Changes in Micronutrient Intake and Their Influencing Factors in Iran: A Multilevel Analysis Using PERSIAN Cohort Data

Abstract

Background: Monitoring intake of minerals like calcium, iron, and zinc is essential for nutritional interventions. Using data from PERSIAN cohort study, changes in mineral intake in Iran were assessed at the baseline phase (2015) and the reassessment phase (2021) alongside influencing factors. Methods: The PERSIAN cohort includes 160,000 adults aged 35–70 from 18 Iranian regions. Dietary data were obtained via a 125-item Food Frequency Questionnaire (FFQ). Given the hierarchical data structure (individual, household, residential area, center), a four-level multilevel model was applied to examine fixed and random effects. Model fit was evaluated using Akaike and Bayesian Information Criteria, and intra-class correlation coefficients quantified variance across levels. Results: Average daily calcium, iron, and zinc intake declined by 142.5 mg, 1.7 mg, and 1.1 mg, respectively. Yet, 91%, 56%, and 48% of participants met adequate iron, zinc, and calcium intake levels. Women consumed 14.3 mg more calcium than men. In 2021, calcium and zinc intake dropped by 35.4 mg and 0.2 mg. Among the highest socioeconomic group, calcium and iron intake decreased by 17.1 mg and 0.4 mg. Obese individuals consumed slightly more calcium and zinc than normal-weight ones. After six years, calcium intake increased by 38.8 mg among diabetics. Variance in mineral intake was mainly attributed to households (20%, 15.5%, 26%) and centers (20%, 45%, 5%) for calcium, iron, and zinc, respectively. Conclusions: Economic challenges, social inequalities, and changes in food subsidies have notably influenced mineral intake in Iran, underscoring the need for targeted nutritional policies and interventions.

Keywords: Multilevel, Calcium intake, Iron intake, Zinc intake, Mineral intake, PERSIAN cohort