slide1 l.
Download
Skip this Video
Loading SlideShow in 5 Seconds..
Social Desirability and Social Approval Biases in Dietary Self-Report: Examples of Epidemiologic Effect Modification PowerPoint Presentation
Download Presentation
Social Desirability and Social Approval Biases in Dietary Self-Report: Examples of Epidemiologic Effect Modification

Loading in 2 Seconds...

play fullscreen
1 / 54

Social Desirability and Social Approval Biases in Dietary Self-Report: Examples of Epidemiologic Effect Modification - PowerPoint PPT Presentation


  • 203 Views
  • Uploaded on

Social Desirability and Social Approval Biases in Dietary Self-Report: Examples of Epidemiologic Effect Modification. James R. Hebert, ScD. Professor and Chair Department of Epidemiology and Biostatistics Norman J. Arnold School of Public Health University of South Carolina.

loader
I am the owner, or an agent authorized to act on behalf of the owner, of the copyrighted work described.
capcha
Download Presentation

PowerPoint Slideshow about 'Social Desirability and Social Approval Biases in Dietary Self-Report: Examples of Epidemiologic Effect Modification' - johana


Download Now An Image/Link below is provided (as is) to download presentation

Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author.While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server.


- - - - - - - - - - - - - - - - - - - - - - - - - - E N D - - - - - - - - - - - - - - - - - - - - - - - - - -
Presentation Transcript
slide1

Social Desirability and Social Approval

Biases in Dietary Self-Report: Examples of Epidemiologic Effect Modification

James R. Hebert, ScD

Professor and Chair

Department of Epidemiology and Biostatistics

Norman J. Arnold School of Public Health

University of South Carolina

slide2

Other Collaborators:

Lynn Clemow, Ph.D.

Ira S. Ockene, M.D.

Cara B. Ebbeling, Ph.D.

Yunsheng Ma, M.D., M.P.H.

Thomas G. Hurley, M.Sc.

Milagros C. Rosal, Ph.D.

Charles E. Matthews, Ph.D.

Judith K. Ockene, Ph.D.

slide3

You’ve got to be kidding!

  • cognitive difficulties
  • emotional aspects issues of prying
  • misleading responses
slide4

Emotional Aspects of Eating -

  • same part of brain processes

sensations of taste, smell, and basic

emotional and instinctual behavior.

  • social messages get overlaid on

psychological and emotional ones.

slide5

Background

Self-report of dietary intake could be biased by

social desirability or social approval thus affecting

risk estimates in epidemiologic studies. These

constructs produce response set biases, which

are evident when testing in domains characterized

by easily recognizable correct or desirable responses.

Given the social and psychological value ascribed

to diet, assessment methodologies used most

commonly in epidemiologic studies are

particularly vulnerable to these biases.

slide6

Social Desirability is a Response Set

reflecting the defensive tendency to respond

in such a way as to avoid criticism in a

situation perceived to be a test.

slide7

Social Approval is a Response Set

reflecting the tendency to actively seek

approval in a situation perceived to be a test.

slide8

Social desirability bias in dietary self-report

may compromise the validity of dietary

intake measures.

International Journal of Epidemiology 1995; 24: 389-398.

slide9

WATCH

WORCESTER

AREA

TRIAL for

COUNSELING in

HYPERLIPIDEMIA

slide10

We Developed Seven-Day Diet Recall (7DDR)

In WATCH

The 7DDR looks very much like a FFQ, but it asks participants to recall specific meals and snacks over the past week. It includes 118 foods, 13 beverages, and a worksheet. Thus it combines elements of the FFQ and produces estimates of dietary intake more like trait measures than does 24HR.

slide11

STUDY DESIGN

WATCH External Validation Study

3 Weeks

Pre

7DDR

Post

7DDR

(7 randomly selected 24-Hrs)

Exactly two years later

social desirability and approval assessed

slide12

Hypothesis: Response Set Biases are expressed

on structured questionnaires such as the Seven Day Dietary Recall (7DDR) or the FFQ.

¨

it is closed-ended and has obvious correct

responses

grid-like obvious response categories

requires report of diet as a trait rather than a state

¨

¨

slide13

Methods:

Social desirability and social approval biases were tested by

comparing nutrient scores derived from multiple twenty-four

hour diet recalls (24HR) on randomly assigned days with

those from two seven-day diet recalls (7DDR) (similar in

some respects to commonly used food frequency

questionnaires), one administered at the beginning of the

test period (pre) and one at the end (post). Statistical analysis

included correlation and multiple linear regression. Except

for b describing relation between methods (where b should

equal 1.0) , H0:b=0.

slide14

Social Desirability

Approval Assessment

Marlowe-Crowne

Social

Desirability

Scale

Martin-Larsen

Approval

Motivation

Scale

33-item (true/false)

20-item (5-point Likert)

slide15

Summary Statistics (from 24HR)

Women (n=27)

Men (n=14)

Energy (kcal/d) 1491 (62) 1971 (600)

Fat (g/d) 51.9 (17.3) 65.1 (23.8)

% Fat 31.3 (5.5) 29.4 (4.6)

Calcium (mg/d) 668 (277) 785 (218)

Cholesterol (mg/d) 185 (65) 261 (195)

* Tabulated values are mean (standard deviation)

slide16

WATCH – External Validation Study –

Summary Statistics

Variable

% or Mean/SD

Female Male

(N=27) (N=14)

% Married 74.1% 64.3%

% White 81.5% 85.7%

Age (years) 51.3/16.1 47.2/13.9

Social Desirability Score 20.5/6.4 18.5/5.9

Social Approval Score 48.4/9.6 44.9/9.1

Total energy (k/cal) 1490/461 1970/599

Total fat (g) 51.9/17.3 65.1/23.8

slide17

Statistical Model

Nutrient test method = Nutrient comparison method +

Social Approval + Social Desirability

+ BMI + Covariates

slide18

WATCH – External Validation Study –

Regression Results (Pre)

24-HR

Score

SD

Score

Total Energy (kcal) b= 0.96 -50.23

SEb = 0.27 22.58

P-value = n.s. (0.06)

Total fat (g) 1.41 -2.34

0.39 1.17

n.s. (0.06)

Saturated fatty acids (g) 1.35 -0.68

0.29 0.32

n.s. (0.04)

slide19

WATCH – External Validation Study –

Regression Results (Post)

24-HR

Score

SD

Score

Total Energy (kcal) b= 0.97 -25.50

SEb = 0.17 14.49

P-value = n.s. (0.09)

Total fat (g) 0.90 -1.18

0.20 0.59

n.s. (0.06)

Saturated fatty acids (g) 0.87 -0.30

0.17 0.20

n.s. n.s.

slide20

Results of General Linear Models to Assess

Gender Differences In Social Desirability Bias

Pre Measurements Post Measurements

Women Men Women Men

b SEb b SEb b SEb b SEb

Dependent Variable

Total fat(g) -3.36 (1.57) -1.11 (1.79) -2.06 (0.64) -0.35 (1.43)

Saturated fatty acids -0.85 (0.45) -0.29 (0.67) -0.62 (0.21) 0.22 (0.49)

Total energy (kcal) -68.05 (30.31) -38.90 (32.00) -47.33 (14.35) -17.31 (32.97)

Fat (% energy) -0.33 (0.23) -0.13 (0.20) -0.01 (0.22) -0.09 (0.21)

Cholesterol -7.17 (2.55) -11.25 (7.56) -3.68 (2.13) 1.48 (6.00)

slide21

Results of nutrient quartile stratification to

assess variation in social desirability bias

Pre Measures Post Measures

Dependent Variable b Seb b SEb Fat

Quartile 1 -1.11 0.85 -1.15 0.64

Quartile 2 0.33 0.65 -0.29 0.32

Quartile 3 -1.42 1.12 -1.48 0.24

Quartile 4 -3.62 2.95 -1.65 1.08

Total Energy

Quartile 1 -18.88 19.56 -22.17 5.76

Quartile 2 6.39 3.42 10.27 4.90

Quartile 3 -22.79 11.22 13.34 24.01

Quartile 4 -72.66 84.96 -13.02 45.27

slide22

WATCH – External Validation Study

Conclusions:

  • A downward bias in the 7DDR due to social

desirability was observed in women.

  • It amounted to about 700 kcal/day across the

interquartile range of social desirability scores

for women

Slide 20

slide23

WATCH Study

Hebert JR, Ma Y, Clemow L, Ockene IS, Saperia G, Stanek EJ, Merriam PA,

Ockene JK. Gender differences in social desirability and social approval bias in dietary self report. Am J Epidemiol 1997; 146:1046-1055.

  • The overall purpose of the Worcester Area Trial for Counseling in Hyperlipidemia was:
  • To evaluate the effectiveness of a physician-delivered nutrition intervention counseling program in reducing dietary fat and LDL
slide24

Data Collection in WATCH Study:

  • Over 8,000 patients screened to determine eligibility
  • Age 20-65 years
  • No prior drug treatment and RD referral
  • First fingerstick for testing cholesterol
  • Upper 25% of cholesterol distribution
  • Second fingerstick
  • Consent

1,278 patients

One year

Single 24HR

7DDR

2 lipid profile

BMI(kg/m2 )

SD and

SA measures

March 1995

Baseline

Single 24HR

7DDR

2 lipid profiles

BMI(kg/m2 )

slide25

Responders Vs. Non-Responders

Variable Responders Non-responder P-value* MEAN (SD) MEAN (SD)

Age (Years) 49.44 (10.63) 48.29 (10.45) 0.06

Baseline BMI 28.80 (5.29) 29.51 (5.90) 0.05

Baseline Blood

Cholesterol (mg/dl) 233.60 (46.85) 223.48 (56.59) 0.0008

Baseline LDL

Cholesterol (mg/dl) 152.82 (39.39) 148.89 (43.19) 0.01

# of extra lipid

measures from

Fallon 2.15 (1.26) 1.92 (1.22) 0.01

*P value based on Chi-square for categorical variables and two sample t-test the two group means

slide26

Male and Female Comparison

Male (n=325) Female (n=434)

MEAN SD# MEAN SD# P- value*

7DDR Nutrients at Baseline

Total Energy (kcal/d) 2085.63 927.83 1786.32 752.11 0.0001

Total Fat (g/d) 88.22 50.94 77.49 41.76 0.004

% Calories from Fat 37.11 8.96 38.17 8.73 0.12

Saturated Fat (g/d) 29.39 17.66 25.25 13.50 0.0009

% Calories from

Saturated Fat 12.38 3.78 12.55 3.44 0.52

*P value based on two sample t-test the difference of two group means

slide27

Results of GLM for Males, WATCH Study

Independent Variables:

Dependent Variables: 24HR SD SCORE AP SCORE BMI

Total Fat (g/d)

b 0.29 0.70 1.21 1.04

(p) (0.0003) (0.24) (0.01) (0.04)

Total Saturated Fat (g/d)

b 0.26 0.25 0.45 0.50

(p) (0.0001) (0.23) (0.001) (0.05)

Total Energy (kcal/d)

b 0.36 9.18 21.50 27.24

(p) (0.0001) (0.38) (0.01) (0.01)

slide28

Results of GLM for Females, WATCH Study

Independent Variables:

Dependent Variables: 24HR SD SCORE AP SCORE BMI

Total Fat (g/d)

b 0.28 -0.78 -0.01 0.52

(p) (0.0002) (0.07) (0.98) (0.18)

Total Saturated Fat (g/d)

b 0.26 -0.26 0.02 0.15

(p) (0.0001) (0.05) (0.78) (0.24)

Total Energy (kcal/d)

b 0.27 -19.16 0.02 8.55

(p) (0.0002) (0.02) (0.99) (0.22)

slide29

Some Perspectives

  • In females: SDSCORE 75th percentile=23, 25th percentile=15, 8 points x 19.16=153.3 kcal energy underreport, or a 6.2g fat underreport
  • In males: APSCORE 75th percentile=41, 25th percentile=32, 9 points x 21.50=193.5 kcal overreport, or a 10.9g fat overreport
slide30

WATCH Social Desirability Study Conclusion

  • Social desirability was associated with a downward bias in dietary fat and energy intake in females
  • Social approval was found to be related to over-reporting energy and fat intake in males
  • Further studies are needed to establish models to adjust for the bias
slide31

The Treatwell 5-a-Day Study

Hebert JR, Peterson KE, Hurley TG, Stoddard AM, Cohen N, Field AE, Sorensen G. The effect of social desirability trait on self-reported dietary measures among multi-ethnic female health center employees. Ann Epidemiol 2001; 11:417-427.

  • Multi-ethnic sample of community health center

workers

  • Representing three control sites
  • Multiple 24HR as “relative criterion”
  • Uses three methods for comparison, including

Harvard/Channing FFQ

  • Predominantly (~85% women)
slide32

The Treatwell 5-a-Day Study – Social Desirability Results by Ethnicity, Women Only

Black

Hispanic

White

(n=23)

(n=31)

(n=30)

Variable:

b

SEb

b

SEb

b

SEb

Total Energy Intake (kcal/d)

15.1

31.1

18.9

20.0

-4.5

15.9

Total Fat Intake (g/d)

0.64

0.94

1.03

1.07

-0.23

0.62

slide33

The Treatwell 5-a-Day Study – Results by

Occupational Category, Women Only

Non-Professional

Professional

p-value for

(n=52)

(n=39)

Ho:

b <coll = b >coll

Variable:

b

SEb

b

SEb

Total Energy Intake (kcal/d)

31.8

18.5

-20.6

14.5

<0.005

<0.05

Total Fat Intake (g/d)

1.12

-0.19

0.57

0.67

ns

Fruit (servings/d) - FFQ

0.011

0.042

-0.004

0.037

ns

Fruit (servings/1000kcal/d)

-0.008

0.031

0.002

0.029

slide34

The Treatwell 5-a-Day Study – Results by

Education, Women Only

Less Than College

College Degree

or More

p-value for

(n=52)

H o:

b <coll = b >coll

(n=39)

Variable:

b

SEb

b

SEb

Total Energy Intake (kcal/d)

36.1

20.0

-23.6

12.8

<0.001

Total Fat Intake (g/d)

1.23

0.78

-0.50

0.41

<0.001

Fruit (servings/d) - FFQ

-0.003

0.046

-0.027

0.033

ns

Fruit (servings/1000kcal/d)

-0.005

0.032

-0.002

0.026

ns

slide35

The Treatwell 5-a-Day Study – Conclusions

The FFQ also appears to be biased by social

desirability in women, but …..

¨

the critical factor determining the bias is

education which is …..

¨

more important than occupational category or

ethnicity/race.

¨

As in the WATCH study, bias is oriented toward

fat/energy intake

¨

slide36

The Energy Study, Worcester, MA - 1997

Hebert JR, Ebbeling CB, Matthews CE, Ma Y, Clemow L, Hurley TG, Druker S. Systematic errors in middle-aged women's estimates of energy intake: Comparing three self-report measures to total energy expenditure from doubly labeled water. Ann Epidemiol 2001; (In Press):00-000.

¨

First such study to focus on the most widely

used FFQ (NCI/WHI)

¨

First study to focus on these biases employing

stable isotope methods for comparison

(TEE from DLW)

slide37

Overview of Study

Doubly-Labeled Water Metabolic Period

7

14

0

1

days

  • Baseline questionnaires
  • Demographic data
  • (education)
  • Social desirability (Marlowe-Crowne Scale, 33-item, true/false)
  • Food frequency questionnaire
  • (WHI)
slide38

Description of the Study Population,

The Energy Study (N=73)

n

%

Married

47

64.4

White

72

98.6

Pre-menopausal

41

56.2

Bachelors Degree or more

33

45.2

Employed Full Time

44

60.3

Professional, Managerial Work

33

55.0

Current Smoker

7

9.6

Sedentary

38

52.1

slide39

Further description of the Study Population,

The Energy Study (N=73)

Interquartile

Mean

Standard

Range

Deviation

Minimum

25%

75%

Maximum

Age

(years)

49.0

6.8

40

44

53

65

Body Mass (kg)

70.0

10.4

43.9

62.1

76.9

90.5

BMI (kg/m2)

27.1

4.1

18.7

24.5

29.8

38.2

Fat-Free Mass (kg)

42.4

5.1

32.3

38.1

46.3

53.7

Social Desirability Score

17.4

5.9

4.0

15.0

22.0

29.0

slide40

Further description of the Study Population,

The Energy Study (N=73)

Interquartile

Mean

Standard

Range

Deviation

Minimum

25%

75%

Maximum

TEE from DLW (kcal/d)

2102

380

1378

1830

2318

3337

24-Hour Recall-Derived

Data (7-day average)

Energy Intake (kcal/d)

1820

464

1147

1494

2002

3566

Food Quotient

0.90

0.03

0.82

0.88

0.92

0.99

FFQ Energy (kcal/d)

Day-0 Administration

1735

764

429

1229

2089

4986

Day-14 Administration

1622

594

639

1186

2028

3703

slide41

Social Desirability Bias (kcal/day/point) by Education

Level (FFQ-Derived Energy Intake Versus TEE from

DLW, Beginning of Metabolic Period), The Energy Study (N=73).

All Education Levels:

-36.6 (-65.7, -7.5)

Whole Sample (n=73)

-12.2 (-34.7, 13.1)

Excluding “Outliers ” (n=69)

High Education (college +)

Whole Sample (n=33)

-73.3 (-113., -32.9)

-31.9 (-63.6, -0.2)

Excluding “Outliers ” (n=31)

slide42

Social Desirability Bias (kcal/day/point) by Education Level (FFQ-Derived Energy Intake Versus TEEfrom DLW, End of Metabolic Period), The Energy Study (N=73).

All Education Levels:

-10.8 (-34.7, 13.1)

Whole Sample (n=73)

Excluding “Outliers ” (n=72)

-13.7 (-35.8, 8.4)

High Education (college +)

Whole Sample (n=33)

-21.8 (-53.5, 9.9)

slide43

Social Desirability Bias

50

25

0

-25

Bias (kcal/day/point)

-50

-75

Beginning

-100

End

-125

-150

Education

Whole

Sample

(n=75)

High

(n=33)

Low

(n=42)

slide44

Revisiting WATCH --- Why?

Hebert JR, Ma Y, Ebbeling CB, Matthews CE, Ockene IS. Self-report data. Compliance in Healthcare and Research. Armonk, NY: Futura, 2001:163-179.

Is there an effect of education when cut at

college+?

¨

What happens with these biases after an

intervention?

¨

slide45

Social Approval Bias in Males, by Education,

WATCH Study,

Worcester, Massachusetts, 1991-1995.

< College (n=150)

Social Approval

BMI

Score

Baseline

Total Energy (kcal/day)

29.8 (0.003)

29.1 (0.07)

Total Fat (g/day)

1.63 (0.004)

1.60 (0.07)

Total SFA (g/day)

0.59 (0.003)

0.53 (0.09)

One-year

< College (n=112)

Total Energy (kcal/day)

36.7 (0.0003)

53.4 (0.001)

Total Fat (g/day)

1.50 (0.004)

1.72 (0.04)

Total SFA (g/day)

0.41 (0.02)

0.57 (0.05)

slide46

Social Approval Bias in Males, by Education,

WATCH Study,

Worcester, Massachusetts, 1991-1995.

³ College (n=70)

Social Approval

BMI

Score

Baseline

Total Energy (kcal/day)

8.6 (0.49)

48.6 (0.05)

Total Fat (g/day)

0.58 (0.39)

3.87 (0.05)

Total SFA (g/day)

0.26 (0.26)

1.34 (0.07)

One-year

³ College (n=56)

Total Energy (kcal/day)

19.9 (0.14)

33.7 (0.14)

Total Fat (g/day)

1.05 (0.11)

0.70 (0.52)

Total SFA (g/day)

0.25 (0.18)

0.15 (0.63)

slide47

Social Approval and Social Desirability Bias

in Females, by Education, WATCH Study,

Worcester, Massachusetts, 1991-1995.

< College (n=220)

Social Approval

Social Desirability

BMI

Score

Score

Baseline

Total Energy (kcal/day)

-0.2 (0.97)

-14.8 (0.14)

6.9 (0.43)

Total Fat (g/day)

-0.02 (0.95)

-0.53 (0.34)

0.25 (0.61)

Total SFA (g/day)

0.03 (0.76)

-0.14 (0.45)

0.05 (0.75)

One-year

< College (n=172)

Total Energy (kcal/day)

11.0 (0.07)

-3.6 (0.77)

11.1 (0.32)

Total Fat (g/day)

0.36 (0.32)

-0.57 (0.43)

0.36 (0.58)

Total SFA (g/day)

0.14 (0.21)

-0.15 (0.52)

0.21 (0.32)

slide48

Social Approval and Social Desirability Bias

in Females, by Education, WATCH Study,

Worcester, Massachusetts, 1991-1995.

³ College (n=64)

Social Approval

Social Desirability

BMI

Score

Score

Baseline

Total Energy (kcal/day)

-2.9 (0.72)

-24.3 (0.04)

19.7 (0.11)

Total Fat (g/day)

-0.34 (0.49)

-1.28 (0.07)

1.42 (0.05)

Total SFA (g/day)

-0.10 (0.52)

-0.53 (0.01)

0.41 (0.07)

One-year

³ College (n=53)

Total Energy (kcal/day)

-5.1 (0.61)

-9.5 (0.54)

35.5 (0.04)

Total Fat (g/day)

-0.23 (0.67)

-0.21 (0.80)

1.98 (0.02)

Total SFA (g/day)

-0.06 (0.74)

-0.05 (0.86)

0.75 (0.01)

slide49

WATCH Study Conclusions:

Education modifies the effect of the social

desirability and social approval

¨

The effects differ by gender

¨

There appears to be a differential effect of the

intervention on the bias according to

gender and education

¨

slide50

The Role of Social Desirability in

Epidemiologic Confounding

SD Score

Psychologic

Predispositions

Physiologic

Responses

(e.g., Immune

Function)

Disease

True

Diet

Reported

Diet

slide51

WATCH Nutritionist Intervention:

Total Fat and Saturated Fat

Never Referred

< 3 Sessions

³ 3 Sessions

0

-0.71

-0.26

-4.95

-2.13

-8.24

-2.73

±0.14

-2

±0.38

±0.49

-4

±0.50

-6

(% total energy)

Change in fat intake

±1.36

-8

Total Fat

-10

±1.39

Saturated Fat

(n=645)

-12

slide52

WATCH Nutritionist Intervention:

Total Cholesterol and LDL

Never Referred

< 3 Sessions

³ 3 Sessions

0.15

0.01

±0.03

-0.02

-0.15

-0.13

-0.43

-0.48

0

±0.03

-0.15

Changes in serum cholesterol

(mmol/L)

±0.11

±0.12

-0.3

-0.45

TC

±0.13

±0.11

-0.6

(n=555)

LDL-C

-0.75

slide53

WATCH Nutritionist Intervention:

Actual Changes in Total Cholesterol vs. 7DDR - Predicted Values

0

-9.9

-8.4

-9.1

-1

-2

-3

-4

(mg/dL)

Change in Total Serum Cholesterol

-5

-6

-7

-8

-9

Keys

Prediction

Hegsted

Prediction

-10

Actual

slide54

Table 4. Effects of social desirability on self-reported

and measured change scores, WATCH Study, Worcester,

Massachusetts, 1991-1995.

*

Variable

P

b

Self-reported data

Fat intake (% energy)

-0.22

0.002

Body weight

(kg)

-0.02

0.59

Measured data

Serum LDL-C (mmol/L)

0.004

0.48

Body weight

(kg)

0.02

0.59

* P-value for the test of H0:=0