Tracie A. Barnett

A comprehensive view of sex-specific issues related to cardiovascular disease

Cardiovascular disease (CVD) is the leading cause of mortality in women. In fact, CVD is responsible for a third of all deaths of women worldwide and half of all deaths of women over 50 years of age in developing countries. The prevalence of CVD risk factor precursors is increasing in children. Retrospective analyses suggest that there are some clinically relevant differences between women and men in terms of prevalence, presentation, management and outcomes of the disease, but little is known about why CVD affects women and men differently. For instance, women with diabetes have a significantly higher CVD mortality rate than men with diabetes. Similarly, women with atrial fibrillation are at greater risk of stroke than men with atrial fibrillation. Historically, women have been underrepresented in clinical trials. The lack of good trial evidence concerning sex-specific outcomes has led to assumptions about CVD treatment in women, which in turn may have resulted in inadequate diagnoses and suboptimal management, greatly affecting outcomes. This knowledge gap may also explain why cardiovascular health in women is not improving as fast as that of men. Over the last decades, mortality rates in men have steadily declined, while those in women remained stable. It is also becoming increasingly evident that gender differences in cultural, behavioural, psychosocial and socioeconomic status are responsible, to various degrees, for the observed differences between women and men. However, the interaction between sex-and gender-related factors and CVD outcomes in women remains largely unknown.

Toward the next generation of research into small area effects on health: a synthesis of multilevel investigations published since July 1998

To map out area effects on health research, this study had the following aims: (1) to inventory multilevel investigations of area effects on self rated health, cardiovascular diseases and risk factors, and mortality among adults; (2) to describe and critically discuss methodological approaches employed and results observed; and (3) to formulate selected recommendations for advancing the study of area effects on health. Overall, 86 studies were inventoried. Although several innovative methodological approaches and analytical designs were found, small areas are most often operationalised using administrative and statistical spatial units. Most studies used indicators of area socioeconomic status derived from censuses, and few provided information on the validity and reliability of measures of exposures. A consistent finding was that a significant portion of the variation in health is associated with area context independently of individual characteristics. Area effects on health, although significant in most studies, often depend on the health outcome studied, the measure of area exposure used, and the spatial scale at which associations are examined.

Do you see what I see? Weight status misperception and exposure to obesity among children and adolescents

Objective:Obesity prevention in childhood is important. However, changing childrens lifestyle behaviors to reduce overweight is a substantial challenge. Accurately perceiving oneself as overweight/obese has been linked to greater motivation to change lifestyle behaviors. Children and adolescents may be less likely to perceive themselves as overweight/obese if they are exposed to overweight/obese people in their immediate environments. This study examined whether youth who are exposed to overweight parents and schoolmates were more likely to misperceive their own weight status.Design:The Quebec Child and Adolescent Health and Social Survey was a provincially representative, school-based survey of children and adolescents conducted between January and May 1999.Subjects:3665 children and adolescents (age 9, n=1267; age 13, n=1186; age 16, n=1212) from 178 schools. Mean body mass index (BMI) was 17.5, 20.6 and 22.2 kg/m2, respectively.Measurements:The misperception score was calculated as the standardized difference between self-perception of weight status (Stunkard Body Rating Scale) and actual BMI (from measured height and weight). Exposure to obesity was based on parent and schoolmate BMI.Results:Overweight and obese youth were significantly more likely to misperceive their weight compared with non-overweight youth (P<0.001). Multilevel modeling indicated that greater parent and schoolmate BMI were significantly associated with greater misperception (underestimation) of weight status among children and adolescents.Conclusion:Children and adolescents who live in environments in which people they see on a daily basis, such as parents and schoolmates, are overweight/obese may develop inaccurate perceptions of what constitutes appropriate weight status. Targeting misperception may facilitate the adoption of healthy lifestyle behaviors and improve the effectiveness of obesity prevention interventions.

Prevalence and Correlates of Physical Activity Behaviors among Elementary Schoolchildren in Multiethnic, Low Income, Inner-City Neighborhoods in Montreal, Canada

PURPOSE To describe the prevalence and correlates of physical inactivity and of participation in organized sports at and outside school among elementary schoolchildren in multiethnic, low income, urban neighborhoods in Montreal, Canada. METHODS As part of the evaluation of a school-based heart health promotion program, baseline data on physical activity behaviors and potential correlates of these behaviors, were collected from 2285 students aged 9-13 in all 130 grade 4 to 6 classes in 24 inner-city elementary schools from May to June 1993. RESULTS One-fifth of boys (20.5%) and 24.4% of girls were inactive; 40.0% and 33.3% of boys and girls respectively, participated in school sports teams; 82.5% and 74.7% participated in organized sports outside school. Declines in activity levels with age were apparent in both genders. Children who participated in organized sports programs at and outside school, those with higher perceived self-efficacy for physical activity, and those with more parental support for engaging in physical activity were more active. Children of Asian family origin were less active. Socioeconomic status was related to participation in organized sports outside school. CONCLUSIONS To reach children in socio-economically disadvantaged areas and to prevent age-related declines in activity levels, interventions promoting physical activity should focus on increasing availability and access to community-based organized sports programs at and outside school. Also they should include components to increase parental support and to improve perceived self-efficacy for physical activity.

Prospective Associations Between Early Childhood Television Exposure and Academic, Psychosocial, and Physical Well-being by Middle Childhood

OBJECTIVE To estimate the influence of early childhood television exposure on fourth-grade academic, psychosocial, and lifestyle characteristics. DESIGN Prospective longitudinal study. SETTING Institut de la Statistique du Québec, Québec, Canada. PARTICIPANTS A total of 1314 (of 2120) children. Main Exposure Parent-reported data on weekly hours of television exposure at 29 and 53 months of age. We conducted a series of ordinary least-squares regressions in which childrens academic, psychosocial, and lifestyle characteristics are linearly regressed on early and preschool television exposure. OUTCOME MEASURES Parent and teacher reports of academic, psychosocial, and health behaviors and body mass index measurements (calculated as weight in kilograms divided by height in meters squared) at 10 years of age. RESULTS Adjusting for preexisting individual and family factors, every additional hour of television exposure at 29 months corresponded to 7% and 6% unit decreases in classroom engagement (95% confidence interval [CI], -0.02 to -0.004) and math achievement (95% CI, -0.03 to 0.01), respectively; 10% unit increases in victimization by classmates (95% CI, 0.01 to 0.05); 13% unit decreases in time spent doing weekend physical activity (95% CI, 0.81 to 2.25); 9% unit decreases in activities involving physical effort (95% CI, -0.04 to 0.00); higher consumption scores for soft drinks and snacks by 9% and 10% (95% CI, 0.00 to 0.04 and 95% CI, 0.00 to 0.02), respectively; and 5% unit increases in body mass index (95% CI, 0.01 to 0.05). Preschool increments in exposure also made a unique contribution to developmental risk. CONCLUSIONS The long-term risks associated with higher levels of early exposure may chart developmental pathways toward unhealthy dispositions in adolescence. A population-level understanding of such risks remains essential for promoting child development.

One- and Two-Year Predictors of Decline in Physical Activity Among Inner-City Schoolchildren

BACKGROUND Alarming secular declines in physical activity (PA) have been observed among youth over the last decade. A better understanding of the predictors of these declines is crucial to identifying those children most at risk and to developing interventions that target youth before the onset of decline. This report identifies 1- and 2-year predictors of decline in PA among fourth- and fifth-grade students from inner-city neighborhoods in Montreal, Canada. METHODS Data for this study were collected in classroom questionnaires each May/June from 1993 to 1997. Analyses for this paper were completed in 2001. The cohort included active (at least one PA per day) children with baseline and 1-year (n =1873) or 2-year (n =509) follow-up data. RESULTS In boys, 1-year predictors of decline to an inactive status identified in generalized estimating equations analysis included moderate (vs high) baseline PA (odds ratio [OR]=1.66, 95% confidence interval [CI]=0.91-3.05); low PA self-efficacy (OR=1.67, 95% CI=1.03-2.71); born outside Canada (OR=2.13; 95% CI=1.31-3.46); Asian origin (OR=1.81; 95% CI=1.03-3.16) and no participation in school teams (OR=1.81, 95% CI=0.93-3.55). In girls, these 1-year predictors included moderate PA (OR=1.91, 95% CI=1.10-3.32); low PA self-efficacy (OR=1.70, 95% CI=1.15-2.49); watching four or more TV programs per day (OR=1.40, 95% CI=0.97-2.02); mother unemployed (OR=1.54, 95% CI=1.07-2.23); and grade five (vs grade four) (OR=1.35, 95% CI=0.94-1.93). Two-year predictors in boys included moderate baseline PA (OR=2.52, 95% CI=0.84-7.50), and born outside Canada (OR=1.96, 95% CI=0.91-4.20). In girls, these 2-year predictors included moderate baseline PA (OR=2.75, 95% CI=1.01-7.49); no participation in school teams (OR=2.14, 95% CI=0.92-5.00); watching four or more TV programs per day (OR=1.93, 95% CI=0.99-3.74); and born outside Canada (OR=1.85, 95% CI=0.96-3.55). CONCLUSIONS Reduced TV viewing among girls and increased participation in school sports teams in boys and girls may prevent declines in PA among pre-adolescents from inner-city neighborhoods.

Association between Neighborhood Active Living Potential and Walking

This paper examines the association between neighborhood active living potential and walking among middle-aged and older adults. A sample of 2,614 (61.1% women) persons aged 45 years or older and living in one of 112 census tracts in Montreal, Canada, were recruited between February and May of 2005 to participate in a 20-minute telephone survey. Data were linked to observational data on neighborhood active living potential in the 112 census tracts and analyzed through multilevel modeling. Greater density of destinations in the census tract was associated with greater likelihoods of walking for any reason at least 5 days per week for at least 30 minutes (odds ratio = 1.53, 95% confidence interval: 1.21, 1.94). Associations were attenuated but remained statistically significant after controlling for socioeconomic, health, lifestyle, and other physical activity characteristics. Sensitivity analyses showed that associations were robust across smaller and larger volumes of walking. No associations were found between dimensions of neighborhood active living potential and walking for recreational reasons. The authors conclude that a larger number and variety of neighborhood destinations in ones residential environment are associated with more walking and possibly more utilitarian walking among middle-aged or older adults.

Prevalence of cardiometabolic risk factors by weight status in a population-based sample of Quebec children and adolescents

BACKGROUND There are few data on the prevalence of cardiometabolic risk factors in population-based samples of overweight and obese youth. OBJECTIVES To compare the prevalence of individual and multiple cardiometabolic risk factors across body mass index (BMI) categories in a population-based sample of youth. METHODS In 1999, a school-based survey of a provincially representative sample of youth nine, 13 and 16 years of age was conducted in Quebec (1778 boys, 1835 girls). Overweight was defined as BMI in the 85th percentile or higher and lower than the 95th percentile of the Centers for Disease Control and Prevention 2000 growth charts, and obesity was defined as BMI in the 95th percentile or higher. Levels of total cholesterol, low-density lipoprotein cholesterol, apolipoprotein B, high-density lipoprotein cholesterol, triglycerides, insulin, glucose, C-reactive protein and systolic blood pressure were categorized as desirable, borderline or unfavourable. RESULTS The proportions of overweight and obese participants were 14% and 10% in boys, and 14% and 7% in girls, respectively. With the exception of total cholesterol and low-density lipoprotein cholesterol in girls, and glucose in both sexes, the prevalence of all investigated risk factors (borderline or unfavourable) was significantly higher among overweight and obese participants. Almost one-third of obese participants had unfavourable levels of at least two of seven risk factors (apolipoprotein B, high-density lipoprotein cholesterol, triglycerides, insulin, glucose, C-reactive protein and systolic blood pressure) compared with 3% of normal weight participants (adjusted OR 15 and 18 in boys and girls, respectively). Thirty-four per cent of obese youth did not have unfavourable levels of any risk factor. CONCLUSION There is marked heterogeneity in the association between excess weight and cardiometabolic risk factors. Nonetheless, the present study highlights a high prevalence of multiple risk factors in a population-based sample of overweight and obese youth.

Distinct trajectories of leisure time physical activity and predictors of trajectory class membership: a 22 year cohort study

BackgroundProspective studies linking social factors to long term patterns of physical activity are lacking. In this 22 year longitudinal study, we seek to identify long term patterns of involvement in leisure time physical activity (LTPA), and explore socioeconomic and demographic predictors of distinct LTPA trajectories.MethodsAmong 2102 individuals aged 18–60 years in 1981 who participated in the 1981 Canada Fitness Survey/1988 Campbells Survey of Well-Being, 1186 (56.4%) completed questionnaires for the 2002/04 follow-up. Complete data on LTPA at all 3 surveys were available for 884 participants. Latent class growth analysis was used to identify major classes of LTPA trajectories; predictors of class membership were identified using polytomous logistic regression.ResultsFour latent classes were identified: inactive, increasers, active, and decreasers (53%, 26%, 12%, and 9% of participants, respectively). Women, older participants, those with lower household income, and with lower educational attainment, were significantly less likely to follow active (Vs. inactive) trajectories of LTPA. Disadvantaged groups with respect to education and income were also significantly more likely to follow decreasing (Vs. active) trajectories.ConclusionThere is a need for continued efforts to increase overall population levels of LTPA, particularly among socially disadvantaged groups with respect to income and education, who are most likely to experience unfavorable trajectories of LTPA.

Opportunities for Student Physical Activity in Elementary Schools: A Cross-Sectional Survey of Frequency and Correlates

The objectives of this study were to describe opportunities for student physical activity (PA) in elementary schools and to identify factors in the school environment associated with higher PA opportunity. Self-report questionnaires were completed by school principals and physical education teachers in 277 schools (88% response) in metropolitan Montreal. Correlates of opportunity were identified using ordinal logistic regression. There was substantial variation in PA opportunities between schools. Higher opportunity was associated with role modeling of PA by school principals, their interest in increasing PA through links to the municipality, adequate financial and human resources, access to school sports facilities, adequate space for storing student sports equipment, and suburban location. There is both the need and the potential for intervention to increase PAopportunities in elementary schools. Addressing barriers related to resources and access to sports facilities may help reduce disparities between schools in opportunities for students to engage in PA.