ABSTRACT BACKGROUND Understanding the complex interaction of risk factors that increase the likelihood of developing common diseases is challenging. The Canadian Partnership for Tomorrow Project ...(CPTP) is a prospective cohort study created as a population-health research platform for assessing the effect of genetics, behaviour, family health history and environment (among other factors) on chronic diseases. METHODS Volunteer participants were recruited from the general Canadian population for a confederation of 5 regional cohorts. Participants were enrolled in the study and core information obtained using 2 approaches: attendance at a study assessment centre for all study measures (questionnaire, venous blood sample and physical measurements) or completion of the core questionnaire (online or paper), with later collection of other study measures where possible. Physical measurements included height, weight, percentage body fat and blood pressure. Participants consented to passive follow-up through linkage with administrative health databases and active follow-up through recontact. All participant data across the 5 regional cohorts were harmonized. RESULTS A total of 307 017 participants aged 30–74 from 8 provinces were recruited. More than half provided a venous blood sample and/or other biological sample, and 33% completed physical measurements. A total of 709 harmonized variables were created; almost 25% are available for all participants and 60% for at least 220 000 participants. INTERPRETATION Primary recruitment for the CPTP is complete, and data and biosamples are available to Canadian and international researchers through a data-access process. The CPTP will support research into how modifiable risk factors, genetics and the environment interact to affect the development of cancer and other chronic diseases, ultimately contributing evidence to reduce the global burden of chronic disease.
To investigate (68)Ga-ventilation/perfusion (V/Q) positron emission tomography (PET)/computed tomography (CT) as a novel imaging modality for assessment of perfusion, ventilation, and lung density ...changes in the context of radiation therapy (RT).
In a prospective clinical trial, 20 patients underwent 4-dimensional (4D)-V/Q PET/CT before, midway through, and 3 months after definitive lung RT. Eligible patients were prescribed 60 Gy in 30 fractions with or without concurrent chemotherapy. Functional images were registered to the RT planning 4D-CT, and isodose volumes were averaged into 10-Gy bins. Within each dose bin, relative loss in standardized uptake value (SUV) was recorded for ventilation and perfusion, and loss in air-filled fraction was recorded to assess RT-induced lung fibrosis. A dose-effect relationship was described using both linear and 2-parameter logistic fit models, and goodness of fit was assessed with Akaike Information Criterion (AIC).
A total of 179 imaging datasets were available for analysis (1 scan was unrecoverable). An almost perfectly linear negative dose-response relationship was observed for perfusion and air-filled fraction (r(2)=0.99, P<.01), with ventilation strongly negatively linear (r(2)=0.95, P<.01). Logistic models did not provide a better fit as evaluated by AIC. Perfusion, ventilation, and the air-filled fraction decreased 0.75 ± 0.03%, 0.71 ± 0.06%, and 0.49 ± 0.02%/Gy, respectively. Within high-dose regions, higher baseline perfusion SUV was associated with greater rate of loss. At 50 Gy and 60 Gy, the rate of loss was 1.35% (P=.07) and 1.73% (P=.05) per SUV, respectively. Of 8/20 patients with peritumoral reperfusion/reventilation during treatment, 7/8 did not sustain this effect after treatment.
Radiation-induced regional lung functional deficits occur in a dose-dependent manner and can be estimated by simple linear models with 4D-V/Q PET/CT imaging. These findings may inform future studies of functional lung avoidance using V/Q PET/CT.
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GEOZS, IJS, NUK, OILJ, UL, UM, UPUK
The intent of the Canadian Alliance for Healthy Hearts and Minds (CAHHM) cohort is to understand the early determinants of subclinical cardiac and vascular disease and progression in adults selected ...from existing cohorts—the Canadian Partnership for Tomorrow’s Health, the Prospective Urban and Rural Evaluation (PURE) cohort, and the Montreal Heart Institute Biobank. We evaluated how well the CAHHM-Health Services Research (CAHHM-HSR) subcohort reflects the Canadian population.
A cross-sectional design was used among a prospective cohort of community-dwelling adults aged 35-69 years who met the CAHHM inclusion criteria, and a cohort of adults aged 35-69 years who responded to the 2015 Canadian Community Health Survey-Rapid Response module. The INTERHEART risk score was calculated at the individual level with means and proportions reported at the overall and provincial level.
There are modest differences between CAHHM-HSR study participants and the 2015 Canadian Community Health Survey-Rapid Response respondents in age (56.3 vs 51.7 mean years), proportion of men (44.9% vs 49.3%), and mean INTERHEART risk score (9.7 vs 10.1). Larger differences were observed in postsecondary education (86.8% vs 70.2%), Chinese ethnicity (11.0% vs 3.3%), obesity (23.2% vs 29.3%), current smoker status (6.1% vs 18.4%), and having no cardiac testing (30.4% vs 55.9%).
CAHHM-HSR participants are older, of higher socioeconomic status, and have a similar mean INTERHEART risk score, compared with participants in the Canadian Community Health Survey. Differing sampling strategies and missing data may explain some differences between the CAHHM-HSR cohort and Canadian community-dwelling adults and should be considered when using the CAHHM-HSR for scientific research.
L’étude Alliance canadienne cœurs et cerveaux sains (CAHHM) vise à mieux comprendre les facteurs déterminants précoces et la progression de l’atteinte cardiovasculaire subclinique chez des adultes sélectionnés au sein de cohortes existantes – soit celles de l’étude menée par le Partenariat canadien pour la santé de demain, de l’étude PURE (Prospective Urban and Rural Evaluation) et de la biobanque de l’Institut de cardiologie de Montréal. Nous avons évalué la mesure dans laquelle la sous-cohorte du volet de recherche sur l’utilisation des services de santé de la CAHHM (CAHHM-HSR) représente la population canadienne.
Nous avons adopté une approche transversale pour étudier une cohorte prospective d’adultes vivant dans la communauté âgés de 35 à 69 ans et répondant aux critères d’inclusion de l’étude CAHHM, ainsi qu’une cohorte d’adultes âgés de 35 à 69 ans ayant participé au volet de réponse rapide de l’Enquête sur la santé dans les collectivités canadiennes (ESCC) de 2015. Le score de risque INTERHEART individuel des participants a été calculé à partir des moyennes et des proportions rapportées à l’échelle globale et à l’échelle provinciale.
Les différences entre les participants du volet CAHHM-HSR et ceux du volet de réponse rapide de l’ESCC de 2015 étaient minimes quant à l’âge (56,3 ans vs 51,7 ans en moyenne), à la proportion d’hommes (44,9 % vs 49,3 %) et au score de risque INTERHEART moyen (9,7 vs 10,1). On a toutefois noté des différences plus importantes en ce qui concerne les caractéristiques suivantes : éducation postsecondaire (86,8 % vs 70,2 %), origine ethnique chinoise (11,0 % vs 3,3 %), obésité (23,2 % vs 29,3 %), tabagisme actuel (6,1 % vs 18,4 %) et absence d’antécédents d’examen cardiaque (30,4 % vs 55,9 %).
Les participants du volet CAHHM-HSR sont plus âgés et ont un statut socioéconomique plus élevé que ceux du volet de réponse rapide de l’ESCC, mais ont un score de risque INTERHEART moyen comparable. Les différences quant aux stratégies d’échantillonnage et des données manquantes pourraient expliquer certains des écarts observés entre la cohorte CAHHM-HSR et celle des adultes canadiens vivant dans la communauté; il conviendrait d’en tenir compte lorsqu’on utilise les données du volet CAHHM-HSR à des fins de recherche scientifique.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
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