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Exercise as it relates to Disease/The impacts of TV viewing and physical activity, on metabolic syndrome in Australian Adults
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This Wikibooks page critiques the article Associations of TV viewing and physical activity with the metabolic syndrome in Australian adults Dunstan D.W, Salmon O.N, Armstrong T, Zimmet P.Z, Welborn T.A, Cameron A.J, Dwyer D, Jolley J, Shaw J.E.; on behalf of the AusDiab Steering Committee. Associations of TV viewing and physical activity with the metabolic syndrome in Australian adults. Diabetologia. 2005;48(11):2254-61.
Background to the Research
Metabolic Syndrome
Metabolic syndrome (MS) are factors which predispose diabetes and cardiovascular diseases, like abnormal glucose tolerance (diabetes, IGT, IFG), elevated blood pressure and insulin resistance [1].
The current study
Where is the research from?
The data was collected by the Australian Diabetes, Obesity and Lifestyle studyTanamas SK, Magliano DJ, Lynch B, Sethi P, Willenberg L, Polkinghorne KR, Chadban S, Dunstan D, Shaw JE. The Australian Diabetes, Obesity and Lifestyle Study. 2012:6-38. , which was designed to represent Australian’s ≥ 25, providing a benchmark of national data on the prevalence of diabetes, obesity, hypertension and kidney disease.
The study had numerous support with funding from:
The Commonwealth Department of Health and Aged Care
Abbott Australasia
The Australian Kidney Foundation
Diabetes Australia
What kind of research was this?
This was a cross-sectional analysis of 6,241 Australian individuals aged over 35 to determine the strength of associations of TV viewing and physical activity with metabolic syndrome. It was a 5 year follow up from the original longitudinal population-based study in 1999-2000, which examined the history of diabetes, pre-diabetes, heart disease, and kidney disease.
What did the research involve?
A number of self-reported, interview-based questionnaires and baseline measurements were conducted on 6,241 participants.
After a >8 hour fast, individuals were assessed on waist circumference, height, weight and blood pressure (BP). The participants were defined as having MS if they had:
Variable Measure Fasting Insulin levels ≥ the upper quartile of the non-diabetic population IGT Fasting plasma glucose <7.0 mmol/L and 2-h plasma glucose ≥7.8 mmol/L but <11.1mmol/L Diabetes Fasting plasma glucose ≥7.0 mmol/L or 2-h plasma glucose ≥11.1 mmol/L Obesity Waist-hip-ratio (men >0.9, women >0.85) or BMI (>30kg/m2) Dyslipidaemia Serum triglycerides ≥1.7 mmol/L or HDL cholesterol <0.9 mmol/L for men or <1.0 mmol/L for women Hypertension BP≥ 140/90 mmHg or antihypertensive medication
A family history of diabetes, smoking habits, and education were also assessed
Dietary intake was measured with a food frequency questionnaire, and nutrient intake was also calculated
Individuals self-reported total time spent watching TV used to create three categories:
Hours per week 0-7 7.01-14 ≥14
The active Australia survey questionnaire was used to attain the frequency and duration of physical activity in the previous week.
Physical Activity Guidelines Hours Per week Meeting the guidelines ≥2.5h moderate intensity (walking) or vigorous activity for ≥1h NOT meeting the guidelines 0-2.49h of moderate intensity or ≤0.99h of vigorous activity
Limitations of the study
Large portion of self-reported questionnaires, which can be subject to bias like incorrect recall, distorting the relationship between TV viewing, physical activity and metabolic syndrome Celis-Morales C.A, Perez-Bravo F, Iban ̃ez L, Salas C, Bailey M E.S, Gill J M.R. Objective vs. Self-Reported Physical Activity and Sedentary Time: Effects of Measurement Method on Relationships with Risk Biomarkers. PLOS One. 2012;7(5):1-2.
Only measures the effects of one sedentary behaviour, others include sitting at a desk, using electronic devices and traveling for long periods of time Tremblay M.S, Aubert S, Barnes J.D, Saunders T.J, Carson V, Latimer-Cheung A.E, Chastin S F.M, Altenburg T.M, Chinapaw M J.M; on behalf of SBRN Terminology Consensus Project Participants. Sedentary Behaviour Research Network (SBRN) - Terminology Consensus Project process and outcome. International Journal of Behavioral Nutrition and Physical Activity. 2017;14(75).
Measuring 2 types of physical activity (moderate and vigorous intensity-based activity). It is plausible that individuals participate in other activities in their day to day basis via jobs or household chores. Kumanyika S, Jeffery RW, Morabia A, Ritenbaugh C, Antipatis V.J. Obesity prevention: The Case for action. International Journal of Obesity. 2002;26:425-36.
Strengths of the study
Large sample size reducing statistical variance and provides stronger evidence to draw informed conclusions
The study notes one of its own limitations and how to improve future research
Future research suggestions
Sampling a population comparing a number of sedentary behaviours and using other physical activity monitors to track all day activities
What were the basic results?
The results of this study show the following:
25% of male and 14% of female participants were diagnosed with MS
MS was highly associated with those who were significantly less active and watched high levels of TV. With every increase in TV by 1 hour, there was a 12% increase in prevalence for MS in men and a 26% increase in women
Higher levels spent watching TV is associated with diabetes, IGT, IFG. Those who watched ≥ 14h each week were also more likely to develop insulin resistance, obesity, and dyslipidemia
MS is inversely related to physical activity, with every 30-minute increase in activity showed a decreased prevalence of 11% and 28% in males and females respectively
What conclusions can we take from this research?
Prolonged TV viewing with insufficient physical activity time does significantly increase the prevalence of MS and several of its components. Individuals should increase their physical activity levels to meet the guidelines and reduce overall time spent watching TV per week.
These conclusions support numerous other studies which suggest sedentary activities should be replaced with more active behaviour like consistent physical activity to improve all risk factor components of metabolic syndrome. Eckel R.H, Grundy S.M, Zimmet P.Z. The Lancet. 2005;365:1415-28. Lakka TA, Laaksonen DE, Lakka HM, Männikkö N, Niskanen LK, Rauramaa R, Salonen JT. Sedentary Lifestyle, Poor Cardiorespiratory Fitness, and the Metabolic Syndrome. Medicine & Science in Sports & Exercise. 2003;35(8):1279-86.
Practical advice:
Clinically, management of metabolic syndrome should focus on the underlying risk factors such as sedentary behaviours, physical inactivity, obesity/overweight, and diet.
Sedentary Behaviour
Individuals should reduce sedentary behaviors by breaking up long periods of sitting as often as possible. The following strategies can be applied;
Strategies at work
Walking during lunch breaks instead of eating behind a desk
Consider standing desks to increase activity
Use the stairs instead of the elevator
Strategies at home
Listen to an audiobook and perform household activities rather than reading on the lounge
Change the channel physically rather than using a remote
Set a reminder on your smart device to move more often
Other strategies
Consider your mode of transport, walk to work rather than drive to decrease sitting time
Physical Activity
The Australian Government has provided the following guidelines Australian Government- Department of Health. Australia's Physical Activity and Sedentary Behaviour Guidelines: Commonwealth of Australia; 2017:
Accumulate 150-300 minutes of moderate intensity activity each week
Accumulate 75-150 minutes of vigorous activity each week
Perform at least 2 muscle-strengthening sessions a week
Further information/resources
Metabolic Syndrome resources
Nutrition Australia- Metabolic Syndrome
The Metabolic Syndrome
Metabolic Syndrome brochure
Organisations within the area
Diabetes Australia
The Heart Foundation
Obesity/Overweight in Australia
Physical activity and sedentary behaviour related resources
Make your move- families
Australia's Physical Activity and Sedentary Guidelines
What is Sedentary Behaviour?
Healthy eating resources
The Australian Guide to Healthy Eating
Eat for Health Calculators
Nutrition and Healthy Eating
References