October 23, 2012
Final Assignment : Sugar-Sweetened Beverages
The article “A Randomized Trial of Sugar-Sweetened Beverages and Adolescent Body Weight”(2012) aims at examining the causal relationship between the consumption of sugar-sweetened beverages and obesity among adolescents. The research for this article is a follow up of a previous pilot study that has been conducted on a period of six months involving normal weight, overweight, and obese adolescents who consumed sugar sweetened beverages regularly. Results showed that there was a significant decrease of body weight and body mass index (BMI) among the overweight and obese adolescents. Due to this result, a further study has been designed to reanalyze the data from the pilot study and further explain the effects of sugar-sweetened beverages.
The research method used was a random sample of 224 adolescents that are obese or overweight who consumed at least one serving of sugar-sweetened beverages or fruit juice per day. Participants were randomly assigned to a control group or an experimental group for two years; where one year would be an intervention and the second year a follow up. Since the participants are young, the parents provided a written consent and the participants a written assent. The multicomponent intervention aimed to reduce the consumption of sugar-sweetened beverages for one year in the experimental group by providing access to home delivery of non-caloric beverages. Motivational telephone calls with parents were conducted on a monthly basis and three check-in visits with participants. The control group on the other hand received $50 supermarket gift cards to participants at four to eight months as a retention strategy but did not instruct them on what to purchase with the cards. It is important to note that the study did not focus attention to other diet methods or physical activity, however, they have included the daily physical activity level and the amount of television watched daily.
The measures for his study:
* Demographics: sex, race, date of birth, ethnic group, parents level of education, and total annual household income. * Physical activity: in collaboration with the persons metabolic equivalence. * Television viewing: hours per day.
* Dietary intake: includes three main items. 1) beverages per servings per day: a-sugar-sweetened, b-fruit juices, c-artificially sweetened, d- unsweetened. 2) energy intake per calorie per day: a-total, b-sugar-sweetened beverages, c-fruit juices. 3)Sugar grams per day. * Weight and height: in kilograms and centimeters (these are used to compute the BMI * BMI as an outcome over the two years: used the bioelectrical impedance analysis (BIA) to calculate body fat. * Adverse events: any symptom or medical attention that was reported during the study.
One single hypothesis was formulated for this study. They hypothesized that the experimental group would gain weight at a slower rate than the control group. Results:
When testing the covariates for interaction, Hispanic ethnic group is found to be the only modifier for group differences, as they have portrayed the most change; causing the study to add an interaction term for the ethnic group. At baseline, regarding the demographics or other variables, there were no differences between the experimental and the control groups. In terms of dietary intake at year one, change in consumption of sugar-sweetened beverages was different between the control and the experimental groups; declining almost to zero for the experimental. Also meaning that the experimental group consumed more artificially or un-sweetened beverages. At year two, same results remained however, the intake of artificially sweetened beverages did not differ between the groups. Also, sugar intake in both years was less for the experimental group. In terms of the outcomes, at year one the net BMI was significant,...