Misreporting in nutritional surveys: methodological implications

Preview:

Citation preview

119

Nutr Hosp. 2015;31(Supl. 3):119-127ISSN 0212-1611 • CODEN NUHOEQ

S.V.R. 318

Misreporting in nutritional surveys: methodological implicationsItandehui Castro-Quezada1, Cristina Ruano-Rodríguez1,2, Lourdes Ribas-Barba2,3 and Lluis Serra-Majem1,2,3

1Research Institute of Biomedical and Health Sciences, University of Las Palmas de Gran Canaria, Spain. 2Ciber Fisiopatología Obesidad y Nutrición (CIBEROBN, CB06/03), Instituto de Salud Carlos III (ISCIII), Spanish Government, Madrid, Spain. 3Community Nutrition Research Centre of the Nutrition Research Foundation, University of Barcelona Science Park, Spain.

Abstract

The reliability of the information collected in dietary assessment can be affected by different factors. One of the main sources of error in dietary assessment is misre-porting which encompass under- and overreporting. Un-derreporting of food intake is one of the major problems in the assessment of habitual dietary intake. Physical and psychosocial characteristics that are related to energy underreporting include sex, age, weight, BMI, fear of negative evaluation and dieting among others. At pre-sent, diverse reference methods are employed to verify the results of dietary assessment and double labelled wa-ter is used as the gold standard method. Underreporting affects the estimation of nutrient intake and also alters associations between diet and disease assessed in epide-miological studies. Therefore, underreporting has to be considered and addressed by researchers through deve-lopment and improvement of dietary intake adjustment methods, and taking advantage of the new technologies for assessing dietary intake in order to minimize unde-rreporting bias.

(Nutr Hosp 2015;31(Supl. 3):119-127)

DOI:10.3305/nh.2015.31.sup3.8760Key words: Underreporting. Nutritional surveys. Dietary

intake. Methodology.

INFRADECLARACIÓN EN LAS ENCUESTAS ALIMENTARIAS: IMPLICACIONES

METODOLÓGICAS

Resumen

La fiabilidad de la información recogida en la evalua-ción dietética puede verse afectada por diferentes fac-tores. Una de las principales fuentes de error en la eva-luación de la dieta es la declaración errónea de consumo de alimentos, que abarca la infradeclaración y sobrede-claración de la dieta. La infradeclaración de la ingesta de alimentos es uno de los principales problemas en la evaluación de la ingesta dietética habitual. Las caracte-rísticas físicas y psicosociales que están relacionadas con la infradeclaración de energía incluyen el sexo, edad, peso, índice de masa corporal, el miedo a la evaluación negativa y estar bajo un régimen de dieta, entre otros. En la actualidad, se emplean diversos métodos de referencia para verificar los resultados de la evaluación dietética, no obstante, el método estándar es el agua doblemente marcada. La infradeclaración afecta a la estimación de la ingesta de nutrientes y también altera las asociaciones entre dieta y enfermedades en estudios epidemiológicos. Por lo tanto, la infradeclaración tiene que ser conside-rada y abordada por los investigadores a través del de-sarrollo y la mejora de los métodos de ajuste de la dieta y el aprovechamiento de las nuevas tecnologías para la evaluación de la ingesta dietética con el fin de minimizar el sesgo ocasionado por la infradeclaración.

(Nutr Hosp 2015;31(Supl. 3):119-127)

DOI:10.3305/nh.2015.31.sup3.8760Palabras clave: Infradeclaración. Encuestas nutriciona-

les. Ingesta dietética. Metodología.

Correspondence: Dr. Lluis Serra Majem. Instituto Universitario de Investigaciones Biomédicas y Sanitarias. Universidad de Las Palmas de Gran Canaria C/ Dr Pasteur s/n. C. P. 35016. Las Palmas de Gran Canaria, España. E-mail: lluis.serra@ulpgc.es

015 Underreporters – Overreporters_Lluis Serra Majem.indd 119 17/02/15 10:39

120 DIETARY SURVEYS AND ENERGY BALANCE: METHODOLOGY, BIAS, ADJUSTMENT AND OTHER ISSUES

Abbreviations

ANR: Average nutrient requirement.BMI: Body mass index.BMR: Basal Metabolic Rate.DLW: Doubly Labelled Water.ENCA: Encuesta Nutricional de Canarias (1997-8).ENCAT: Encuesta Nutricional de Cataluña (2002-3).ENKID: Encuesta Nutricional de la población in-

fantil y juvenil española (1998-2000).EPIC: European Prospective Investigation Into

Cancer and Nutrition.FFQ: Food Frequency Questionnaire.IDEFICS: Identification and prevention of Dietary-

and lifestyle-induced health Effects In Children and infants.

ICT: Information and communication technologies.IDAMES: Innovative Dietary Assessment Methods

in Epidemiological Studies and Public Health.PDA: Personal digital assistants.pTEE: Predicted total energy expenditure equations.

Background

In nutritional assessment, diverse methods are used to evaluate food and nutrient intake. It can be done via questionnaires (i.e. Food records, Dietary recalls, Food frequency questionnaires, Short questionnaires) or through biochemical methods. The selection of the appropriate method should consider the level of evalua-tion according to the target population, either individuals or groups. When nutrient intake is estimated, it can be compared to the nutrient requirement of the individual or population and therefore the probability of adequacy can be estimated. Nutritional adequacy enables to iden-tify if there is sufficient intake of essential nutrients, needed to fulfill nutritional requirements for optimal health. Therefore, to assess dietary intake correctly is crucial to enhance the effectiveness of interventions and policies both at the individual and population level1.

However, dietary intake assessment is a difficult task and different factors can affect the accuracy of the information collected. The reliability of dietary assess-ment can be affected by intra-individual variability, seasonal variability or misreporting. One of the main sources of error in dietary assessment is misreporting, comprising both under and overreporting2. Underre-porting of food intake is one of the major obstacles preventing the collection of accurate habitual dietary intake data3 (Figure 1). Although less frequent, overre-porting is also a problem, and is related to certain indi-vidual characteristics, for instance in eating behaviors it is common to alter the consumption report of fruits and vegetables.

A recent study conducted in European countries, assessed the prevalence of low micronutrient intakes and the presence of underreporting by using nationa-lly representative dietary survey data from Belgium,

Denmark, France, Germany, The Netherlands, Poland, Spain and the United Kingdom. The proportion of pos-sible underreporters in children aged 1–3 years ranged from 0.6% in Belgium to 1.7% in The Netherlands. For those aged 4–10 years, it varied from 0.5% in Denmark to about 5% of the German girls. For participants aged from 11 to 17 years, the underreporting values ranged from 0.6% of the Dutch boys to 34% of the Danish boys. For women aged 14–50 years, it ranged from 1.1% in The Netherlands to 14% in Germany. For tho-se aged 18–60 years, it ranged from about zero in the Dutch men to 26% in women from France. For elderly subjects over 60 years of age, it ranged from 0.4% of women in the Netherlands to 28% of women in Spain4.

Misreporting affects not only the estimation of energy intake, but also in other nutrients2. Therefore, misreporting of food intake is a major challenge for nutrition research when evaluating the relationship be-tween diet and health outcomes.

Characteristics of low energy reporters

In 2003, Livingston & Black reviewed the characte-ristics of low energy reporters in 25 adult studies5. Age and sex have been associated with energy underrepor-ting. Some studies have found that women and elderly subjects are more likely to underreport energy intake. However, these associations are inconsistent and fur-ther investigation is needed in representative popula-tion samples that have identified underreporters at all levels of energy requirement. Another characteristic identified is weight status. Low-energy reporting has been associated with a high body mass index (BMI), and the probability that an individual will underreport rise as BMI increases5. Education and socioeconomic status are less predictable characteristics in low energy reporters; however, in some studies underreporting has been associated with low education or socioeconomic status. Subjects with lower levels of education and consequently reduced literacy skills might be expected

Fig. 1.—Underreporting effect on nutrient distribution.

015 Underreporters – Overreporters_Lluis Serra Majem.indd 120 17/02/15 10:39

Misreporting in nutritional surveys: methodological implications 121

to result in underreporting. Nevertheless, subjects with more knowledge of health topics or diet conscious-ness6 or those of higher socioeconomic status might have the same response5. Another aspects associated with misreporting include dieting, efforts to maintain weight stability, attempt to lose weight, self-percep-tion of high weight and weight changer over 5 years5.

Children and adolescents also tend to underreport energy intake. Higher weight, BMI and adiposity have been consistently associated with underreported ener-gy intake7. In Spain, a study conducted in children and adolescents, the ENKID study (1998-2000) compared the psychosocial characteristics between underrepor-ters and plausible reporters in children and youth aged 2-24 years. A higher probability to underreport was found for female group and for adolescents and young adults (14-24 years). According to geographical re-gion, individuals from Canary Islands had higher odds to underreport, while children living in the Northern region had lower odds to underreport. Misreporting was also associated with skipping breakfast and having a high BMI or weight (over percentile 85)8. Another study conducted in adolescents has shown that obese participants were 5.0 times more likely to underreport energy intake than subjects with normal weight9.

Some psychosocial characteristics have also been associated to low energy reporting such as eating res-traint, social desirability, depression, anxiety and fear of negative evaluation10. For instance, higher social desirability, known as the tendency to respond to ques-tions in a socially appropriate and accepted manner, has been related with a higher incidence of energy un-derreporting, especially in women10.

Energy misreporting, specifically underreporting, also results from incomplete recordkeeping on the part of the subject due to one or many established factors, for example: recording fatigue, memory disturban-ces, misrepresentation of portion size consumed and “unconscious” omission of certain eating occasion or item10. In order to improve the estimation of portion size, some tools are used, for instance, the use of hou-sehold measures, drawings and photographs or food models.

Since the characteristics of low energy reporters and associated physical and psychosocial factors play an important role in the observed reporting bias, further investigation is needed in order to properly account for such factors in future studies.

Reference Methods to identify energy misreporting

Nowadays there are a number of reference methods to verify the results of dietary assessment. Reference me-thods include urine nitrogen, total energy expenditure, resting metabolic rate and physical activity, and total wa-ter loss. The gold standard reference method for assessing total energy expenditure is doubly labelled water (DLW).

This accurate and noninvasive method is used for valida-tion of reported energy intake by subjects in free living situations11.

In the DLW, subjects receive a loading dose of water labeled with the stable isotopes 2H and 18O, and these isotopes mix with the hydrogen and oxygen in body wa-ter within a few hours. As energy is expended, CO2 and water are excreted. Urine samples are collected at baseli-ne before administration of the dose and subsequently ei-ther daily or at the beginning and end of the measurement period. The urine samples are analyzed to determine the rate of disappearance of each isotope from the body. Usually, the measurement period in adults is 14 days. The energy expenditure calculated is then compared with the reported energy intake and the deviation is expressed as magnitude of misreporting (as a percentage of energy expenditure or as an absolute deviation in kJ or kcal)2. However, DLW cannot be widely used as validating me-thod for energy intake, due to the high costs since it needs a sophisticated laboratory and analytical back-up5.

Urinary nitrogen loss is used to validate reported pro-tein intake. Healthy adults are in nitrogen balance, and nitrogen loss in urine was found to be 81± 5% of total nitrogen loss per 24 hours11. However, within-subject va-riation in daily nitrogen excretion of individuals may be large, and repeat collections of consecutive 24 hour urine samples are necessary if the method is going to be used to validate the protein intakes of individuals.

To assess the dietary intake of other nutrients (i.e. Na or K), the urinary excretion of such nutrients for which urine is the major excretory route has also been used as a biomarker. To measure dietary Na intake, Na excretion can be used, however, the day-to-day fluctuations in Na excretion are larger than those for nitrogen. Therefore more collections are needed to correctly characterize Na excretion in an individual2.

The Goldberg cut-off method reports energy intake as a multiple of basal metabolic rate (BMR), and using this index (Energy intake/BMR) in comparison to expected energy expenditure as a validity check for negative bias in energy intake. The Goldberg equation calculates the confidence limits (cut-offs) that evaluate if mean repor-ted energy intake is plausible as a valid measure of food intake even if chance has produced a dataset with a high proportion of genuinely low (or high) intake. Sensitivi-ty of the Goldberg cut-off was improved when subjects were assigned to low, medium and high activity levels and different physical activity levels and cut-off values were applied to each level2. BMR for the calculation of the Goldberg cut-off can be either measured or estimated from predictive equations specific for age and sex, such as the Schofield equations12. In the method of indirect ca-lorimetry that measures BMR, the subject must be in a fasting state and with minimal physical disturbance.

Finally, another method to validate reported dietary intake is to compare it with the actual intake of sub-jects. Actual intake is obtained by direct observation of people eating during the study period. This method at-tempts to measure absolute validity, but it is very time

015 Underreporters – Overreporters_Lluis Serra Majem.indd 121 17/02/15 10:39

122 DIETARY SURVEYS AND ENERGY BALANCE: METHODOLOGY, BIAS, ADJUSTMENT AND OTHER ISSUES

consuming and presents some practical difficulties and limitations. Each individual with a sufficient diet that meets adequately the energy requirements presents a stable body weight during the trial2. However the use of this method can lead to bias in vulnerable groups, for example, in older persons with declining weight which is related to low energy intake, and under eating may be falsely perceived as underreporting13.

Underreporting according to dietary assessment methods

Underreporting is prevalent and persists in diverse dietary assessment methods although in different propor-tions5,14. In 2009, an investigation evaluated the effects of different dietary assessment methods on assessing  risk of  nutrient adequacy with data of two regional repre-sentative surveys conducted in Spain15. The first survey,

The Catalan Nutrition Survey Study on nutritional status and food habits of the Catalan population (ENCAT), was a cross sectional study, carried out in population aged 12–80 years. The second survey was The Canary Islands Nutrition Survey (ENCA), that evaluated nutritional sta-tus and food habits of the population from the Canary Islands, conducted on a random sample of the population aged 6–75 years. In total, 2542 subjects were included in the analyses15. In that investigation, Ribas-Barba et al. found that the percentage of underreporters changed depending on the instrument used, with values over 40% when using daily methods (one or two 24 hour recalls) and 28% when using the FFQ. When diet was assessed with dietary recalls, higher proportions of underreporters were found in women, on the contrary, when the FFQ was used, a higher proportion of underreporters was found for men (30.5%) than women (25.7%)15.

In a systematic review conducted in 2009, the propor-tion of misreporters was compared for three methods: 24 hour recall, estimated and weighed food record2. The Authors did not found significant differences between the medians of percentage of misreporters for all three methods (around 30%). Regarding underreporters, not significant difference was found, however, a higher pro-portion was observed for weighed food record (18%) than the other two methods (13.4% in 24 hour recall and 12.2% in estimated food record). The result that the magnitude of misreporting was not lower for weighed record studies could be caused by a smaller number of weighed food record studies providing data on the per-centage of underreporters, but it is possible that subjects in weighed food record studies did not underreport, but underrate as a result of a change in dietary habits to faci-litate the reporting during the study2.

Underreporting bias in estimating nutrient intake

Underreporting represents a problem for the estima-tion of nutrient intake in epidemiological studies since

underreporting of energy intake usually is related with underreporting of some nutrients.

A study of Mexican-American women showed that estimated energy, protein, cholesterol, dietary fiber, and vitamin E intakes were significantly higher among the plausible reporters compared with the implausible energy intake reporters group. Most implausible repor-ters underreported energy intake (86%). There was a significant difference between the proportions of plau-sible versus implausible reporters meeting recommen-dations for several nutrients, with a larger proportion of plausible reporters meeting recommendations16.

In children and adolescents, the ENKID study has also evaluated the differences in nutrient intake be-tween plausible reporters and low energy reporters (Table I). Higher intakes were observed among plau-sible reporters for energy, carbohydrates, total fat in-take, cholesterol, sodium, phosphorus and calcium when compared to estimated intakes including unde-rreporters in the sample8. Similar results were obser-ved in 96 adolescents from Brazil, where energy intake misreporting (under or overreporting) was identified in 65.6% of adolescents. Underreporters also showed higher rates of insufficient intake of carbohydrate, li-pids and cholesterol intake than plausible reporters9. Another survey conducted in Australian children aged 2–16 years, revealed, that those classified as underre-porters had significantly higher intakes of protein and starch but lower intakes of sugar and fat, as percen-tage from energy, than plausible reporters, whereas overreporters had higher fat and lower carbohydrate intakes17.

In the analyses of the ENCAT and ENCA previously cited, the nutritional adequacy of Vitamin A, Vitamin C, Vitamin E, Thiamin, Riboflavin, Niacin, Vitamin B6 , Folate, Vitamin B12, Fe, Mg, P and Zn intake was estimated for the entire sample and excluding underre-porters (defined by the Goldberg cut-off method) (Ta-ble II). The exclusion of underreporters substantially reduced inadequacy of intake for all vitamins assessed by daily methods (one 24 hour recall and a mean of two non-consecutive 24 hour recalls) and FFQ15. Data from daily methods adjusted for intra-individual va-riability were the least modified by underreporters. The highest reduction of inadequacy (above 10%) was found for thiamin, Mg, Zn and vitamin E (except in 24 hour recall adjusted by intra-individual variability)15.

Implications of underreporting

The implications of underreporting are that they may alter diet and disease associations. Underrepor-ting is a problem that has to be considered in nutritio-nal studies, especially in some cases such as the eva-luation of the relationship of dietary intake and obesity or studies examining the nutritional adequacy of the diet5. Furthermore, it is important for the creation and evaluation of dietary guidelines and nutrition policies.

015 Underreporters – Overreporters_Lluis Serra Majem.indd 122 17/02/15 10:39

Misreporting in nutritional surveys: methodological implications 123

Tabl

e I

Ener

gy a

nd n

utrie

nt in

take

(per

cent

ile 9

5th)

from

the

ENKI

D (n

=18

57) a

nd E

NCAT

(n=

1840

) stu

dies

, in

tota

l sam

ple,

exc

ludi

ng u

nder

repo

rters

, and

diff

eren

ce b

etwe

en th

em*

Age

grou

p

Men

Wom

enTo

tal

All

With

out

unde

rrep

orte

rD

ifere

nce

All

With

out

unde

rrep

orte

rD

ifere

nce

All

With

out

unde

rrep

orte

rD

ifere

nce

P 95

P 95

All-W

ithou

t un

der.

P 95

P 95

All-W

ithou

t un

der.

P 95

P 95

All-W

ithou

t un

der.

4-10

y E

NK

IDEn

ergy

(kca

l)23

82,3

2388

,8-6

,522

28,7

2232

,7-4

,123

18,9

2323

,4-4

,5

Cal

cium

(mg)

1197

,011

97,4

-0,4

1132

,211

37,0

-4,7

1167

,411

87,8

-20,

4

Mag

nesi

um (m

g)32

6,0

327,

3-1

,329

6,3

297,

2-0

,930

9,4

312,

2-2

,7

Iron

(mg)

16,1

16,2

-0,1

13,6

13,6

0,0

15,4

15,5

0,0

Phos

phor

us (m

g)16

75,4

1677

,5-2

,115

42,1

1548

,3-6

,216

25,1

1627

,5-2

,4

Tota

l Vita

min

A (µ

g)70

5,5

702,

92,

659

5,4

603,

6-8

,264

3,9

645,

1-1

,2

Vita

min

B6

(mg)

2,3

2,3

0,0

2,0

2,0

0,0

2,2

2,2

0,0

Nia

cin

(mg)

26,3

26,4

-0,1

24,0

24,1

-0,1

25,3

25,4

-0,2

Vita

min

E (m

g)8,

68,

7-0

,110

,110

,10,

09,

19,

2-0

,1

11-1

7 y

ENK

IDEn

ergy

(kca

l)30

26,7

3125

,8-9

9,1

2329

,623

43,8

-14,

228

63,5

2910

,3-4

6,8

Cal

cium

(mg)

1356

,513

86,0

-29,

510

75,7

1087

,2-1

1,6

1267

,612

92,1

-24,

5

Mag

nesi

um (m

g)37

9,0

382,

8-3

,829

3,2

295,

4-2

,235

8,8

363,

2-4

,4

Iron

(mg)

20,4

20,7

-0,3

14,4

14,6

-0,2

19,0

19,3

-0,3

Phos

phor

us (m

g)20

01,7

2027

,5-2

5,8

1572

,815

90,4

-17,

618

80,1

1919

,8-3

9,7

Tota

l Vita

min

A (µ

g)76

6,4

774,

9-8

,555

7,1

560,

1-3

,066

6,0

677,

0-1

1,0

Vita

min

B6

(mg)

2,4

2,4

0,0

1,8

1,8

0,0

2,2

2,3

0,0

Nia

cin

(mg)

30,7

30,8

-0,1

25,6

25,9

-0,2

29,6

29,7

-0,1

Vita

min

E (m

g)10

,310

,30,

09,

49,

8-0

,410

,010

,00,

0

18-8

0 y

ENC

ATEn

ergy

(kca

l)28

74,3

3001

,0-1

26,6

2293

,824

35,4

-141

,626

58,5

2830

,2-1

71,7

Cal

cium

(mg)

1201

,612

78,3

-76,

810

52,3

1113

,3-6

1,0

1107

,612

03,8

-96,

2

Mag

nesi

um (m

g)39

5,8

410,

0-1

4,1

350,

136

7,7

-17,

637

4,4

404,

6-3

0,2

Iron

(mg)

12,0

12,7

-0,7

9,6

10,2

-0,6

11,0

11,8

-0,8

Phos

phor

us (m

g)15

,716

,3-0

,613

,113

,6-0

,515

,115

,6-0

,6

015 Underreporters – Overreporters_Lluis Serra Majem.indd 123 17/02/15 10:39

124 DIETARY SURVEYS AND ENERGY BALANCE: METHODOLOGY, BIAS, ADJUSTMENT AND OTHER ISSUES

Tabl

e II

An

alys

is o

f Spa

nish

Pop

ulat

ion

aged

12–

80 y

ears

(n=

261

5) w

ith in

take

s be

low

ave

rage

nut

rien

t req

uire

men

t (AN

R)

cut p

oint

in th

e en

tire

sam

ple

and

excl

udin

g un

derr

epor

ters

.

One

24H

our

Reca

ll (%

)Tw

o 24

Hou

r Re

call

(%)

24H

R ad

just

ed fo

r in

trai

ndiv

idua

l va

riab

ility

(%)

FFQ

(%)

All

With

out

unde

rrep

orte

rsD

iffer

ence

All

With

out

unde

rrep

orte

rsD

iffer

ence

All

With

out

unde

rrep

orte

rsD

iffer

ence

All

With

out

unde

rrep

orte

rsD

iffer

ence

Vita

min

A

52.1

41

.7

10.4

47.9

38

.9

9.0

57.7

52

.7

5.0

15.6

9.

9 5.

7

Vita

min

C

39.1

32

.8

6.3

33.0

29

.7

3.3

22.9

21

.3

1.6

9.4

7.3

2.1

Vita

min

E

78.8

66

.2

12.6

80.6

70

.3

10.3

96

.7

94.2

2.

5 50

.8

40.2

10

.6

Thia

min

35

.4

14.1

21

.3

30.7

13

.1

17.6

16.3

4.

8 11

.5

19.2

8.

4 10

.8

Rib

ofla

vin

16.0

4.6

11

.4

12.5

4.

0 8.

5 2.

8 0.

6 2.

2 5.

8 1.

3 4.

5

Nia

cin

15.7

6.

0 9.

7 9

.8

2.9

6.9

0.4

0.1

0.3

4.1

0.9

3.2

Vita

min

B6

20.4

6.

5 13

.9

16.7

5.

8 10

.9

4.1

0.7

3.4

6.7

1.

6 5.

1

Vita

min

B12

13

.9

5.3

8.6

6.7

2.7

4.0

0.2

0.0

0.2

0.9

0.

1 0.

8

Mg

59.3

37

.5

21.8

61

.0

43.4

17

.6

71.1

58

.9

12.2

37

.8

24.9

12

.9

Zn

43.1

23

.5

19.6

41

.7

23.0

18

.7

42.0

25

.7

16.3

31

.2

15.1

16

.1

Tabl

e I (

cont

.) En

ergy

and

nut

rient

inta

ke (p

erce

ntile

95t

h) fr

om th

e EN

KID

(n=

1857

) and

ENC

AT (n

=18

40) s

tudi

es, i

n to

tal s

ampl

e, e

xclu

ding

und

erre

porte

rs, a

nd d

iffer

ence

bet

ween

them

*

Age

grou

p

Men

Wom

enTo

tal

All

With

out

unde

rrep

orte

rD

ifere

nce

All

With

out

unde

rrep

orte

rD

ifere

nce

All

With

out

unde

rrep

orte

rD

ifere

nce

P 95

P 95

All-W

ithou

t un

der.

P 95

P 95

All-W

ithou

t un

der.

P 95

P 95

All-W

ithou

t un

der.

Tota

l Vita

min

A (µ

g)18

02,3

1885

,2-8

2,9

1502

,415

76,3

-73,

916

90,6

1799

,0-1

08,4

Vita

min

B6

(mg)

402,

441

8,3

-15,

928

5,0

298,

1-1

3,1

360,

438

0,3

-19,

9

Nia

cin

(mg)

313,

132

1,5

-8,4

288,

729

5,5

-6,8

303,

231

0,6

-7,4

Vita

min

E (m

g)26

,528

,5-2

,021

,422

,1-0

,825

,126

,3-1

,2*D

ata

from

two

24-h

our r

ecal

ls a

djus

ted

for i

ntra

-indi

vidu

al v

aria

bilit

y. Id

entif

icat

ion

of u

nder

repo

rted

food

inta

ke w

as c

ondu

cted

by

the

EI/B

MR

(ene

rgy

inta

ke/B

asal

Met

abol

ic R

ate)

ratio

: les

s tha

n 1.

14.

ENK

ID: H

abito

s alim

enta

rios y

est

ado

nutri

cion

al d

e la

pob

laci

ón in

fant

il y

juve

nil e

spañ

ola

(199

8-20

00)

ENC

AT: E

nque

sta

Nut

ricio

nal d

e la

pob

laci

ó ca

tala

na (2

002-

2003

)

015 Underreporters – Overreporters_Lluis Serra Majem.indd 124 17/02/15 10:39

Misreporting in nutritional surveys: methodological implications 125

A recent investigation within the frame of the Euro-pean Prospective Investigation Into Cancer and Nutri-tion-Spain (EPIC) has evaluated the effect of accoun-ting for misreporters in the associations between some dietary factors and BMI18. Misreporters were identified by comparing reported energy intakes with estimated energy requirements obtained by three methods: 1) the original Goldberg method 2) using basal metabolic rate equations that are more valid at higher BMIs and 3) doubly labeled water-predicted total energy expen-diture equations (pTEE). The results indicate that after excluding implausible reporters using each approach, coefficients for several diet-BMI associations changed in magnitude or direction. The consideration for mis-reporters yielded associations between diet and BMI that were more consistent with previous findings. For example, among women, initially negative associa-tions between BMI and energy intake became positi-ve (Figure 2), a neutral association with fruit became negative and a positive association with vegetables became negative. Although all methods had consistent effects on estimates, the magnitude of these diet-BMI associations was generally stronger when we used the pTEE and revised Goldberg methods than when the standard Goldberg method was used. In contrast, ex-cluding subjects with extreme energy intakes by using recommended cutoffs had no meaningful effect18.

Similar results were observed in 5357 European children aged 2–9 years19. The IDEFICS study (Identi-fication and prevention of Dietary- and lifestyle-indu-ced health Effects In Children and infantS) investiga-ted the effect of handling implausible reporters in the association between dietary intakes (total energy, soft drinks, fruits/vegetables) and overweight/obesity. In the basic model, no significant association was found for energy intake and soft drink intake with overwei-ght/obesity and a significant positive association be-tween overweight/obesity and fruit/vegetable intake was found. However, when underreporters and overre-porters were excluded, a positive association between

energy intake and overweight/obesity was observed19. This finding was also observed when models were ad-justed for misreporting, energy intake and overweight/obesity were associated and even more pronounced compared with the model excluding misreporters. Moreover, after adjustment for the propensity score, which combined various indicators for misreporting into one summary measure, Authors found a positive association between soft drinks and overweight/obe-sity and a negative association was found for fruit/vegetable intakes19. The adjustment for propensity score is an alternative that could be useful to minimi-ze misreporting error. Nevertheless, Börnhorst et al. recommend that future studies have to be careful when applying the propensity score approach, which requi-res the identification of the relevant determinants of misreporting according to the study population. There-fore, the effectiveness of the propensity score adjust-ment in adolescent and adult populations is a task for future research19.

SOLUTION: New technologies for assessing intake?

Given all the previously recognised limitations, re-search has focused on refining assessment methods to more accurately evaluate food intake. What could be the solution? The possibilities of developing new applications of information and communication tech-nologies (ICT) to improve dietary as well as physical activity assessment have been explored.

Adaptations of technology have led to extensive changes in how dietary assessment is performed. The most common objective has been to reduce the costs of both the collection and processing of dietary intake information due to the amounts and complexity of data usually involved. The early Framingham and Te-cumseh community studies were the first to establish cohorts for the express purpose of examining diet and

Fig. 2.—Associations between energy intakes and body mass index among women, determined using alternative adjust-ments for estimated under- and overreporting in the Spanish cohort of the European Investigation Into Cancer and Nu-trition18. Coefficients from multivariable linear regression models were adjusted for age, center, height, activity, educa-tional level, smoking status, season, alcohol intakes, parity, diabetes, and use of special diets.Abbreviations: SE, standard error; GB 1.5, Goldberg method with 1.5-standard-deviation cutoffs; GB 2.0, Goldberg me-thod with 2.0-standard-deviation cutoffs; GB-R 2.0, revised Goldberg methods with 2.0-standard-deviation cutoffs; pTEE 2.0, pTEE method with 2.0-standard-deviation cutoffs.

015 Underreporters – Overreporters_Lluis Serra Majem.indd 125 17/02/15 10:39

126 DIETARY SURVEYS AND ENERGY BALANCE: METHODOLOGY, BIAS, ADJUSTMENT AND OTHER ISSUES

disease relationships, but their tools were interviewer administered, and the data processed manually20.

The application of ICT in dietary and physical acti-vity assessment offers several potential advantages. In-novative methodological approaches can improve data quality, consistency and completeness. Furthermore, new technologies hold considerable promise for redu-cing costs as the presence of trained interviewers is not required for a complete interview. Moreover, compu-terised assessment can save considerable time in data coding as data are immediately stored. Because of less respondent burden, it may be possible to collect long-term data on both food intake and physical activity1.

New technologies may also help to simplify the self-monitoring process, which increases compliance and validity of self-reported food and energy intake21. ICT may enhance dietary intake assessment by simpli-fying the process and making it less time consuming to monitor food intake, as well as increasing the subject’s motivation to complete the task. As such, willingness to record intake may increase and therefore more relia-ble data are obtained.

Old methods done in new ways:

ICT was applied in FFQ, 24HR and diet histories. Self-administered computerised assessment makes it possible for participants to register and assess their dietary intake at their own pace and convenience. Fur-thermore, computerised assessment tools can direct-ly calculate nutrient intake and energy expenditure, which makes it possible for immediate feedback1, 22.

However, some subjects may need more instruc-tions before or during completion of the questionnai-re. Applying alerts to warn subjects of improbable answers could also decrease the problem of overrepor-ting as well as reduce the amount of data cleaning by researchers. These types of questionnaires may be use-ful for web-based data collection and could be applied as an alternative to in-person or self-administered questionnaires in studies where participants attend a central study visit site, as well as for questions on sensitive topics. When using computerised self-assess-ment, questions about risky or sensitive behaviours may be answered more truthfully23.

A disadvantage of self-administered computerised as-sessment is that it requires the user to have a minimum level of knowledge about computer use. Certain popu-lation groups may have difficulty using a computerised assessment tool, for example, older and less educated individuals23. This is less problematic in interviewer-ad-ministered computerised assessment tools.

Personal digital assistants PDA

A PDA is a handheld computer that can be used for various purposes. This technology has been applied for

data collection in medical settings for over 15 years24. PDA with specifically designed dietary software pro-gram can be used to register and self-monitor dietary intake. Subjects are required to record their food intake immediately after consumption by scrolling through a list of foods or by selecting a food group and then a specific food item. After food item selection, portion sizes are entered.

PDA-based food records have several advantages as individuals can be provided with immediate feed-back and data stored on the PDA can be reviewed at any point in time. Although the advantages of PDA show their potential to improve data quality, there are several limitations. The use of PDA-based food re-cords increases the respondent burden compared with paper diaries. Studies report subjects having difficulty using the search function and experienced inability to find certain foods25, 26. Furthermore, like paper diaries, PDA-based food records require participants to be lite-rate. As such, older or less educated individuals might have difficulty using a PDA for recording food intake1.

Digital photography

The main advantage of digital photography is the possibility to collect dietary intake data from large groups relatively quickly, with minimal disruption and impact on the eating behaviour of participants. Because data are immediately stored on the compu-ter, the researchers have more time to analyse and process the obtained data. Furthermore, the partici-pants’ identities can be kept anonymous, which can be seen as an advantage. Studies show that digital photography is a reliable and valid tool to measu-re food intake in dining facilities both in adult- and school-age populations.

New measurement methods:Barcode scanner/ Smart card

An advantage of using the smart card system to me-asure food choice is that it can collect long-term data from large groups on individual food behaviour. Fur-thermore, the costs are relatively low as smart cards are inexpensive and fewer researchers are needed sin-ce data are stored when the diner uses the smart card to pay for the meal. More research is needed to determine whether this tool can be applied to measure food intake in a variety of population groups.

Summarizing, several dietary-assessment tools applying ICT have been developed and some have shown to be valid and reliable for diverse purposes and target groups. Recently, results from the Euro-pean Commission project, Innovative Dietary As-sessment Methods in Epidemiological Studies and Public Health (IDAMES)27, concluded that web ba-sed approach in adult study populations it might take

015 Underreporters – Overreporters_Lluis Serra Majem.indd 126 17/02/15 10:39

Misreporting in nutritional surveys: methodological implications 127

more time to have participation rates similar to paper versions. In terms of feasibility, more than two con-tacts (24-hour recalls) will result in a drop of parti-cipation, favouring a non-linear calibration approach and that it is still unclear whether web based or other new technologies can provide ranking instruments better than FFQs in respect to ranking and feasibility. In general, which tool is the most suitable to collect dietary data depends on the objectives of the study and the target group. Before selecting a given tool, it is important to review the advantages and disadvan-tages of each method27.

References

1. Ngo J, Engelen A, Molag M, Roesle J, García-Segovia P, Se-rra-Majem L. A review of the use of information and communi-cation technologies for dietary assessment. Br J Nutr 2009;101 Suppl 2:S102-12

2. Poslusna K, Ruprich J, de Vries JH, Jakubikova M, van’t Veer P. Misreporting of energy and micronutrient intake estimated by food records and 24 hour recalls, control and adjustment methods in practice. Br J Nutr 2009;101 Suppl 2:S73-85.

3. Macdiarmid J, Blundell J. Assessing dietary intake: Who, what and why of under-reporting. Nutr Res Rev 1998;11(2):231-53.

4. Mensink GB, Fletcher R, Gurinovic M, Huybrechts I, Lafay L, Serra-Majem L, et al. Mapping low intake of micronutrients across Europe. Br J Nutr 2013;110(4):755-73.

5. Livingstone MB, Black AE. Markers of the validity of reported energy intake. J Nutr 2003;133 Suppl 3:895S-920S.

6. Rasmussen LB, Matthiessen J, Biltoft-Jensen A, Tetens I. Cha-racteristics of misreporters of dietary intake and physical acti-vity. Public Health Nutr 2007;10(3):230-7.

7. Forrestal SG. Energy intake misreporting among children and adolescents: a literature review. Matern Child Nutr 2011;7(2):112-27.

8. Serra-Majem L, Ribas L, Pérez-Rodrigo C, García-Closas R, Peña-Quintana L, Aranceta J. Determinants of nutrient intake among children and adolescents: results from the enKid Study. Ann Nutr Metab 2002;46 Suppl 1:31-8.

9. Santos LC, Pascoal MN, Fisberg M, Cintra IP, Martini LA. Misreporting of dietary energy intake in adolescents. J Pediatr (Rio J) 2010;86(5):400-4.

10. Maurer J, Taren DL, Teixeira PJ, Thomson CA, Lohman TG, Going SB, et al. The psychosocial and behavioral characte-ristics related to energy misreporting. Nutr Rev 2006;64(2 Pt 1):53-66. PubMed PMID: 16536182.

11. Westerterp KR, Goris AH. Validity of the assessment of dietary intake: problems of misreporting. Curr Opin Clin Nutr Metab Care 2002;5(5):489-93.

12. Food and Agriculture Organization of the United Nations. Human Energy Requirements: Report of a Joint FAO/WHO/ONU Expert Consultation. FAO/WHO/ONU, editor. Rome,

Italy: Food and Agriculture Organization of the United Na-tions 2001.

13. Shahar DR, Yu B, Houston DK, Kritchevsky SB, Newman AB, Sellmeyer DE, et al. Misreporting of energy intake in the elder-ly using doubly labeled water to measure total energy expen-diture and weight change. J Am Coll Nutr 2010;29(1):14-24.

14. Subar AF, Kipnis V, Troiano RP, Midthune D, Schoeller DA, Bingham S, et al. Using intake biomarkers to evaluate the extent of dietary misreporting in a large sample of adults: the OPEN study. Am J Epidemiol 2003;158(1):1-13.

15. Ribas-Barba L, Serra-Majem L, Roman-Vinas B, Ngo J, Gar-cia-Alvarez A. Effects of dietary assessment methods on asses-sing risk of nutrient intake adequacy at the population level: from theory to practice. Br J Nutr 2009;101 Suppl 2:S64-72.

16. Banna JC, Fialkowski MK, Townsend MS. Misreporting of Dietary Intake Affects Estimated Nutrient Intakes in Low-In-come Spanish-Speaking Women. J Acad Nutr Diet 2014. doi: 10.1016/j.jand.2014.06.358.

17. Rangan A, Allman-Farinelli M, Donohoe E, Gill T. Misrepor-ting of energy intake in the 2007 Australian Children’s Survey: differences in the reporting of food types between plausible, under- and over-reporters of energy intake. J Hum Nutr Diet 2014;27(5):450-8.

18. Mendez MA, Popkin BM, Buckland G, Schroder H, Amiano P, Barricarte A, et al. Alternative methods of accounting for underreporting and overreporting when measuring dietary in-take-obesity relations. Am J Epidemiol 2011;173(4):448-58.

19. Börnhorst C, Huybrechts I, Hebestreit A, Vanaelst B, Molnár D, Bel-Serrat S, et al. Diet-obesity associations in children: approaches to counteract attenuation caused by misreporting. Public Health Nutr 2013;16(2):256-66.

20. Thompson FE, Subar AF, Loria CM, Reedy JL, Baranowski T. Need for technological innovation in dietary assessment. J Am Diet Assoc 2010;110(1):48-51.

21. Kroeze W, Werkman A, Brug J. A systematic review of ran-domized trials on the effectiveness of computer-tailored edu-cation on physical activity and dietary behaviors. Ann Behav Med 2006;31(3):205-23.

22. Lagerros YT, Mucci LA, Bellocco R, Nyrén O, Bälter O, Bälter KA. Validity and reliability of self-reported total ener-gy expenditure using a novel instrument. Eur J Epidemiol 2006;21(3):227-36.

23. Edwards SL, Slattery ML, Murtaugh MA, Edwards RL, Bry-ner J, Pearson M, et al. Development and use of touch-screen audio computer-assisted self-interviewing in a study of Ameri-can Indians. Am J Epidemiol 2007;165(11):1336-42.

24. Koop A, Mösges R. The use of handheld computers in clinical trials. Control Clin Trials 2002;23(5):469-80.

25. Welch J, Dowell S, Johnson CS. Feasibility of using a personal digital assistant to self-monitor diet and fluid intake: a pilot study. Nephrol Nurs J 2007;34(1):43-8.

26. Yon BA, Johnson RK, Harvey-Berino J, Gold BC, Howard AB. Personal digital assistants are comparable to traditional diaries for dietary self-monitoring during a weight loss pro-gram. J Behav Med 2007;30(2):165-75.

27. Innovative Dietary Assessment Methods in Epidemiological Studies and Public Health I. WebHome 2015 [cited 2015]. Available from: http://nugo.dife.de/wiki/bin/view/IDAMES/.

015 Underreporters – Overreporters_Lluis Serra Majem.indd 127 17/02/15 10:39