Predictors of Body Mass Index among Iowa Elementary School Students

Overweight/obesity prevalence rates have been well-documented by using self-reported height and weight across age groups in Iowa. However, validity and reliability limitations related to self-reported data have been noted. Further, inadequate standardized assessments have been conducted to document the overweight/obesity prevalence rate among elementary school-aged children across the state. The current study objective was to determine the prevalence rate and predictors of overweight/obesity among Iowa elementary school students. A random sample of 30 elementary schools across the state, stratified by rural/urban status, participated. Parents provided consent and responded to questions concerning child gender, race/ethnicity, participation in the free/reduced lunch program (F/RL), and consumption of sugar-sweetened beverages (SSB). Participation rate was 76%. The majority of the participants (88%) were Caucasian; 51% were boys. Participants' mean age was 8.5 years; 32% of sampled 3rd graders were overweight/obese. The rate did not differ by gender or rural/urban school status. Students who participated in F/RL had higher BMI scores (r= –.08, p < .01). A mixed modeling statistical analysis, controlling for student nesting within schools, found that F/RL and SSB significantly predicted BMI (F = 5.3, p < .05). A two-way interaction between gender (boys) and SSB significantly predicted BMI (F = 3.0, p < .05). In conclusion, it is important to have valid and reliable measures of BMI to document increasing prevalence rates. BMI predictors can be a valuable tool to develop policies and environmental strategies to address the increasing trend. Specifically, policies to address F/RL and SSB may significantly impact BMI status.