OBJECTIVE: To assess the impact of body mass index (BMI) screening with parental notification on weight status for California public school students. DESIGN: A natural experiment wherein nearly all California school districts conducted annual BMI screening in the fifth, seventh, and ninth grades, but parental notification of BMI screening results was optional. SETTING: Data from mandatory fitness testing in California public schools for 2001 through 2008. PARTICIPANTS: A total of 6 967 120 fifth-, seventh-, and ninth-grade youth (73% of enrolled students). INTERVENTION: School-based BMI screening with optional parent notification. MAIN OUTCOME MEASURE: Body mass index z score was the main outcome in adjusted mixed-effects linear regression models, assessing whether notifying parents of their child's BMI in a given year predicted BMI z score 2 years hence. RESULTS: Rates of parental notification of BMI screening results increased from 35% in 2001 to 52% in 2008. Body mass index notification in fifth and/or seventh grade had no impact on subsequent BMI z scores (95% confidence interval, −0.03 to 0.01) compared with no notification. No differences in the impact of notification were seen by race/ethnicity. Results did not vary with sensitivity analyses. CONCLUSIONS: These findings suggest that while BMI screening itself could have benefits, parental notification in its current form may not reduce pediatric obesity. Until effective methods of notification are identified, schools should consider directing resources to policies and programs proven to improve student health.
