Patterns of physical activity and sedentary behaviour and cardiovascular health in children

Introduction: Physical activity (PA) and sedentary behaviours are important modifiable risk factors for cardiovascular disease in adults; however, we know much less about their role for enhancing and sustaining children’s cardiovascular health. The aim of this thesis is to evaluate the relation between PA, sedentary time, and cardiovascular health in children. Methods: Participants were volunteers in a two-year randomized controlled dissemination trial of a whole school PA model (30 schools; 1,529 children). Activity intensity was measured via accelerometry (n=629), arterial compliance by applanation tonometry (n=250), and cardiovascular fitness (CVF) using a 20-meter shuttle run test (n=1,319). Results: In study 1, epoch length influenced the volume of activity recorded; however, the direction and magnitude of the bias depended on activity intensity and volume. In study 2, girls accumulated less moderate-to-vigorous PA (MVPA) and more sedentary time compared with boys, except during physical education. Fewer girls than boys met PA guidelines during school, recess, and lunch. Similarly few boys and girls (< 3%) met PA guidelines during physical education. In study 3, PA was beneficially associated with small, but not large, artery compliance. Bouted MVPA was not associated with small or large artery compliance. In study 4, activity was associated with CVF in children. However, the association between bouted MVPA and CVF was not independent of total MVPA. In study 5, girls and boys randomized to intervention schools had 31-37% greater CVF at the end of year one compared with children attending control schools; the magnitude was clinically relevant, but not statistically significant after adjusting for school clusters. There was no betweengroup difference across year two. Conclusions: Objective measures of activity improve the relation between PA and cardiovascular health thus future research should standardize methods and use accelerometers to assess children’s activity whenever possible. Children undertake little PA during school, particularly during physical education. Whole school PA interventions may enhance the cardiovascular health of children; however, generalist teachers require training and support for sustained effects. Long term prospective trials of activity (assessed by accelerometry) and targeted PA interventions that control for school clusters would fill a notable gap in the paediatric literature.Medicine, Faculty ofMedicine, Department ofExperimental Medicine, Division ofGraduat

Building organisational readiness for implementation in public health programs in community-based organisations for adults and/or older adults: a scoping review

Protocol for the scoping review of building organisational readiness for implementation in public health programs in community-based organisations for adults and/or older adult

Scaling up Action Schools! BC: How Does Voltage Drop at Scale Affect Student Level Outcomes? A Cluster Randomized Controlled Trial

Action Schools! BC (AS! BC) was scaled-up from an efficacy trial to province-wide delivery across 11 years (2004–2015). In this study we: (1) describe strategies that supported implementation and scale-up; (2) evaluate implementation (teachers’ physical activity (PA) delivery) and student’s PA and cardiorespiratory fitness (CRF) within a cluster randomized controlled trial during years 2 and 3 of scale-up; and (3) assess relationships between teacher-level implementation and student-level outcomes. We classified implementation strategies as process, capacity-building or scale-up strategies. Elementary schools (n = 30) were randomized to intervention (INT; 16 schools; 747 students) or usual practice (UP; 14 schools; 782 students). We measured teachers’ PA delivery (n = 179) using weekly logs; students’ PA by questionnaire (n = 30 schools) and accelerometry (n = 9 schools); and students’ CRF by 20-m shuttle run (n = 25 schools). INT teachers delivered more PA than UP teachers in year 1 (+33.8 min/week, 95% CI 12.7, 54.9) but not year 2 (+18.8 min/week, 95% CI −0.8, 38.3). Unadjusted change in CRF was 36% and 27% higher in INT girls and boys, respectively, compared with their UP peers (year 1; effect size 0.28–0.48). Total PA delivered was associated with change in children’s self-reported MVPA (year 1; r = 0.17, p = 0.02). Despite the ‘voltage drop’, scaling-up school-based PA models is feasible and may enhance children’s health. Stakeholders must conceive of new ways to effectively sustain scaled-up health promoting interventions if we are to improve the health of students at a population level. Clinical Trials registration: NCT01412203.Medicine, Faculty ofOther UBCNon UBCFamily Practice, Department ofOrthopaedic Surgery, Department ofReviewedFacult

“It makes me feel not so alone”: features of the Choose to Move physical activity intervention that reduce loneliness in older adults

Background: Despite the well-known health benefits of physical activity (PA), older adults are the least active citizens. Older adults are also at risk for loneliness. Given that lonely individuals are at risk for accelerated loss of physical functioning and health with age, PA interventions that aim to enhance social connectedness may decrease loneliness and increase long-term PA participation. The objectives of this mixed-method study are to: (1) evaluate whether an evidence-based PA intervention (Choose to Move; CTM) influenced PA and loneliness differently among self-identified ‘lonely’ versus ‘not lonely’ older adults and (2) to describe factors within CTM components most likely to promote social connectedness/reduce loneliness. Methods: CTM is a flexible, scalable, community-based health promoting physical activity intervention for older adults. Two community delivery partner organizations delivered 56 CTM programs in 26 urban locations across British Columbia. We collected survey data from participants (n = 458 at baseline) at 0 (baseline), 3 (mid-intervention) and 6 (post-intervention) months. We conducted in depth interviews with a subset of older adults to understand how CTM facilitated or impeded their PA and social connectedness. Results: PA increased significantly from baseline to 3 months in lonely and not lonely participants. PA decreased significantly from 3 to 6 months in lonely participants; however, PA at 6 months remained significantly above baseline levels in both groups. Loneliness decreased significantly from baseline to 3 and 6 months in participants identifying as lonely at baseline. Factors within CTM components that promote social connectedness/reduce loneliness include: Activity coach characteristics/personality traits and approaches; opportunity to share information and experiences and learn from others; engagement with others who share similar/familiar experiences; increased opportunity for meaningful interaction; and accountability. Conclusion: Health promoting interventions that focus on PA and social connectedness through group-based activities can effectively reduce social isolation and loneliness of older adults. Given the ‘epidemic of loneliness’ that plagues many countries currently, these kinds of interventions are timely and important. Research that further delineates mechanisms (e.g., sharing experiences vs. lectures), that modify the effect of an intervention on social connectedness outcomes for older adults engaged in community-based PA programs would be a welcome addition to the literature.Medicine, Faculty ofOther UBCFamily Practice, Department ofReviewedFacult

A systematic review of the evidence for Canada's Physical Activity Guidelines for Adults

This systematic review examines critically the scientific basis for Canada's Physical Activity Guide for Healthy Active Living for adults. Particular reference is given to the dose-response relationship between physical activity and premature all-cause mortality and seven chronic diseases (cardiovascular disease, stroke, hypertension, colon cancer, breast cancer, type 2 diabetes (diabetes mellitus) and osteoporosis). The strength of the relationship between physical activity and specific health outcomes is evaluated critically. Literature was obtained through searching electronic databases (e.g., MEDLINE, EMBASE), cross-referencing, and through the authors' knowledge of the area. For inclusion in our systematic review articles must have at least 3 levels of physical activity and the concomitant risk for each chronic disease. The quality of included studies was appraised using a modified Downs and Black tool. Through this search we identified a total of 254 articles that met the eligibility criteria related to premature all-cause mortality (N = 70), cardiovascular disease (N = 49), stroke (N = 25), hypertension (N = 12), colon cancer (N = 33), breast cancer (N = 43), type 2 diabetes (N = 20), and osteoporosis (N = 2). Overall, the current literature supports clearly the dose-response relationship between physical activity and the seven chronic conditions identified. Moreover, higher levels of physical activity reduce the risk for premature all-cause mortality. The current Canadian guidelines appear to be appropriate to reduce the risk for the seven chronic conditions identified above and all-cause mortality.Experimental Medicine, Division ofMedicine, Department ofMedicine, Faculty ofOther UBCReviewedFacult

Pragmatic evaluation of physical activity in older adults

We assessed convergent validity and responsiveness to change of the single item physical activity measure in adults aged 60 years and older at baseline (n=205) and 6 months (n=177) of Choose to Move, a health promotion program. We used Spearman correlations to examine associations between physical activity as measured by the single item measure and CHAMPS questionnaire at baseline and for 6-month change in all participants, and sex and age (60-74 years, > 75 years) subgroups. We used effect size to assess responsiveness to change in physical activity for both tools. Baseline physical activity by the single-item measure correlated moderately with CHAMPS physical activity in all participants, and subgroups. Correlations were weaker for change in physical activity. Effect size for physical activity change was larger for the single-item measure than CHAMPS. The single-item measure is a valid, pragmatic tool for use in intervention and scale-up studies with older adults.Medicine, Faculty ofNon UBCFamily Practice, Department ofReviewedFacultyResearche

Status Quo or Drop-Off : Do Older Adults Maintain Benefits From Choose to Move—A Scaled-Up Physical Activity Program—12 Months After Withdrawing the Intervention?

Background: Choose to Move (CTM) is one of few scaled-up health-promoting interventions for older adults. We evaluated whether CTM participants maintained their intervention-related gains in physical activity (PA), mobility and social connectedness 12 months after the intervention ended. Methods: We assessed PA, mobility, loneliness, social isolation and muscle strength via questionnaire and objective measures in 235 older adults at baseline, 6-months (end of intervention) and 18-months (12-months post-intervention). We fitted linear mixed models to examine change in each outcome from 6 to 18 months (primary objective) and 0 to 18 months (secondary objective) and report by age group (60-74; 75+ yrs). Results: In younger participants, PA decreased between 6- and 18-months but remained significantly higher than at baseline. Intervention-related benefits in loneliness, social isolation, mobility and muscle strength were maintained between 6 and 18 months in younger participants. Older participants maintained their intervention benefits in loneliness, mobility and muscle strength. When compared with baseline, PA levels in older participants were unchanged whereas social isolation increased. Conclusions: Older adults maintained some, but not all, health benefits of CTM 12 months after the intervention ended. Long-term commitments are needed to deliver effective health-promoting interventions for older adults--if benefits are to be maintained.Education, Faculty ofKinesiology, School ofMedicine, Faculty ofFamily Practice, Department ofOrthopaedics, Department ofNon UBCReviewedFacultyResearche

Influence of Physical Activity on Bone Strength in Children and Adolescents: A Systematic Review and Narrative Synthesis

A preponderance of evidence from systematic reviews supports the effectiveness of weight‐bearing exercises on bone mass accrual, especially during the growing years. However, only one systematic review (limited to randomized controlled trials) examined the role of physical activity (PA) on bone strength. Thus, our systematic review extended the scope of the previous review by including all PA intervention and observational studies, including organized sports participation studies, with child or adolescent bone strength as the main outcome. We also sought to discern the skeletal elements (eg, mass, structure, density) that accompanied significant bone strength changes. Our electronic‐database, forward, and reference searches yielded 14 intervention and 23 observational studies that met our inclusion criteria. We used the Effective Public Health Practice Project (EPHPP) tool to assess the quality of studies. Due to heterogeneity across studies, we adopted a narrative synthesis for our analysis and found that bone strength adaptations to PA were related to maturity level, sex, and study quality. Three (of five) weight‐bearing PA intervention studies with a strong rating reported significantly greater gains in bone strength for the intervention group (3% to 4%) compared with only three significant (of nine) moderate intervention studies. Changes in bone structure (eg, bone cross‐sectional area, cortical thickness, alone or in combination) rather than bone mass most often accompanied significant bone strength outcomes. Prepuberty and peripuberty may be the most opportune time for boys and girls to enhance bone strength through PA, although this finding is tempered by the few available studies in more mature groups. Despite the central role that muscle plays in bones’ response to loading, few studies discerned the specific contribution of muscle function (or surrogates) to bone strength. Although not the focus of the current review, this seems an important consideration for future studies. © 2014 American Society for Bone and Mineral Research

Reexamining the surfaces of bone in boys and girls during adolescent growth: A 12-Year mixed longitudinal pQCT Study

We revisit Stanley Garn's theory related to sex differences in endocortical and periosteal apposition during adolescence using a 12-year mixed longitudinal study design. We used peripheral quantitative computed tomography to examine bone parameters in 230 participants (110 boys, 120 girls; aged 11.0 years at baseline). We assessed total (Tt.Ar, mm2), cortical (Ct.Ar, mm2), and medullary canal area (Me.Ar, mm2), Ct.Ar/Tt.Ar, cortical bone mineral density (Ct.BMD, mg/cm3), and polar strength-strain index (SSIp, mm3) at the tibial midshaft (50% site). We used annual measures of height and chronological age to identify age at peak height velocity (APHV) for each participant. We compared annual accrual rates of bone parameters between boys and girls, aligned on APHV using a linear mixed effects model. At APHV, boys demonstrated greater Tt.Ar (ratio = 1.27; 95% confidence interval [CI] 1.21, 1.32), Ct.Ar (1.24 [1.18, 1.30]), Me.Ar (1.31 [1.22, 1.40]), and SSIp (1.36 [1.28, 1.45]) and less Ct.Ar/Tt.Ar (0.98 [0.96, 1.00]) and Ct.BMD (0.97 [0.96, 0.97]) compared with girls. Boys and girls demonstrated periosteal bone formation and net bone loss at the endocortical surface. Compared with girls, boys demonstrated greater annual accrual rates pre-APHV for Tt.Ar (1.18 [1.02, 1.34]) and Me.Ar (1.34 [1.11, 1.57]), lower annual accrual rates pre-APHV for Ct.Ar/Tt.Ar (0.56 [0.29, 0.83]) and Ct.BMD (–0.07 [–0.17, 0.04]), and similar annual accrual rates pre-APHV for Ct.Ar (1.10 [0.94, 1.26]) and SSIp (1.14 [0.98, 1.30]). Post-APHV, boys demonstrated similar annual accrual rates for Ct.Ar/Tt.Ar (1.01 [0.71, 1.31]) and greater annual accrual rates for all other bone parameters compared with girls (ratio = 1.23 to 2.63; 95% CI 1.11 to 3.45). Our findings support those of Garn and others of accelerated periosteal apposition during adolescence, more evident in boys than girls. However, our findings challenge the notion of greater endocortical apposition in girls, suggesting instead that girls experience diminished endocortical resorption compared with boy