rurality and rates of alcohol-related ED visits and hospitalizations were evaluated using hierarchical Bayesian spatial regression models. FINDINGS: Rates of alcohol-related ED visits and hospitalizations varied substantially between subregions, with high rates clustering in Northern Ontario. Overall, increasing rurality was associated with higher subregion-level rates of alcohol-related ED visits (males adjusted relative rate [aRR]: 1.67, 95% credible interval [CI]: 1.49-1.87; females aRR: 1.78, 95% CI: 1.60-1.98) and hospitalizations (males aRR: 1.34, 95% CI: 1.24-1.45; females aRR: 1.59, 95% CI: 1.45-1.74). However, after the province was separated into Northern and Southern strata, this association only held in Northern subregions. In contrast, increasing rurality was associated with lower rates of alcohol-related ED visits in Southern subregions (males aRR: 0.87, 95% CI: 0.79-0.96; females aRR: 0.88, 95% CI: 0.81-0.97). CONCLUSIONS: There are regional differences in the association between rurality and alcohol-related health service use. This regional variation should be considered when developing health policies to minimize geographic disparities in alcohol-related harm.

Geographic clustering of travel-acquired infections in Ontario, Canada, 2008-2020.

As the frequency of international travel increases, more individuals are at risk of travel-acquired infections (TAIs). In this ecological study of over 170,000 unique tests from Public Health Ontario's laboratory, we reviewed all laboratory-reported cases of malaria, dengue, chikungunya, and enteric fever in Ontario, Canada between 2008-2020 to identify high-resolution geographical clusters for potential targeted pre-travel prevention. Smoothed standardized incidence ratios (SIRs) and 95% posterior credible intervals (CIs) were estimated using a spatial Bayesian hierarchical model. High- and low-incidence areas were described using data from the 2016 Census based on the home forward sortation area of patients testing positive. A second model was used to estimate the association between drivetime to the nearest travel clinic and incidence of TAI within high-incidence areas. There were 6,114 microbiologically confirmed TAIs across Ontario over the study period. There was spatial clustering of TAIs (Moran's I = 0.59, p<0.0001). Compared to low-incidence areas, high-incidence areas had higher proportions of immigrants (p<0.0001), were lower income (p = 0.0027), had higher levels of university education (p<0.0001), and less knowledge of English/French languages (p<0.0001). In the high-incidence Greater Toronto Area (GTA), each minute increase in drive time to the closest travel clinic was associated with a 3% reduction in TAI incidence (95% CI 1-6%). While urban neighbourhoods in the GTA had the highest burden of TAIs, geographic proximity to a travel clinic in the GTA was not associated with an area-level incidence reduction in TAI. This suggests other barriers to seeking and adhering to pre-travel advice.

Downstream health impacts of employment losses during the COVID-19 pandemic.

OBJECTIVES: The Canadian workforce has experienced significant employment losses during the COVID-19 pandemic, in part as a result of non-pharmaceutical interventions to slow COVID-19 transmission. Health consequences are likely to result from these job losses, but without historical precedent for the current economic shutdown they are challenging to plan for. Our study aimed to use population risk models to quantify potential downstream health impacts of the COVID-19 pandemic and inform public health planning to minimize future health burden. METHODS: The impact of COVID-19 job losses on future premature mortality and high-resource health care utilization (HRU) was estimated using an economic model of Canadian COVID-19 lockdowns and validated population risk models. Five-year excess premature mortality and HRU were estimated by age and sex to describe employment-related health consequences of COVID-19 lockdowns in the Canadian population. RESULTS: With federal income supplementation like the Canadian Emergency Response Benefit, we estimate that each month of economic lockdown will result in 5.6 new high-resource health care system users (HRUs), and 4.1 excess premature deaths, per 100,000, over the next 5 years. These effects were concentrated in ages 45-64, and among males 18-34. Without income supplementation, the health consequences were approximately twice as great in terms of both HRUs and premature deaths. CONCLUSION: Employment losses associated with COVID-19 countermeasures may have downstream implications for health. Public health responses should consider financially vulnerable populations at high risk of downstream health outcomes.

RéSUMé: OBJECTIFS: La population active canadienne a connu d'importantes pertes d'emplois durant la pandémie de COVID-19, en partie en raison des interventions non pharmaceutiques menées pour ralentir la transmission du virus. Ces pertes d'emplois auront probablement des conséquences pour la santé, mais en l'absence d'un précédent historique au ralentissement économique actuel, il est difficile de planifier quoi faire pour atténuer ces conséquences. Notre étude visait à chiffrer les éventuels effets sanitaires de la pandémie de COVID-19 en aval à l'aide de modèles de risque pour la population et à éclairer la planification en santé publique afin de réduire le futur fardeau pour la santé. MéTHODE: Nous avons estimé l'impact des pertes d'emplois dues à la COVID-19 sur les chiffres futurs de mortalité prématurée et d'utilisation élevée des soins de santé (UESS) à l'aide d'un modèle économique des confinements dus à la COVID-19 au Canada et de modèles de risque pour la population validés. Nous avons estimé la surmortalité prématurée et l'UESS par âge et par sexe dans cinq ans afin de décrire les conséquences pour la santé des effets sur l'emploi des confinements dus à la COVID-19 dans la population canadienne. RéSULTATS: Avec les mesures fédérales de supplémentation du revenu comme la Prestation canadienne d'urgence, nous estimons qu'avec chaque mois de confinement économique, il y aura 5,6 nouveaux grands usagers du système de soins de santé (GUSSS) et 4,1 décès prématurés supplémentaires pour 100 000 habitants au cours des cinq prochaines années. Ces effets seront concentrés dans la tranche d'âge des 45 à 64 ans et chez les hommes de 18 à 34 ans. Sans supplémentation du revenu, les conséquences pour la santé seront environ le double, tant pour le nombre de GUSSS que de décès prématurés. CONCLUSION: Les pertes d'emplois associées aux mesures de prévention de la COVID-19 pourraient avoir des conséquences pour la santé en aval. Les interventions de santé publique devraient donc tenir compte des populations financièrement vulnérables à risque élevé de connaître des problèmes de santé en aval.

Prevalence and health care costs of mitochondrial disease in Ontario, Canada: A population-based cohort study.

BACKGROUND: Mitochondrial disease prevalence has been estimated at 1 in 4000 in the United States, and 1 in 5000 worldwide. Prevalence in Canada has not been established, though multi-linked health administrative data resources present a unique opportunity to establish robust population-based estimates in a single-payer health system. This study used administrative data for the Ontario, Canada population between April 1988 and March 2019 to measure mitochondrial disease prevalence and describe patient characteristics and health care costs. RESULTS: 3069 unique individuals were hospitalized with mitochondrial disease in Ontario and eligible for the study cohort, representing a period prevalence of 2.51 per 10,000 or 1 in 3989. First hospitalization was most common between ages 0-9 or 50-69. The mitochondrial disease population experiences a high need for health care and incurred high costs (mean = CAD$24,023 in 12 months before first hospitalization) within the single-payer Ontario health care system. CONCLUSIONS: This study provides needed insight into mitochondrial disease in Canada, and demonstrates the high health burden on patients. The methodology used can be adapted across jurisdictions with similar routine collection of health data, such as in other Canadian provinces. Future work should seek to validate this approach via record linkage of existing disease cohorts in Ontario, and identify specific comorbidities with mitochondrial disease that may contribute to high health resource utilization.

Access to diagnostic imaging and incidental detection of differentiated thyroid cancer in Ontario: A population-based retrospective cohort study.

Global increases in thyroid cancer incidence (≥90% differentiated thyroid cancers; DTC) are hypothesized to be related to increased use of pre-diagnostic imaging. These procedures can detect DTC during imaging for conditions unrelated to the thyroid (incidental detection). The objectives were to evaluate incidental detection of DTC associated with standardized, regional imaging capacity and drivetime from patient residence to imaging facility (the exposures). We conducted a population-based retrospective cohort study of 32,097 DTC patients in Ontario, 2003-2017. We employed sex-specific spatial Bayesian hierarchical models to evaluate the exposures and examine the adjusted odds of incidental detection by administrative regions. Regional capacities of computed tomography and magnetic resonance imaging scanners are positively associated with incidental detection, but vary by sex. Contrary to hypothesis, drivetimes in urban areas are positively associated with incidental detection. Access to primary care may play a role in several administrative regions with higher adjusted odds of incidental detection.

Relative contribution of trends in myocardial infarction event rates and case fatality to declines in mortality: an international comparative study of 1·95 million events in 80·4 million people in four countries.

BACKGROUND: Myocardial infarction mortality has declined since the 1970s, but contemporary drivers of this trend remain unexplained. The aim of this study was to compare the contribution of trends in event rates and case fatality to declines in myocardial infarction mortality in four high-income jurisdictions from 2002-15. METHODS: Linked hospitalisation and mortality data were obtained from New South Wales (NSW), Australia; Ontario, Canada; New Zealand; and England, UK. People aged between 30 years and 105 years were included in the study. Age-adjusted trends in myocardial infarction event rates and case fatality were estimated from Poisson and binomial regression models, and their relative contribution to trends in myocardial infarction mortality calculated. FINDINGS: 1 947 895 myocardial infarction events from a population of 80·4 million people were identified in people aged 30 years or older. There were significant declines in myocardial infarction mortality, event rates, and case fatality in all jurisdictions. Age-standardised myocardial infarction event rates were highest in New Zealand (men 893/100 000 person-years in 2002, 536/100 000 person-years in 2015; women 482/100 000 person-years in 2002, 271/100 000 person-years in 2015) and lowest in England (men 513/100 000 person-years in 2002, 382/100 000 person-years in 2015; women 238/100 000 person-years in 2002, 173/100 000 person-years in 2015). Annual age-adjusted reductions in event rates ranged from -2·6% (95% CI -3·0 to -2·3) in men in England to -4·3% (-4·4 to -4·1) in women in Ontario. Age-standardised case fatality was highest in England in 2002 (48%), but declined at a greater rate than in the other jurisdictions (men -4·1%/year, 95% CI -4·2 to -4·0%; women -4·4%/year, -4·5 to -4·3%). Declines in myocardial infarction mortality rates ranged from -6·1%/year to -7·6%/year. Event rate declines were the greater contributor to myocardial infarction mortality reductions in Ontario (69·4% for men and women), New Zealand (men 68·4%; women 67·5%), and NSW women (60·1%), whereas reductions in case fatality were the greater contributor in England (60% in men and women) and for NSW men (54%). There were greater contributions from case fatality than event rate reductions in people younger than 55 years in all jurisdictions, with contributions to mortality declines varying by country in those aged 55-74 years. Event rate declines had a greater impact than changes in case fatality in those aged 75 years and older. INTERPRETATION: While the mortality burden of myocardial infarction has continued to fall across these four populations, the relative contribution of trends in myocardial infarction event rates and case fatality to declining mortality varied between jurisdictions, including by age and sex. Understanding the causes of this variation will enable optimisation of prevention and treatment efforts. FUNDING: National Health and Medical Research Council, Australia; Australian Research Council; Health Research Council of New Zealand; Canadian Institutes of Health Research, Canada; National Institute for Health Research, UK.

Association between lead in school drinking water systems and educational outcomes in Ontario, Canada.

PURPOSE: The purpose of this study is to use province-wide lead testing data from school drinking water systems and standardized educational assessments to investigate the association between lead exposure in schools and educational outcomes in Ontario, Canada for 2008-09 to 2015-16 school years. METHODS: Lead testing data were linked to assessment results in reading, writing, and mathematics from Ontario's Education Quality and Accountability Office and school neighborhood characteristics from the Ontario Marginalization Index. Sequential negative binomial models were used to estimate the relative risk of lower Education Quality and Accountability Office achievement in schools with lead exceedances in the preceding year, compared with those without. RESULTS: Between 2008-09 and 2015-16, 78% of schools with Education Quality and Accountability Office scores were linked to lead testing results. In schools with lead exceedances, 8% more students failed to achieve the provincial standard for math (95% confidence interval (CI) = 1.07-1.09), 6% more students failed to achieve the provincial standard for reading (95% CI = 1.05-1.08), and 10% more students failed to achieve the provincial standard for writing (95% CI = 1.08-1.11). Associations of attenuated magnitude persisted after covariate adjustment. CONCLUSIONS: Routinely collected lead testing data from school drinking water systems are associated with educational outcomes in the school-aged population and may present an opportunity for ongoing investigation of childhood lead exposures.

Characterising mental health and addictions and assault-related health care use in the year prior to death: a population-based linked cohort study of homicide victims.

INTRODUCTION: Homicide is an important cause of death for older youth and adult Canadians; however, little is known about health care use prior to death among this population. OBJECTIVES: To characterise health care use for mental health and addictions (MHA) and serious assault (herein referred to assault) one year prior to death among individuals who died by homicide in Ontario, Canada using linked mortality and health care utilisation data. METHODS: We report rates of health care use for MHA and assault in the year prior to death among all individuals 16 years and older in Ontario, Canada, who died by homicide from April 2003 to December 2012 (N = 1,541). Health care use for MHA included inpatient stays, emergency department (ED) visits and outpatient visits, whereas health care use for assault included only hospital-based care (ED visits and inpatient stays). Sociodemographic characteristics and health care utilisation were examined across homicide deaths, stratified by sex. RESULTS: Overall, 28.5% and 5.9% of homicide victims sought MHA and assault care in the year prior to death, respectively. A greater proportion of females accessed care for MHA, whereas a greater proportion of males accessed assault-related health care. Males were more likely to be hospitalised following an ED visit for a MHA or assault related reason, in comparison to females. The most common reason for a MHA hospital visit was for substance-related disorders. We found an increase over time for hospital-based visits for assault prior to death, a trend that was not observed for MHA-related visits. CONCLUSIONS: A large proportion of homicide victims interacted with the health care system for MHA or assault in the year prior to death. An increase in hospital-based visits for assault-related reasons prior to death was observed. These trends may offer insight into avenues for support and prevention for victims of homicide.

Agreement between area- and individual-level income measures in a population-based cohort: Implications for population health research.

Socioeconomic status is an important determinant of health, the measurement of which is of great significance to population health research. However, individual-level socioeconomic factors are absent from much health administrative data, resulting in widespread use of area-level measures in their place. This study aims to clarify the role of individual- and area-level socioeconomic status in Ontario, Canada, through comparison of income measures. Using data from four cycles (2005-2012) of the Canadian Community Health Survey, we assessed concordance between individual- and area-level income quintiles using percent agreement and Kappa statistics. Individual-level characteristics were compared at baseline. Cumulative adult premature mortality was calculated for 5-years following interview. Rates were calculated separately for area-level and individual-level income, and jointly for each combination of income groups. Multivariable negative binomial models were fit to estimate associations between area- and individual-level income quintile and premature mortality after adjustment for basic demographics (age, sex, interview cycle) and key risk factors (alcohol, smoking, physical activity, and body mass index). Agreement between individual- and area-level income measures was low. Kappa statistics for same and similar (i.e. ±1 quintile) measures were 0.11 and 0.48, indicating low and moderate agreement, respectively. Socioeconomic disparities in premature mortality were greater for individual-level income than area-level income. When rates were stratified by both area- and individual-level income quintiles simultaneously, individual-level income gradients persisted within each area-level income group. The association between income and premature mortality was significant for both measures, including after full adjustment. Area-level socioeconomic status is an inappropriate proxy for missing individual-level data. The low agreement between area- and individual-level income measures and differences in demographic profile indicate that the two socioeconomic status measures do not capture the same population groups. However, our findings demonstrate that both individual- and area-level income measures are associated with premature mortality, and describe unique socioeconomic inequities.

Incidental detection, imaging modalities and temporal trends of differentiated thyroid cancer in Ontario: a population-based retrospective cohort study.

BACKGROUND: Incidence rates of thyroid cancer in Ontario have increased more rapidly than those of any other cancer, whereas mortality rates have remained relatively stable. We evaluated the extent to which incidental detection of differentiated thyroid cancer during unrelated prediagnostic imaging procedures contributed to Ontario's incidence rates. METHODS: We conducted a retrospective cohort study involving Ontarians who received a diagnosis of differentiated thyroid cancer from 1998 to 2017 using linked health care administrative databases. We classified cases as incidentally detected if a nonthyroid diagnostic imaging test (e.g., computed tomography [CT]) preceded an index event (e.g., prediagnostic fine-needle aspiration biopsy); all other cases were nonincidentally detected cases. We used Joinpoint and negative binomial regressions to characterize sex-specific rates of differentiated thyroid cancer by incidentally detected status and to quantify potential age, diagnosis period and birth cohort effects. RESULTS: The study included 36 531 patients with differentiated thyroid cancer, of which 78.7% were female. Incidentally detected cases increased from 7.0% to 11.0% of female patients and from 13.5% to 18.2% of male patients over the study period. Age-standardized incidence rates increased more rapidly for incidentally detected cases (4.2-fold for female and 3.7-fold for male patients) than for nonincidentally detected cases (2.6-fold for female and 3.0-fold for male patients; p < 0.001). Diagnosis period was the primary factor associated with increased incidence rates of differentiated thyroid cancer, adjusting for other factors. Within each period, incidentally detected rates increased faster than nonincidentally detected rates, adjusting for age. Our results showed that CT was the most common imaging procedure preceding incidentally detected diagnoses. INTERPRETATION: Incidentally detected cases represent a large and increasing component of the observed increases in differentiated thyroid cancer in Ontario over the past 20 years, and CT scans are primarily associated with these cases despite the modality having similar, increasing rates of use compared with magnetic resonance imaging (1993-2004). Recent increases in rates of differentiated thyroid cancer among males and incidentally detected cases among females in Ontario appear to be unrelated to birth cohort effects.

Changing relative and absolute socioeconomic health inequalities in Ontario, Canada: A population-based cohort study of adult premature mortality, 1992 to 2017.

BACKGROUND: This study aimed to characterize trends in absolute and relative socioeconomic inequalities in adult premature mortality between 1992 and 2017, in the context of declining population-wide mortality rates. We conducted a population-based cohort study of all adult premature deaths in Ontario, Canada using provincial vital statistics data linked to census-based, area-level deprivation indices for socioeconomic status. METHODS: The cohort included all individuals eligible for Ontario's single-payer health insurance system at any time between January 1, 1992 and December 31, 2017 with a recorded Ontario place of residence and valid socioeconomic status information (N = 820,370). Deaths between ages 18 and 74 were used to calculate adult premature mortality rates per 1000, stratified by provincial quintile of material deprivation. Relative inequalities were measured using Relative Index of Inequality (RII) measures. Absolute inequalities were estimated using Slope Index of Inequality (SII) measures. All outcome measures were calculated as sex-specific, annual measures for each year from 1992 to 2017. RESULTS: Premature mortality rates declined in all socioeconomic groups between 1992 and 2017. Relative inequalities in premature mortality increased over the same period. Absolute inequalities were mostly stable between 1992 and 2007, but increased dramatically between 2008 and 2017, with larger increases to absolute inequalities seen in females than in males. CONCLUSIONS: As in other developed countries, long-term downward trends in all-cause premature mortality in Ontario, Canada have shifted to a plateau pattern in recent years, especially in lower- socioeconomic status subpopulations. Determinants of this may differ by setting. Regular monitoring of mortality by socioeconomic status is the only way that this phenomenon can be detected sensitively and early, for public health attention and possible corrective action.

Predicting population health with machine learning: a scoping review.

OBJECTIVE: To determine how machine learning has been applied to prediction applications in population health contexts. Specifically, to describe which outcomes have been studied, the data sources most widely used and whether reporting of machine learning predictive models aligns with established reporting guidelines. DESIGN: A scoping review. DATA SOURCES: MEDLINE, EMBASE, CINAHL, ProQuest, Scopus, Web of Science, Cochrane Library, INSPEC and ACM Digital Library were searched on 18 July 2018. ELIGIBILITY CRITERIA: We included English articles published between 1980 and 2018 that used machine learning to predict population-health-related outcomes. We excluded studies that only used logistic regression or were restricted to a clinical context. DATA EXTRACTION AND SYNTHESIS: We summarised findings extracted from published reports, which included general study characteristics, aspects of model development, reporting of results and model discussion items. RESULTS: Of 22 618 articles found by our search, 231 were included in the review. The USA (n=71, 30.74%) and China (n=40, 17.32%) produced the most studies. Cardiovascular disease (n=22, 9.52%) was the most studied outcome. The median number of observations was 5414 (IQR=16 543.5) and the median number of features was 17 (IQR=31). Health records (n=126, 54.5%) and investigator-generated data (n=86, 37.2%) were the most common data sources. Many studies did not incorporate recommended guidelines on machine learning and predictive modelling. Predictive discrimination was commonly assessed using area under the receiver operator curve (n=98, 42.42%) and calibration was rarely assessed (n=22, 9.52%). CONCLUSIONS: Machine learning applications in population health have concentrated on regions and diseases well represented in traditional data sources, infrequently using big data. Important aspects of model development were under-reported. Greater use of big data and reporting guidelines for predictive modelling could improve machine learning applications in population health. REGISTRATION NUMBER: Registered on the Open Science Framework on 17 July 2018 (available at https://osf.io/rnqe6/).

Association between the regional variation in premature mortality and immigration in Ontario, Canada.

OBJECTIVES: Health region differences in immigration patterns and premature mortality rates exist in Ontario, Canada. This study used linked population-based databases to describe the regional proportion of immigrants in the context of provincial health region variation in premature mortality. METHODS: We analyzed all adult premature deaths in Ontario from 1992 to 2012 using linked population files, Canadian census, and death registry databases. Geographic boundaries were analyzed according to 14 health service regions, known as Local Health Integration Networks (LHINs). We assessed the role of immigrant status and regional proportion of immigrants in the context of these health region variations and assessed the contribution using sex-specific multilevel negative binomial models, accounting for age, individual- and area-level immigration, and area-level material deprivation. RESULTS: We observed significant premature mortality variation among health service regions in Ontario between 1992 and 2012. Average annual rates ranged across LHINs from 3.03 to 6.40 per 1000 among males and 2.04 to 3.98 per 1000 among females. The median rate ratio (RR) decreased for men from 1.14 (95% CI 1.06, 1.19) to 1.07 (95% CI 1.00, 1.11) after adjusting for year, age, area-based material deprivation, and individual- and area-level immigration, and among females reduced from 1.13 (95% CI 1.05, 1.18) to 1.04 (95% CI 1.00, 1.05). These adjustments explained 84.1% and 94.4% of the LHIN-level variation in males and females respectively. Reduced premature mortality rates were associated with immigrants compared with those for long-term residents in the fully adjusted models for both males 0.43 (95% CI 0.42, 0.44) and females 0.45 (0.44, 0.46). CONCLUSION: The findings demonstrate that health region differences in premature mortality in Ontario are in part explained by individual-level effects associated with the health advantage of immigrants, as well as contextual area-level effects that are associated with regional differences in the immigrant population. These factors should be considered in addition to health system factors when looking at health region variation in premature deaths.