Indirect Assessment of Diet Quality Trends in Iranian Households, 1991–2020 Publisher



Emami O ; Dorosty Motlagh A ; Takian A ; Farkhani E M
Source: Journal of Research and Health Published:2026

Abstract

Background: The healthy eating index (HEI) is a valuable tool in health and nutrition research, providing a measure of diet quality aligned with key recommendations from the Dietary Guidelines for Americans. This study aimed to examine the trends and sociodemographic correlates of dietary quality, as measured by the HEI-2015, among Iranian households over 30 years from 1991 to 2020. Methods: Data from the Household Income-expenditure Survey of 665,254 Iranian households (out of 926,339 surveyed from 1991 to 2020) were analyzed in this cross-sectional study. A hierarchical age-period-cohort (HAPC) model, implemented in SAS software, version 9.4, was used to disentangle age, period, and cohort effects. Results: HEI scores initially increased from 1999 to 2017, indicating improved dietary quality, then declined since 2018. Significant sociodemographic disparities were observed, with higher household income (P<0.0001), education level (P<0.0001), and urban residence (P<0.0001) associated with higher HEI scores. The HAPC model enabled disentangling age, period, and cohort effects, providing insights into the distinct influences shaping dietary patterns across population subgroups over time. This study revealed a statistically significant positive trend in scores, with a mean increase of 8 points over 18 years (1999-2000 to 2015-2016). Scores rose from 43.86 (1999-2000) to 51.86 (2015-2016). Conclusion: This study highlights the need for targeted interventions to promote healthy eating habits, particularly among socioeconomically disadvantaged and rural populations. Addressing the observed decline in dietary quality and sociodemographic disparities is crucial for improving the overall population health and well-being. © 2026 The Author(s);.