Margaret A. McDowell

Dietary methods research in the third National Health and Nutrition Examination Survey: underreporting of energy intake.

Assessment of diet is a critical component of the third National Health and Nutrition Examination Survey (NHANES III), which was designed to describe the health and nutritional status of the US population. We analyzed data collected with the primary dietary assessment instrument used in NHANES III, the 24-h recall, for 7769 nonpregnant adults aged > or = 20 y to investigate underreporting of total energy intake. Underreporting was addressed by computing a ratio of energy intake (EI) to estimated basal metabolic rate (BMRest). EI:BMRest was 1.47 for men and 1.26 for nonpregnant women; a population level of 1.55 is expected for a sedentary population. About 18% of the men and 28% of the women were classified as underreporters. Underreporting of energy intake was highest in women and persons who were older, overweight, or trying to lose weight. Underreporting varied according to smoking status, level of education, physical activity, and the day of the week the 24-h recall covered. Additionally, underreporting was associated with diets lower in fat (P < 0.01) and alcohol (P < 0.01 in women) when expressed as a percentage of total energy intake.

Hair Mercury Levels in U.S. Children and Women of Childbearing Age: Reference Range Data from NHANES 1999–2000

Exposure to methyl mercury, a risk factor for neurodevelopmental toxicity, was assessed in U.S. children 1–5 years of age (n = 838) and women 16–49 years of age (n = 1,726) using hair mercury analysis during the 1999–2000 National Health and Nutrition Examination Survey (NHANES). The data are nationally representative and are based on analysis of cross-sectional data for the non-institutionalized, U.S. household population. The survey consisted of interviews conducted in participants’ homes and standardized health examinations conducted in mobile examination centers. Distributions of total hair mercury levels expressed as micrograms per gram hair Hg and the association of hair Hg levels with sociodemographic characteristics and fish consumption are reported. Geometric mean (standard error of the geometric mean) hair mercury was 0.12 μg/g (0.01 μg/g) in children, and 0.20 μg/g (0.02 μg/g) in women. Among frequent fish consumers, geometric mean hair mercury levels were 3-fold higher for women (0.38 vs. 0.11 μg/g) and 2-fold higher for children (0.16 vs. 0.08 μg/g) compared with nonconsumers. The NHANES 1999–2000 data provide population-based data on hair mercury concentrations for women and children in the United States. Hair mercury levels were associated with age and fish consumption frequency.

Total folate and folic acid intake from foods and dietary supplements in the United States: 2003–2006

BACKGROUND The term total folate intake is used to represent folate that occurs naturally in food as well as folic acid from fortified foods and dietary supplements. Folic acid has been referred to as a double-edged sword because of its beneficial role in the prevention of neural tube defects and yet possible deleterious effects on certain cancers and cognitive function. Previous monitoring efforts did not include folic acid from dietary supplements and are therefore not complete. OBJECTIVE Our objective was to combine data on dietary folate (as measured by two 24-h recalls) and folic acid from dietary supplements (collected with a 30-d frequency questionnaire) with the use of the bias-corrected best power method to adjust for within-person variability. DESIGN The National Health and Nutrition Examination Survey (NHANES) is a nationally representative, cross-sectional survey. Linear contrasts were constructed to determine differences in dietary and total folate intake for age and racial-ethnic groups by sex; prevalence of inadequate and excessive intakes is presented. RESULTS In 2003-2006, 53% of the US population used dietary supplements; 34.5% used dietary supplements that contained folic acid. Total folate intake (in dietary folate equivalents) was higher for men (813 +/- 14) than for women (724 +/- 16) and higher for non-Hispanic whites (827 +/- 19) than for Mexican Americans (615 +/- 11) and non-Hispanic blacks (597 +/- 12); 29% of non-Hispanic black women had inadequate intakes. Total folate and folic acid intakes are highest for those aged > or =50 y, and 5% exceed the Tolerable Upper Intake Level. CONCLUSIONS Improved total folate intake is warranted in targeted subgroups, which include women of childbearing age and non-Hispanic black women, whereas other population groups are at risk of excessive intake.

Trends of elevated blood pressure among children and adolescents: data from the National Health and Nutrition Examination Survey 1988-2006.

BACKGROUND Elevated blood pressure (EBP) in children and adolescents increases future risk of cardiovascular disease. Among children and adolescents, increased weight is associated with EBP. METHODS National cross-sectional data for children and adolescents aged 8-17 years from the National Health and Nutrition Examination Surveys (NHANESs): 1988-1994, 1999-2002, and 2003-2006. The main outcome measures were EBP and pre-EBP estimates. RESULTS Overweight boys (odds ratio (OR) 1.54, confidence interval (CI) 1.11-2.13) and both obese boys and girls were significantly more likely to be classified as pre-EBP (boys, OR 2.81, CI 2.13-3.71; girls, OR 2.55, CI 1.75-3.73) and having EBP (boys aged 8-12 years, OR 6.06, CI 2.73-13.44, boys aged 13-17, OR 9.62 CI 4.86-19.06; girls, OR 2.33, CI 1.31-4.13) when compared to the reference weight and controlling for all other covariates.During 2003-2006, 13.6% (s.e. = 1.2) of boys aged 8-17 years and 5.7% (s.e. = 0.7) of the girls aged 8-17 years were classified as pre-EBP and 2.6% (s.e. = 0.5) of the boys aged 8-17 and 3.4% (s.e. = 0.7) of the girls aged 8-17 were having EBP. After controlling for age, race/ethnicity, and body mass index (BMI), girls only were significantly more likely to have EBP during 2003-2006 than during 1988-1994 (OR 2.17, CI 1.05-4.49). In contrast, adolescent boys aged 13-17 years were significantly less likely to be having EBP during 2003-2006 than during 1988-1994 (OR 0.32, CI 0.13-0.81). CONCLUSIONS Obesity is strongly, positively, and independently associated with EBP and pre-EBP among youths. However, controlling for all covariates including BMI, EBP has increased among girls but decreased among adolescent boys aged 13-17, during 2003-2006 when compared with 1988-1994.

Total energy intake of the US population: the third National Health and Nutrition Examination Survey, 1988-1991.

The third National Health and Nutrition Examination Survey (NHANES III) was conducted to assess the health and nutritional status of the US population. As part of the nutritional status assessment, reliable 24-h dietary recalls were collected for 14,801 examined persons. Mean (+/- SEM) energy intakes are reported for persons aged > or = 2 mo by age, sex, and race-ethnicity. Males had higher mean energy intakes than did females. Energy intakes peaked during late adolescence and young adulthood and declined thereafter. Energy intake patterns were similar among non-Hispanic whites, non-Hispanic blacks, and Mexican Americans. Underreporting was addressed by computing a ratio of energy intake (EI) to estimated basal metabolic rate (BMRest). This ratio (EI:BMRest) was 1.47 for adult males and 1.26 for nonpregnant adult females. Overweight adults had a lower mean EI:BMRest (1.09 in females and 1.28 in males). Underreporting in food consumption surveys remains problematic among females and overweight persons.

Calcium intakes of Mexican Americans, Cubans, Puerto Ricans, non-Hispanic whites, and non-Hispanic blacks in the United States

OBJECTIVE To compare dietary calcium intakes from food in Mexican Americans, Cubans, Puerto Ricans, non-Hispanic whites, and non-Hispanic blacks aged 11 through 74 years. DESIGN Population survey data from the Hispanic Health and Nutrition Examination Survey and the second National Health and Nutrition Examination Survey were used to calculate calcium intake from a single 24-hour recall. These data were compared by age and sex between the five population groups. Food sources of calcium in the three Hispanic groups were also examined using 24-hour recall data. SUBJECTS The sample consisted of 11,773 non-Hispanic whites, 1,728 non-Hispanic blacks, 4,739 Mexican Americans, 1,076 Cubans, and 1,835 Puerto Ricans. MAIN OUTCOME MEASURES Mean calcium intake, percentage intake of Recommended Dietary Allowance, and, for Hispanics, food sources of calcium. STATISTICAL ANALYSES Means were compared within age and sex groups between the five population groups using a t test. RESULTS Calcium intakes from food in the three Hispanic groups were similar to intakes of non-Hispanic whites and higher than intakes of non-Hispanic blacks. Although dairy foods were the main sources of calcium for Hispanics, corn tortillas were important calcium sources among Mexican Americans. Women consumed less calcium than the Recommended Dietary Allowance in all age and racial or ethnic groups. APPLICATIONS When assessing calcium intakes of the three Hispanic groups, ethnic differences in food sources of calcium need to be considered. Efforts to increase calcium intake in Hispanics also need to account for ethnic differences.

Total folate and folic acid intakes from foods and dietary supplements of US children aged 1–13 y

BACKGROUND Total folate intake includes naturally occurring food folate and folic acid from fortified foods and dietary supplements. Recent reports have focused on total folate intakes of persons aged > or =14 y. Information on total folate intakes of young children, however, is limited. OBJECTIVE The objective was to compute total folate and total folic acid intakes of US children aged 1-13 y by using a statistical method that adjusts for within-person variability and to compare these intakes with the Dietary Reference Intake guidelines for adequacy and excess. DESIGN Data from the 2003-2006 National Health and Nutrition Examination Survey, a nationally representative cross-sectional survey, were analyzed. Total folate intakes were derived by combining intakes of food folate (naturally occurring and folic acid from fortified foods) on the basis of 24-h dietary recall results and folic acid intakes from dietary supplements on the basis of a 30-d questionnaire. RESULTS More than 95% of US children consumed at least the Estimated Average Requirement (EAR) for folate from foods alone. More than one-third (35%) of US children aged 1-13 y used dietary supplements, and 28% used dietary supplements containing folic acid. Supplement users had significantly higher total folate and folic acid intakes than did nonusers. More than half (53%) of dietary supplement users exceeded the Tolerable Upper Intake Level (UL) for total folic acid (fortified food + supplements) as compared with 5% of nonusers. CONCLUSIONS Total folate intakes of most US children aged 1-13 y meet the EAR. Children who used dietary supplements had significantly higher total folate intakes and exceeded the UL by >50%.

Health characteristics of U.S. adults by body mass index category : Results from NHANES 1999-2002

Objectives. We examined self-reported health characteristics, health care utilization, activity patterns, and demographic characteristics of U.S. adults 20 years and over by body mass index (BMI) category. We hypothesized that overweight and obese adults would report fair/poor health more often, report more health provider visits annually, experience more joint pain, report greater limitations in their daily activities, and report more hours of sedentary leisure-time activity than normal-weight adults. Methods. Self-reported health characteristics of U.S. adults from the National Health and Nutrition Examination Survey (NHANES) 1999–2002 were examined for three BMI categories: normal weight (BMI 18.5–24.9), overweight (BMI 25.0–29.9), and obese (BMI ≥30.0). Covariates included gender, race/ethnicity, cigarette smoking, and educational attainment. We examined BMI group differences using descriptive and regression methods. Results. Compared to normal-weight individuals, overweight individuals reported fair/poor health more often, more limitations in daily activities, and more health provider contacts. Overweight and obese subjects reported more hours of television watching and video game use compared to normal-weight subjects. Conclusion. Our findings are useful to describe the health characteristics of U.S. adults and may be used to anticipate future demand for health services and to support intervention programs that help individuals achieve desirable weight status.

Quantifying portion sizes for selected snack foods and beverages in 24-hour dietary recalls

Abstract The purpose of this study was to determine individual recall accuracy for selected snack foods and beverages using various measurement aids and to investigate the cognitive strategies associated with aid selection for snacks and beverages in a 24-hour recall. Individuals (n=202) estimated the amounts of snack foods and beverages consumed the previous day while watching a 30-minute videotaped television program. Individuals were provided ad libitum amounts of snacks (potato chips, tortilla chips, or popcorn alone or with salsa or mixed nuts) in various sizes bags and or bowls. Beverages were provided with snacks in either standard 20 oz bottles or 8, 10, or 16 oz glasses. During consumption estimation, a variety of aids including aids used in previous National Health and Nutrition Examination Studies (NHANES) were provided. Average recall errors, by weight, for each of the 10 snack/container groups were within 16 g with percentage recall errors for these groups ranging from −36.8 to +38.7%. Bowls were selected to estimate consumption at least eight times more than any other aid and provided an accurate average recall estimation. Beverage consumption was consistently overestimated. Respondent confidence in estimation accuracy did not correlate with actual error for either snacks or beverages. Results suggest that average recall errors for groups consuming snacks are likely to be within one-half of a standard portion size and that bowls provide a means by which individuals can accurately estimate snack consumption in a 24-hour recall.

US demographic trends in mid-arm circumference and recommended blood pressure cuffs for children and adolescents: data from the National Health and Nutrition Examination Survey 1988-2004.

ObjectiveMid-arm circumference measurement is a prerequisite for the selection of properly sized blood pressure cuffs for accurate blood pressure readings in children and youth. This study examined recent trends in the mid-arm circumference distribution and the distribution of corresponding recommended blood pressure cuff sizes using National Health and Nutrition Examination Survey III (1998–1994) and National Health and Nutrition Examination Survey 1999–2004 data. DesignBoth studies were complex, cross-sectional surveys providing nationally representative samples of the civilian noninstitutionalized US population. ParticipantsChildren of 7–17 years of age were studied. A total of 2515 boys and 2596 girls participated in National Health and Nutrition Examination Survey III, and 3941 boys and 3917 girls in National Health and Nutrition Examination Survey 1999–2004. Statistical AnalysisMean mid-arm circumference and recommended National High Blood Pressure Education Program Working Group on High Blood Pressure in Children and Adolescents defined blood pressure cuff sizes were assessed by sex, age, and race/ethnicity. US boys aged 7–12 years and girls aged 7–12 and 13–17 years had significant increases in mid-arm circumference (P<0.05) across the two surveys. Moreover, from 1988–1994 to 1999–2004, there were statistically significant increases in the percentage of boys (age 7–12 and 13–17 years) and girls (age 13–17 years) needing large blood pressure adult cuffs (P<0.05). National Health and Nutrition Examination Survey 1999–2004 data show that both boys and girls aged 13–17 years had a mean mid-arm circumference ≥27 cm, which requires an adult blood pressure cuff fit. Furthermore, 52% boys and 42% girls aged 13–17 years, required a standard adult cuff fit. ConclusionMean mid-arm circumference has increased among US children and adolescents, with important implications for the accuracy of blood pressure measurement in clinical practice.