School Meals and BMI Percentile: Secondary Analyses of Non-Self-Report Data

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DESCRIPTION (provided by applicant): There is concern that participation in food assistance programs may be related to obesity because many obese individuals are served by such programs. An Expert Panel convened in 03/2004 found no consistent evidence of association between childhood obesity and participation in the School Breakfast Program (SBP) and National School Lunch Program (NSLP). That Panel recommended investigative approaches including 1) use natural opportunities for controlled trials; 2) add weight, height, and program participation to existing studies; 3) initiate smaller studies with specific populations; and 4) use existing data sets to understand relationships. Data sets for approach 4 are available from R01 HL063189, which ended in 08/2005. Published results from a small study indicated that observed (but not self-reported) energy intake at school meals was higher for 4th-grade children of high-BMI (e85th percentile) than low-BMI (e5th and <50th percentiles). Unpublished results from preliminary analyses of data from another study provide further evidence that observed energy intake at school meals varies by 4th-grade children's BMI percentile, but results differed when self-reported energy intake was analyzed. We now propose a 2-year project using data for 4th-grade children from 4 studies for R01 HL063189. Aim 1 is to investigate a possible relationship between SBP and NSLP participation and childhood obesity. We have nametag records (compiled on an average of 10 to 34 random days) of SBP and NSLP participation in 4th-grade for 1,542 children total (51% Black, 49% White; 51% girls). Aim 1 has 2 research questions (RQs) for the 4 studies separately and combined: RQ1 - What is the relationship between BMI percentile and SBP and NSLP participation in 4th grade, and does this differ a) for SBP and NSLP participation separately vs. combined, b) by sex, and c) by race? RQ2 - How accurate are parental responses on consent forms concerning children's SBP and/or NSLP participation compared to nametag records, and does this differ by BMI percentile, sex, and race? How does RQ1 differ when parental responses are used? Aim 2 is to examine behaviors and selections for a subset of children to understand differences in actual (observed) school-meal intake. For the subset, we observed 344 children (54% Black, 46% White; 50% girls) for 1 to 3 breakfasts and 1 to 3 lunches for 1,268 total school meals (50% breakfast). For the subset, Aim 2 has 2 RQs for the 4 studies separately and combined: RQ3 - What is the relationship between BMI percentile and observed energy intake at school meals, and does this differ a) for breakfast and lunch separately vs. combined, b) by sex, and c) by race? RQ4 - To what extent are RQ3 differences explained by a) amounts eaten of standardized portions, b) trades, c) milk flavor/fat selections, d) cold (i.e., ready-to-eat cereal) vs. hot (e.g., sausage biscuit) breakfast selection, and e) ` la carte ice cream? Results will inform the design of future controlled trials and/or cohort studies to understand pathways to obesity among children who participate in SBP and NSLP. PUBLIC HEALTH RELEVANCE: Participation in the School Breakfast Program (SBP) and National School Lunch Program (NSLP) may be related to childhood obesity, but previous research has been unable to provide evidence of a consistent relationship. The secondary analyses in this project are an efficient and timely next step because results will add new knowledge and inform the design of future controlled trials and/or cohort studies aimed at understanding pathways to obesity among children who participate in SBP and NSLP. Features of our 4 existing data sets that uniquely position us to use non-self-report data to investigate the relationship between body mass index (BMI) percentile and SBP and NSLP participation as well as differences in children's actual (observed) energy intake at school meals by BMI percentile along with various aspects of observed behaviors and food/beverage selections at school meals include the following: nametag records of SBP and NSLP participation on an average of 10 to 34 random days for each of 1,542 children; observed intake at school meals for a subset of 344 children (with acceptable results from inter- observer reliability); and weight/height measurements for 1,542 children (with acceptable results from inter- measurer reliability).