Exercise as it relates to Disease/Adolescents: improving physical activity and sedentary behaviour

Adolescents: improving physical activity and sedentary behaviour
The following is an analysis of the article "Successful overweight prevention in adolescents by increasing physical activity: a 4-year randomized controlled intervention" by Arveiler et al.(2008)

Background
It has long been understood that obesity results in a greater risk of consequential poor health such as type 2 diabetes, increased cardiovascular risk factors and also an increased mortality rate . Looking specifically at the last two generations, the prevalence of adolescent obesity has been steadily increasing (2) This is believed to be due to a decrease in physical activity and an increase in sedentary behaviour during this age group. Other research also suggests that an active lifestyle during adolescence will lead to an active lifestyle later in life. Interventions are needed to counter this global problem to ensure this trend is not continued. Low level interventions such as measuring physical activity, encouraging schools to get adolescents to be involved in at least 150 minutes of physical activity a week, and educating adolescents about the importance of physical activity could be easily implemented. This study focuses on an intervention designed to promote physical activity by changing attitudes through discussion and the use of interesting and engaging physical activity, and also by providing social support and environmental changes encouraging different types of physical activity

Source of the research
The study was carried out by the Louis Pasteur University of Strasbourg, France. The research paper was published in the International Journal of Obesity (2008). To ensure a broad socioeconomic representation, the sample of schools was stratified by geographical location, city size and the type of economic neighbourhood. Four pair of schools were randomly selected from 77 public middle schools from the Department of Bas-Rhin (Eastern France) region, and from those, 954 students aged 12 (sixth graders) agreed to participate in the study.

Given the specific nature of the region, some of the instruments used such as the questionnaire were modified to better fit French physical activity habits. However, the vast majority of the study and the methods used could be applied to similar interventions around the world.

Research type
The research was a randomised controlled study. 479 students were included in the control cohort and 475 students in the group where interventions were trialled. All participants were monitored over the four-year study. Data was collected via the following body measurements: body mass index (BMI), body composition, plasma, lipids and glucose levels, insulin resistance and also through specific physical activity questionnaires.

Methodology
The four-year randomised trial started in 2002 across eight middle schools in Eastern France. The intervention, randomised at the school level, was designed to promote physical activity by changing attitudes through raising awareness and by providing social support and environmental changes which encouraged and normalised physical activity. A total of 954 students were involved (479 controls and 475 intervention students) in the intervention program that started during the first school year and lasted until the end of the fourth school year. The intervention program was in addition to the standard school curriculum requirements for physical education (which, in France, consists of three 50-min physical education classes per week).

The control students followed their usual school curriculum without any changes. The theory-based multilevel intervention, were conducted both in the school setting and also involved other partnerships with three main objectives: (1) changing attitudes toward physical activity, (2) promoting social support by parents and educators,(3) providing environmental and institutional conditions encouraging the adolescents to use the knowledge and physical activity skills they had acquired. The program included an educational component which looked at the results of physical activity and the risks of sedentary behaviour.

All interventions included an element of fun aimed at increasing the number of activities and the opportunities for the students to be more active in a variety of ways.

I believe the support system to help encourage physical activity was very positive; this is an element which is rarely considered when trying to promote physical activity at the school level. This, in addition to education on the risks of not exercising and the multitude of benefits gained from exercise are essential in decreasing sedentary behaviour in the wider population. By raising awareness early in adolescence we are more likely to maintain a healthy attitude throughout the life of an individual. Alerting students to the health risks they face if they remain inactive, and by educating them at a young age on how to combat these issues is far more likely to result in a positive outcome for the group.

As we all know, making activities fun is crucial to the success of such a project. If the students do not enjoy the programme, they are unlikely to continue in the long term. Allowing opportunities to interact with their peers and by having a variety of different exercise activities available were significant in this study.

One aspect of the study is obviously problematic in my opinion. Even though the questionnaires were administered by trained interviewers to small groups (3–6 children), there is always a tendency for participants to overestimate their physical activity behaviour and to underestimate sedentary levels. Any participant, even a child will know that exercise is considered a good thing, and if this is the only measure of the amount of activity taking place it is likely to be somewhat unreliable. Physical activity logs, regularly monitored by parents, teachers or qualified individuals could be another way to monitor physical activity levels and sedentary behaviour rather than questionnaires which can be very inaccurate, depending on the perception of the subject at this time.

Another limitation that I found, is not all the statistics quoted in the article were supported with data. For example, the study found that after 4 years, 4.2% of the initially non-overweight students were overweight in the intervention cohort, compared to 9.8% in the control. Having all statistics quoted would allow for the reader to fact check, rather than rely on the authors comments.

Another restriction of the research is that it is conducted only in one country and we are not clear on the extent of the differences between the schools. To strengthen the research a similar experiment should be conducted in other countries, notably not within Europe, to be able to make inferences about the population in general.

Results
Arveiler et al found that the students in the intervention group showed a lower increase in BMI over the study compared to that of the control. It was also found that the total incidence of overweight participants after the study was lower in the intervention group than that of the control group (Graph 1). The study found that after 4 years, 4.2% of the initially non-overweight students were overweight in the intervention cohort, compared to 9.8% in the control. A beneficial increase of high-density lipoprotein cholesterol concentrations was also observed, however, the short term BMI effects in overweight students did not continue over time. It was also found that the amount of supervised leisure activity increased in the intervention students, whereas it slightly decreased in the control group over the same period. Intervention students also had a greater reduction over time of television and screen viewing compared to the control group. It was also found that initially overweight students however had a higher rise in BMI in the intervention group, compared to the control group. Table 1

Conclusion
Adolescent interventions focusing on changing attitudes towards physical activity could potentially be an effective way to combat the obesity and overweight epidemic in both adolescents and subsequently in adults, however we would require more data to confirm this. While there were some positive outcomes in some of the measured criteria, equally, there were also areas where the control group did better without an intervention, for example in the initially overweight category, the increase was greater in the intervention group compared to the control in the BMI and body fat percentage categories. One reason for this could be that these students were always going to gain weight regardless of any intervention, because of their prior disposition towards exercise, and no amount of intervention would change this.

Any large scale intervention costs significant amounts of money, and would only be sustained if the results were significantly better than that of any control group. I am not convinced this is the case in this study. My evaluation of this study is that further research must be conducted to ensure the financial investment is worthwhile.

Practical advice
My advise to a school principal who is considering participating in a program such as the one in the study is as follows: 1) Any intervention which increases the amount of physical activity for any group of students is likely to have a positive outcome. 2) Depending on the cost of the interventions, this might be a satisfactory intervention to run, if it is not financially onerous as there are positive results. 3) More research is needed to determine the best way forward for schools in a variety of different socioeconomic and cultural environments.

Further information on physical activity and sedentary behaviours in adolescents:

 * Australia's Physical Activity and Sedentary Behsviour Guidelines, Young People: http://www.health.gov.au/internet/main/publishing.nsf/Content/health-pubhlth-strateg-phys-act-guidelines/$File/FS-YPeople-13-17-Years.PDF
 * Make a Difference at Your School: http://www.cdc.gov/healthyyouth/keystrategies/pdf/make-a-difference.pdf
 * https://en.wikibooks.org/wiki/Exercise_as_it_relates_to_Disease/Strategies_to_increase_physical_activities_in_youth_sedentary_behaviour