Friday, August 14, 2009

More Water, Fewer Sweetened Beverages: Effects on Children

From Medscape Pediatrics > Viewpoints
William T. Basco, Jr., MD, FAAP

Read more Promotion and Provision of Drinking Water in Schools for Overweight Prevention: Randomized, Controlled Cluster Trial
Muckelbauer R, Libuda L, Clausen K, Toschke AM, Reinehr T, Kersting M
Pediatrics. 2009;123:e661-e667

The study authors sought to reduce childhood obesity through a community-wide approach. They noted that previous randomized studies had demonstrated that altering caloric intake via changing beverage types appears to be a successful method to moderate weight gain.

The study authors conducted a randomized controlled (cluster) trial that both encouraged increased intake of water and made water readily available at schools in Germany. The subjects were in the second or third grades and attended elementary schools in low-income, urban areas. There were 17 schools (1641 children) in the intervention group and 15 schools (1309 children) in the control group. The study took place during the 2006-2007 school year.

The intervention consisted of the following: installation of a new water fountain in the school (2 if the school was big enough); provision of a plastic water bottle to each child; instruction to teachers to facilitate having the children fill water bottles each morning (at school); and delivery by teachers of 4 standardized lessons over the course of the academic year (45 minutes each lesson) on water needs.

Investigators measured the children's height and weight at enrollment and at follow-up in order to calculate their body mass indices. The study authors were interested in obesity prevalence as the primary outcome. The subjects completed 24-hour recall questionnaires to record beverage consumption (volume and type) at enrollment and at follow-up.

In the final analyses, the study authors controlled for subject weight at baseline and sex. Baseline juice consumption was slightly higher in the intervention groups (by 0.2 glasses per day), but the groups were otherwise very similar at enrollment. At enrollment, the intervention group had a 23.4% prevalence of overweight, and the control group 25.9%, but this difference was not significant (P = .21). However, at the end of the intervention, 23.5% (increase of 0.1 percentage point) of the intervention group and 27.8% (increase of 1.9 percentage points) of the control group were obese, and this difference was significant ( odds ratio for obesity in intervention, 0.69; 95% confidence interval, 0.48-0.98).

On average, the intervention group increased water consumption by 1.1 glasses per day over the control group. There were no effects on either change in juice or soft drink consumption between the groups. The study authors concluded that this combined educational and environmental intervention was effective in preventing overweight.

Impact of Change in Sweetened Caloric Beverage Consumption on Energy Intake Among Children and Adolescents
Wang YC, Ludwig DS, Sonneville K, Gortmaker SL
Arch Pediatr Adolesc Med. 2009;163:336-343

The study authors utilized 2003-2004 data from the National Health and Nutrition Examination Survey to estimate daily caloric intake due to sweetened beverages. They determined that subjects derived 35% of their beverage intake from sweetened beverages and that replacing those with water would reduce daily caloric intake by 235 kcal.

Just as reductions in cigarette smoking have been mostly achieved through societal approaches (limiting advertising, increasing prices, and limiting access, for example), interventions to reduce obesity may be most successful when attempted on larger scales. The first study by Muckelbauer and colleagues is a large-scale project with promising results. It demonstrated the potential value of advocating for healthy choices and education in local schools. It should also give some encouragement to practitioners who are "slugging it out" on a daily basis, attempting to educate parents and children about healthy food choices to limit weight gain. In addition, the second study by Wang and colleagues also offers good numbers to support this fight, with estimates of a substantial reduction in calories (over 10% of total daily caloric intake in that study) if children would replace all sweetened beverages with water.

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