PA children 7-12 Flashcards
Common physical health outcomes studied in PA research in children. Strongest evidence?
BMI - also comp/ lean mass Bone health - particularly girls Cardiometabolic health (cholesterol, metabolic syndrome) Obesity Fitness, Motor control/ perf/ literacy Depression Asthma Injury Academic performance Grades Indicators e.g. Memory
Strongest for cardiometabolic health, mental health, fitness and bone health
Describe risk of bias (ROB) in PA in children literature
Valid measure of SB used
-cut points valid for children/adolescents
Covariates such as MVPA included in analysis
Representative sampling/ random selection
Adequate % with complete data?
TV viewing associated with?
More than 2 hr a day unfavorable:
- body comp
- decreased self esteem
- pro social behaviour
- academic achievement in school aged children
Limitation of TV viewing data
Mostly self report/ proxy report
What is cognition? 3 main areas
Basic mental process we use in everyday life
- Attention
-Memory (working and longer term)
-Executive fuinction - (cognitive control)
Also percepton from various senses
How can we measure cognition?
Event -stimulus ID -Response selection - Response programming Repsonse Cognitive processes jointly measured by reaction time
Behavioural measurements pratical of cognition
D2 test of attention
Phyiological studies e.g. EEG
Activity/ cognition higher after walking than sedentary
Findings from a systematic review of PA/SB and cognitive function, academic achievement and limitations
Fitness, Single bouts of PA, particip[ation in an intervention benefit cognitive function
Depends on constructs measured
Caution as little experimental evidence
Why might there be cognitive benefits with PA/SB?
Not much explaination why?
Physiological mech
INCREASED BF and perfusion - MRI etc
Socialsation in sport - decisions etc.
Exposure - PA, sport, fitness (hard to unpick independent relationships)
Combined impact cognitive, pyscho-socail (ability to work in groups, support etc) and improved school engagement leading to improved education achievement.
Mixed evidence for each.
Another review, CDC, relationship between school-based PA (including PE) and academic performance? Backed up by later evidence?
PE, recess, classroom and extracurricular PA • Of all the associaXons examined, 50.5% were posi;ve, 48% not significant, and 1.5% were negative.
Second review by Singh
Strong evidence of a significant positive relationship between PA and academic performance later. Mostly from observational studies - more PA is related to improved academic from high quality evidence.
How can we measure academic achievement?
Standardised tests vs subjective grades
Can active breaks/ lessons benefit academic perf? CDC
Active breaks/ lessons benefit 8/9 studies
Variation in physically active lesson implementation/ idea behind them
Integration of movement into teaching of academic content
Longer duration
Across the curriculum
Why do PA/Sb and cognitive function outcomes vary?
depends on constructs studies
Single bouts vs daily PA on cognition?
Single bouts can benefit cog function in children, daily PA and cognition is equivocal (ambiguous)
Longer term active lesson evidence?
After 2 years - 4 months learning gains in stardised test scores from maths and spelling PAL (x3 a week)
Associations between SB/PA and GCSEs in the UK?
Objective PA and Self reported sed behaviour e.g. Screen and non screen activities and GCSE results from national records. Prospective 845 adolescents.
1 hr screen time at 14.5y associated with 2 fewer GCSE grades
Still assoc after adjustment for PA and other SB
Inverse u shaped relationship between non screen sedentary behaviour and academic perf with association peaking at 4h/day
Method of a systematic review
Keywords
Search databases
Remove duplicates
Read all abstracts/ papers
Common mental health outcomes/ functioning outcomes in PA research
Anxiety Mental well-being Depression Cognitive functioning Educational performance i.e. Academic achievement
Aims of Cliff et al 2016
Is objectively measure total SB assoc with adverse health/development outcomes
Patterns of SB assoc ^?
Are associations independent of MVPA?
What moderators of the association e.g. Age group or risk of bias?
Reults of Cliff et al 2016
No association with Adiposity (despite 11 with sig pos association)
No association with Cardio-metabolic outcomes (8/29 at keast ibe sig outcome)
Stat sig meta analysis between sedentary time and 5 studies with glucose/insulin. Weak positive association (r=0.07).
ROB and MVPA were sig moderators however
Publication bias
No association with health related fitness
Inconsistent/uncertain association with bone and musculoskeletal outcomes
ROB in all studies regarding psychosocial outcomes
No association (inconsistent/uncertain for 1/4 which was low ROB)
Inconsistent/ uncertain gross motor function - few studies (3)
Inconsitent/ uncertain for cognitive outcomes - few studies (3)
Cliff et al 2016 comment on strength of association between ST and health and development?
Limited evidence that total ST is associated with health and development in children and yound people, particularly when accounting for ROB and MVPA
Limitations in literature highlighted by Cliff et al 2016
However small number of subdies that adjusted for MVPA, bone and MSK, psychosocial development, gross motor skills and cognitiive outcomes.
Small number of studies that examines associations for patterns of ST
Conflicting findings to Cliff et al 2016
Screen based SB time studies
Evidence inadults which indicated overall ST and patterns are adversely associated with health outcomes
Why may Screen time behaviour studies conflict with Cliff et al 2016
May be unique mechanisms for TV viewing/electron media to influence health and development in young ppl, not common to all SB
Proxy report/ self
Increasd sitting time and decreased energy expenditure
Increased energy intake from unhealthy snacking and sugary beverage consumption during and following exposure
Exposure to advertising
Displacement of opportunities for social and education development
Exposure to content which promotes socially undesorable behaviour
Develoment of biological processes of dependence
Interference of cognitive processes
Displacement of MVPA
Why may adults SB literature differ (overall ST and patterns are adversely assoc with health outcomes) Cliff et al 2016
Difficult to say (issues with measuring):
Measurement issues of SB
Validity of cutpoints - standing still classified as SB in accelerometry
However adult studies with these limitation still founds assoc
Potential codependence of SB and PA (waking hours are finite so if not in SB then in LPA) therefore intrisically codependent
Lower levels/ shorted lifetime exposure to SB Higher levels of PA and time in MVPA Healthier profiles for cardio-metabolic outcomes investigated in children Above 3 Indicated by: A day of prolonged sitting did not have adverse effects compared to a daybroken up with LPA Also: Some evidence that obese/ overwight children may benefit as unhealthier cardio-metab profiles, greater SB exposure or lower MVPA. allowing detection of adverse effects earlier.
Implications for literature from comparisons of results with existing literature from Cliff et al 2016
Compositional analyses needed to understand optimal balance between SB, LPA, MVPA and sleep to maximise health and developments
Further experimental evidence needed to detect shifts from sitting to standing or LPA More exp/log evidence using direct measure of sitting posture and examining multiple outocmes at different age groups independent of MVPA.
Can review claim the excessive SB does not adversely impact health and development in children and adolescents? Why?
Premature to conclude that excessive SB does not adversely impact health and development in children and adolescents
Adverse effects among adults and some evidence of tracking of SB across the life course, encouragement of limiting SB in children is prudent.
Limitations of Cliff et al 2016
Limitations of evidence base
No experimental studies
<50% had low ROB
Impacts strength of conclusions
However finding were consitent across ROB categories (not adiposity meta)
Cross sectional with some longitudinal in obesity
Using activity monitors at hip/ wrist still limited to differentiate between sitting and standing likely leading to ST being overestimated
Not all studies in evidence summaries included in met-analysis - not all authors contacted.
Multiple markers of cardiometabolic measured in studies increasing chance of positive result
Validity of outcome measured not considered - ROB
But all but one psychological study were validatied
Strengths of Cliff et al 2016
Wide range of health outcomes explored
First to focus on objectively measured SB vol and patterns
Categorised level of evidence for each outcome
Findings enhances by examination of potential moderating effects of ROM and MVPA adjustment
Why might girls be less active than boys?
Biological maturity affecting social factors
Do we socialise adolescent girls out of PA?
FM and FFM differences gender?
FFM much greater increase in males
FM same
% fat different to boys and girls
Skinfold changes with age gender
Females always higher, more marked after age 12
Both extremities and trunk
Boys sigmoid - drops, increases, drops, increases (overall increasing less marked than girls)
higher in extremities
Muscle mass changes with age
Similar steady increase in male and female
Increases after puberty (age 12ish)
Is there an obesity epidemic?
Epidemic = rapid rise in cases
Both in developed and undeveloped
UK not doing well
Childhood remained stable over last 20 years - national health survey
Describe the national child measurement program, categorisation and key 14/15 findings
80% healthy weight in reception
Obesity = more extreme excess of adiposity
Overweight = >= 85%
Obesity >= 95%
91 and 98 may be better - these are used in letters for parents but 85 95 used in official statements
Most sign posted national programme -
Underweight = <=2%
Year 6
More obese than overweight
65% Healthy
Misclassification from BMI - tends to wash out over whole pop
Health survey for england findings
Health Survey for England
Similar stats
Similar at 2-10, higher older for girls
Measurement issues with national measurement programs?
Critical thought - Measurement issues
Minimal training for nurses
Calibrated scales should be used
Check stadiometer for flexing
No standardisation of time of day - loss of 2cm
Eat more and drink more throughout the day
Wholeschools disadvantaged if measured in the afternoon
7.5% of girls shifted to overweight or obese girls from measuring in afternoon
Changes in obesity prev different areas nationally, meaning?
Overweight prev in West mid and London
Obesity slightly diff - London and North East
Sociodemographic and economic factors?
Describe the trend in prev of excess weight in Uk from health survey for England
Statistically hard to say in 20 years
More marked in Aus and US?
Epidemic?
Similar in obesity - 5% change
trend from national child measurement prog
Not massive change Down in boys over time in reception Overall decrease in reception Year 6 Increasing
How has BMI distribution changed in UK since 1990?
1990 data = reference data Reception Slight shift to right Similar shape Year 6 children Heavy children getting heavier Skewness to the right
Medical complications of obesity in childhood
OSA Type 2 diabetes Gynacoglogical problems Abnormal mesnses Infertility PCOS
Describe OSA
Disorder of breathing during sleep characterised by prolonged partial/ complete upper airway obstruction that disrupts normal ventilation and normal sleep patters
Symptoms including havitual snoring, sleep difficulties and/or daytime neurobehavioural problems
1-1.5%
Causes of OSA in children
Lymphoid tissues blocking (milder lymphoid hypertrophy) associated with obesity
Type II
Obesity cause or consequence
1BMI increase above 50th% = 12% increase in OSA
45% of obese children with OSA have adenotonsillar hypertrophy
What is metabolic syndrome
Clustering of most dangerous RFs for CVD and type 2 diabetes Abdominal obesity High cholesterol HBP Diabetes/ raised fassting glucose Raised fasting plasma glucose Children Many definitions in children Age specific cutoffs - IDF Includes Obesity (WC) Triglycerides HDL-C BP Glucose or T2DM Cant be diagnosed under 10
Prevention and primary management of metabolic syndrome
Non-specific prevention guidelines due to lack of evidence
IDF (international diabetes Fed)
Moderate calorie restriction to achieve a 5-10per cent loss of body weight in first year
Moderate increase in PA
Change in dietary comp
Recommendation for future work on metabolic syndrome IDF
Improved understanding of relationship between body fat and distribution
Do early growth patterns predict future adiposity and other features (LBW too)
Investigate definitions sensitive to normal variation
Better measurement than BMI of central adiposity
Ethnic specific, age specific cut points for waist circum
Screening opportunities for T2DM?
HBA1c and 1,5-anhydroglucitol potentially useful in screening in a pediatric obesity clinic
Cause of T2DM
Destruction of islet cells within the pancreas causes this resistance
Obesity a cause
Other RFs
Changes in prev of T2DM in chidlren?
admission rates in youth <18yrs in UK icnreased by 63.5% from 96-04
Why T2DM in children is a worry?
earlier develop the clinical manifestations of T2DM, the earlier complications might appear
Best predictors of T2DM in children? Mcgavock et al 2007
Metbaolic syndrome RFs better predicter of T2DM than Fx and fasting glucose
Complications of T2DM in children Mcgavock et al 2007
Hypertension
Nephropathy - Microalbuminuria also RF assoc
Dyslipidaemia - specifically TGs, total cholest, LDL, HDL-C
Hepatic steatosis - increased risk of cirrhosis and portal hypertension
-raised liver enzymes
Subclinical risk factors
Elevated CRP
Reduced serum adiponectin
Endothelial dysfunction, arterial stiffness?
Central adiposity
When are PA interventions most effective in reducing BMI in children? Mcgavock et al 2007
Hypertension
Nephropathy - Microalbuminuria also RF assoc
Dyslipidaemia - specifically TGs, total cholest, LDL, HDL-C
Hepatic steatosis - increased risk of cirrhosis and portal hypertension
-raised liver enzymes
Subclinical risk factors
Elevated CRP
Reduced serum adiponectin
Endothelial dysfunction, arterial stiffness?
Central adiposity
What should be considered in ‘dose’ prescription of exercise to youth? Mcgavock et al 2007
Duration and intensity should be considered in the prescription of a dose for management and prevention of T2DM in youth
MVPA better correlated with overweight risk than total PA.
Describe insulin sensitivity in youth Mcgavock et al 2007
Early manifestation of T2DM
PA important in prevention
Resistnace in insulin-mediated glucose disposal causes
Correlated with PA - RCTs confirm
40-60mins daily for a minimum of 4 months
Describe Sedentary (screen) time in youth and relation to DM Mcgavock et al 2007
Time spent watching TV, working on a comp or playing video games
Related to obesity and metabolic risk
Adiposity and RF clustering increase incrementally with incresing screen time, independent of PA patterns.
Interventions targetting screen time attenuate weight gain in young children
Should be targeted as an infependent RF for DM as it is a RF for obesity.
American diabetes association/ AHA recommendation for PA/Screen time/ diet Mcgavock et al 2007
PA, >1hr MVPA daily and reduction of screen time below 2 hours daily - American Diabetes Association and American Heart association.
Adolescents are asked to achieve total and sat fat intake <30% and 10% respectively, fibre intake 25-35g daily and increased consumption of fruit and veg. (based on adults with T2DM).
Yet to perform RCT in children with T2DM, however shown to benefit metab profile in children without.
The effect of exercise alone or with diet Mcgavock et al 2007
Enhance insulin sensitiveity
Reduced SBP
Lower Tc, raise HDLC
Improve endothelial function
The effect of dietary restriction alone Mcgavock et al 2007
Reduce BP
Improve lipoprotein profile
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