There is no relationship between academic achievement and body mass index among fourth-grade, predominantly African-American children.

School-based initiatives to combat childhood obesity may use academic performance to measure success. This cross-sectional study investigated the relationship between academic achievement and body mass index percentile, socioeconomic status (SES), and race by linking existing datasets that are not routinely linked. Data from a school-based project (with National Institutes of Health funding) concerning dietary recall accuracy were linked with data from the state's Department of Education through the state's Office of Research and Statistics. Data were available on 1,504 fourth-grade, predominantly African-American children from 18 schools total in one district in South Carolina during the 2004-2005, 2005-2006, and 2006-2007 school years. School staff administered standardized tests in English, math, social studies, and science. Researchers measured children's weight and height. Children were categorized as low-SES, medium-SES, or high-SES based on eligibility for free, reduced-price, or full-price school meals, respectively. Results from marginal regression analyses for each sex for the four academic subjects, separately and combined, showed that test scores were not related to body mass index percentile, but were positively related to SES (P values <0.0001), and were related to race, with lower scores for African-American children than children of other races (P values <0.0039). Cost-efficient opportunities exist to create longitudinal data sets to investigate relationships between academic performance and obesity across kindergarten through 12th-grade children. State agencies can house body mass index data in state-based central repositories where staff can use globally unique identifiers and link data across agencies. Results from such studies could potentially change the way school administrators view nutrition and physical education.