Dairy Intake and Type 2 Diabetes Mellitus in Iranian Older Adults: Insights From the Baseline Phase of the Birjand Longitudinal Aging Study Publisher



Darabi M ; Tajik A ; Movahedi Aliabadi M ; Shakeri Z ; Mohammadi M ; Fakhrzadeh H ; Moudi M ; Khorashadizadeh M ; Varmaghani M ; Sharifi F
Source: Endocrinology, Diabetes and Metabolism Published:2026

Abstract

Background: Type 2 diabetes mellitus (T2DM) is a growing public health concern among older adults worldwide including in Iran. Despite extensive research on the metabolic effects of dairy products, their association with T2DM remains inconsistent, particularly in non-Western populations. This study examined the relationship between dairy consumption including specific types, and T2DM among older adults in eastern Iran. Methods: This cross-sectional study utilised baseline data from the Birjand Longitudinal Aging Study (BLAS), which included community-dwelling adults aged 60 years and older. Dietary intake was assessed using structured questionnaires, and participants were categorised into tertiles based on dairy consumption (low, moderate, high). T2DM status was determined by FBS ≥ 126 mg/dL or a previous physician diagnosis. Logistic regression models estimated the odds ratios (ORs) and 95% confidence intervals (CIs) for T2DM across different levels of dairy intake, adjusting for potential confounders. Results: Data from 1348 participants were analysed, with an overall T2DM prevalence of 27.15%. Individuals in the highest tertiles of yogurt and cheese intake had significantly increased odds of T2DM (OR = 1.454, 95% CI = 1.08–2.20, p = 0.08; OR = 1.44, 95% CI = 1.04–2.00, p = 0.029). No significant association was found between milk consumption and T2DM risk. Total dairy consumption showed no significant association with T2DM in the fully adjusted model (OR = 1.42, 95% CI = 1.00–2.403, p = 0.05). Conclusions: This study reveals a complex association between dairy intake and the risk of T2DM in Iran, in which high consumption of yogurt and cheese was paradoxically associated with increased odds of disease. This finding may be explained by the high fat content of these products, residual confounding from unmeasured dietary patterns, or biological pathways related to diabetes pathology and gut microbiota modulation that were not captured in our analysis. © 2026 The Author(s). Endocrinology, Diabetes & Metabolism published by John Wiley & Sons Ltd.