Effectiveness of the CANRISK tool in the identification of dysglycemia in a Canadian South Asian Population. / Efficacité de l'outil CANRISK pour détecter la dysglycémie au sein d'une population d'origine sud-asiatique au Canada.

INTRODUCTION: South Asians have a higher than average risk of developing type 2 diabetes. We ascertained the effectiveness of CANRISK, an existing diabetes risk assessment tool, examining its sensitivity and specificity at two different predetermined scoring cut-off points comparing those participants under the age of 40 and those 40 and over. We examined the predictive ability of a model based on CANRISK variables, comparing ethno-specific body mass index (BMI) and waist circumference (WC) cut-off points with the original BMI and WC cut-off points to see if predictive ability could be improved for this population. METHODS: Canadian South Asians of unknown diabetes status, age 18 to 78, were recruited across seven provinces from various community or health centers. CANRISK variables were collected followed by oral glucose tolerance testing. Descriptive analysis, logistic regression including alternative ethno-specific BMI and WC cut-off points, and sensitivity and specificity analyses were performed. RESULTS: 832 participants were recruited (584 under age 40). Using the entire study sample, logistic regression models including CANRISK variables predicted dysglycemia effectively (AUC of 0.80). However, by using alternative BMI/WC cut-off points with the scoring algorithm, predictive power via AUC was not improved. Sensitivity and specificity of CANRISK using the original pre-determined "high risk" cut-off point of 33 points in individuals age 40 years or over were 93% and 35%, respectively; in individuals under 40, these were 33% and 92%, respectively. Using the lower pre-determined "moderate risk" cut-off point of 21 points improved the sensitivity to 77% and specificity to 53% in the younger age group. CONCLUSION: The existing CANRISK is an adequate risk assessment tool for dysglycemia in Canadian South Asians for those age 40 years and over; however, the tool does not work as well for individuals under 40. The lower cut-off of 21 points may be warranted for younger individuals to minimize false negatives. Ethno-specific BMI/WC cutoff points did not improve predictive ability of the CANRISK scoring algorithm as measured by AUC.

INTRODUCTION: Les personnes d'origine sud-asiatique présentent un risque supérieur à la moyenne de développer un diabète de type 2. Nous avons vérifié l'efficacité de CANRISK, un outil d'évaluation du risque de diabète, en examinant sa sensibilité et sa spécificité en fonction de deux seuils de cotation différents prédéfinis et en comparant les participants de 40 ans et plus et ceux de moins de 40 ans. Nous avons examiné la valeur prédictive d'un modèle fondé sur les variables de CANRISK en comparant des seuils ethnospécifiques de l'indice de masse corporelle (IMC) et du tour de taille (TT) avec les seuils originaux d'IMC et de TT, afin de voir l'on pouvait améliorer cette valeur prédictive au sein de cette population. MÉTHODOLOGIE: On a recruté, dans diverses communautés et divers centres de santé de sept provinces, des Canadiens d'origine sud-asiatique âgés de 18 à 78 ans dont l'état diabétique était inconnu. On a recueilli les données de CANRISK puis réalisé une épreuve d'hyperglycémie provoquée par voie orale. On a procédé à une analyse descriptive, à une régression logistique incluant des seuils ethnospécifiques d'IMC et de TT et à des analyses de sensibilité et de spécificité. RÉSULTATS: On a recruté 832 participants (dont 584 de moins de 40 ans). Sur l'ensemble de l'échantillon, les modèles de régression logistique fondés sur les données de CANRISK ont prédit la dysglycémie de manière efficace (aire sous la courbe [ASC] de 0,80). En revanche, en utilisant différents seuils d'IMC et de TT avec l'algorithme de cotation, la valeur prédictive fondée sur l'ASC ne s'est pas améliorée. La sensibilité et la spécificité de CANRISK avec le seuil prédéterminé « risque élevé ¼ original à 33 points étaient de respectivement 93 % et 35 % chez les 40 ans ou plus et de respectivement 33 % et 92 % chez les moins de 40 ans. L'utilisation du seuil prédéterminé « risque modéré ¼ à 21 points a permis d'améliorer la sensibilité à 77 % et la spécificité à 53 % au sein du groupe d'âge plus jeune. CONCLUSION: Le questionnaire actuel CANRISK est un outil d'évaluation du risque adéquat pour la dysglycémie chez les Canadiens d'origine sud-asiatique âgés de 40 ans et plus, mais il ne fonctionne pas aussi bien pour les moins de 40 ans. Utiliser un seuil plus faible à 21 points est pertinent chez les plus jeunes afin de diminuer les faux négatifs. Les seuils d'IMC et de TT fondés sur l'origine ethnique n'ont pas permis d'améliorer la valeur prédictive de l'algorithme de cotation de CANRISK que mesure l'ASC.

Effectiveness of the CANRISK tool in the identification of dysglycemia in First Nations and Métis in Canada. / Efficacité de l'outil CANRISK pour détecter la dysglycémie chez les membres des Premières Nations et les Métis au Canada.

INTRODUCTION: First Nations/Métis populations develop diabetes earlier and at higher rates than other Canadians. The Canadian diabetes risk questionnaire (CANRISK) was developed as a diabetes screening tool for Canadians aged 40 years or over. The primary aim of this paper is to assess the effectiveness of the existing CANRISK tool and risk scores in detecting dysglycemia in First Nations/Métis participants, including among those under the age of 40. A secondary aim was to determine whether alternative waist circumference (WC) and body mass index (BMI) cut-off points improved the predictive ability of logistic regression models using CANRISK variables to predict dysglycemia. METHODS: Information from a self-administered CANRISK questionnaire, anthropometric measurements, and results of a standard oral glucose tolerance test (OGTT) were collected from First Nations and Métis participants (n = 1479). Sensitivity and specificity of CANRISK scores using published risk score cut-off points were calculated. Logistic regression was conducted with alternative ethnicity-specific BMI and WC cut-off points to predict dysglycemia using CANRISK variables. RESULTS: Compared with OGTT results, using a CANRISK score cut-off point of 33, the sensitivity and specificity of CANRISK was 68% and 63% among individuals aged 40 or over; it was 27% and 87%, respectively among those under 40. Using a lower cut-off point of 21, the sensitivity for individuals under 40 improved to 77% with a specificity of 44%. Though specificity at this threshold was low, the higher level of sensitivity reflects the importance of the identification of high risk individuals in this population. Despite altered cut-off points of BMI and WC, logistic regression models demonstrated similar predictive ability. CONCLUSION: CANRISK functioned well as a preliminary step for diabetes screening in a broad age range of First Nations and Métis in Canada, with an adjusted CANRISK cutoff point for individuals under 40, and with no incremental improvement from using alternative BMI/WC cut-off points.

INTRODUCTION: Le diabète touche en plus grande proportion et à un plus jeune âge la population des Premières Nations et des Métis que le reste de la population canadienne. Cet article vise principalement à évaluer l'efficacité et les scores de risque de CANRISK (Questionnaire canadien sur le risque de diabète, un outil de dépistage du diabète destiné aux Canadiens de 40 ans et plus) pour détecter la dysglycémie chez les participants issus des Premières Nations et d'origine métisse en incluant les moins de 40 ans. L'objectif secondaire de cette étude est de déterminer si une modification des seuils relatifs au tour de taille (TT) et à l'indice de masse corporelle (IMC) améliore la valeur prédictive de modèles de régression logistique lorsque les variables du questionnaire CANRISK sont utilisées pour prédire la dysglycémie. MÉTHODOLOGIE: Nous avons recueilli auprès de 1479 participants métis et des Premières Nations des données provenant d'un questionnaire CANRISK autoadministré, de mesures anthropométriques et de résultats d'épreuve standard d'hyperglycémie provoquée par voie orale (HGPO). Nous avons calculé la sensibilité et la spécificité des scores CANRISK en appliquant les seuils usuels de classification des risques. Une régression logistique a été effectuée en utilisant des seuils tenant compte de l'origine ethnique pour l'IMC et le TT pour prédire la dysglycémie à l'aide des variables CANRISK. RÉSULTATS: Appliqué aux résultats de l'épreuve d'HGPO, le score seuil CANRISK à 33 points a conduit à une sensibilité et une spécificité de l'outil CANRISK de respectivement 68 % et 63 % chez les 40 ans et plus, et de respectivement 27 % et 87 % chez les moins de 40 ans. L'utilisation d'un seuil inférieur, à 21 points, a fait monter à 77 % la sensibilité chez les moins de 40 ans, avec une spécificité de 44 %. Malgré la faible spécificité correspondant à ce seuil, l'augmentation de la sensibilité montre son importance à identifier les personnes à risque au sein de cette population. Après modification des seuils d'IMC et de TT, les modèles de régression logistique ont présenté une valeur prédictive comparable. CONCLUSION: L'utilisation du questionnaire CANRISK s'est révélée efficace comme première étape de dépistage du diabète chez les membres des Premières Nations et les Métis d'un large éventail d'âge au Canada, dans la mesure où le seuil CANRISK a été adapté aux moins de 40 ans, et sans que l'on constate d'amélioration différentielle en modifiant les seuils d'IMC et de TT.

Ethnic dependent differences in diagnostic accuracy of glycated hemoglobin (HbA1c) in Canadian adults.

AIM: Previous studies have shown varying sensitivity and specificity of hemoglobin A1c (HbA1c) to identify diabetes and prediabetes, compared to 2-h oral glucose tolerance testing (OGTT) and fasting plasma glucose (FPG), in different ethnic groups. Within the Canadian population, the ability of HbA1c to identify prediabetes and diabetes in First Nations, Métis and Inuit, East and South Asian ethnic groups has yet to be determined. METHODS: We collected demographic, lifestyle information, biochemical results of glycemic status (FPG, OGTT, and HbA1c) from an ethnically diverse Canadian population sample, which included a purposeful sampling of First Nations, Métis, Inuit, South Asian and East Asian participants. RESULTS: Sensitivity and specificity using Canadian Diabetes Association (CDA) recommended cut-points varied between ethnic groups, with greater variability for identification of prediabetes than diabetes. Dysglycemia (prediabetes and diabetes) was identified with a sensitivity and specificity ranging from 47.1% to 87.5%, respectively in Caucasians to 24.1% and 88.8% in Inuit. Optimal HbA1c ethnic-specific cut-points for dysglycemia and diabetes were determined by receiver operating characteristic (ROC) curve analysis. CONCLUSIONS: Our sample showed broad differences in the ability of HbA1c to identify dysglycemia or diabetes in different ethnic groups. Optimal cut-points for dysglycemia or diabetes in all ethnic groups were substantially lower than CDA recommendations. Utilization of HbA1c as the sole biochemical diagnostic marker may produce varying degrees of false negative results depending on the ethnicity of screened individuals. Further research is necessary to identify and validate optimal ethnic specific cut-points used for diabetic screening in the Canadian population.

Faces elicit different scanning patterns depending on task demands.

Eye movements were recorded while participants discriminated upright and inverted faces that differed with respect to either configural or featural information. Two hypotheses were examined: (1) whether featural and configural information processing elicit different scanning patterns; (2) whether fixations on a specific region of the face dominate scanning patterns. Results from two experiments were compared to examine whether participants' prior knowledge of the kind of information that would be relevant for the task (i.e., configural vs featural) influences eye movements. In Experiment 1, featural and configural discrimination trials were presented in random order such that participants were unaware of the information that would be relevant on any given trial. In Experiment 2, featural and configural discrimination trials were blocked and participants were informed of the nature of the discriminations. The results of both experiments suggest that faces elicit different scanning patterns depending on task demands. When participants were unaware of the nature of the information relevant for the task at hand, face processing was dominated by attention to the eyes. When participants were aware that relational information was relevant, scanning was dominated by fixations to the center of the face. We conclude that faces elicit scanning strategies that are driven by task demands.

Modulations of eye movement patterns by spatial filtering during the learning and testing phases of an old/new face recognition task.

In two experiments, we examined the effects of varying the spatial frequency (SF) content of face images on eye movements during the learning and testing phases of an old/new recognition task. At both learning and testing, participants were presented with face stimuli band-pass filtered to 11 different SF bands, as well as an unfiltered baseline condition. We found that eye movements varied significantly as a function of SF. Specifically, the frequency of transitions between facial features showed a band-pass pattern, with more transitions for middle-band faces (≈5-20 cycles/face) than for low-band (≈<5 cpf) or high-band (≈>20 cpf) ones. These findings were similar for the learning and testing phases. The distributions of transitions across facial features were similar for the middle-band, high-band, and unfiltered faces, showing a concentration on the eyes and mouth; conversely, low-band faces elicited mostly transitions involving the nose and nasion. The eye movement patterns elicited by low, middle, and high bands are similar to those previous researchers have suggested reflect holistic, configural, and featural processing, respectively. More generally, our results are compatible with the hypotheses that eye movements are functional, and that the visual system makes flexible use of visuospatial information in face processing. Finally, our finding that only middle spatial frequencies yielded the same number and distribution of fixations as unfiltered faces adds more evidence to the idea that these frequencies are especially important for face recognition, and reveals a possible mediator for the superior performance that they elicit.