Changes In BMI Percentile Status Of Elementary School Students Over One Year

Abstract

According to the Centers for Disease Control and Prevention (CDC), a normal healthy weight is considered a BMI between the 5th and 85th percentile for age and gender. National population surveys have examined BMI percentile status, but the amount of weight gain as children change weight status over a time period has not been evaluated. PURPOSE: To examine the change in BMI percentile and weight gain of elementary students over one year. METHODS: Heights and weights of 1,661 elementary students (K-4; age: 8.02±1.48 years) were measured during the spring semester during two consecutive school years using standard height stadiometer and platform scale. BMI (kg/m2) was calculated and plotted, controlling for age and gender, on charts developed by the CDC to determine weight status of underweight (<5th percentile), normal weight (<85th percentile), at risk of overweight (85th-94th percentile) or overweight (≥95th percentile). Comparisons were made between the number of students that changed weight status: normal to at risk (N-AR), normal to overweight (N-O), or at risk to overweight (AR-O) and students that maintained normal weight status (N-N) using an ANOVA. RESULTS: N-N students gained 3.24±1.53 kg and consisted of 61.95% (N=933) of the sample. The percentage of students in the N-AR group was 6.84% (N=103), and gained 6.39±2.29 kg. The AR-O group was 3.39% (N=51) of the sample and had a weight gain of 7.60±2.64 kg. Ten students were in the N-O group for a percentage of 0.66%, and gained an average of 13.29±6.34 kg. Students who changed weight status groups showed a significant difference in weight gain from the group of students who started and remained within the healthy weight category. CONCLUSION: Students remaining in the healthy weight status gain an average of 3.24±1.53 kg which can be contributed to normal growth and maturation. Students moving from a normal weight to AR or O gained 50-75% more weight than what can be attributed to normal growth and maturation. Promotions aimed at attenuating excessive weight gain among already at risk youth are essential for moderation of health.