Childhood overweight and obesity trends in Canada. / Tendances en matière d'embonpoint et d'obésité chez les enfants au Canada.

INTRODUCTION: Excess weight is a key risk factor for chronic disease, and the systematic collection, analysis and reporting of key trends are important to surveillance of overweight and obesity. METHODS: We used univariate analyses to calculate current prevalence estimates of excess weight among Canadian children and youth. RESULTS: Almost 1 in 7 children and youth is obese. Rates vary based on sociodemographic factors such as age, sex, socioeconomic status and place of residence. Overall, the rates of excess weight have been relatively stable over the past decade. CONCLUSION: Ongoing monitoring of childhood obesity will provide useful information to assist with sustained actions to promote healthy weights.

INTRODUCTION: L'excès de poids est un facteur de risque important de maladies chroniques. La collecte, l'analyse et la diffusion systématiques des tendances clés dans ce domaine sont importantes pour la surveillance de l'embonpoint et de l'obésité. MÉTHODOLOGIE: Nous avons utilisé des analyses univariées pour calculer des estimations de la prévalence actuelle de l'excès de poids chez les enfants et les jeunes canadiens. RÉSULTATS: Près d'un enfant ou jeune sur sept est obèse. Les taux varient en fonction de facteurs sociodémographiques comme l'âge, le sexe, le statut socioéconomique et le lieu de résidence. Dans l'ensemble, les taux d'excès de poids sont demeurés relativement stables depuis dix ans. CONCLUSION: Faire le suivi de l'obésité juvénile fournit des renseignements utiles à la prise de mesures à long terme pour la promotion d'un poids santé.

Evidence Brief--Trends and projections of obesity among Canadians.

The prevalence of obesity, defined as body mass index (BMI) of 30 kg/m2 or higher for adults and as 2 standard deviations above the World Health Organization growth standard mean for children, has increased in many parts of the world. Obese adults are at an increased risk of certain chronic conditions, including hypertension, type 2 diabetes, cardiovascular diseases and some cancers, and of premature death. Obese children have increased cardiometabolic risk, including dyslipidemia, insulin resistance and elevated blood pressure. Excess childhood body weight that continues into adulthood can affect quality of life, educational attainment and earnings over the lifecourse. The Public Health Agency of Canada has projected an annual direct health care cost (including physician, hospitalization and medication costs) of those categorized as obese in Canada in constant 2001 Canadian dollars. Calculated as $7.0 billion in 2011, this annual direct health care cost is projected to rise to $8.8 billion by 2021, based on simulated average direct health care costs, which are higher among the obese ($2,283) than the overweight ($1,726), the underweight ($1,298) and those at normal weight ($1,284). Canadian estimates from 2006 and 2008 that used different methodologies place the annual economic burden (direct and indirect costs) of obesity between $4.6 billion and $7.1 billion. The purpose of this evidence brief is to show current Canadian obesity prevalence rates and estimates for the future using objectively measured height and weight to calculate BMI. The use of objectively measured height and weight to derive BMI is strongly recommended, especially for children and adolescents, as self- or proxy-reported height and weight tend to underestimate actual weight and consequently BMI and obesity prevalence.

TITRE: Synthèse portant sur les données probantes - Tendances et projections relatives à l'obésité chez les Canadiens. INTRODUCTION: La prévalence de l'obésité ­ soit un indice de masse corporelle (IMC) supérieur ou égal à 30 kg/m2 chez les adultes ou deux écarts-types au-dessus de la médiane de la norme de croissance de l'Organisation mondiale de la santé chez les enfants ­ a augmenté dans de nombreuses régions du monde. Les adultes obèses sont plus susceptibles d'être atteints de certaines affections chroniques, notamment d'hypertension, de diabète de type 2, de cardiopathies et de certains cancers, ainsi que de mourir prématurément. Les enfants obèses présentent aussi un risque cardiométabolique accru (dyslipidémie, résistance à l'insuline et hypertension artérielle). Un excès pondéral pendant l'enfance qui se poursuit à l'âge adulte peut nuire à la qualité de vie, au rendement scolaire et au revenu tout au long de la vie. L'Agence de la santé publique du Canada a estimé les coûts annuels directs, en dollars canadiens constants de 2001, des soins de santé (coûts liés aux médecins, aux hospitalisations et aux médicaments) pour les personnes classées comme obèses au Canada. Évalués à 7,0 milliards de dollars en 2011, ils devraient atteindre 8,8 milliards de dollars d'ici 2021, d'après un calcul à partir des moyennes actuelles qui font qu'ils sont plus élevés chez les obèses (2 283 $) que chez les personnes en surpoids (1 726 $), les personnes en insuffisance pondérale (1 298 $) et les personnes de poids normal (1 284 $). Des estimations canadiennes antérieures, de 2006 et 2008 et obtenues par des méthodologies différentes, ont évalué le fardeau économique annuel (coûts directs et indirects) de l'obésité dans une fourchette allant de 4,6 à 7,1 milliards de dollars. Cette synthèse fondée sur des données probantes vise à présenter les taux de prévalence de l'obésité au Canada à la fois actuels et projetés, à partir d'un calcul de l'IMC reposant sur des mesures objectives de la taille et du poids. L'utilisation de mesures objectives de la taille et du poids pour calculer l'IMC est fortement recommandée, particulièrement chez les enfants et les adolescents, car lorsque la taille et le poids sont autodéclarés ou obtenus par procuration, le poids réel est généralement sous-estimé, ce qui fait que l'IMC et la prévalence de l'obésité le sont également.

Prevalence and patterns of chronic disease multimorbidity and associated determinants in Canada.

INTRODUCTION: Multimorbidity is increasingly recognized as a key issue in the prevention and management of chronic diseases. We examined the prevalence and correlates of chronic disease multimorbidity in the general adult Canadian population in relation to age and other key determinants. METHODS: We extracted data from the Canadian Community Health Survey 2011/12 on 105 416 Canadian adults. We analysed the data according to the number of multimorbidities (defined as 2+ or 3+ diseases from a list of 9) and examined the determinants of multimorbidity using regression analyses. RESULTS: Our findings show that 12.9% of Canadians report 2+ chronic diseases and 3.9% report 3+ chronic diseases. Those reporting 3 or more chronic diseases were more likely to be female, older, living in the lowest income quintile and to have not completed high school. In the overall population, social deprivation is associated with a 3.7 odds of multimorbidity, but when examined across age groups, the odds of multimorbidity were notably higher in middle age, 7.5 for those aged 35 to 49 years and 5.4 for those aged 50 to 64 years. DISCUSSION: As the proportion of Canadians living with multiple chronic diseases increases, we need to assess chronic disease from a holistic perspective that captures multimorbidity and upstream factors, to facilitate broader and more context-appropriate associations with healthy living, quality of life, health care costs and mortality. Special consideration should be given to the role that social deprivation plays in the development of multimorbidity. Canadians living in the lowest socioeconomic group are not only more likely to develop multimorbidity, but the onset of multimorbidity is also likely to be significantly earlier.

TITRE: Prévalence et profils de la multimorbidité au Canada et déterminants associés. INTRODUCTION: La prise en compte de la multimorbidité est de plus en plus reconnue comme un élément fondamental de la prévention et de la prise en charge des affections chroniques. Cette étude porte sur la prévalence et les corrélats de la multimorbidité chez les adultes canadiens en fonction de l'âge et de certains autres déterminants clés. MÉTHODOLOGIE: Nous avons extrait des données portant sur 105 416 adultes canadiens ayant répondu à l'Enquête sur la santé dans les collectivités canadiennes de 2011-2012. Nous les avons analysées en fonction du nombre d'affections concomitantes présentes (deux ou plus ou trois ou plus, sur une liste de neuf) et nous avons cherché à caractériser les déterminants de la multimorbidité à l'aide de régressions. RÉSULTATS: D'après notre analyse, 12,9 % des Canadiens souffraient de deux affections chroniques ou plus et 3,9 % de trois ou plus. Les répondants ayant déclaré souffrir de trois affections chroniques ou plus étaient plus susceptibles d'être des femmes, d'être plus âgés, de faire partie d'un ménage dont le revenu fait partie du quintile le plus faible et dont le niveau de scolarité le plus élevé de l'un des membres était inférieur aux études secondaires. La multimorbidité en lien avec le dénuement social était associée à une cote de 3,7 dans la population en général, mais de 7,5 chez les 35 à 49 ans et de 5,9 chez les 50 à 64 ans, soit la population d'âge moyen. ANALYSE: La proportion de Canadiens atteints de multiples affections chroniques étant en augmentation, nous devons adopter, pour étudier les affections chroniques et leurs facteurs en amont, une approche globale qui tienne compte de la multimorbidité, afin d'agir de manière globale et adaptée au contexte pour favoriser une vie saine et une meilleure qualité de vie et pour réduire les coûts des soins de santé et la mortalité. On devrait particulièrement tenir compte du rôle joué par le dénuement social dans l'apparition de la multimorbidité, car non seulement les Canadiens du groupe socioéconomique le plus démuni sont plus susceptibles de souffrir de multimorbidité, mais celle-ci surgira aussi probablement beaucoup plus précocement.

Type-specific human papillomavirus infections and Pap test findings in Inuit and non-Inuit women in Nunavut, Canada.

OBJECTIVE: To determine the prevalence and distribution of type-specific human papillomavirus (HPV) infections and their association with cytological outcomes in women living in the Canadian territory of Nunavut. METHODS: Surveillance of type-specific HPV infection was conducted. Cervical specimens of all Inuit, First Nations and non-Aboriginal women in Nunavut who presented for a Pap test in any clinical setting between January 2008 and March 2009 were tested for HPV infection. The association between high-grade cervical lesions and HPV type was also examined. RESULTS: HPV results were available for 4,043 individual women (13 to 77 years). Of those with known ethnicity (N=4,033), 89.2% were Inuit, 0.4% were First Nations and 10.4% were non-Aboriginal. First Nations women were included in all analyses except those making comparisons by ethnicity, due to the small number of individuals in this group. Overall, 29.9% of women were found to be infected with HPV (any type) and 19.9% with any high-risk HPV (type 16, 18, 31, 33, 35, 39, 45, 51, 52, 56, 58 or 59). Most often, women were infected with HPV 16 (6.4%) followed by HPV 31 (3.1%). There were no statistically significant differences between Inuit and non-Aboriginal (reference group) women 20 years of age and older regarding the prevalence of any HPV (odds ratios (OR): 1.19, 95% confidence intervals (CI): 0.92-1.54), high-risk HPV (OR: 1.06, 95% CI: 0.78-1.44) or HPV 16 and 18 (OR: 0.81, 95% CI: 0.51-1.27). HPV 31 was the only type that was significantly more frequent among Inuit than non-Aboriginal women (OR: 3.95, 95% CI: 1.24-12.54). There was no difference in the overall occurrence of cervical abnormalities between non-Aboriginal and Inuit women (p-value = 0.17). HPV 16 was strongly associated with cervical dysplasia, being present in 50.9% of specimens with a high-grade lesion. CONCLUSION: HPV is a significant public health issue in the territory of Nunavut. The findings presented in this article are similar to those in other studies among Inuit women, with prevalence of HPV being higher than in studies conducted among non-Inuit women in other regions of Canada. These results provide a baseline of HPV prevalence that precedes the introduction of the Nunavut HPV Immunization Program in 2010 and will allow for future evaluation. The high prevalence of HPV infection among women living in Nunavut can be reduced through immunization and associated high-grade cervical abnormalities mitigated by regular cervical screening.

Characterizing viral subtypes to assess patterns of HIV transmission.

We characterized HIV-1 subtypes among 204 persons newly diagnosed with HIV in Ontario from 2003 to 2005 using samples from the Canadian HIV Strain and Drug Resistance Surveillance Program. We examined HIV-1 subtype by demographic characteristics and exposure category, and determined independent predictors of infection with a non-B HIV subtype using multivariate logistic regression. The distribution of HIV subtypes was: B 77.0%, C 10.3%, AG 4.9%, A 2.5%, AE 2.5% and others 3.0%. Overall, 23.0% were non-B, greater in women than in men (62.8% versus 12.4%, P < 0.0001) and persons under 35 years (31.1% versus 18.5% in those ≥35, P = 0.04). Non-B subtype was predominant (78.9%) among persons from HIV-endemic regions and considerable (28.6%) among other persons infected heterosexually. In multivariate modelling adjusted for gender, non-B subtype was significantly associated with birth in an HIV-endemic region (adjusted odds ratio [aOR] 59.2, P < 0.0001) and heterosexual exposure (aOR 6.3, P = 0.02). Additionally, compared with men who had sex with men, non-B subtype was greater among heterosexual women (aOR 17.8, P < 0.001) and women who injected drugs (injection drug use, aOR 13.4, P = 0.01). We found a non-negligible proportion of non-B subtypes among women infected heterosexually not from HIV-endemic countries, providing interesting insights into HIV transmission patterns.

Trends in testing behaviours for hepatitis C virus infection and associated determinants: results from population-based laboratory surveillance in Alberta, Canada (1998-2001).

Little is currently known about hepatitis C virus (HCV) test seeking behaviours at the population level. Given the centralized nature of testing for HCV infection in the province of Alberta, Canada, we had an opportunity to examine HCV testing behaviour at the population level on all newly diagnosed HCV-positive cases using laboratory data to validate the time and number of prior tests for each case. Record linkage identified 3323, 2937, 2660 and 2703 newly diagnosed cases of HCV infections in Alberta during 1998, 1999, 2000 and 2001, respectively, corresponding to age-adjusted rates of 149.8, 129, 114.3 and 113.7 per 100,000 population during these years, respectively. Results from secondary analyses of laboratory data suggest that the majority of HCV cases (95.3%) who were newly diagnosed between 1998 and 2001 were first-time testers for HCV infection. Among repeat testers, analysis of a negative test result within 1 year prior to a first of a positive test report suggests that 211 (38.4%) may be seroconvertors. These findings suggest that 339 or 61.7% of repeat testers may not have discovered their serostatus within 1 year of infection. Among this group, HCV testing was sought infrequently, with a median interval of 2.3 years between the last negative and first positive test. This finding is of concern given the risks for HCV transmission, particularly if risk-taking behaviours are not reduced because of unknown serostatus. These findings also reinforce the need to make the most of each test-seeking event with proper counselling and other appropriate support services.

Estimating the size of hard-to-reach populations: a novel method using HIV testing data compared to other methods.

OBJECTIVE: To estimate population size of hard-to-reach groups such as injecting drug users and men who have sex with men. DESIGN: Several different methods were used to estimate the size of these populations in Canada's three largest cities (Toronto, Montreal and Vancouver). METHODS: A novel method (referred to as the indirect method) was developed for use in Toronto and Vancouver that combines HIV serodiagnostic information with data on HIV testing behavior. Population size estimates were obtained by dividing the number of injecting drug users or men who have sex with men recorded in HIV serodiagnostic databases in a given year by the proportion of the corresponding group that reported being tested in a 1-year period. Results of this method were compared with four other methods: (1) population surveys; (2) capture-recapture (for injecting drug users only); (3) a modified Delphi technique; and (4) a method based on the proportion of never-married men aged 45 and over (for men who have sex with men only). Only these other methods were used in Montreal. RESULTS: The survey method gave the lowest estimates which are best viewed as minimum estimates given the relative inability of surveys to access these populations and the reluctance of participants to admit to sensitive behaviors. The indirect method produced results more closely comparable with those obtained by other methods, but they are probably slight overestimates, at least for injecting drug users, due to possible underestimation of the proportion tested for HIV. Point estimates using the indirect method were 17,700 and 17,500 for injecting drug users in Toronto and Vancouver, respectively, and 39,100 and 15,900 for men who have sex with men. In Toronto, results for the other methods ranged from 12,300-13,360 for injecting drug users and 18,800-35,000 for men who have sex with men. For Vancouver, these ranges were 6400-11,670 and 7000-26,500, respectively. In Montreal, ranges were 4300-12,500 for injecting drug users and 18,500-40,000 for men who have sex with men. CONCLUSIONS: This novel method provides estimates of population size of hard-to-reach groups such as injecting drug users and men who have sex with men that are comparable with results derived by other methods. These estimates may be useful for the purposes of planning, implementing and evaluating prevention and care services, especially when they are combined with the results of other estimation methods to improve the degree of confidence in the resulting estimates.

Transcriptional analysis of the Streptococcus mutans hrcA, grpE and dnaK genes and regulation of expression in response to heat shock and environmental acidification.

The dental pathogen Streptococcus mutans persists and causes diseases in highly dynamic environments and gains a selective ecological advantage in environmental conditions that frequently exceed the limits for growth of the organism, particularly with regard to environmental pH. The goal of this study was to begin a molecular genetic analysis of a major stress protein, DnaK/Hsp70, to begin to understand how stress responses are regulated in this lactic acid bacterium and to establish a relationship between dnaK gene expression and exposure to acidic environments. Cloning and nucleotide sequence analysis revealed that the dnaK gene is preceded by, and is in an operon-like arrangement with, the hrcA and grpE genes, although intergenic spacing was unlike that described in other bacteria. An inverted repeat (a CIRCE element) was identified by sequence analysis and, using primer extensions, a heat shock-responsive, sigmaA-type promoter, P1, 5' to the hrcA gene, and a sigmaB-type promoter, 5' to the grpE translational start site, were identified. No promoters were detected between grpE and dnaK. A strain carrying a strongly polar insertion in the hrcA gene had markedly diminished levels of dnaK mRNA, indicating that dnaK was transcribed as part of an operon from P1, and to a lesser extent from P2. Results from physiological manipulation of S. mutans in continuous chemostat culture demonstrated that steadystate levels of S. mutans dnaK mRNA and DnaK protein were (i) increased in response to acid shock; (ii) elevated in acid 'adapted' cells; and (iii) induced in response to alkali shock of acid 'adapted' cells. In all cases, increased amounts of dnaK mRNA could be correlated with enhanced transcription from P1. This study provides the first detailed analysis of the expression of a heat shock gene from an oral isolate, and the evidence provided suggests that sigmaB-like promoters may also be involved in class I heat shock gene expression in some Gram-positive organisms.

DnaK expression in response to heat shock of Streptococcus mutans.

The oral pathogen, Streptococcus mutans, persistently colonizes human hosts and initiates oral disease despite extreme variations in environmental conditions. To begin to investigate the role of the stress protein, DnaK (Hsp70), in environmental stress responses by S. mutans, pulse-chase experiments were initially used to establish that a functional heat shock response existed in this organism. A C-terminal fragment of the S. mutans dnaK gene was cloned and engineered to be expressed with a histidine tag. Using the recombinant DnaK protein that had been purified by nickel affinity chromatography, an antibody specific for the S. mutans DnaK protein was generated to analyse DnaK expression under homeostatic and heat shock conditions. Western blot analysis indicated that the anti-recombinant DnaK antibody specifically recognized a protein (molecular mass approx. 68 kDa) which was induced in response to thermal stress. Elucidating the role of DnaK in responses by S. mutans to various environmental stressors will provide a better understanding of how DnaK is involved in survival of extreme environments and the contribution of the DnaK protein to the virulence of S. mutans.