E. M. F. van Sluijs

Associations between sedentary behaviour and physical activity in children and adolescents: a meta-analysis

Physical activity and sedentary behaviour are associated with metabolic and mental health during childhood and adolescence. Understanding the inter‐relationships between these behaviours will help to inform intervention design. This systematic review and meta‐analysis synthesized evidence from observational studies describing the association between sedentary behaviour and physical activity in young people (<18 years). English‐language publications up to August 2013 were located through electronic and manual searches. Included studies presented statistical associations between at least one measure of sedentary behaviour and one measure of physical activity. One hundred sixty‐three papers were included in the meta‐analysis, from which data on 254 independent samples was extracted. In the summary meta‐analytic model (k = 230), a small, but significant, negative association between sedentary behaviour and physical activity was observed (r = −0.108, 95% confidence interval [CI] = −0.128, −0.087). In moderator analyses, studies that recruited smaller samples (n < 100, r = −0.193, 95% CI = −0.276, −0.109) employed objective methods of measurement (objectively measured physical activity; r = −0.233, 95% CI = −0.330, −0.137) or were assessed to be of higher methodological quality (r = −0.176, 95% CI = −0.215, −0.138) reported stronger associations, although effect sizes remained small. The association between sedentary behaviour and physical activity in young people is negative, but small, suggesting that these behaviours do not directly displace one another.

Changes in Children's Physical Activity Over 12 Months: Longitudinal Results From the SPEEDY Study

OBJECTIVE: We measured physical activity changes among 10-year-old British children over 12 months and assessed biological and demographic determinants. METHODS: Physical activity was measured with accelerometers (counts per minute) over ≥3 days at baseline and 1 year later in a prospective study of 844 children (41.6% male; mean ± SD baseline age: 10.2 ± 0.3 years) from 92 schools. Meeting physical activity recommendations was defined as ≥60 minutes/day at ≥2000 counts per minute. Biological (height, weight, and fat percentage) and demographic factors (gender, rural/urban home location, and socioeconomic status) were assessed at baseline. Associations between physical activity changes and multiple factors were studied. RESULTS: Physical activity decreased over 1 year (baseline: 665.7 ± 209.8 counts per minute; follow-up: 623.2 ± 179.2 counts per minute; P < .001), with 70.4% of children meeting physical activity recommendations at the baseline evaluation and 65.8% at the follow-up evaluation (P < .001). The decrease occurred mainly on weekends (−47.2 ± 395.8 counts per minute; P = .002), with no significant change on weekdays (8.0 ± 201.6 counts per minute; P = .20). Girls (P < .001), participants with greater body fat percentage (P = .001), and participants of higher socioeconomic status (P = .008) were more likely to exhibit physical activity decreases. CONCLUSIONS: Physical activity decreased over 1 year among children in primary school, predominantly during the weekend. Because these children were relatively active at baseline, prevention of physical activity decreases in childhood, particularly among girls and on weekends, may be a suitable health promotion target.

Activity levels in mothers and their preschool children.

OBJECTIVES: To investigate the association between objectively measured maternal and preschool-aged children’s physical activity, determine how this association differs by demographic and temporal factors, and identify factors associated with maternal activity levels. METHODS: In the UK Southampton Women’s Survey, physical activity levels of 554 4-year-olds and their mothers were measured concurrently by using accelerometry for ≤7 days. Two-level mixed-effects linear regression was used to model the association between maternal and children’s minutes spent sedentary, in light (LPA) and moderate-to-vigorous physical activity (MVPA). Linear regression was used to investigate correlates of maternal activity. RESULTS: Mother-child daily activity levels were positively associated at all activity intensities (sedentary, LPA, and MVPA; all P < .001). The association for sedentary time was stronger for normal-weight children (versus those who were overweight/obese), and those attending preschool part-time (versus full-time). The mother-child association for LPA differed by maternal education and was stronger at the weekend (versus weekdays). The opposite was true for MVPA. Sedentary time and MVPA were most strongly associated in mornings, with LPA most strongly associated in the evenings. Maternal BMI, age leaving school, number and age of children at home, and working hours were independently associated with maternal daily sedentary time and LPA. CONCLUSIONS: Physical activity levels in mothers and their 4-year-old children are directly associated, with associations at different activity intensities influenced by temporal and demographic factors. Influences on maternal physical activity levels also differ by activity intensity. Providing targeted interventions for mothers of young children may increase both groups’ activity.

Family-based interventions to increase physical activity in children: a systematic review, meta-analysis and realist synthesis.

Family‐based interventions represent a potentially valuable route to increasing child physical activity (PA) in children. A dual meta‐analysis and realist synthesis approach examined existing interventions to assist those developing programmes to encourage uptake and maintenance of PA in children.

The school environment and adolescent physical activity and sedentary behaviour: a mixed-studies systematic review

There is increasing academic and policy interest in interventions aiming to promote young peoples health by ensuring that the school environment supports healthy behaviours. The purpose of this review was to summarize the current evidence on school‐based policy, physical and social‐environmental influences on adolescent physical activity and sedentary behaviour. Electronic databases were searched to identify studies that (1) involved healthy adolescents (11–18 years old), (2) investigated school‐environmental influences and (3) reported a physical activity and/or sedentary behaviour outcome or theme. Findings were synthesized using a non‐quantitative synthesis and thematic analysis. Ninety‐three papers of mixed methodological quality were included. A range of school‐based policy (e.g. break time length), physical (e.g. facilities) and social‐environmental (e.g. teacher behaviours) factors were associated with adolescent physical activity, with limited research on sedentary behaviour. The mixed‐studies synthesis revealed the importance of specific activity settings (type and location) and intramural sport opportunities for all students. Important physical education‐related factors were a mastery‐oriented motivational climate and autonomy supportive teaching behaviours. Qualitative evidence highlighted the influence of the wider school climate and shed light on complexities of the associations observed in the quantitative literature. This review identifies future research needs and discusses potential intervention approaches to be considered.

Breakfast consumption and physical activity in British adolescents

Studies show an inverse relationship between breakfast frequency and weight gain. This may reflect poor eating habits generally and associated low physical activity (PA) or direct impacts of breakfast on mechanisms leading to lethargy and reduced PA. The relationship between breakfast frequency and PA is inconclusive. We aimed to determine whether breakfast frequency is associated with PA levels in British adolescents independent of body composition and socio-economic status (SES). Habitual breakfast frequency (self-report questionnaire) was assessed in 877 adolescents (43% male, age 14·5 (SD 0·5) years old). PA was measured over 5 d (accelerometry, average counts/ min; cpm). Associations between daily PA and breakfast frequency were assessed using linear regression adjusted for body fat percentage and SES. Effect modification by sex and associations with PA during the morning (06.00-12.00 hours) were explored. For boys, there were no significant associations between breakfast frequency and PA. For girls, less frequent breakfast consumption was significantly associated with lower PA (cpm) during the morning (occasional v. frequent b - 6·1 (95% CI - 11·1, -1·1), P = 0·017) when adjusted for body fat percentage and SES. There were no associations between PA and breakfast consumption over the whole day; however, for girls, less frequent breakfast consumption may be associated with lower PA levels during the morning, suggesting that breakfast consumption should perhaps be taken into consideration when aiming to promote PA in adolescent girls.

Association between diet and physical activity and sedentary behaviours in 9–10-year-old British White children

Summary Objectives To examine the association between diet and physical activity and sedentary behaviours in 9–10-year-old children. Study design A cross-sectional study using data from the SPEEDY (Sport, Physical activity and Eating behaviour: Environmental Determinants in Young People) study undertaken in Norfolk, UK. Methods Data from 4-day food diaries and 7 days of accelerometery were matched on concurrent days. Time spent in moderate-to-vigorous physical activity (MVPA), time spent in sedentary behaviour and various measures of dietary intake were collected. Covariates included age, sex, weight status, family socio-economic status, and energy intake reporting quality. Multivariable regression models, adjusted for clustering of children by school and stratified by sex, were fitted to examine the associations between dietary measures and physical activity and sedentary outcomes. Results In total, 1317 children (584 boys and 733 girls) provided concurrent data. Boys in the highest quartile of energy percentage from protein spent approximately 6 min [95% confidence interval (CI) 0–12] less in MVPA compared with boys in the lowest quartile. Those in the highest quartiles of fruit and vegetable intake and fruit juice intake had respective average activity counts per minute that were 56 above (95% CI 8–105) and 48 below (95% CI 2–95) those in the lowest quartiles, whilst those in the highest quartile of fizzy drink consumption spent approximately 7 min (95% CI 2–13) more in MVPA and approximately 14 min (95% CI 5–24 min) less in sedentary behaviour. Boys in the highest quartile of savoury snack consumption spent approximately 8 min (95% CI 2–13 min) more in MVPA per day, and approximately 12 min (95% CI 2–23) less in sedentary behaviour. No significant associations were apparent among girls. Conclusions Few associations were detected, and the directions of those that were apparent were mainly counterintuitive. The extent to which this reflects a true lack of association or is associated with the measurement methods used for diet and physical activity needs further investigation.

Exploring equity in primary-care-based physical activity interventions using PROGRESS-Plus: a systematic review and evidence synthesis

BackgroundLittle is known about equity effects in primary care based physical activity interventions. This review explored whether differences in intervention effects are evident across indicators of social disadvantage, specified under the acronym PROGRESS-Plus (place of residence, race/ethnicity, occupation, gender, religion, education, social capital, socioeconomic status, plus age, disability and sexual orientation).MethodsSix bibliographic databases were systematically searched for randomised controlled trials (RCTs) of physical activity interventions conducted in primary care. Harvest plots were used to synthesize findings from RCTs reporting subgroup or interaction analyses examining differences in intervention effects across levels of at least one PROGRESS-Plus factor.ResultsThe search yielded 9052 articles, from which 173 eligible RCTs were identified. Despite PROGRESS-Plus factors being commonly measured (N = 171 RCTs), differential effect analyses were infrequently reported (N = 24 RCTs). Where reported, results of equity analyses suggest no differences in effect across levels or categories of place of residence (N = 1RCT), race (N = 4 RCTs), education (N = 3 RCTs), socioeconomic status (N = 3 RCTs), age (N = 16 RCTs) or disability (N = 2 RCTs). Mixed findings were observed for gender (N = 22 RCTs), with some interventions showing greater effect in men than women and others vice versa. Three RCTs examined indicators of social capital, with larger post-intervention differences in physical activity levels between trial arms found in those with higher baseline social support for exercise in one trial only. No RCTs examined differential effects by participant occupation, religion or sexual orientation.ConclusionThe majority of RCTs of physical activity interventions in primary care record sufficient information on PROGRESS-Plus factors to allow differential effects to be studied. However, very few actually report details of relevant analyses to determine which population subgroups may stand to benefit or be further disadvantaged by intervention efforts.

A systematic review of methods to measure family co-participation in physical activity: Family physical activity: Co-participation

The family environment is key in influencing childrens health behaviours. Encouraging family co‐participation in physical activity may therefore be an effective approach to increasing childrens physical activity levels. Yet, little is known about how to best assess family co‐participation in physical activity. This review summarizes methods to measure family co‐participation in physical activity, which was defined as joint physical activities including at least one healthy child (0–18 years) and one other family member. Methods were identified through a systematic literature search, cross‐referencing pre‐selected reviews and contacting research groups. Thirty‐seven measurement methods were included. Questionnaires were the most common method used, with the majority assessing frequency of co‐participation and few also assessing duration and type. Reliability and internal consistency of scales were often reported, but rarely specified for the item(s) relevant to co‐participation. Other methods of measuring co‐participation included diaries, event history calendars, direct observations and accelerometry combined with diary, ecological momentary assessment or global positioning systems (GPS). Whilst a large number of measurement methods of family co‐participation in physical activity exist, few are comprehensive and/or report acceptable psychometric properties. Future work should focus on reaching consensus in defining family co‐participation in physical activity, and subsequently developing reliable and valid measures.

A cumulative meta-analysis of the effects of individual physical activity interventions targeting healthy adults: A cumulative meta-analysis

Despite a large and increasing evidence base on physical activity interventions, the high rates of physical inactivity and associated chronic diseases are continuing to increase globally. The purpose of this cumulative meta‐analysis was to investigate the evolution of randomized controlled trial evidence of individual‐level physical activity interventions to asses if new trials are contributing novel evidence to the field. Through a two‐staged search process, primary studies examining the effects of interventions targeted at increasing physical activity within healthy adult populations were pooled and selected from eligible systematic reviews. Cumulative meta‐analyses were performed on effect sizes immediately post‐intervention (n = 62), and for long‐term behaviour change (≥12‐month post‐baseline; n = 27). Sufficiency and stability of the evidence was assessed through application of pre‐published indicators. Meta‐analyses suggest overall positive intervention effects on physical activity. The evidence base for effectiveness immediately post‐intervention reached levels of sufficiency and stability in 2007; and for long‐term follow‐up in 2011. In the time since, intervention effectiveness has not substantially changed, and further trials are unlikely to change the direction and magnitude of effect. Substantial evidence exists demonstrating that physical activity interventions can modify individual behaviour in controlled settings. Researchers are urged to shift focus towards investigating the optimization, implementation, sustainability and cost‐effectiveness of interventions.