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Appendix I
Data Sources and Study Methodology: SNDA-III and 2008 Diet Quality Report1

THIRD SCHOOL NUTRITION DIETARY ASSESSMENT STUDY

Sample Design and Sampling

The Third School Nutrition Dietary Assessment Study (SNDA-III) (USDA, 2007a) sample was designed to be representative of all public school food authorities (SFAs) participating in the NSLP, schools in those SFAs, and students in grades 1–12 in those schools. The SFAs sampled were selected with probability proportional to size (PPS; the measure of size was the student enrollment). Within each SFA, one elementary school, one middle school, and one high school were selected with PPS, in general (in districts without all three levels, the procedures were adjusted). The students within the schools were randomly sampled. In addition, a supplemental sample of SFAs and schools from which no student-level data were collected was included to provide additional precision for school-level estimates. If any SFAs, schools, or students declined to participate in the data collection effort, they were replaced by randomly chosen substitutes.

SFAs eligible for the sample were public SFAs that were located in the continental United States and that did not serve either residential facilities or solely special education students. The schools within these SFAs were eligible unless they served only prekindergarten, kindergarten, or special education students. All students in grades 1–12 in these schools except those in self-contained special education classes were eligible to participate. Students in self-contained special education classes were omitted from the study because of concerns about their ability to complete the recall interview.

A total of 130 SFAs participated in the study. School-level data were collected from 398 schools in these SFAs. Student-level data were collected onsite from students in a random subset of 287 schools in 94 SFAs. About 8 students per school completed both a dietary recall and had a parent complete an interview, the criteria for being included in the analysis sample; 2,314 students met those criteria.

1

Sources: the third School Nutrition Dietary Assessment (USDA, 2007a) and Diet Quality of American School-Age Children by School Lunch Participation Status: data from the National Health and Nutrition Examination Survey, 1999–2004 (USDA, 2008l).



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Appendix I Data Sources and Study Methodology: SNDA-III and 2008 Diet Quality Report1 THIRD SCHOOL NUTRITION DIETARY ASSESSMENT STUDY Sample Design and Sampling The Third School Nutrition Dietary Assessment Study (SNDA-III) (USDA, 2007a) sample was designed to be representative of all public school food authorities (SFAs) participating in the NSLP, schools in those SFAs, and students in grades 1–12 in those schools. The SFAs sampled were selected with probability proportional to size (PPS; the measure of size was the student enrollment). Within each SFA, one elementary school, one middle school, and one high school were selected with PPS, in general (in districts without all three levels, the procedures were adjusted). The students within the schools were randomly sampled. In addition, a supplemental sample of SFAs and schools from which no student-level data were collected was included to provide additional precision for school-level estimates. If any SFAs, schools, or students declined to participate in the data collection effort, they were replaced by randomly chosen substitutes. SFAs eligible for the sample were public SFAs that were located in the continental United States and that did not serve either residential facilities or solely special education students. The schools within these SFAs were eligible unless they served only prekindergarten, kindergarten, or special education students. All students in grades 1–12 in these schools except those in self- contained special education classes were eligible to participate. Students in self-contained special education classes were omitted from the study because of concerns about their ability to complete the recall interview. A total of 130 SFAs participated in the study. School-level data were collected from 398 schools in these SFAs. Student-level data were collected onsite from students in a random subset of 287 schools in 94 SFAs. About 8 students per school completed both a dietary recall and had a parent complete an interview, the criteria for being included in the analysis sample; 2,314 students met those criteria. 1 Sources: the third School Nutrition Dietary Assessment (USDA, 2007a) and Diet Quality of American School- Age Children by School Lunch Participation Status: data from the National Health and Nutrition Examination Survey, 1999–2004 (USDA, 2008l). 161

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162 NUTRITION STANDARDS AND MEAL REQUIREMENTS Collection and Analysis of Dietary Recall Data SNDA-III dietary recalls were collected by using a modified version of the Automated Multiple Pass Method software (version 2.3, 2003, Agricultural Research Service, Food Surveys Research Group, Beltsville, MD), which has been used to collect data for the for National Health and Nutrition Examination Survey (NHANES) since 2003. Children in middle and high schools were interviewed in the morning and reported the previous day’s intake (from midnight to midnight). Because young children tend to have difficulty recalling their intakes, interviews with young children were completed in two parts and with parental assistance. These children were first interviewed during the school day, after lunch if possible, and were asked to report everything that they had consumed that day since awakening. They were then interviewed a second time to report their intakes for the rest of the 24-hour period. The second interviews were conducted on the next day, if possible, and were conducted no more than 48 hours after the first interview. Parents attended the second in-person interviews and were asked to help their children recall and describe the foods and beverages consumed. The SurveyNet coding system (version 3.14, 2004, Agricultural Research Service, U.S. Department of Agriculture [USDA], Beltsville, MD) was used to link each item reported in the 24-hour recalls to the Food and Nutrient Database for Dietary Studies (FNDDS; version 1.0, 2004, Agricultural Research Service, Food Surveys Research Group, Beltsville, MD). Subsequently, for foods and beverages that were obtained at school from reimbursable meal sources and that were reported on school menus, FNDDS nutrient values were replaced with nutrient values from the analysis of the school menus (USDA, 2007a). This step ensured that foods provided as part of the National School Lunch Program and the School Breakfast Program were represented in the analysis as accurately as possible. For example, rather than hamburgers or cheese pizzas obtained at school being consistently represented by the default values available in the nutrient database, the nutrient value of the hamburgers and pizzas actually served in each child’s school were used. Thus, if a school purchased extra-lean hamburger patties or pizzas made with less or low-fat cheese, this was reflected in the 24-hour recall data. 2008 DIET QUALITY REPORT All tabulations for the Diet Quality of American School-Age Children by School Lunch Participation Status (referred to as the 2008 Diet Quality Report) are based on data from NHANES 1999–2004, analyzed alone or in conjunction with data from the MyPyramid Equivalents Database. NHANES is conducted by the National Center for Health Statistics (NCHS), which is part of the Centers for Disease Control and Prevention. NHANES has been conducted on a periodic basis since 1971. Beginning in 1999, NHANES has been a continuous annual survey and data are released in public data files every 2 years (e.g., 1999–2000, 2001–2002, and 2003–2004). NCHS recommends that data from two or more 2-year cycles of the continuous NHANES be combined to increase the sample size and produce estimates with greater statistical reliabilities. Most of the tabulations presented in this report are based on three 2-year cycles of NHANES data (1999–2004) and are based on data from the following NHANES data files: • Body Measures (BMX); • Demographics (DEMO);

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APPENDIX I 163 • Dietary Interview Individual Food Files (DRXIFF); and • Dietary Interview, Total Nutrient Intakes (DRXTOT). The analysis sample for estimates of usual nutrient intakes included 3,546 children who were enrolled in school and completed a 24-hour recall during NHANES 1999–2004 on a weekday when school was in session. 2,3 Estimates of MyPyramid food intakes are based on a sample of 2,597 children who completed a 24-hour recall under similar circumstances during NHANES 1999–2002. 4 2 The sample was limited in this manner to capture dietary behavior among children attending school. NHANES did not begin collecting data on whether a child attended school on the day of the dietary recall until 2003. For the other years, school calendars collected from counties represented in the NHANES sample were used to identify the calendar dates when school was likely to be in session. However, some children may not actually have been in school on the day of the recall because of illness, the children were absent for another reason, the school had a snow day, or the school was closed for some other reason. 3 NHANES did not begin collecting the second 24-hour recall needed to estimate usual energy and nutrient intake distributions until the 2003 data collection cycle. The second recall is attempted with all respondents and is done by telephone. In 2003–2004, 87 percent of the NHANES respondents who completed the first 24-hour call completed the second recall. The usual energy and nutrient intake distributions reported in the 2008 Diet Quality Report are based on single 24-hour recalls reported in NHANES 1999–2004 and the second 24-hour recalls reported in NHANES 2003–2004. 4 Children in the NHANES 2003–2004 sample were not included in these tabulations because a companion database used to estimate food intakes (the MyPyramid Equivalents Database for USDA Food Codes [version 1.0; USDA, 2006a]) provides data only for NHANES 1999–2000 and 2001–2002.

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