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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.
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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)
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
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 0.57 Total Fat Intake (g/d) 1.12 0.67 -0.19 <0.05 ns 0.037 Fruit (servings/d) - FFQ 0.011 0.042 -0.004 Fruit (servings/1000kcal/d) -0.008 0.031 0.002 0.029 ns
The Treatwell 5-a-Day Study – Results by Education, Women Only College Degree or More p-value for Less Than College (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
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 ¨
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)
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)
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
Further description of the Study Population, The Energy Study (N=73) Interquartile Range Mean Standard 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
Further description of the Study Population, The Energy Study (N=73) Interquartile Range Mean Standard Deviation Minimum 25% 75% Maximum 380 1378 1830 2318 3337 TEE from DLW (kcal/d) 2102 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
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: Whole Sample (n=73) -36.6 (-65.7, -7.5) Excluding “Outliers ” (n=69) -12.2 (-34.7, 13.1) High Education (college +) Whole Sample (n=33) -73.3 (-113., -32.9) Excluding “Outliers ” (n=31) -31.9 (-63.6, -0.2)
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: Whole Sample (n=73) -10.8 (-34.7, 13.1) Excluding “Outliers ” (n=72) -13.7 (-35.8, 8.4) High Education (college +) Whole Sample (n=33) -21.8 (-53.5, 9.9)
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)
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? ¨
Social Approval Bias in Males, by Education, WATCH Study, Worcester, Massachusetts, 1991-1995. < College (n=150) Social Approval BMI Score Baseline 29.8 (0.003) 29.1 (0.07) Total Energy (kcal/day) 1.60 (0.07) Total Fat (g/day) 1.63 (0.004) 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)
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)
Social Approval and Social Desirability Bias in Females, by Education, WATCH Study, Worcester, Massachusetts, 1991-1995. < College (n=220) Social Approval Social Desirability Score Score BMI 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) 0.05 (0.75) Total SFA (g/day) 0.03 (0.76) -0.14 (0.45) 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)
Social Approval and Social Desirability Bias in Females, by Education, WATCH Study, Worcester, Massachusetts, 1991-1995. ³ College (n=64) Social Approval Social Desirability Score Score BMI 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)
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 ¨
The Role of Social Desirability in Epidemiologic Confounding SD Score Psychologic Predispositions Physiologic Responses (e.g., Immune Function) Disease True Diet Reported Diet
WATCH Nutritionist Intervention: Total Fat and Saturated Fat Never Referred < 3 Sessions ³ 3 Sessions -0.71 -0.26 -4.95 -2.13 -8.24 -2.73 0 ±0.14 -2 ±0.38 ±0.49 -4 ±0.50 (% total energy) Change in fat intake -6 ±1.36 -8 Total Fat -10 Saturated Fat ±1.39 (n=645) -12
WATCH Nutritionist Intervention: Total Cholesterol and LDL Never Referred < 3 Sessions ³ 3 Sessions 0.01 0.15 ±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 -0.6 ±0.11 LDL-C -0.75 (n=555)
WATCH Nutritionist Intervention: Actual Changes in Total Cholesterol vs. 7DDR - Predicted Values 0 -9.9 -8.4 -9.1 -1 -2 -3 -4 Change in Total Serum Cholesterol (mg/dL) -5 -6 -7 -8 -9 Keys Prediction Hegsted Prediction -10 Actual
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 -0.02 0.59 (kg) Measured data Serum LDL-C (mmol/L) 0.004 0.48 Body weight 0.02 0.59 (kg) * P-value for the test of H0:=0