Originally published by 2 Minute Medicine® (view original article). Reused on AccessMedicine with permission.

1. Implementation of ‘Water First’, a program consisting of classroom lessons, water promotion, and water stations, was associated with a lower increase in overweight prevalence compared to the control group.

2. No significant change was seen in obesity prevalence in schools exposed to the intervention.

Evidence Rating Level: 1 (Excellent)

Study Rundown:

Childhood obesity is a major risk factor for the development of chronic illnesses in adulthood. Given that sugar-sweetened beverages (SSBs) are linked to childhood overweight and obesity, this cluster-randomized control trial sought to examine if a school-based drinking water promotion program could address overweight prevalence in elementary school students by reducing SSB consumption. 18 public elementary schools that served low-income and ethnically diverse children were included in the study. ‘Water First’, a program consisting of classroom lessons, water promotion, and water stations, was implemented in 9 schools, while the other 9 served as controls. 7 and 15 months after the start of the study, participants’ BMI and self-reported dietary caloric intake were measured. At 15 months, there was a significantly lower increase in overweight prevalence in the intervention group (0.5%) compared to the control group (3.7%). However, there was no significant difference in obesity prevalence between the two groups. Intervention participants drank more water after 7 and 15 months of the program. This study adds to the limited body of evidence that supports school-based water promotion as a cost-effective intervention against overweight in childhood. However, the feasibility of implementing this labor-intensive program on a large scale is questionable, and therefore its ability to impact real-world health outcomes is difficult to ascertain. Nonetheless, this useful study demonstrates that targeting the consumption of SSBs is a promising tool to address the growing problem of childhood overweight and obesity.

In-Depth [randomized control trial]:

1262 children across 18 schools were randomized to either the intervention (n = 680, 9 schools) or the control group (n = 582, 9 schools). After losing participants to follow-up, data from 548 participants in the intervention group and 510 participants in the control group were analyzed. The participants’ mean age was 9.6 years (SD = 0.4), 47.4% were female, and 69.4% qualified for free or reduced-price meals. BMI percentile, mean BMI, BMI z-score, and prevalence of overweight, obesity, and severe obesity were calculated. From baseline to 7 months, no significant changes were seen in the proportion of overweight participants between the intervention and control groups (-0.4%) (adjusted ratio of ORs: 0.7 [CI 0.2-0.9] P = 0.68). At 15 months, intervention participants had significantly lower increases in overweight prevalence (0.5%) when compared to control participants (3.7%), as well as significantly lower change in overweight prevalence (adjusted ratio of ORs: 0.1 [CI 0.03-0.7] P = 0.017) when compared to control participants. At both follow-ups, the intervention had no effect on the prevalence of obesity or severe obesity. Dietary caloric intake was calculated from 24-hour dietary recalls at baseline and at 7 months, and between-group analyses showed no statistically significant changes over time. To measure the frequency of water consumption, 1-week beverage frequency questionnaires were used. Intervention participants, when compared to control participants, displayed a significantly greater increase in frequency of water consumption at 7 months (1 time/day for intervention participants, -0.5 time/day for control participants; adjusted percent difference in change: 23.2% [CI 13.1-34.2]) and at 15 months (0.1 time/day for intervention participants, -0.9 time/day for control participants; adjusted percent difference in change: 14.7% [CI 4.5-25.9]). Intervention participants also displayed a significantly greater decrease in the frequency of SSB consumption at 7 months (-1.1 time/day) in comparison to control participants (-0.7 time/day). This change was not statistically significant within the 18 schools that completed data collection, but sensitivity analyses that estimated a full sample including an additional 8 schools projected this greater decrease in frequency of SSB consumption in intervention participants to be significant.

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