Usual intake of dairy products and the chance of pre-diabetes regression to normal glycemia or progression to type 2 diabetes: a 9-year follow-up

Nutrition & Diabetes ARTICLE www.nature.com/nutd OPEN Usual intake of dairy products and the chance of pre-diabetes regression to normal glycemia or progression to type 2 diabetes: a 9-year follow-up Zahra Bahadoran1, Parvin Mirmiran 2✉ and Fereidoun Azizi3 1234567890();,: © The Author(s) 2024 BACKGROUND: We assessed the possible effect of usual dairy consumption on pre-diabetes (Pre-DM) remission or progression to type 2 diabetes (T2D). METHODS: Pre-DM adults (n = 334, mean age of 49.4 years, and 51.5% men) were assessed for dairy intakes (2006–2008) and followed up to 9 years for incidence of T2D or normal glycemia (NG). All biochemical measurements were done at baseline and all subsequent examinations with 3-y follow-up intervals. Multinomial regression models with adjustment of confounding variables were used to estimate odds ratios (OR) and 95% confidence intervals (CIs) of incident T2D and NG for each serving/d dairy consumption. RESULTS: The odds of NG was significantly elevated by 69% (OR = 1.69, 95% CI = 1.00–2.86, P = 0.05) per 200 g/d increased high-fat dairy intake, while the amount of total dairy or low-fat dairy was not related to the outcomes. Higher intakes of yogurt were more likely to be associated with an increased odds of NG (OR = 1.82, 95% CI = 1.20–2.74, P = 0.01). Usual intakes of milk, cheese, or creambutter were not associated to Pre-DM remission or progression to T2D. CONCLUSION: Regular dairy consumption may increase the chance of Pre-DM regression to NG. Nutrition and Diabetes (2024)14:15 ; https://doi.org/10.1038/s41387-024-00257-7 INTRODUCTION Pre-diabetes (Pre-DM), an intermediate hyperglycemic condition [1], is affecting about 27% of the middle-aged adults worldwide [2], and will surpass up to 470 million people by 2030 [3]. Distinct pathophysiologic pathways, i.e., obesity and insulin resistance or loss of β-cell function, are involved in occurrence of Pre-DM. Approximately, 5–10% of Pre-DM subjects progress to T2D annually [4, 5], corresponding to 70% within ten years [6]. PreDM subjects are highly at risk of developing cardiovascular diseases and premature death [7, 8]. Although T2D risk factors are well established, far less is known about potential moderators of Pre-DM regression and progression. Lifestyle modifications effectively prevent developing T2D in Pre-DM subjects by 36% (28–43%) [2]. Adherence to a healthy low-calorie, low-fat diet, and moderate physical activity level (PAL) results in PreDM remission by two-folds [9]. We recently reported that the chance of Pre-DM remission increased by 58% [OR = 1.58, 95% CI = 1.03–2.40] in subjects who had a PAL > 1500 MET-minutes/ week [10], while having a Western-style dietary pattern significantly increased risk of developing T2D by 38% in Pre-DM subjects [11]. Regular intakes of dairy products, supplying protein and essential minerals (i.e., calcium, magnesium, potassium, and vitamin D) [12], have been reported can prevent developing Pre-DM and T2D [13, 14]. Whether dairy products may affect PreDM remission or progression to T2D is less documented [15]. Here, we aimed to investigate the association of usual intakes of dairy products and Pre-DM regression and progression in cohort of middle-aged adult participated in the Tehran Lipid and Glucose Study (TLGS). We also examined possible associations of different levels of dairy intake on long-term changes of glycemic parameters over 9 years. MATERIAL AND METHODS Study population This longitudinal study was conducted in an ongoing community-based prospective study (the Tehran Lipid and Glucose Study, TLGS), which started in 1999 on the 15,005 Tehranian residents, aged ≥3 years to investigate and prevent non-communicable diseases [16]. In this analysis, adult men and women (age ≥21 y) with Pre-DM (n = 334) who had completed data on usual diet, demographics, anthropometrics, and biochemical measurements in the third phase of the TLGS (2006-2008) were included, and followed up to a median of 9 years. Written informed consent was obtained from all participants. The ethics research council of the Research Institute for Endocrine Sciences, Shahid Beheshti University of Medical Sciences, Tehran, Iran, approved the study protocol (Ethics code: IR.SBMU.ENDOCRINE.REC.1401.080). 1 Nutrition and Endocrine Research Center, Research Institute for Endocrine Sciences, Shahid Beheshti University of Medical Sciences, Tehran, Iran. 2Department of Clinical Nutrition and Dietetics, Faculty of Nutrition and Food Technology, National Nutrition and Food Technology Research Institute, Shahid Beheshti University of Medical Sciences, Tehran, Iran. 3Endocrine Research Center, Research Institute for Endocrine Sciences, Shahid Beheshti University of Medical Sciences, Tehran, Iran. ✉email: Received: 23 May 2022 Revised: 16 March 2023 Accepted: 9 January 2024 Z. Bahadoran et al. 2 Demographic, anthropometric, and biochemical measurements Details of data collection and measurements of the variables (i.e., demographic, anthropometrics, blood pressure, medical history) in the TLGS have been reported elsewhere [16]. Details of biochemical measurements in the TLGS samples have been described elsewhere [17]. In brief, biochemical measurements [i.e., fasting serum glucose (FSG), triglyceride (TG), and high-density lipoprotein cholesterol (HDL-C] levels were all done after a 12-to 14-h overnight fast, at baseline and all subsequent examinations (with a 3-y follow-up intervals). The standard oral glucose tolerance test (OGTT) was performed for all adults (age≥21 y) who were not on glucose-lowering medications. Details of PAL measurements have been reported elsewhere [10]. Dietary assessment The usual dietary intakes of the participants over the previous year were assessed using a validated semi-quantitative 168-item food frequency questionnaire (FFQ) at baseline (2006–2008) [18]. Details of dietary assessment in the TLGS were described elsewhere [19, 20]. A residual adjustment was performed using a regression model (with total caloric intake as the independent variable and food/nutrients intake as the dependent variable) to mask the confounding effect of under-or overreport of energy intakes on estimated intakes of food groups and nutrients [21]. Dairy products were defined as stated by USDA and Food and Agriculture Organization (FAO) as “fluid beverage milk, fermented milk, cheese, butter and cream, ice cream, yogurt, dry milk products, condensed milk, and whey products”. Low-fat dairy intakes (g/d) was calculated as the sum of low-fat milk and low-fat yogurt, and high-fat dairy was calculated as the sum of high-fat milk, chocolate milk, high-fat yogurt, cream yogurt, regular and cream cheese, cream and butter. Total dairy consumption (g/d) was calculated as the sum of low- and high-fat dairy products. One serving of each dairy products was converted as follows: 120 g for milk and yogurt; 28 g for cream cheese and regular cheese; 5 g for cream and butter; and 120 (...truncated)