Assessing dietary intakes in food environment research: Implications for policy and practice SHARON KIRKPATRICK University of Waterloo JILL REEDY, KEVIN DODD, AMY SUBAR, FRAN THOMPSON, ROBIN MCKINNON US National Cancer Institute EBONEÉ BUTLER University of North Carolina at Chapel Hill

Assessing dietary outcomes in food environment research Food environment Diet Body weight and other risk factors Incidence of chronic diseases The food environment, diet and health

Assessing dietary outcomes in food environment research The food environment, diet and health Lytle L, AJPM 2009

Assessing dietary outcomes in food environment research Recent reviews highlight a lack of consensus in the existing literature

Assessing dietary outcomes in food environment research ► Context ► Measures of the food environment:  Capturing different aspects, e.g., density or distance to a particular type of food outlet, variety and quality of in-store offerings, perceived availability of food in a particular area  Error ► Measures of dietary intake:  Capturing different aspects, e.g., whole diet versus particular foods or food groups  Error What might account for inconsistencies in the evidence?

Assessing dietary outcomes in food environment research ► Context ► Measures of the food environment:  Capturing different aspects, e.g., density or distance to a particular type of food outlet, variety and quality of in-store offerings, perceived availability of food in a particular area  Error ► Measures of dietary intake:  Capturing different aspects, e.g., whole diet versus particular aspects of diet  Error What might account for inconsistencies in the evidence?

Assessing dietary outcomes in food environment research ► Widely recognized that data collected using self-report dietary instruments contain substantial bias ► Bias can:  Mask relationships that actually exist  Result in spurious effects − Particularly problematic if differential error among populations (e.g., low versus high income)  Reduce statistical power Measuring dietary outcomes in food environment research Barrier to policy and program interventions

Assessing dietary outcomes in food environment research Methods for assessing diet Recall or record Food frequency questionnaire Brief instrument (screener) less more less Bias Number of dietary factors Distribution of dietary factors Time [Money]

Assessing dietary outcomes in food environment research Methods for assessing diet ► 24 hour recalls and food records ► Food frequency questionnaires

Assessing dietary outcomes in food environment research ► Brief instruments focused on ‘indicator foods’ (e.g., fruits, vegetables, salty or sugary snacks)  Screeners or checklists  1 or 2 questions ( e.g., how many servings of fruit/vegetables do you usually eat each day? ) Methods for assessing diet

Assessing dietary outcomes in food environment research ► What is the state of food environment research in terms of assessment of dietary outcomes? ► Review of peer-reviewed literature published from January 2007 through June 2012  Food environments include food stores, restaurants, schools, home, farmers’ markets, recreational facilities, etc. Research question and method Kirkpatrick et al., AJPM, 2014

Assessing dietary outcomes in food environment research ► Systematic search  Search engines: − PubMed, SCOPUS, PsycInfo, Web of Science  Search terms: − [Food or nutrition or diet] AND [environment or community or neighborhood or neighbourhood] AND [measure] AND [assess] − Food environment ► Measures of the Food Environment web compilation (appliedresearch.cancer.gov/mfe) ► Literature cited by each article Search strategy

Assessing dietary outcomes in food environment research 2450 unique articles identified and screened 368 abstracts reviewed to assess eligibility 149 full-text articles assessed for eligibility 51 articles included in systematic review 2082 articles excluded after initial screen 219 articles excluded after review of abstracts 111 articles excluded after full-text review 13 additional articles identified via the reference lists of included articles and relevant reviews and the Measures of the Food Environment website 38 eligible articles identified

Assessing dietary outcomes in food environment research Dietary assessment in food environment research (n=51)

Assessing dietary outcomes in food environment research 24-hour recall Record/ Diary Food frequency questionnaire ScreenerTwo ItemsSingle Item Fruit and/or Vegetables (n=35) Sugar- sweetened beverages (n=14) Fast Food (n=9) Diet Quality (n=9) Note: - The count of instruments exceeds the number of studies reviewed because one or more studies used multiple instruments. - The outcomes included are those most commonly examined among the studies reviewed. Note that a single study may include multiple outcomes and so the sum of studies examining unique outcomes exceeds the total number of studies reviewed. Dietary assessment in food environment research (n=51)

Assessing dietary outcomes in food environment research ► Tendency toward the use of brief (more error-prone) assessment instruments  Low cost and respondent burden  Results in focus on ‘indicator foods’ (or due to a priori interest in specific food groups?) Dietary assessment in food environment research (n=51)

Assessing dietary outcomes in food environment research ► Existence of bias in dietary data and the potential implications for study results rarely discussed ► In several papers, it was noted that the dietary assessment tool was ‘validated’  Validity often assessed by comparing the instrument to another self-report instrument  limited utility Dietary assessment in food environment research (n=51)

Assessing dietary outcomes in food environment research ► Relationships between food environment features and dietary outcomes more consistent in studies using less error-prone measures Dietary assessment in food environment research (n=51) Studies with 24HR, diaries, FFQ 76% showed overall effects in the expected direction Studies with screeners, 1-2 items 55% showed overall effects in the expected direction

Assessing dietary outcomes in food environment research ► Explosion of research examining relationships between features of food environments and dietary intakes ► Bias in dietary data may be substantial, particularly if estimates are based on brief dietary instruments  May lead to spurious effects and reduced statistical power to detect associations ► Barrier to establishing policy and program interventions to improve diet and health Conclusions

Assessing dietary outcomes in food environment research ► Effects of bias when diet is the outcome (rather than an exposure) not thoroughly examined – need more research to inform strategies ► In the meantime?  Start with the best instrument possible: technologic advances allow collection of more detailed and less biased dietary data  Use available strategies to reduce the effects of error (e.g., calibrate data from brief instruments using other sources)  Discuss potential implications of bias on study results and inconsistencies with other studies Moving forward

Assessing dietary outcomes in food environment research Questions or comments?