Associations of adiposity with measured and self-reported academic performance in early adolescence.

OBJECTIVE: To examine the associations of adiposity with measured and self-reported academic performance independently of demographics and physical activity among U.S. adolescents. RESEARCH METHODS AND PROCEDURES: We surveyed 666 students 11 to 14 years old from seven middle schools in Los Angeles, CA. Weight and height were measured. Actual grade point average was obtained from school records. Self-reported school grades and physical activity time were measured by questionnaire. Adiposity measures included BMI, BMI percentile (> or =85th percentile defined as at-risk-of-overweight), and percentage body fat (bioimpedance).
RESULTS: After adjusting for gender, ethnicity, age, and physical activity time, overweight at-risk status, BMI, and percentage body fat were negatively related to only self-reported (p < 0.01) but not measured grades. Level of moderate-to-vigorous physical activity time was negatively related to measured and self-reported grades, independently of adiposity (p < 0.01). DISCUSSION: To our knowledge, this is the first study to examine both body mass and body fat in relation to measured and self-reported school grades. Adiposity did not relate to actual academic performance in a sample of predominantly Latino and Asian-American adolescents. The use of measured vs. self-reported academic outcomes may represent different constructs and influence study conclusions. Cultural factors may also play a role in our findings, but this requires further study.