Dietary methods research in the third National Health and Nutrition Examination Survey: underreporting of energy intake
Dietary methods researchin the third National Health and NutritionExaminationSurvey:underreportingof energy
R Briefel 0
Alaimo 0
T Sempos 0
A McDowell 0
0 I From the Division of Health Examination Statistics, National Center for Health Statistics, Centers for Disease Control and Prevention , Hyatts ville, MD. 2 Address reprint requests to: RR Briefel , National Center for Health Statistics , 6525 Belcrest Road, Room 1000, Hyattsville, MD 20782 , USA
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 20 y to investigate underreporting of total energy intake. Underreporting was addressed by computing a ratio of energy intake (El) to estimated basal metabolic rate (BMR@@1E).I:BMRes1 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. Underreport ing 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. Am J Clin Nutr l997;65(suppl): 1203S—9S.
Ronette; Katherine; Dietary assessment methods; energy; national nutrition surveys; National Health and Nutrition Examination Survey; NHANES; energy intake; estimated basal metabolic rate; underreporting
INTRODUCTION
Dietary interviews are included in the National Health and
Nutrition Examination Survey (NHANES) as part of the as
sessment of nutritional status (1—4). Since the First Interna
tional Conference on Dietary Assessment in 1992 (
4, 5
), di
etary research at the National Center for Health Statistics
(NCHS), Centers for Disease Control and Prevention, has
focused on two areas: release of dietary reference data from
NHANES III, conducted in 1988—1994 (6—8),and improve
ment of the comparability and usefulness of dietary intake
methods for national nutrition monitoring and tracking of
health objectives for the year 2000 (
9, 10
). A 1994 report
summarized recommendations and research needs for dietary
assessment identified by participants in an NCHS-sponsored
consensus workshop held in 1993 (
10
).
In addition to efforts to improve the comparability of dietary
data collected in national surveys, NCHS has ongoing dietary
assessment research to identify dietary indicators (ie, particular
foods or behaviors associated with diet) with use of food
frequency and 24-h recall data, to compare the intake of foods
and foods rich in certain nutrients with selected risk factors (eg,
intake of foods high in calcium with hypertension), and to
compare reported frequencies of consumption (such as never
and daily) from use of food-frequency instruments with 24-h
recall data.
In the fall of 1994, population reference data on diet for the
first nationally representative phase of NHANES III were
released (
7, 8
). Mean and median intakes of macronutrients,
vitamins, minerals, and fiber were based on I d of intake
estimated with use of 24-h recalls. Since the release of this
information, research has focused on the underreporting of
energy intake and its effect on the intake of other nutrients (1 1),
the use of multiple 24-h recalls collected in a subsample of the
population, and the effect of improved dietary assessment
methods on identifying trends in intake.
Because the NHANES dietary data are used to establish
nutrition policy, to track progress toward achieving health and
nutrition objectives, to provide reference information on nutri
ent intakes, to develop dietary guidance, and to study diet
health relations (1, 3, 12—18),continued methodologic research
is essential to proper interpretation of national dietary data. We
present the major findings on underreporting of energy intake
in NHANES III (1988—1991). The issue of underreporting is
important because it affects the interpretation of trends in diet
and overweight in the US population since NHANES II, con
ducted in 1976—1980.
SURVEY
DESIGN AND
METHODS
The NHANES III sample was designed to be representative
of the civilian noninstitutionalized population of the United
States (
1, 19
). The survey included a household interview and
a physical examination conducted in a mobile examination
center. The examination included a 24-h dietary recall, body
l203S
1204S
measurements, blood and urine tests, and recording of numer
ous other physical variables (I).
NHANES III was designed as a 6-y survey and was con
ducted in t (...truncated)