Reduced away-from-home food expenditure and better nutrition knowledge and belief can improve quality of dietary intake among US adults.
OBJECTIVE
To test whether reduced away-from-home food expenditure (AFHFE) and better nutrition knowledge and beliefs (NKB) are associated with dietary quality among US adults.


METHODS
The dietary intake data (average of two 24 h recalls) used were collected from US adults (20-65 years) participating in two cross-sectional surveys, the 1994-96 Continuing Survey of Food Intake by Individuals (CSFII; n 7148) and the CSFII/Diet and Health Knowledge Survey (DHKS; n 4252).


METHODS
Dietary quality was assessed using selected nutrients and food groups and the 2005 revised US Department of Agriculture Healthy Eating Index (HEI). EXPOSURE VARIABLES: (i) Absolute AFHFE (weekly, per capita) and proportion of this exposure out of total food expenditure (relative expenditure); (ii) NKB score using a composite of an eleven-item scale elicited among the CSFII/DHKS subgroup.


METHODS
We used t tests, chi2 tests, Wilcoxon rank-sum tests and multivariate linear regression models adjusting standard errors for sample design complexity. We utilized a change-in-estimate approach to assess mediation. For effect modification, we tested the significance of interaction terms (NKB x AFHFE).


RESULTS
Absolute AFHFE was positively associated with grams of fat (beta = 0.14 (SE 0.06)) and saturated fat (beta = 0.02 (SE 0.01)) and negatively associated with fibre (beta = -0.02 (SE 0.01)) and HEI (beta = -0.08 (SE 0.01)). Relative AFHFE mediated NKB effects on intakes such as fat, saturated fat, cholesterol, Na, and fruits and vegetables (change in estimate >10 %). Among subjects with a poor NKB score, higher AFHFE resulted in lower diet quality, particularly Na and cholesterol intakes.


CONCLUSIONS
Higher AFHFE was associated with a lower dietary quality and interacted antagonistically with NKB in some instances, while mediating the relationship between NKB and dietary quality in others.
Beydoun
May A
MA
Center for Human Nutrition, Department of International Health, Johns Hopkins Bloomberg School of Public Health, 615 N Wolfe Street E2546, Baltimore, MD 21205, USA.
Powell
Lisa M
LM
Wang
Youfa
Y
D000328:Adult; D000368:Aged; D003132:Commerce; D003430:Cross-Sectional Studies; D004032:Diet / Q000191:economics* / Q000592:standards*; D005247:Feeding Behavior; D005260:Female; D005502:Food / Q000191:economics / Q000592:standards; D005518:Food Preferences; D007722:Health Knowledge, Attitudes, Practice; D006801:Humans; D016014:Linear Models; D008297:Male; D011939:Mental Recall; D008875:Middle Aged; D015999:Multivariate Analysis; D009749:Nutrition Surveys; D009765:Obesity / Q000191:economics / Q000453:epidemiology / Q000209:etiology; D012147:Restaurants / Q000191:economics*; D014481:United States