Association between Socioeconomic Status and the Mexican Diet Quality Index score in Adults. Results from the Mexican National Health and Nutrition Survey 2012
Authors: Lopez‐Olmedo Nancy , Taillie Lindsey Smith , Popkin Barry M 
Published: November 2023

BackgroundUnderstanding diet quality is relevant to identify those who would benefit from nutrition interventions and policies. An understanding of overview quality of the Mexican diet is missing so the objective is to create a Mexican Diet Quality Index (Mx‐DQI) and examine it by socioeconomic status (SES) among Mexican adults.Data/methodsDietary data was collected by 24‐hour recall in 3,173 adults aged 20 years or older who participated in the nationally representative Mexican National Health and Nutrition Survey 2012. The Mx‐DQI was constructed based on the 2015–2020 Dietary Guidelines for Americans, which aligns well with Dietary Guidelines in Mexico. An adequacy category encompassed total fruit, whole fruit, total vegetables, greens and beans, whole grains, dairy, total protein foods, and seafood and plant proteins, whereas a moderation category included refined grains, fatty acids, sodium, and added sugars. Weights for each category followed the Health Eating Index model with updates for the new guidelines. The maximum total Mx‐DQI score was 100 points. Household assets were used to create three tertiles of socioeconomic status. Unadjusted means with standard errors were computed for both the total Mx‐DQI score and the individual Mx‐DQI component scores by SES. The continuous measure of the total Mx‐DQI score was then categorized into tertiles for evaluating variations in the diet quality score. Survey weights were applied to make results nationally representative.ResultsThe difference in total Mx‐DQI score was small but significant among SES groups (high SES=42.1 pts; medium SES=39.2 pts; low SES=40.1 pts, p<0.01). Adults with high compared with medium and low SES had higher scores for total fruit (2.1 pts; 1.5 pts; 1.3 pts, respectively, p<0.01), whole fruit (2.5 pts; 1.9 pts; 1.7 pts, respectively, p<0.01), greens and beans (1.2 pts; 0.9 pts; 0.6 pts, respectively, p<0.01), dairy (3.9 pts; 3.0 pts; 2.1 pts, respectively, p<0.01), and refined grains (5.5 pts; 4.2 pts; 3.2 pts, respectively, p<0.01). Conversely, adults with low versus medium and high SES had higher scores for fatty acids (9.1 pts; 7.3 pts; 6.2 pts, respectively, p<0.01), and added sugars (5.6 pts; 4.1 pts; 4.0 pts, respectively, p<0.01). To examine problem areas of diet more closely in each SES group, we looked at the group of individuals in the lowest Mx‐DQI score tertile. Medium SES compared with low and SES had the highest proportion of individuals with a poor score (37.7%; 34.3%; and 31.5%; respectively). The proportion of adults with poorer Mx‐DQI scores for total fruit, whole fruit, dairy, and refined grains was consistently lower in high versus medium and low SES, while the proportion of individuals with poorer Mx‐DQI scores for fatty acids and added sugars was consistently lower in low versus medium and high SES groups.ConclusionThere is a small but significant difference in total Mx‐DQI score by SES. However, differences in Mx‐DQI score distribution by SES are higher. The findings of this study provide an insight for targeting nutrition interventions and policies that can impact diet quality according to SES.Support or Funding InformationThis support comes primarily from the Bloomberg Philanthropies (grants to UNC and CINyS INSP), with support from the NIH R01DK108148, Robert Wood Johnson Foundation (Grant 71698), and the Carolina Population Center and its NIH Center grant (P2C HD0550924).