Drinking From Water Jets in Schools Helps Students Lose Weight

Marcia Frellick

January 19, 2016

Adding "water-jet" machines to school lunchrooms in New York was significantly linked to reduced body mass index (BMI) and fewer milk carton purchases, according to a new study in JAMA Pediatrics published online January 19.

Water jets are electrically cooled, large, clear jugs that oxygenate, chill, and dispense water quickly. They cost about $1000 per machine.

New York City's Department of Health and Mental Hygiene and the Department of Education started adding the machines school by school in 2009 to increase access to drinking water at lunchtime. The idea was to get students thinking about water when they were thirsty instead of grabbing a sugar-sweetened beverage.

"This work adds to the literature on school-based water interventions and informs future efforts to curb childhood obesity," say Amy Ellen Schwartz, PhD, of the Maxwell School at Syracuse University, in New York, and colleagues, in their paper.

Almost Half of Schools Got Water Jets

Dr Schwartz and her team studied the effects of installing water jets using a school-level database of cafeteria equipment deliveries between 2008–2009 and 2012–2013. Nearly 40% of the 1227 schools (483) had received the water jets, and 744, or 60.7%, had not.

They used a difference-in-difference strategy, comparing outcomes for treated and nontreated students before and after installation of the dispensers.

"We identified a student as being 'treated' by a water jet if he or she spent 60 or more cumulative school days in a school with a water jet," they explain, cautioning however that "these estimates should be interpreted as 'intent to treat' because we did not identify whether or how much an individual student used the water jet."

This study included 1,065,562 students within New York City public elementary and middle schools. Researchers found adoption of water jets was linked with a 0.025 reduction of standardized body mass index (BMI) for boys and a 0.022 reduction of standardized BMI for girls (P < .01).

The water jets were also linked with lower likelihood of being overweight. Researchers found a 0.9-percentage-point reduction in likelihood of being overweight for boys and a 0.6-percentage-reduction in the likelihood of being overweight for girls (P < .05).

They also found a decrease in the number of half-pint cartons of milk purchased per student per year (12.3 fewer; P < .01), though the big difference was the drop in fat-free chocolate milk purchases, at 13.6 fewer half-pint cartons per student per year (P < .01), with an insignificant decrease in purchases of low-fat and skim white milk.

"Water jets could be an important part of the toolkit for obesity-reduction techniques at the school setting," the researchers conclude.

Modest Effects but Study Shows Scalability

In an accompanying editorial, Lindsey Turner, PhD, with the College of Education at Boise State University in Idaho, and Erin Hager, PhD, with the department of pediatrics, growth and nutrition division, and department of epidemiology and public health at the University of Maryland School of Medicine in Baltimore, agree with the authors' conclusions and estimate the potential for benefit beyond the study population.

"Although the size of the effect reported by Schwartz et al for this drinking water intervention is relatively modest, it is nevertheless significant and therefore quite valuable," they write.

"Although school-based interventions sometimes have relatively small effects, at a population level, such interventions can improve health outcomes for a large number of children, and the work of Schwartz et al provides evidence of scalability on a large level."

They point out that more consumption of water and less of sugared drinks has other health benefits as well, such as fewer dental caries and improved cognitive performance from proper hydration.

And at $1000 per machine, the intervention is much less costly than many other interventions to fight obesity.

"Sometimes, a very simple intervention can have a powerful effect," they note.

"The study by Schwartz and colleagues in this issue of JAMA Pediatrics adds to a growing body of evidence supporting the importance of providing drinking-water access in schools."

They note that water access in schools was a key provision of the Healthy, Hunger-Free Kids Act of 2010, which required all schools participating in federal meals programs to provide students with free access to drinking water in the cafeteria during lunchtime.

But in practice, issues such as water quality, taste, and sanitation may deter students from accessing such drinking water — at approximately a quarter of middle and high schools nationwide, administrators reported concerns about water-quality problems in drinking fountains, Drs Turner and Hager point out.

This project was supported by the Eunice Kennedy Shriver National Institute of Child Health and Human Development. Neither the authors nor editorialists report any relevant financial relationships.

JAMA Pediatr. Published online January 19, 2016. Article, Editorial

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