Systematic errors in middle-aged women's estimates of energy intake: comparing three self-report measures to total energy expenditure from doubly labeled water.
OBJECTIVE
To evaluate energy intake (EI) derived from a food frequency questionnaire (FFQ), seven-day dietary recall (7DDR), and seven 24-hour dietary recall interviews (24HR) for reporting errors associated with social desirability and social approval.


METHODS
The FFQ and 7DDR were administered once before and once after a 14-day metabolic period during which total energy expenditure was determined using the doubly labeled water method (TEE(dlw)). Seven 24HR were conducted over the 14-day period. Data obtained from 80 healthy women (mean age = 49.1 years) were fit to linear regression models in which the EI estimates were the dependent variables and estimates of social desirability and social approval traits, body mass index [weight (kg)/ height (m)(2)], and TEE(dlw) were fit as independent variables.


RESULTS
indicated that in college-educated women there was an underestimate associated with social desirability on the FFQ (-42.24 kcal/day/point on the social desirability scale; 95% CI:-75.48, -9.00). For college-educated women with an average social desirability score ( approximately 17 points) this would equal an underestimate of 507 kcal/day compared to women with the minimum score (4 points). The 7DDR was associated with a differential effect of social approval when comparing by education; i.e., there was a difference of 36.35 kcal/day/point between the two groups (-14.69 in women with >/=college and 21.66 in women with <college) (95% CI: 10.25, 62.45).


CONCLUSIONS
Social desirability and social approval distort energy intake estimates from structured questionnaires, in a manner that appears to vary by educational status. Results observed have important implications for subject recruitment, data collection, and for methods of detection and control of biases in epidemiologic studies.
Hebert
James R
JR
Department of Epidemiology and Biostatistics and the Nutrition Research Center, University of South Carolina, Columbia, SC 29208, USA. jherbert@sph.sc.edu
Ebbeling
Cara B
CB
Matthews
Charles E
CE
Hurley
Thomas G
TG
MA
Yunsheng
Y
Druker
Susan
S
Clemow
Lynn
L
D000328:Adult; D000368:Aged; D000886:Anthropometry; D015982:Bias; D002149:Energy Intake; D005247:Feeding Behavior / Q000523:psychology*; D005260:Female; D006801:Humans; D007407:Interviews as Topic; D008404:Massachusetts; D011939:Mental Recall; D008875:Middle Aged; D015596:Nutrition Assessment; D012650:Self Disclosure; D011795:Surveys and Questionnaires; D014867:Water; D014930:Women / Q000523:psychology*
D014867:Water