Fast food fruits and vegetables prices’ association with dietary intakes among US adults: Is there modification by family income?

摘要

We examined effects of prices of fast foods (FF) and fruits and vegetables (FV) on dietary intake, body mass index (BMI) and obesity risks and whether the associations varied across groups according to their family income. Data from the US Department of Agriculture Continuing Survey of Food Intakes by Individuals (CSFII, 1994–96) for 7,331 individuals aged 20–65 years with complete data on two 24-hr recalls were used. We computed two food price indices (FFPI and FVPI) which were linked to individuals through geocoded identifiers. Main outcomes included dietary intakes of energy, selected nutrients and food groups, fast food consumption, and diet quality measured using two indices (HEI and aMED), BMI and obesity. Interaction terms between key variables were tested in regression analyses and in further stratified analysis by family income. Higher fast food prices (FFPI) were associated with higher, fiber intake, low saturated fat, and better overall diet quality as measured by aMED. FVPI was positively associated with improved dietary quality as well in terms of lower cholesterol and sodium intakes, improved HEI and lower BMI. Most of these associations showed homogeneous strengths across income groups as evidenced by a non-significant FFPI*PIR or FVPI*PIR interaction term (p<0.10). While increasing FFPI by one standard deviation was only borderline protective against FF consumption (OR=0.89; 95% CI: 0.78, 1.02), its association with other binary outcomes that were considered was non-significant. In contrast, FVPI was protective against obesity, particularly among the near poor. It was also associated with improved aMED score (OR: 2.22; 95% CI: 1.22, 4.03). Analyses of these national data suggest that changing fast food and fruit and vegetable prices may affect people’s dietary quality and to some extent their adiposity, although the present study is limited by the available food price data.