Impact of Weight Status Reporting on Childhood Body Mass Index.

<b><i>Background:</i></b> Many states have adopted school-based BMI screening or surveillance programs in an effort to address high rates of childhood obesity, some of which involve provision of confidential BMI reports to parents. While there is evidence that parents are attuned to information in the reports, there is less evidence showing that the reports are effective in preventing excess childhood weight gain. <b><i>Methods:</i></b> Data from Arkansas, the state with the nation's first and longest running and BMI screening program, were used to measure the impact of BMI reports. This was done through a regression discontinuity design that compared future BMI <i>z</i>-scores among children falling within a narrow band around the obese and overweight thresholds. We derived the effects of BMI reports by comparing students who received different types of reports around the relevant threshold. <b><i>Results:</i></b> While we are unable to detect any differences in BMI <i>z</i>-scores between the children who received the overweight report and the children who received the healthy weight report, we detected some differences between children who received the obese report and children who received the overweight report. These findings hold across subsamples by age, minority status, and school meal status. <b><i>Conclusions:</i></b> Based on these data, overweight or obese reports to do not meaningfully impact future BMI <i>z</i>-scores. This may be due, in part, to the format of parental reports, which may dampen the surprise element of an overweight or obese report.