Blood pressure in Canadian children and adolescents

BACKGROUND

Because blood pressure (BP) tracks from childhood to adulthood, assessing levels in youth is relevant. There are no recent BP data for Canadian children and adolescents, and past studies have used a variety of design and measurement devices.

DATA AND METHODS

With a clinically validated oscillometric device, resting BP was measured in 2,079 respondents aged 6 to 19 years from the Canadian Health Measures Survey. The average of the last five of six BP measures taken one minute apart at a single visit was used in this report. Borderline or elevated BP was defined as greater than or equal to the 90th percentile of US reference values for participants aged 6 to 17 years. Borderline or elevated BP for 18- to 19-year-olds was defined as equal to or greater than 120 systolic BP or equal to or greater than 80 diastolic BP. Participants of any age who reported taking antihypertensive medication in the past month were also defined as having elevated BP.

RESULTS

At ages 6 to 11 years, mean (standard error) systolic/diastolic blood pressure was 93(0)/61(1) in boys and 93(0)/60(0) mmHg in girls, and at ages 12 to 19 years, 101(1)/63(1) and 98(1)/63(1) mmHg, respectively. An estimated 2.1% (95% confidence interval 1.3% to 3.0%) of Canadian children and youth had borderline levels; 0.8% (0.4% to 1.4%) had elevated BP.

INTERPRETATION

Despite the prevalence of obesity among young people, BP levels were lower than reported in provincial samples, which may, in part, reflect differences in methodologies and measurement instruments.

Child Health Ecological Surveillance System (CHESS) for childhood obesity: a feasibility study

OBJECTIVE

To assess the feasibility of employing an ecologically guided childhood obesity relevant surveillance system.

METHODS

Cross-sectional qualitative and quantitative data were collected from 31 organizational representatives across 28 unique organizations and/or departments from three purposively sampled communities in the Capital Health Region in Alberta, Canada.

RESULTS

All the organizational representatives surveyed reported awareness of childhood obesity and 36% reported participation in child obesity initiatives. Data to support a surveillance system are available but not in a suitable format, and privacy legislation present significant barriers. Interest in developing and sustaining an ecologically based surveillance system was low (18%).

CONCLUSION

Due to the heterogeneity of available data and limited vision for the development and implementation of a surveillance system, the application of an ecologically based surveillance system relevant to childhood obesity may be constrained. Broad-based awareness of childhood obesity by a wide range of organizations could assist in establishing an effective coalition to address this issue over the long term by supporting the establishment of a surveillance system.

Process description and evaluation of Canadian Physical Activity Guidelines development

BACKGROUND

This paper describes the process used to arrive at recommended physical activity guidelines for Canadian school-aged children and youth (5-17 years), adults (18-64 years) and older adults (>/=65 years).

METHODS

The Canadian Society for Exercise Physiology (CSEP) Physical Activity Measurement and Guidelines (PAMG) Steering Committee used the Appraisal of Guidelines for Research Evaluation (AGREE II) Instrument to inform the guideline development process. Fourteen background papers and five systematic reviews were completed. Systematic review authors appraised and synthesized the data, and proposed specific recommendations at an international consensus conference of invited experts and key stakeholders. Independently, an international panel of experts interpreted the evidence from the systematic reviews and developed recommendations following attendance at the Consensus Conference.

RESULTS

Using the AGREE II instrument as a guide, specific foci for each of the guidelines were defined and systematic review methodology was used to synthesize the evidence base. The expert panel, CSEP PAMG Steering Committee and methodological consultants reviewed the systematic reviews and Consensus Statement. The expert panel achieved consensus on the level of evidence informing the physical activity guidelines and developed a separate document outlining key recommendations, interpretation of the evidence and justification of each recommendation.

CONCLUSION

The CSEP and Public Health Agency of Canada followed a rigorous process to examine the evidence informing potential revisions to existing physical activity guidelines for Canadians. It is believed that this is the first physical activity guideline development process in the world to be guided and assessed by AGREE II and AMSTAR instruments.

Fitness of Canadian adults: results from the 2007-2009 Canadian Health Measures Survey

BACKGROUND

Estimates of obesity, based on body mass index (BMI) reveal that Canadian adults have become heavier over the past quarter century. However, a comprehensive assessment of fitness requires additional measures. This article provides up-to-date estimates of fitness levels of Canadians aged 20 to 69 years. Results are compared with estimates from 1981.

DATA AND METHODS

Data are from the 2007-2009 Canadian Health Measures Survey (CHMS). Historical estimates are from the 1981 Canada Fitness Survey. Means, medians and cross-tabulations were used to compare fitness levels by sex and age group and between survey years.

RESULTS

Mean scores for aerobic fitness, flexibility, muscular endurance and muscular strength declined at older ages, and BMI, waist circumference, skinfold measurements and waist-to-hip ratio increased. Males had higher scores than females for aerobic fitness, muscular endurance and muscular strength; females had higher scores for flexibility. Muscular strength and flexibility decreased between 1981 and 2007-2009; BMI, waist circumference and skinfold measurements increased.

INTERPRETATION

Based on results of the fitness tests and anthropometric measurements, many Canadian adults face health risks due to suboptimal fitness levels.

Blood pressure in Canadian adults

BACKGROUND

Hypertension is estimated to cause more than one-eighth of all deaths worldwide. In Canada, the last national surveys to include direct measures of blood pressure (BP) took place over the years 1985-1992; hypertension was estimated at 21%.

DATA AND METHODS

Data are from cycle 1 of the Canadian Health Measures Survey, conducted from March 2007 through February 2009. The survey included direct BP measures using an automated device. Weighted frequencies, means and cross-tabulations were produced to estimate levels of hypertension awareness, treatment and control in the population aged 20 to 79 years.

RESULTS

Among adults aged 20 to 79 years, hypertension (systolic BP higher than or equal to 140 or diastolic BP higher than or equal to 90 mm Hg, or self-reported recent medication use for high BP) was present in 19%. Another 20% had BP in the pre-hypertension range (systolic 120 to 139 or diastolic 80 to 89 mm Hg). Of those with hypertension, 83% were aware, 80% were taking antihypertensive drugs, and 66% were controlled. Uncontrolled hypertension was largely due to high systolic BP.

INTERPRETATION

Hypertension prevalence is similar to that reported in 1992. Since then, the level of hypertension control has increased considerably.

Quality control and data reduction procedures for accelerometry-derived measures of physical activity

BACKGROUND

This article describes four key quality control and data reduction issues that researchers should consider when using accelerometry to measure physical activity: monitor reliability, spurious data, monitor wear time, and number of valid days required for analysis.

DATA SOURCE AND METHODS

Exploratory analyses were conducted on an unweighted subsample (n=987) of the accelerometry data from the Canadian Health Measures Survey. Participants were asked to wear an accelerometer for 7 consecutive days. Calibration, reliability, biological plausibility and compliance issues were explored using descriptive statistics.

RESULTS

Ongoing calibration is an effective method for identifying malfunctioning accelerometers. The percentage of files deemed viable for analysis depends on participant compliance, the allowable interruption period chosen and the minimum wear-time-per-day criterion. A 60-minute allowable interruption period and 10-hours-per-day wear time criteria resulted in 95% of the subsample having at least 1 valid day, and 84% having at least 4 valid days.

INTERPRETATION

Before the derivation of physical activity outcomes, accelerometry data should undergo standardized quality control and data reduction procedures to prevent mis-representation of the results. Incomplete accelerometry data should be handled carefully, and strategies to improve compliance in the field are warranted.

Fitness of Canadian children and youth: results from the 2007-2009 Canadian Health Measures Survey

BACKGROUND

The fitness of Canadian children and youth has not been measured in more than two decades, a period during which childhood obesity and sedentary behaviours have increased. This paper provides up-to-date estimates of the fitness of Canadians aged 6 to 19 years.

DATA AND METHODS

Data are from the 2007-2009 Canadian Health Measures Survey (CHMS), the most comprehensive direct health measures survey ever conducted on a nationally representative sample of Canadians. Descriptive statistics for indicators of body composition, aerobic fitness and musculoskeletal fitness are provided by sex and age group, and comparisons are made with the 1981 Canada Fitness Survey (CFS).

RESULTS

Fitness levels of children and youth have declined significantly and meaningfully since 1981, regardless of age or sex. Significant sex differences exist for most fitness measures. Fitness levels change substantially between ages 6 and 19 years. Youth aged 15 to 19 years generally have better aerobic fitness and body composition indicators than 20- to 39-year-olds.

INTERPRETATION

This decline in fitness may result in accelerated chronic disease development, higher health care costs, and loss of future productivity.

Resting blood pressure and heart rate measurement in the Canadian Health Measures Survey, cycle 1

BACKGROUND

Directly measured blood pressure (BP) data have not been collected in Canada since the Canadian Heart Health Surveys, conducted between 1985 and 1992. Because hypertension is often asymptomatic, a large proportion of those with the condition are unaware of it.

DATA AND METHODS

These analyses use BP and heart rate (HR) data from cycle 1 of the 2007-2009 Canadian Health Measures Survey (CHMS) for respondents aged 6 to 79 years. Methods and quality assurance and control procedures are explained. Logistical and feasibility issues that arose during data collection are discussed. The reasons for repeating a series of measures are given. Between- and within- series variations and inter-tester variability are assessed.

RESULTS

The BP and HR of almost all respondents who attended the examination centre were measured. Only one series of measurements was taken for 88% of respondents. The series was repeated for around 5% with variability in their BP or HR measurements. About 3% had HR or BP values above the screening cut-offs for the fitness tests. Almost 35% of respondents with HR or BP values above the screening cut-offs after their first series had values below the cut-points after the second series; a further 3% had values below after the third series. Within a series of six measurements, BP decreased until about the fourth measure, after which it remained stable. Mean BP and HR values indicated no inter-tester variability.

INTERPRETATION

The protocol for measuring BP and HR by oscillometry in the CHMS appears to have produced reliable estimates. No benefit to repeating the series of six measurements a third time for screening purposes is evident. Four measurements may be sufficient to provide reliable BP and HR data. Oscillometry appears to eliminate inter-tester variability.

The bias in self-reported obesity from 1976 to 2005: a Canada-US comparison

The objective of this study was to determine whether the bias in self-reported estimates of obesity has changed over time and followed different patterns in Canada and the United States. Using age-standardized data from three waves of the National Health and Nutrition Examination Survey (NHANES) in the United States and the Canadian Community Health Survey (CCHS) and the Canadian Heart Health Survey (CHHS) in Canada, discrepancies were compared between reported and measured estimates of height, weight, and obesity (based on the BMI) from 1976 to 2005. Results indicated that obesity increased in both countries, but rates were higher in the United States. The discrepancy between self-reported and measured obesity was small in the United States with reported data underestimating measured prevalence by about 3%; this stayed relatively constant over time. In Canada, the discrepancy was large and doubled in the past decade (from 4 to 8%). In the United States, self-reported data may be more accurate in monitoring changes in obesity over time, as the estimates have consistently remained about 3% below the measured estimates, whereas in Canada, monitoring obesity based solely on self-reported height and weight may produce inaccurate estimates because of the increasing discrepancy between self-reported and measured data.

ParticipACTION: Overview and introduction of baseline research on the "new" ParticipACTION

Background

This paper provides a brief overview of the Canadian physical activity communications and social marketing organization "ParticipACTION"; introduces the "new" ParticipACTION; describes the research process leading to the collection of baseline data on the new ParticipACTION; and outlines the accompanying series of papers in the supplement presenting the detailed baseline data.

Methods

Information on ParticipACTION was gathered from close personal involvement with the organization, from interviews and meetings with key leaders of the organization, from published literature and from ParticipACTION archives. In 2001, after nearly 30 years of operation, ParticipACTION ceased operations because of inadequate funding. In February 2007 the organization was officially resurrected and the launch of the first mass media campaign of the "new" ParticipACTION occurred in October 2007. The six-year absence of ParticipACTION, or any equivalent substitute, provided a unique opportunity to examine the impact of a national physical activity social marketing organization on important individual and organizational level indicators of success. A rapid response research team was established in January 2007 to exploit this natural intervention research opportunity.

Results

The research team was successful in obtaining funding through the new Canadian Institutes of Health Research Intervention Research (Healthy Living and Chronic Disease Prevention) Funding Program. Data were collected on individuals and organizations prior to the complete implementation of the first mass media campaign of the new ParticipACTION.

Conclusion

Rapid response research and funding mechanisms facilitated the collection of baseline information on the new ParticipACTION. These data will allow for comprehensive assessments of future initiatives of ParticipACTION.

ParticipACTION: awareness of the participACTION campaign among Canadian adults--examining the knowledge gap hypothesis and a hierarchy-of-effects model

Background

ParticipACTION was a pervasive communication campaign that promoted physical activity in the Canadian population for three decades. According to McGuire's hierarchy-of-effects model (HOEM), this campaign should influence physical activity through intermediate mediators such as beliefs and intention. Also, when such media campaigns occur, knowledge gaps often develop within the population about the messages being conveyed. The purposes of this study were to (a) determine the current awareness of ParticipACTION campaigns among Canadians; (b) confirm if awareness of the ParticipACTION initiative varied as a function of levels of education and household income; and, (c) to examine whether awareness of ParticipACTION was associated with physical activity related beliefs, intentions, and leisure-time physical activity (LTPA) as suggested by the HOEM. Specifically, we tested a model including awareness of ParticipACTION (unprompted, prompted), outcome expectations, self-efficacy, intention, and physical activity status.

Methods

A population-based survey was conducted on 4,650 Canadians over a period of 6 months from August, 2007 to February, 2008 (response rate = 49%). The survey consisted of a set of additional questions on the 2007 Physical Activity Monitor (PAM). Our module on the PAM included questions related to awareness and knowledge of ParticipACTION. Weighted logistic models were constructed to test the knowledge gap hypotheses and to examine whether awareness was associated with physical activity related beliefs (i.e., outcome expectations, self-efficacy), intention, and LTPA. All analyses included those respondents who were 20 years of age and older in 2007/2008 (N = 4424).

Results

Approximately 8% of Canadians were still aware of ParticipACTION unprompted and 82% were aware when prompted. Both education and income were significant correlates of awareness among Canadians. The odds of people being aware of ParticipACTION were greater if they were more educated and reported higher income. Awareness of ParticipACTION was also associated with outcome expectations, self-efficacy, intention, and LTPA status.

Conclusion

Awareness of ParticipACTION is associated with LTPA. Knowledge gaps in awareness are associated with level of education and household income. Thus, future promotion campaigns should include specific strategies to target different segments of the population, especially people who are living in deprived conditions with lower levels of education.

ParticipACTION: Baseline assessment of the capacity available to the 'New ParticipACTION': A qualitative study of Canadian organizations

Background

Evaluation of the original ParticipACTION campaign effects focused on individual awareness, recall, and understanding. Less studied has been the impact such campaigns have had on the broader organizational capacity to mobilize and advocate for physical activity. With the relaunch of ParticipACTION, the purpose of this study was to qualitatively explore baseline organizational capacity to promote physical activity messages, programs, and services within the Canadian context.

Methods

Using a purposeful sampling strategy, we conducted semi-structured telephone interviews with 49 key informants representing a range of national, provincial, and local organizations with a mandate to promote physical activity. Interview data were analysed using a thematic analytic approach.

Results

Key informants painted a generally positive picture of current organizational capacity to promote physical activity messages, programs, and services in Canada. Will and leadership were clear strengths while infrastructure limitations remained the greatest concern. Some specific challenges included: 1) funding issues: the absence of core funding in a climate of shifting funding priorities; 2) the difficulty of working without a national physical activity policy (lack of leadership); 3) inconsistent provincial and educational sector level policies; and 4) a persistent focus on obesity rather than physical inactivity.

Conclusion

The data generated here can be utilized to monitor the future impact of ParticipACTION on enhancing and utilizing this organizational capacity. A range of indicators are suggested that could be used to illustrate ParticipACTION's impact on the broad field of physical activity promotion in the future.

Relaunching a national social marketing campaign: expectations and challenges for the "new" ParticipACTION

ParticipACTION is a Canadian physical activity communications and social marketing organization that has been relaunched in 2007 after a 6-year hiatus. The purpose of this study is to qualitatively identify and describe the expectations and challenges the relaunch of the new ParticipACTION may present for existing physical activity organizations. Using a purposeful sampling strategy, the authors conduct semistructured telephone interviews with 49 key informants representing a range of national, provincial, and local organizations with a mandate to promote physical activity. Overall, there is strong support in seeing ParticipACTION relaunched. However, organizational expectations and/or their ideal vision for it are mixed. Organizations envision and support its performing an overarching social marketing and advocacy role, and in providing tools and resources that supplement existing organizational activities. Four major organizational challenges are identified concerning overlapping mandates, partnership and leadership concerns, competition for funding, and capacity concerns. Social marketing initiatives, such as ParticipACTION, may not be able to maximize their impact unless they address the expectations and concerns of competing organizations with a mandate to promote physical activity.

Desk potatoes: the importance of occupational physical activity on health

OBJECTIVES

To determine the relationship between occupational physical activity (OPA) and chronic disease after controlling for leisure-time physical activity (LTPA) and other risk factors.

METHODS

Using cycle 2.1 of the Canadian Community Health Survey, OPA energy expenditure was derived. The association of OPA with any self-reported chronic disease, heart disease or diabetes was determined using logistic regression while controlling for confounders. The analyses of OPA controlled for age, sex, ethnicity, BMI, smoking status, time since immigration, income, education and LTPA.

RESULTS

High OPA was associated with reduced odds of having any chronic disease (OR = 0.89) independent of LTPA status. Similar significant associations were also observed for heart disease (OR = 0.61) and diabetes (OR = 0.72).

CONCLUSION

High OPA is associated with reduced odds of chronic disease independent of LTPA. Accordingly, it is important that physical activity questionnaires carefully assess OPA in addition to LTPA.

The feasibility of establishing correction factors to adjust self-reported estimates of obesity

BACKGROUND

This study examines the feasibility of developing correction factors to adjust self-reported measures of body mass index (BMI) to more closely approximate measured values.

DATA AND METHODS

Data are from the 2005 Canadian Community Health Survey (subsample 2), in which respondents were asked to report their height and weight, and were subsequently measured. Regression analyses were used to determine which socio-demographic and health characteristics were associated with the discrepancies between self-reported and measured values. The sample was then split into two groups. In the first, self-reported BMI and the predictors of the discrepancies were regressed on measured BMI. Correction equations were generated using all predictor variables that were significant at the p < 0.05 level. These correction equations were then tested in the second group to derive estimates of sensitivity, specificity and obesity prevalence. Logistic regression was used to examine relationships between self-reported, measured and corrected BMI and obesity-related health conditions.

RESULTS

Corrected estimates provide more accurate measures of obesity prevalence, mean BMI and sensitivity levels (percentage correctly classified). In almost all cases, associations between BMI and health conditions are more accurate when based on corrected versus self-reported values.

Moving forward by looking back: children’s physical activity across the ages

Some cultural groups provide a glimpse at the past because they preserve or adhere to traditional behaviours and (or) living conditions. This brief introduction outlines a series of papers presented at the Canadian Society for Exercise Physiology Conference that used this model to explore changes in the physical activity behaviour of children over time.

Moving forward by looking back: lessons learned from long-lost lifestyles

The paper briefly reviews the status and trends in physical activity, physical inactivity, and overweight/obesity in Canada; discusses the consequences of these trends; examines evidence that our frame of reference with respect to physical activity and obesity is changing; promotes the importance of getting “back to the basics” as a strategy for enhancing childhood physical activity; and provides suggestions for future research in this area. In addressing these topics, the paper explores and contrasts the lifestyles and characteristics of Old Order Amish and Old Order Mennonite children with children exposed to contemporary modern living. This exploration is used as a model to learn from traditional lifestyles, which were comparatively active and resistant to obesity. The fitness characteristics and physical activity levels of traditional and contemporary groups are compared and demonstrate significant differences among groups. This evidence may provide important insight for informing future physical activity recommendations. Idiosyncrasies of performing research on these traditional-living groups are also provided.

Desk potatoes: the importance of occupational physical activity on health

OBJECTIVES

To determine the relationship between occupational physical activity (OPA) and chronic disease after controlling for leisure-time physical activity (LTPA) and other risk factors.

METHODS

Using cycle 2.1 of the Canadian Community Health Survey, OPA energy expenditure was derived. The association of OPA with any self-reported chronic disease, heart disease or diabetes was determined using logistic regression while controlling for confounders. The analyses of OPA controlled for age, sex, ethnicity, BMI, smoking status, time since immigration, income, education and LTPA.

RESULTS

High OPA was associated with reduced odds of having any chronic disease (OR = 0.89) independent of LTPA status. Similar significant associations were also observed for heart disease (OR = 0.61) and diabetes (OR = 0.72).

CONCLUSION

High OPA is associated with reduced odds of chronic disease independent of LTPA. Accordingly, it is important that physical activity questionnaires carefully assess OPA in addition to LTPA.

Effects of measurement on obesity and morbidity

OBJECTIVES

This article compares associations between body mass index (BMI) categories based on self-reported vers measured data with selected health conditions. The goal is to see if the misclassifications resulting from the use of self-reported data alters associations between excess body weight and these health conditions.

METHODS

The analysis is based on 2,667 respondents aged 40 years or older from the 2005 Canadian Community Health Survey (CCHS) who, during a face-to-face interview, provided self-reported values for height and weight and were then measured by trained interviewers. Multiple logistic regression analysis was used to examine associations between BMI categories (based on self-reported and measured data) and obesity-related health conditions.

RESULTS

On average, BMI based on self-reported height and weight was 1.3 kg/m2 lower than BMI based on measured values. Consequently, based on self-reported data, a substantial proportion of individuals with excess body weight were erroneously placed in lower BMI categories. This misclassification resulted in elevated associations between overweight/obesity and morbidity.

Sedentary behaviour and obesity

OBJECTIVES

This article examines sedentary behaviours (television viewing, computer use and reading) in relation to obesity among Canadian adults aged 20 to 64 years.

METHODS

The analysis is based on 42,612 respondents from the 2007 Canadian Community Health Survey Cross-tabulations were used to compare the prevalence of obesity by time engaged in sedentary behaviours. Multiple logistic regression models were used to determine if associations between sedentary behaviours and obesity were independent of the effects of sociodemographic variables, leisure-time physical activity and diet.

RESULTS

Approximately one-quarter of men (25%) and women (24%) who reported watching television 21 or more hours per week were classified as obese. The prevalence of obesity was substantially lower for those who averaged 5 or fewer hours of television per week (14% of men and 11% of women). When examined in multivariate models controlling for leisure-time physical activity and diet, the associations between time spent watching television and obesity persisted for both sexes. Frequent computer users (11 or more hours per week) of both sexes had increased odds of obesity, compared with those who used computers for 5 or fewer hours per week. Time spent reading was not related to obesity.

Estimates of obesity based on self-report versus direct measures

OBJECTIVES

Based on a representative sample of the Canadian population, this article quantifies the bias resulting from the use of self-reported rather than directly measured height, weight and body mass index (BMI).

METHODS

The analysis is based on 4,567 respondents to the 2005 Canadian Community Health Survey (CCHS) who, during a face-to-face interview, provided self-reported values for height and weight and were then measured by trained interviewers.

RESULTS

On average, males over-reported their height by 1 cm, and females, by 0.5 cm. Females under-reported their weight by an average of 2.5 kg; males, by 1.8 kg. Reporting bias in weight was strongly associated with measured BMI category. Under-reporting of weight was high among people who were overweight, and particularly high among those who were obese, compared with people of normal weight. When based on measured rather than on self-reported values, the prevalence of obesity was 9 percentage points higher among males and 6 points higher among females.