Abstract P233: Correlations Between Grocery Purchase Quality Index Scores and Healthy Eating Index Scores Vary by Demographics and Shopping Habits

Abstract

Introduction: The Grocery Purchase Quality Index (GPQI) is a new, objective diet quality index that assesses adherence of household grocery purchases to the US Dietary Guidelines. Currently, little is known about the correlation between the GPQI and other common diet quality metrics like the Healthy Eating Index (HEI), and whether shopper characteristics (e.g., demographics, shopping habits) influence the strength of this correlation and the utility of the GPQI as a tool for tracking diet quality. Hypothesis: The GQPI and HEI-2010 will be moderately correlated at baseline in a cohort of shoppers enrolled in a study testing strategies to promote healthier grocery purchases, and these correlations will vary by shopper characteristics. Methods: Data from 224 households recruited from a single medium-sized grocery store were analyzed. Eligible participants were ≥18y, the primary shopper of their household, and did ≥50% of household shopping at store. Participants completed a baseline (Aug-Oct 2018) validated online food frequency questionnaire (FFQ) and a questionnaire about demographics and shopping habits. HEI-2010 scores were calculated from FFQs and GPQI scores were calculated from 2-6 weeks of baseline purchasing data; higher scores reflected healthier diets. Correlations between HEI and GQPI scores (reported as percent of total score) were calculated in SAS 9.4 for the overall sample and by demographic characteristics and shopping habits of interest. Results: The sample was predominantly female (90%), older (mean age=55.6±13.7), and higher socioeconomic status (47.9% >college degree, 49.7% household income >$100k). The mean HEI score was 73.0±9.3% out of 100pts, the mean GQPI score was 54.5±11.4% out of 75pts, and the mean BMI was 25.4±4.6. The two scores were moderately correlated in the overall sample (r=0.31, p<0.001); correlations were stronger in men (r=0.52, p=0.02), middle-income ($60-100k) households (r=0.51, p=0.001), and individuals with underweight (n=14, r=0.58, p=0.03), and obesity (r=0.39, p=0.04) and weaker in individuals with normal weight (r=0.28, p=0.003). The GPQI and HEI were not correlated for individuals with overweight (r=0.16) low-income (<$60k) households (r=0.16) or for those who shopped at farmer’s markets within the past month (r=0.15) whereas individuals who shopped at other grocery or superstores (r=0.31-0.35) had correlations similar to the overall sample. Conclusion: These findings suggest that food purchasing data reflects the individual diet quality and may be a promising tool for evaluating and monitoring individual-level diet quality. Further research should explore influential demographics and shopping habits on the strength of the correlation between the GQPI and HEI to develop more accurate predictive models using objective household purchasing data as a proxy for individual-level intake.