Relationship between a range of sedentary behaviours and blood pressure during early adolescence

Seated Elliptical Exercise, But Not Periodic Standing, Alleviates Sitting-Induced Changes to Arterial Wave Reflections

PURPOSE

Sedentary behavior may contribute to increased central wave reflection due to associated peripheral vasoconstriction, yet its impact on central hemodynamics and the mitigating effects of interventional strategies have not been thoroughly investigated. We tested whether standing or seated elliptical breaks alleviate the deleterious effects of prolonged sitting on central wave reflections.

METHODS

Eighteen healthy adults (9 9 females, 25 ± 3 yr) completed three 3-h protocols on separate days: uninterrupted sitting, sitting with periodic standing, and sitting with periodic seated elliptical activity. Central wave reflection, central pulse wave velocity, and lower-limb pulse wave velocity were measured before and after each intervention.

RESULTS

Central relative wave reflection magnitude (RM) increased during sitting (0.31 ± 0.05 to 0.35 ± 0.05; P < 0.01) but did not change after standing (0.30 ± 0.05 to 0.32 ± 0.04; P = 0.19) or elliptical protocols (0.30 ± 0.05 to 0.30 ± 0.04; P > 0.99). The change in RM during prolonged sitting (ΔRM) was attenuated with elliptical activity (0.04 ± 0.05 vs 0.00 ± 0.03; P = 0.02) but not with periodic standing (0.04 ± 0.04 vs 0.02 ± 0.05; P = 0.54). In addition, augmentation index and central pulse wave velocity increased after sitting (both P < 0.01) and periodic standing (both P < 0.01) but were unchanged after elliptical activity. Lower limb pulse wave velocity did not change after sitting ( P = 0.73) or standing ( P = 0.21) but did decrease after elliptical activity ( P = 0.03).

CONCLUSIONS

Prolonged sitting without interruptions increased central wave reflection, whereas elliptical but not standing interruptions were able to ameliorate multiple sitting-induced vascular consequences. More work is required to examine the long-term effectiveness of interruption strategies, as well as the optimal type, frequency, and duration for reducing vascular risk associated with sedentary behaviors.

Physical activity and eating behaviors patterns associated with high blood pressure among Chinese children and adolescents

BACKGROUND

Physical activity and eating behavior are associated with hypertension in children and adolescents. Revealing the associations between physical activity patterns, eating behavior patterns and high blood pressure (HBP) could help improve the problem of hypertension from the actual children's physical activities and eating behaviors.

METHODS

A total of 687 students aged 8-15 years were selected from two nine-year primary and secondary schools using stratified cluster random sampling method. The students' body height, weight, systolic blood pressure (SBP) and diastolic blood pressure (DBP) were measured, and their physical activity time and eating behaviors were surveyed by using CLASS questionnaire and self-made eating behavior questionnaire, respectively. Exploratory factor analysis (EFA) was used to extract moderate to vigorous physical activity factor (MVPAF), sedentary activity factor (SAF), healthy eating behavior factor (HEBF), unhealthy eating behavior factor (UHEBF). MVPAF ≥ SAF was defined as moderate to vigorous physical activity pattern (MVPAP), MVPAF < SAF was defined as sedentary activity pattern (SAP). HEBF ≥ UHEBF was defined as healthy eating behavior pattern (HEBP), while the opposite was defined as unhealthy eating behavior pattern (UHEBP). Lifestyles includes physical activity patterns and eating behavior patterns.

RESULTS

The overall prevalence of hypertension was 5.8% (40/687), and was 5.69% (21/369) in boys and 5.97% (19/318) in girls, respectively. The MVPAF and UHEBF in boys were significantly higher than those in girls (P < 0.01), while the SAF in girls was significantly higher than that in boys (P < 0.05). The SAF was positively correlated with SBP in girls (β(SE) = 0.14 (0.50), P = 0.016), and was positively correlated with SBP (β(SE) = 0.21 (1.22), P = 0.000 and DBP (β(SE) = 0.14 (0.49), P = 0.006) in boys. The MVPAF was negatively correlated with DBP (β(SE)=-0.11 (0.40), P = 0.022) in boys. In boys, the SAP increased the risks of HBP (OR (95% CI):3.34 (1.30-8.63)) and high DBP (OR (95% CI):3.08 (1.02-9.34)) compared with MVPAP.

CONCLUSION

Compared with the boys with MVPAP, boys with SAP may increase the risks of HBP and high DBP. The SAF may be positively associated with SBP in boys and girls, while the MVPAF may be negatively associated with DBP in boys.

A Cross-Sectional Investigation of Preadolescent Cardiometabolic Health: Associations with Fitness, Physical Activity, Sedentary Behavior, Nutrition, and Sleep

BACKGROUND

Cardiometabolic disease (CMD) risk often begins early in life. Healthy lifestyle behaviors can mitigate risk, but the optimal combination of behaviors has not been determined. This cross-sectional study simultaneously examined the associations between lifestyle factors (fitness, activity behaviors, and dietary patterns) and CMD risk in preadolescent children.

METHODS

1480 New Zealand children aged 8-10 years were recruited. Participants included 316 preadolescents (50% female, age: 9.5 ± 1.1 years, BMI: 17.9 ± 3.3 kg/m²). Fitness (cardiorespiratory fitness [CRF], muscular fitness), activity behaviors (physical activity, sedentary, sleep), and dietary patterns were measured. Factor analysis was used to derive a CMD risk score from 13 variables (adiposity, peripheral and central hemodynamics, glycemic control, and blood lipids).

RESULTS

Only CRF (β = -0.45, p < 0.001) and sedentary time (β = 0.12, p = 0.019) were associated with the CMD risk score in the adjusted multivariable analysis. CRF was found to be nonlinear (VO₂ max ≤ ≈42 mL/kg/min associated with higher CMD risk score), and thus a CRF polynomial term was added, which was also associated (β = 0.19, p < 0.001) with the CMD risk score. Significant associations were not found with sleep or dietary variables.

CONCLUSION

The findings indicate that increasing CRF and decreasing sedentary behavior may be important public health targets in preadolescent children.

The impact of screen exposure on attention abilities in young children: a systematic review

BACKGROUND

The neurocognitive consequences of exposure to screens in school-aged children have been the subject of multiple studies. However, the relationship between screen exposure and neurocognitive development, especially attentional functions, remains unclear in preschool children. The aim of this systematic review was to evaluate the immediate and long-term impact of screen exposure on attentional functions in preschoolers.

METHODS

Three electronic databases (PubMed, COCHRANE, and SCOPUS) were searched for studies published between January 1, 2000, and November 30, 2020. Two reviewers independently selected studies. Inclusion criteria were observational studies, inclusion of children aged less than seven years with no neurodevelopmental disorders, evaluation of screen time, and evaluation of attentional functions. Data extracted including participants' ages, number of participants, screen exposure time, attention assessment tool, and confounding factors. Study quality was evaluated using the Newcastle-Ottawa Scale.

RESULTS

Five cross-sectional studies were included: all reported significant, positive associations between high levels of screen exposure and attention difficulties. Ten longitudinal studies were included: six found a significant impact of earlier screen exposure on subsequent attentional function and four found no relationship. Eight of the studies included evaluated the direction of the relationship between screen exposure and attentional difficulties: seven suggested the relationship is bidirectional.

CONCLUSIONS

These findings support current guidelines to limit screen time in preschoolers to prevent the development of attention difficulties.

Enabling Better Physical Activity and Screen Time Behaviours for Adolescents from Middle Eastern Backgrounds: Semi-Structured Interviews with Parents

The unrelenting obesity pandemic in Middle Eastern (ME) adolescents living in Australia warrants culturally responsive and locally engineered interventions. Given the influence of parents on the lifestyle behaviours of adolescents, this qualitative study aimed to capture the opinions of ME parents on the barriers and enablers to sufficient physical activity and limiting screen time behaviours in adolescents. Semi-structured interviews were conducted with 26 ME parents (female) aged 35–59 years old, most of whom resided in lower socioeconomic areas (n = 19). A reflexive thematic analysis using the Theoretical Domains Framework and the Capability, Opportunity, Motivation-Behaviour model was performed for coding. Parents voiced confidence in their knowledge of the importance of physical activity and limiting screen time but were less optimistic in their ability to enable change in behaviours, especially for older adolescents without outside support. Despite adolescents having the necessary skills to engage in a wide array of sports, the parents admitted deep fears regarding the safety of the social environment and restricted their children’s independent mobility. Gender differences were noted, with parents reporting older girls expressing disinterest in sports and having limited physical opportunities to participate in sports at school. It may be that a community-based participatory framework is needed to improve physical activity opportunities and to address specific physical, social, and cultural barriers.

Gender Differences in The Factors associated with Hypertension in Non-Diabetic Saudi Adults-A Cross-Sectional Study

The association between lifestyle practices, obesity and increased BP are under-investigated. We aimed to investigate this association to identify the factors associated with hypertension and prehypertension in Saudis. Non-diabetic adults were recruited from public healthcare centers using a cross-sectional design. Recruits were interviewed using a predesigned questionnaire. Weight, height, waist circumference (WC), hip circumference (HC), neck circumference (NC) and BP were measured. The variables were analyzed by comparing the prehypertensive and hypertensive groups with the normotensive group. A total of 1334 adults were included. The study found that 47.2% of men and 24.7% of women were prehypertensive, and 15.1% of men and 14.4% of women were hypertensive. High BMI, WC, NC, and WC: HC ratios were associated with an increased risk of prehypertension and hypertension in men and women. Low physical activity was associated with an increased risk of elevated BP in men, while sleep duration of ≤6 h and sitting for ≥4 h were associated with increased risk in women. Women from central Asia, southeast Asia, and those of mixed origin had a higher prevalence of hypertension compared to those from Arabian tribes. In conclusion, prehypertension and hypertension increase with age and obesity. Gender differences were apparent in the association between several lifestyle practices and prehypertension or hypertension among various ethnic/racial groups.

Urban greenery cushions the decrease in leisure-time physical activity during the COVID-19 pandemic: A natural experimental study

The coronavirus disease 2019 (COVID-19) pandemic and related social distancing measures have altered the daily lifestyles of people worldwide. Although studies on this disease are emerging rapidly, less is known about the impacts of COVID-19 and urban greenery on leisure-time physical activity, which is critical to maintain health for urban residents during the pandemic. In this study, we used a natural experimental research design to identify whether urban greenery cushions the decrease in leisure-time physical activity caused by the pandemic and related social distancing measures in a high-density city. The two-wave physical activity data (before and during the pandemic) were collected for urban residents in neighborhoods with high or low levels of greenery. The results of difference-in-differences model suggest that urban greenery mitigated the decrease in physical activity during the pandemic. People who lived in greener neighborhoods experienced a lesser decrease in the leisure-time physical activity level than those who lived in less green neighborhoods. Additionally, people who lived in greener neighborhoods experienced increased levels of physical activity related to visits to country parks during the pandemic. These findings suggest that urban green spaces play a significant role in shaping physical activity and providing a refuge for the public during crises. Our study is among the first to investigate the impact of urban greenery on pandemic-induced changes in leisure-time physical activity in densely populated Asian cities, and our findings shed light on the potential protective role of urban greenery on public health during the COVID-19 pandemic and beyond.

Physical Activity, Sedentary Behavior and Sleep Time:Association with Cardiovascular Hemodynamic Parameters, Blood Pressure and Structural and Functional Arterial Properties in Childhood

An association between movement behavior (MB) components (sleep time (ST), physical activity (PA) and sedentary behavior (SB)) and the state of the cardiovascular (CV) system in children has been postulated. However, it is still controversial whether MB components and/or sub-components (domains) during childhood are independently associated with aortic and peripheral blood pressure (BP), and structural or functional arterial properties. Aims: (1) to evaluate MB components and subcomponents associations with CV characteristics, (2) to analyze the explanatory capacity of interindividual variations in MB on CV properties inter-individual variations at the beginning of school age. Methods: Anthropometric, aortic and peripheral BP, hemodynamic levels (cardiac output, systemic vascular resistances), wave reflection indexes, and arterial structural (diameter, intima–media thickness) and functional (blood flow velocities, Doppler-indexes, local and regional arterial stiffness) parameters of elastic (carotids), transitional (brachial) and muscular (femoral) arteries and time spent in MB (PA questionnaires) were assessed in 816 children (5–6 years). Cardiovascular variables were standardized (z-scores), using age- and sex-related mean values and standard deviations obtained from subjects non-exposed to CV risk factors (CRFs) and who complied with 24 h MB recommendations (reference subgroup). Multiple linear regression models were constructed considering the CV z-scores as dependent variables and CRFs and MB components and subcomponents as independent variables. Results: CV variables showed independent association with MB variations. However, their explanatory capacity on CV characteristics was lesser than that of anthropometric indexes, sex and/or high BP. Conclusions: MB components and sub-components were associated with CV characteristics regardless of other factors, but their capacity to explain variations was lesser than that of anthropometric data, sex or high BP state. MB subcomponents (e.g., sedentary play and screen time in case of SB) showed different (even opposite) associations with CV parameters. ST was associated mainly with indexes of the ventricle ejective function, rather than with CV structural characteristics. SB component and subcomponents were associated with BP, but not with structural parameters. PA component and subcomponents were associated with both BP and structural parameters. The different arterial types, as well central and peripheral parameters showed independent associations with MB components and subcomponents. None of these were independently associated with arterial stiffness.

Factors Associated with Primary Hypertension in Pediatric Patients: An Up-to-Date

BACKGROUND

Arterial hypertension in children is considered a common alteration nowadays, mainly because obesity is a growing worldwide problem closely related to increased blood pressure. Childhood hypertension can be classified as primary or secondary, depending on the etiology. Primary or essential hypertension still has its pathophysiology not fully elucidated, and there is no consensus in the literature on most underlying mechanisms. In this review, genetic and environmental factors, including sodium and potassium intake, socioeconomic status, ethnicity, family structure, obesity, sedentary lifestyle, prematurity and low birth weight, prenatal and postnatal exposures are highlighted.

OBJECTIVE

The present study aimed to perform an update on primary hypertension in childhood, providing clinicians and researchers an overview of the current state of the literature regarding the influence of genetic and environmental factors.

METHODS

This integrative review searched for articles on genetic and environmental factors related to primary hypertension in pediatric patients. The databases evaluated were PubMed and Scopus.

RESULTS

The studies have provided insights regarding many genetic and environmental factors, in addition to their association with the pathophysiology of primary hypertension in childhood. Findings corroborated the idea that primary hypertension is a multifactorial disease. Further studies in the pediatric population are needed to elucidate the underlying mechanisms.

CONCLUSION

The study of primary hypertension in pediatrics has utmost importance for the adoption of preventive measures and the development of more efficient treatments, therefore reducing childhood morbidity and the incidence of cardiovascular diseases and other health consequences later in life.

Sedentary behavior is more related with cardiovascular parameters in normal weight than overweight adolescents

This study analyzed the relationship between sedentary behavior and cardiovascular parameters in normal weight and overweight adolescents. The sample included 449 boys and 555 girls with mean age of 13 years from public schools, which were divided into five geographical regions, with data collections performed in one selected school from each region. Sedentary behavior was assessed by screen time on TV, computer, videogame and cell phone/tablet, with good reliability in adolescents. Physical activity was assessed by Baecke's questionnaire, validated for adolescents. Measures of body weight, height and waist circumference were collected. Adolescents were classified as overweight or normal weight by cut-off points of body mass index for age and sex. Cardiovascular parameters were evaluated by oscillometric device and heart rate by specific monitor. Computer use was positively related to systolic blood pressure (SBP) (β = 0.35; 95%CI = 0.07-0.62) and diastolic blood pressure (DBP) (β = 0.25; 95%CI = 0.05-0.44) in normal weight but not in overweight adolescents. Similar results were observed for cell phone/tablet in SBP (β = 0.46; 95%CI = 0.20-0.72) and DBP (β = 0.36; 95%CI = 0.18-0.54), only for normal weight. The cluster of screen time was related to SBP in normal weight (β = 0.44; 95%CI = 0.03-0.84) and overweight (β = 0.60; 95%CI = 0.01-1.19). Screen time in computer and cell phone/tablet was more related to cardiovascular parameters in normal weight than overweight adolescents.

Acute Effects of Interrupting Prolonged Sitting With Intermittent Physical Activity on Blood Pressure in Preadolescent Children

PURPOSE

To compare the acute effects of intermittent physical activity (PA) across 4 different intensities on blood pressure.

METHODS

Thirty children (12 males and 18 females; aged 7-11 y; 33% overweight/obese; 53% nonwhite) completed 4 experimental conditions in random order: 8 hours sitting interrupted with 20, 2-minute low-, moderate-, high-intensity PA breaks, or sedentary screen-time breaks. PA intensity corresponded with 25%, 50%, and 75% of heart rate reserve. Blood pressure was measured during each condition in the morning (0800 h), noon (1200 h), and afternoon (1600 h).

RESULTS

There were no significant differences across conditions for systolic blood pressure (SBP; all Ps > .05). There was a significant effect of time with SBP decreasing throughout the day for all conditions (average morning SBP: 106 [1] mm Hg, average noon SBP: 101 [2] mm Hg, average afternoon SBP: 103 [1] mm Hg; P = .01). There were no significant effects of condition or time on diastolic blood pressure (all Ps > .05).

CONCLUSION

While sedentary behavior is known to be associated with hypertension in both adults and children, a single bout of prolonged sitting may be insufficient to produce hypertensive effects in otherwise healthy children. Future research should examine the appropriate dose of intermittent PA to accrue hypotensive responses in preadolescent children.

Adverse physiological and psychological effects of screen time on children and adolescents: Literature review and case study

A growing body of literature is associating excessive and addictive use of digital media with physical, psychological, social and neurological adverse consequences. Research is focusing more on mobile devices use, and studies suggest that duration, content, after-dark-use, media type and the number of devices are key components determining screen time effects. Physical health effects: excessive screen time is associated with poor sleep and risk factors for cardiovascular diseases such as high blood pressure, obesity, low HDL cholesterol, poor stress regulation (high sympathetic arousal and cortisol dysregulation), and Insulin Resistance. Other physical health consequences include impaired vision and reduced bone density. Psychological effects: internalizing and externalizing behavior is related to poor sleep. Depressive symptoms and suicidal are associated to screen time induced poor sleep, digital device night use, and mobile phone dependency. ADHD-related behavior was linked to sleep problems, overall screen time, and violent and fast-paced content which activates dopamine and the reward pathways. Early and prolonged exposure to violent content is also linked to risk for antisocial behavior and decreased prosocial behavior. Psychoneurological effects: addictive screen time use decreases social coping and involves craving behavior which resembles substance dependence behavior. Brain structural changes related to cognitive control and emotional regulation are associated with digital media addictive behavior. A case study of a treatment of an ADHD diagnosed 9-year-old boy suggests screen time induced ADHD-related behavior could be inaccurately diagnosed as ADHD. Screen time reduction is effective in decreasing ADHD-related behavior.

CONCLUSIONS

Components crucial for psychophysiological resilience are none-wandering mind (typical of ADHD-related behavior), good social coping and attachment, and good physical health. Excessive digital media use by children and adolescents appears as a major factor which may hamper the formation of sound psychophysiological resilience.

Eating breakfast and snacks while television viewing are associated with some cardio metabolic risk factors among Iranian children

AIM

We aimed to investigate the association of eating meals while television viewing (TVV) and screen-based behaviors with cardio metabolic risk factors (CRFs) among school-aged children in Shiraz.

MATERIALS AND METHODS

This cross-sectional study was done on 409 primary school children (217 boys), aged 6-9 years. Physical activity, time spent on screen-based behaviors and frequency of eating meals while TVV were measured using a questionnaire. Anthropometric indices, fasting blood sugar (FBS), blood lipids, blood pressure (BP), dietary intakes and physical activity were assessed. Association of eating while TVV with CRFs were assessed using linear regression, adjusted for potential confounders. All statistical analysis were conducted using the Stata 13 software.

RESULTS

Fully adjusted model showed that TVV time had significant positive association with waist circumferences (WC), and BP (p <0.05). Also, we found an inverse relationship between using Computer and Video games with TG level (β=-0.3; CI: -0.64, -0.09). Children who ate two or more breakfast meal while TVV had higher WC (β=2.02; CI: 0.51, 3.53) and FBS (β=3.58; CI: 0.39, 6.78) compared to who never ate breakfast while TVV. After adjustment for Screen time and BMI, eating snacks while TVV was positively associated with FBS and systolic BP. However, Eating dinner and lunch while TVV were not significantly associated with any of CRFs after adjustment for confounders.

CONCLUSIONS

We found that both eating breakfast and snacks while TVV were associated with WC, FBS and BP in children. Also, excessive TVV was associated with WC and BP.

Association between Sedentary Time and Cardiovascular Risk Factors in Korean Adults

Background

Sedentary behavior has been shown to have deleterious effects on cardiovascular outcomes. This study aimed to examine the association between sedentary time and cardiovascular risk factors in Korean adults.

Methods

A cross-sectional study was performed using data from adults aged 19 years and above in the 2013 Korean National Health and Nutrition Examination Survey. Sedentary time was self-reported and categorized into quintiles. Cardiovascular risk factors, including blood pressure (BP), total cholesterol, high-density lipoprotein (HDL) cholesterol, triglycerides, low-density lipoprotein cholesterol, and fasting glucose levels, were categorized into dichotomous variables according to the Adult Treatment Panel III criteria. Multivariate logistic regression was performed with adjustment for various demographic and lifestyle variables, body mass index (BMI), waist circumference (WC), and moderate-to-vigorous physical activity. Complex sampling design was used, and survey weights and sample design variables were applied in analyses.

Results

A total of 3,301 individuals were included in the analyses, and mean sedentary time was 6.1 h/d. Prolonged sedentary time was significantly associated with high diastolic BP (top vs. bottom quintile: adjusted odds ratio [OR], 1.71; 95% confidence interval [CI], 1.09–2.68; P_trend=0.03) and low HDL cholesterol level (top vs. bottom quintile: adjusted OR, 1.42; 95% CI, 1.02–1.98; P_trend=0.02) after adjustment for BMI, WC, moderate-to-vigorous physical activity, and other variables. No significant associations were found between sedentary time and other cardiovascular risk factors.

Conclusion

Prolonged sedentary time was significantly associated with high diastolic BP and low HDL cholesterol level in Korean adults. The associations were independent of general and abdominal obesity and moderate-to-vigorous physical activities.

Predictors of screen viewing time in young Singaporean children: the GUSTO cohort

Background

Higher screen viewing time (SVT) in childhood has been associated with adverse health outcomes, but the predictors of SVT in early childhood are poorly understood. We examined the sociodemographic and behavioral predictors of total and device-specific SVT in a Singaporean cohort.

Methods

At ages 2 and 3 years, SVT of 910 children was reported by their parents. Interviewer-administered questionnaires assessed SVT on weekdays and weekends for television, computer, and hand-held devices. Multivariable linear mixed-effect models were used to examine the associations of total and device-specific SVT at ages 2 and 3 with predictors, including children’s sex, ethnicity, birth order, family income, and parental age, education, BMI, and television viewing time.

Results

At age 2, children’s total SVT averaged 2.4 ± 2.2 (mean ± SD) hours/day, including 1.6 ± 1.6 and 0.7 ± 1.0 h/day for television and hand-held devices, respectively. At age 3, hand-held device SVT was 0.3 (95% CI: 0.2, 0.4) hours/day higher, while no increases were observed for other devices. SVT tracked moderately from 2 to 3 years (r = 0.49, p < 0.0001). Compared to Chinese children, Malay and Indian children spent 1.04 (0.66, 1.41) and 0.54 (0.15, 0.94) more hours/day watching screens, respectively. Other predictors of longer SVT were younger maternal age, lower maternal education, and longer parental television time.

Conclusions

In our cohort, the main predictors of longer children’s SVT were Malay and Indian ethnicity, younger maternal age, lower education and longer parental television viewing time. Our study may help target populations for future interventions in Asia, but also in other technology-centered societies.

Trial registration

This ongoing study was first registered on July 1, 2010 on NCT01174875 as. Retrospectively registered.

Electronic supplementary material

The online version of this article (doi:10.1186/s12966-017-0562-3) contains supplementary material, which is available to authorized users.

Sedentary behaviours among adults across Canada

OBJECTIVES: While cross-Canada variations in physical activity and weight status have been illustrated, less is known about sedentary behaviour (SB). The aim of this study was to describe various SBs and their correlates among Canadian adults. METHODS: Cross-sectional data from the 2011-2012 Canadian Community Health Survey included 92,918 respondents aged 20-75+ years, representative of &gt;22 million Canadian adults. TV/video viewing, computer, video game playing and reading time were self-reported. Associations with socio-demographic, health and health behaviour variables were examined. RESULTS: About 31% of adults reported &gt;2 hours/day TV viewing, while 47% of men and 41% of women reported &gt;5 hours/week computer use, 24% of men and 12% of women reported ≥1 hour/week video game playing, and 33% of men and 46% of women reported &gt;5 hours/week reading; 28% of respondents reported ≥5 hours/day total SB time. Age was the strongest correlate: adults 75+ had 5 and 6 times greater odds respectively of reporting &gt;2 hours/day TV viewing and &gt;5 hours/week reading, but far lesser odds of reporting high computer or video game time, compared to adults 20-24. Other variables associated with specific SBs included gender, marital status, education, occupation, income and immigrant status, as well as BMI, weight perceptions, smoking, diet and physical activity. CONCLUSION: Common sedentary behaviours were associated with numerous socio-demographic, health and health behaviour characteristics in a large representative sample of Canadians. These correlates differed according to the type of SB. Public health interventions targeting SB should be behavior-specific and tailored to the population segment of interest.

Systematic review of sedentary behaviour and health indicators in school-aged children and youth: an update

This systematic review is an update examining the relationships between objectively and subjectively measured sedentary behaviour and health indicators in children and youth aged 5–17 years. EMBASE, PsycINFO, and Medline were searched in December 2014, and date limits were imposed (≥February 2010). Included studies were peer-reviewed and met the a priori-determined population (apparently healthy children and youth, mean age: 5–17 years), intervention (durations, patterns, and types of sedentary behaviours), comparator (various durations, patterns, and types of sedentary behaviours), and outcome (critical: body composition, metabolic syndrome/cardiovascular disease risk factors, behavioural conduct/pro-social behaviour, academic achievement; important: fitness, self-esteem) study criteria. Quality of evidence by outcome was assessed using the Grading of Recommendations Assessment, Development, and Evaluation framework. Due to heterogeneity, a narrative analysis was conducted. A total of 235 studies (194 unique samples) were included representing 1 657 064 unique participants from 71 different countries. Higher durations/frequencies of screen time and television (TV) viewing were associated with unfavourable body composition. Higher duration/frequency of TV viewing was also associated with higher clustered cardiometabolic risk scores. Higher durations of TV viewing and video game use were associated with unfavourable behavioural conduct/pro-social behaviour. Higher durations of reading and doing homework were associated with higher academic achievement. Higher duration of screen time was associated with lower fitness. Higher durations of screen time and computer use were associated with lower self-esteem. Evidence ranged from “very low” to “moderate” quality. Higher quality studies using reliable and valid sedentary behaviour measures should confirm this largely observational evidence.

Parental perceptions of technology and technology-focused parenting: Associations with youth screen time

In the present study we propose a model linking parental perceptions of technology to technology-related parenting strategies to youth screen time, and, finally, to internalizing and externalizing problem behaviors. Participants were 615 parents drawn from three community samples of families with children across three developmental stages: young childhood, middle childhood, and adolescence. The model was tested at each stage with the strongest support emerging in the young childhood sample. One component of parental perceptions of technology, perceived efficacy, was related to technology-related parenting strategies across developmental stages. However, the association of these strategies to child screen time and, in turn, problem behaviors, diminished as children increased in age. Implications for intervention are considered.

The association between time spent in sedentary behaviors and blood pressure: a systematic review and meta-analysis

BACKGROUND AND OBJECTIVE

Sedentary behaviors, defined as waking behaviors with low energy expenditure while sitting, are positively associated with several adverse health outcomes. However, the association between sedentary behaviors and blood pressure (BP) is inconclusive. This study aimed to conduct a systematic review and meta-analysis on the association between time spent in sedentary behaviors and BP.

METHODS

We searched PubMed, MEDLINE, and Web of Science for papers published before August 2014 that assessed the association between time spent in sedentary behaviors and BP. Studies on both adults and children were included. Only good quality studies were included. The pooled estimates of systolic BP (SBP) and diastolic BP (DBP) increase per hour of time spent in sedentary behaviors a day were computed using a fixed-effects model and a random-effects model, respectively. Another pooled estimate of odds ratio per hour of time spent in sedentary behaviors a day on having high BP was computed using a fixed-effects model. A sub-group analysis was conducted for studies using self-reported and objectively assessed time spent in sedentary behaviors separately.

RESULTS

A total of 31 papers of good quality were included in the systematic review, 18 of which found no association between time spent in sedentary behaviors and BP (58.1%). A total of 28 papers were included in the meta-analysis. Pooled effects showed that an additional hour of time spent in sedentary behaviors per day was associated with an increase of 0.06 mmHg (108,228 participants, 95% CI 0.01-0.11, p = 0.01) of SBP and 0.20 mmHg (107,791 participants, 95% CI 0.10-0.29, p < 0.001) of DBP. Accelerometer-assessed time spent in sedentary behaviors was not associated with either SBP (p = 0.06) or DBP (p = 0.33). The odds ratio (OR) of having high BP with an additional hour of time spent in sedentary behaviors per day was 1.02 (98,798 participants, 95% CI 1.003-1.03, p = 0.02).

CONCLUSIONS

Self-reported but not accelerometer-assessed time spent in sedentary behaviors was associated with BP. Further studies are warranted to determine the preventive effect of reducing sedentary behaviors on high BP.

Effects of clustering of multiple lifestyle-related behaviors on blood pressure in adolescents from two observational studies

BACKGROUD

Several lifestyle-related behaviors are associated with cardiovascular health outcomes in adolescents. To examine the associations between clustered lifestyle-related behaviors and blood pressure (BP) levels in adolescents.

METHODS

Participants were recruited by multistage random cluster in two cross-sectional studies; one conducted in 2006 and 2007 in ten cities from nine European countries: Athens and Heraklion in Greece, Dortmund in Germany, Ghent in Belgium, Lille in France, Pécs in Hungary, Rome in Italy, Stockholm in Sweden, Vienna in Austria, and Zaragoza in Spain; and another conducted in 2007 one city in Brazil (Maringá/PR). Systolic BP (SBP) and diastolic BP (DBP) (outcomes) and clustered behaviors (weekly consumption of fruits and vegetables, weekly consumption of sugar-sweetened beverages, sleep duration, screen time and physical activity) were analyzed.

RESULTS

The Healthy Eating cluster was negatively associated with DBP in European girls, β=-2.46 (-4.62; -0.30), and with SBP in Brazilian boys, β=-2.79 (-3.10; -0.15). Furthermore, the Unhealthy Eating cluster was associated with increased SBP in European girls, β=4.54 (1.29; 7.79), and in Brazilian boys, β=4.10 (0.80; 7.40).

CONCLUSION

The Healthy Eating cluster was associated with lower blood pressure, whereas the Unhealthy Eating cluster was associated with increased SBP in adolescents.

Activity behaviors in schoolchildren and subsequent 5-yr change in blood pressure

PURPOSE

This study aimed to establish whether time spent in sport-related physical activities and sedentary behaviors (e.g., TV viewing, videogame usage, and homework) was prospectively associated with change in blood pressure (BP) for 5 yr.

METHODS

Eight hundred and twenty-one students age 6 yr at baseline (397 girls and 424 boys) were examined from 2003-2004 to 2009-2011. Children completed detailed activity questionnaires. BP was measured using a standardized protocol.

RESULTS

After adjusting for age, ethnicity, parental education, parental history of hypertension, baseline height, BP, body mass index (BMI), baseline time spent in corresponding activity behavior, and change in BMI, each hour per day spent in total screen time was associated with a 0.69 and 0.59 mm Hg increase in diastolic BP (P = 0.01) and mean arterial BP (P = 0.01), respectively. In boys, each hour per day spent in TV viewing was associated with a concurrent 1.42-mm Hg increase in diastolic BP (P = 0.04) during the 5 yr. Children engaging in low sport-related physical activities at baseline but who engaged in high levels of physical activity (≥ 60 min · d(-1)) at follow-up (n = 154) compared with those engaging in low sport-related physical activities at both examinations (n = 305) demonstrated significantly lower mean arterial BP, 7.26 versus 9.61 mm Hg (P = 0.04).

CONCLUSIONS

Time spent in physical activity and screen time could influence BP measures during childhood.

Time Spent on the Internet and Adolescent Blood Pressure

Internet use is nearly ubiquitous among adolescents. Growing evidence suggests heavy Internet use negatively impacts health, yet the relationship between time spent on the Internet and adolescent blood pressure (BP) is unknown. We examined the association between Internet use and elevated BP in a racially diverse cross-sectional sample of 331 healthy adolescents (ages 14–17 years). Heavy Internet use was defined as ≥2 hr/day, moderate use as <2 hr/day and ≥5 days/week, and light use as <2 hr/day and ≤4 days/week. Elevated BP was defined as systolic or diastolic BP ≥90th percentile. Heavy Internet users had statistically significantly higher odds of elevated BP compared to light Internet users. School nurses can play an important role in preventing high BP through assessment of BP and other health behaviors including Internet use, and health teaching to individuals, student groups, faculty, and parents to increase awareness of the relationship between Internet use and health.

Screen-Time Weight-loss Intervention Targeting Children at Home (SWITCH): a randomized controlled trial

BACKGROUND

Screen-based activities, such as watching television (TV), playing video games, and using computers, are common sedentary behaviors among young people and have been linked with increased energy intake and overweight. Previous home-based sedentary behaviour interventions have been limited by focusing primarily on the child, small sample sizes, and short follow-up periods. The SWITCH (Screen-Time Weight-loss Intervention Targeting Children at Home) study aimed to determine the effect of a home-based, family-delivered intervention to reduce screen-based sedentary behaviour on body composition, sedentary behaviour, physical activity, and diet over 24 weeks in overweight and obese children.

METHODS

A two-arm, parallel, randomized controlled trial was conducted. Children and their primary caregiver living in Auckland, New Zealand were recruited via schools, community centres, and word of mouth. The intervention, delivered over 20 weeks, consisted of a face-to-face meeting with the parent/caregiver and the child to deliver intervention content, which focused on training and educating them to use a wide range of strategies designed to reduce their child's screen time. Families were given Time Machine TV monitoring devices to assist with allocating screen time, activity packages to promote alternative activities, online support via a website, and monthly newsletters. Control participants were given the intervention material on completion of follow-up. The primary outcome was change in children's BMI z-score from baseline to 24 weeks.

RESULTS

Children (n = 251) aged 9-12 years and their primary caregiver were randomized to receive the SWITCH intervention (n = 127) or no intervention (controls; n = 124). There was no significant difference in change of zBMI between the intervention and control groups, although a favorable trend was observed (-0.016; 95% CI: -0.084, 0.051; p = 0.64). There were also no significant differences on secondary outcomes, except for a trend towards increased children's moderate intensity physical activity in the intervention group (24.3 min/d; 95% CI: -0.94, 49.51; p = 0.06).

CONCLUSIONS

A home-based, family-delivered intervention to reduce all leisure-time screen use had no significant effect on screen-time or on BMI at 24 weeks in overweight and obese children aged 9-12 years.

TRIAL REGISTRATION

Australian New Zealand Clinical Trials RegistryWebsite: http://www.anzctr.org.au

TRIAL REGISTRATION NUMBER

ACTRN12611000164998.

Screen time and cardiometabolic function in Dutch 5-6 year olds: cross-sectional analysis of the ABCD-study

Background

Evidence on the association between different screen behaviours and cardiometabolic biomarkers in children is limited. We examined the independent relationship of TV time and PC time with cardiometabolic biomarkers in Dutch 5–6 year old children.

Methods

Cross-sectional analyses were conducted December 2012-March 2013 using data from a multi-ethnic cohort (the ABCD study, n = 1,961). TV and PC time and physical activity were assessed by parent-report. Body weight, height, waist circumference and blood pressure were measured using a standard protocol. Fasting capillary blood samples were collected. A cardiometabolic function score was computed as the mean of the inverted standardised values of waist circumference, mean of systolic and diastolic blood pressure, glucose, HDLC (not inverted), and triglycerides.

Results

Mean TV time was 1.2 (±0.8) hr/day and mean PC time was 0.2 (±0.4) hr/day. After adjustment for birth weight, height, maternal education, PC time, and physical activity, excessive TV time (>2 hrs/day) was adversely associated with waist circumference (b = 0.39, 95% CI: 0.004;0.78) while PC time was beneficially associated with HDLC levels (b = 0.04, 95% CI: 0.001;0.08). We found no additional significant associations of TV time, or PC time with any of the cardiometabolic biomarkers.

Conclusions

We found no convincing evidence for an association between TV or PC time and cardiometabolic function in apparently healthy 5–6 yr olds.

[High blood pressure and physical exercise]

High blood pressure is a frequent pathology with many cardiovascular complications. As highlighted in guidelines, the therapeutic management of hypertension relies on non-pharmacological measures, which are diet and regular physical activity, but both patients and physicians are reluctant to physical activity prescription. To acquire the conviction that physical activity is beneficial, necessary and possible, we can take into account some fundamental and clinical studies, as well as the feedback of our clinical practice. Physical inactivity is a major risk factor for cardiovascular morbidity and mortality, and hypertension contributes to increase this risk. Conversely, regular practice of physical activity decreases very significantly the risk by up to 60%. The acute blood pressure changes during exercise and post-exercise hypotension differs according to the dynamic component (endurance or aerobic and/or strength exercises), but the repetition of the sessions leads to the chronic hypotensive benefit of physical activity. Moreover, physical activity prescription must take into account the assessment of global cardiovascular risk, the control of the hypertension, and the opportunities and desires of the patient in order to promote good adherence and beneficial lifestyle change.

Evidence-based guidelines for wise use of electronic games by children

Electronic games (e-games) are widely used by children, often for substantial durations, yet to date there are no evidence-based guidelines regarding their use. The aim of this paper is to present guidelines for the wise use of e-games by children based on a narrative review of the research. This paper proposes a model of factors that influence child-e-games interaction. It summarises the evidence on positive and negative effects of use of e-games on physical activity and sedentary behaviour, cardio-metabolic health, musculoskeletal health, motor coordination, vision, cognitive development and psychosocial health. Available guidelines and the role of guidelines are discussed. Finally, this information is compiled into a clear set of evidence-based guidelines, about wise use of e-games by children, targeting children, parents, professionals and the e-game industry. These guidelines provide an accessible synthesis of available knowledge and pragmatic guidelines based on e-game specific evidence and related research.

Sedentary behavior in a cohort of 8- to 10-year-old children at elevated risk of obesity

OBJECTIVES

Sedentary behavior (SB) is distinct from physical inactivity. Children's guidelines recommend ≤2h/day screen time and ≥60min/day moderate-to-vigorous physical activity (MVPA). This study describes SB in children at elevated risk of obesity, including the possibility of high SB in otherwise active children.

METHODS

Participants were 534 children from Quebec, Canada, aged 8-10years with ≥1 obese parent in 2005-2008. SB and MVPA were measured by accelerometer and specific SBs by self-report, and height and weight were directly measured.

RESULTS

Overweight/obese children were significantly more sedentary overall and reported higher screen time than normal weight children. About 19% of boys and 46% of girls met screen time but not PA guidelines; 28% of boys and 5% of girls met PA but not screen time guidelines. About 46% of overweight/obese children met neither guideline (32% normal weight); only 5% overweight/obese children met both (21% normal weight). Reported behaviors contributed 60%-80% of total SB time; the most sedentary children had the most unaccounted for SB time.

CONCLUSIONS

Overweight/obese children are more sedentary overall and report higher screen time than normal weight children. Public health efforts targeting PA and SB in children must consider sex and weight status while being cognizant that being sufficiently active is not exclusive of high levels of SB.

Screen-based media use clusters are related to other activity behaviours and health indicators in adolescents

Background

Screen-based media (SBM) occupy a considerable portion of young peoples’ discretionary leisure time. The aim of this paper was to investigate whether distinct clusters of SBM use exist, and if so, to examine the relationship of any identified clusters with other activity/sedentary behaviours and physical and mental health indicators.

Methods

The data for this study come from 643 adolescents, aged 14 years, who were participating in the longitudinal Western Australian Pregnancy Cohort (Raine) Study through May 2003 to June 2006. Time spent on SBM, phone use and reading was assessed using the Multimedia Activity Recall for Children and Adults. Height, weight, muscle strength were measured at a clinic visit and the adolescents also completed questionnaires on their physical activity and psychosocial health. Latent class analysis (LCA) was used to analyse groupings of SBM use.

Results

Three clusters of SBM use were found; C1 ‘instrumental computer users’ (high email use, general computer use), C2 ‘multi-modal e-gamers’ (both high console and computer game use) and C3 ‘computer e-gamers’ (high computer game use only). Television viewing was moderately high amongst all the clusters. C2 males took fewer steps than their male peers in C1 and C3 (-13,787/week, 95% CI: -4619 to -22957, p = 0.003 and -14,806, 95% CI: -5,306 to -24,305, p = 0.002) and recorded less MVPA than the C1 males (-3.5 h, 95% CI: -1.0 to -5.9, p = 0.005). There was no difference in activity levels between females in clusters C1 and C3.

Conclusion

SBM use by adolescents did cluster and these clusters related differently to activity/sedentary behaviours and both physical and psychosocial health indicators. It is clear that SBM use is not a single construct and future research needs to take consideration of this if it intends to understand the impact SBM has on health.

Adiposity and different types of screen time

OBJECTIVE

Few prospective studies have examined separate forms of screen time in relation to adiposity. Our objective was to assess independent relations of television, electronic games (video/computer), and digital versatile disc (DVD)/videos and total screen time with change in adolescent BMI.

METHODS

Using data from the 2004, 2006, and 2008 waves of the ongoing Growing up Today Study II, we assessed baseline and 2-year change in reported screen time in relation to concurrent change in BMI among 4287 girls and 3505 boys aged 9 to 16 years in 2004. Gender-specific models adjusted for previous BMI, age, race/ethnicity, growth/development, months between questionnaires, and physical activity.

RESULTS

Among girls and boys, each hour per day increase in reported television viewing was associated with a 0.09 increase in BMI (Ps < .001), and each hour per day increase in total screen time was associated with a 0.07 increase among girls and 0.05 increase among boys (Ps < .001). Among girls only, greater baseline television, games, and total screen time and change in DVDs/videos were associated with gains in BMI (Ps < .05). BMI gains associated with change in television and total screen time were stronger among overweight girls than lean girls (Ps-heterogeneity < .001).

CONCLUSIONS

Television, which remains the steadiest source of food advertising, was most consistently associated with BMI gains. Among girls, electronic games and DVDs/videos were also related to increased BMI, possibly due to influences of product placements and advergames on diet and/or distracted eating. Adolescents, especially overweight adolescents, may benefit from reduced time with multiple types of media.

Sedentary Behavior and Health Outcomes in Children and Adolescents

The purpose of this review was to summarize findings from epidemiological studies that determined if sedentary behavior was associated with obesity, metabolic risk factors, and cardiorespiratory fitness in children and adolescents. We noted if studies adjusted for moderate-to-vigorous physical activity (MVPA), dietary intakes, and/or sleep duration. Articles were identified through PubMed using the search terms: (sedentary OR sitting OR television) AND (adiposity OR blood pressure OR body mass index OR cardiometabolic OR metabolic risk OR waist circumference). The search was limited to ages 6 to 18 years, humans, and published between January 1, 2008 and September 26, 2012. Cross-sectional and longitudinal studies observed associations between more sedentary behavior, especially screen-based sedentary behavior, and measures of obesity; and most associations were independent of MVPA and dietary intake. Cross-sectional and longitudinal studies reported associations between screen-based sedentary behavior and lower cardiorespiratory fitness, and most associations were independent of MVPA and obesity. Cross-sectional studies observed associations between more screen-based and objectively measured sedentary behavior and lower insulin sensitivity; and most associations were independent of MVPA and obesity. There was little-to-no evidence that sedentary behavior was associated with increased blood pressure and increased blood lipids.

Changes in cardiovascular disease risk factors from age 9 to 19 and the influence of television viewing

OBJECTIVE

The purpose of this study was to determine if time spent watching television is associated with changes in cardiovascular disease (CVD) risk factors from age 9 to 19.

DESIGN AND METHODS

Participants were girls enrolled in the NHLBI Growth and Health Study (n = 1,702), and CVD risk factors were measured at ages 10, 12, 14, 16, and 19. Longitudinal quantile regression was used to determine if television viewing was associated with changes in CVD risk factors over time at the 10th, 25th, 50th, 75th, and 90th percentiles of the CVD risk factors.

RESULTS

In black girls, television viewing (h/wk) was positively associated with sum of skinfolds (mm) at the 75th (0.22, 99% CI, 0.06-0.38) and 90th percentiles (0.21, 99% CI, 0.05-0.36), but not at the 10th, 25th, or 50th percentiles. In white girls, television viewing (h/wk) was positively associated with sum of skinfolds (mm) with the strength of the associations progressively stronger toward the upper tail of the skinfold distribution, adjusting for physical activity and other covariates (10th percentile: 0.08, 99% CI, 0.03-0.13; 90th percentile: 0.42, 99% CI, 0.24-0.59). All associations were adjusted for physical activity, dietary factors, sleep, and maturation. No associations were observed between television viewing and changes in systolic blood pressure, triglycerides, or cholesterol levels in black or white girls.

CONCLUSION

Girls who spent more time watching television had greater increases in sum of skinfolds from age 9 to 19, independent of physical activity levels and other covariates. The associations observed were stronger at the upper tail of the skinfold distribution.

Dietary and physical activity/inactivity factors associated with obesity in school-aged children

Diet and physical activity (PA) are essential components of nutritional status. Adequate nutrition and an active lifestyle are key factors during childhood, because food habits track into adulthood. Children spend more time in school than in any other environment away from home. Studying the diet factors and patterns of PA that affect obesity risk in children during school hours and the complete school day can help identify opportunities to lower this risk. We directly measured the time children spent performing moderate to vigorous PA (MVPA) at school, compared the amount and intensity of PA during school hours with after-school hours, and tried to determine if diet behaviors and PA or inactivity were associated with excess weight and body fat. This cross-sectional study included 143 normal-weight (NLW) and 48 obese children aged 8-10 y. Diet data were obtained from two 24-h recalls. Body composition was measured by bioimpedance. Screen time and sports participation data were self-reported. NLW children drank/ate more dairy servings than the obese children, who consumed more fruit-flavored water than the NLW group. Consumption of soft drinks, sugar-added juices, and fresh juices was low in both groups. Children were less active during school hours than after school. MVPA was lower during school hours in the obese group than in the NLW group. Schools, parents, and authorities should be more involved in promoting strategies to improve the dietary habits and PA levels of school-aged children, because this group is not achieving the recommended level of daily MVPA.