SAN ANTONIO – Consumption of sugar-sweetened beverages was nearly eliminated among overweight and obese adolescents following a 1-year intervention involving biweekly home delivery of noncaloric beverages, and the increase in body mass index at 1 year was smaller among those adolescents than among controls.
The between-group differences for changes in body mass index and weight among the 224 participants randomized to the intervention group or to a control group were statistically significant at 1 year (–0.57 and –1.9 kg, respectively), Cara B. Ebbeling, Ph.D., reported at the annual meeting of the Obesity Society.
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Cutting down on sugary beverages in adolescents via intervention produced positive results.
The difference between the groups with respect to the primary outcome measure of change in mean BMI at 2 years did not reach statistical significance, but this finding may reflect increasing consumption of sugar-sweetened beverages in the intervention group after 1 year, decreasing intake in the control group at 1 year (perhaps due to "a secular trend resulting from efforts to eliminate these beverages from schools"), or both, said Dr. Ebbeling of Boston Children’s Hospital.
Her presentation of the findings coincided with their publication online in the Sept. 21 issue of the New England Journal of Medicine (N. Engl. J. Med. 2012 Sept. 21 [doi: 10.1056/NEJMoa1203388]).
Study participants were 9th- and 10th-grade students with an average age of 15 years and a BMI at or above the 85th percentile for sex and age (average BMI of 30). The 124 boys and 100 girls in the study had similar baseline levels of reported consumption of sugar-sweetened beverages (1.7 servings per day). Those in the experimental group received home delivery of bottled water and diet beverages every 2 weeks, and had three 20-minute check-in visits for assessment of results. Additionally, parents of the participants agreed to monthly 30-minute motivational phone calls aimed at encouraging role-modeling and removing sugar-sweetened beverages from the home, and intervention messages with instructions to drink the delivered beverages – and to not buy or drink sugar-sweetened beverages – were mailed to participants.
Control group participants received $50 supermarket gift cards at 4 and 8 months as a retention strategy, but were not instructed on what to purchase with the cards, Dr. Ebbeling said.
At 1-year follow-up, consumption of sugar-sweetened beverages in the experimental group declined to almost zero, and remained significantly lower than in the control group at 2 years, she noted.
The consumption of unsweetened beverages was significantly higher in the intervention group than in the control group at 2 years.
The investigators also found that Hispanic ethnic group was a significant effect modifier for between-group differences in the change in BMI.
"Among Hispanics, there were significant intervention effects on the change in BMI at 1 year (–1.79) and at 2 years (–2.35) and on the change in body weight at 1 year (–6.4 kg) and at 2 years (–8.8kg)," they wrote, noting that the findings, which were corroborated by a reanalysis of data from a prior 19-month prospective observational study involving 548 middle school students, should nonetheless be interpreted with caution given the small size of the Hispanic subgroup of study participants.
Strengths of the current study include a focus on a single dietary behavior in the home environment, a diverse sample, excellent retention rates of 97% at 1 year and 93% at 2 years, collection of data on dietary process measures, and assessment of physical activity and television screen time. Limitations include a small sample size relative to multisite studies and reliance on self-reporting of diet and activity information, but given that nationally representative data suggest that overweight and obese adolescents obtain about 15% of their total daily energy intake – about 300 kcal per day – from sugar-sweetened beverages, the findings, especially when considered in the context of prior studies in other age groups, provide support for public health guidelines that recommend limiting consumption of sugar-sweetened beverages, Dr. Ebbeling and her colleagues concluded.
This study was funded by the National Institute of Diabetes and Digestive and Kidney Diseases, the National Center for Research Resources, the Harvard Catalyst Clinical and Translational Science Center, and the New Balance Foundation. The observational study reanalyzed by the investigators was funded by the National Institute of Child Health and Human Development, the Centers for Disease Control and Prevention, and the Robert Wood Johnson Foundation. Author disclosures are available with the full text of the article at www.nejm.org.