Evolution of prediabetes in an urban cohort of adults living in a Mediterranean area

Nutrition & Diabetes ARTICLE www.nature.com/nutd OPEN Evolution of prediabetes in an urban cohort of adults living in a Mediterranean area ✉ Carola Buscemi1,2, Cristiana Randazzo 2,3 , Anna Maria Barile ✉ 2 2 Piero Colombrita , Martina Lombardo and Silvio Buscemi 2,3 2,3 , Rosalia Caldarella2,4, Alexis Elias Malavazos5,6, Roberta Caruso2, 1234567890();,: © The Author(s) 2025 BACKGROUND: Prediabetes (PD) precedes type 2 diabetes (T2D), it can be easily recognized by fasting plasma glucose concentrations (FPG) or HbA1c or 2 h post glucose load glycemia, thereby enabling prevention strategies. We investigated the progression of PD to T2D in the ABCD study (Alimentazione, Benessere Cardiovascolare e Diabete -ISRCTN15840340) that included a representative cohort of adult people living in the Mediterranean area of Palermo (Italy). MATERIALS AND METHODS: The ABCD cohort was enrolled in 2011 and re-evaluated in 2015. The FPG, HbA1c, physical activity level and dietary habits were investigated. In 2011 participants and their family doctors were informed about their health conditions and indications concerning realistic changes for a healthier lifestyle were provided. RESULTS: Complete information was obtained on 742 out of 1233 individuals. In 2011, the prevalence of PD was 30.7% of which 12.7% developed T2D and 43.9% reversed to normal glucose tolerance (NGT) at follow-up. In 2015, 106 previously NGT participants developed PD. The progression as to T2D as to PD were associated with age (P < 0.001) and sex (P < 0.001). Body weight, BMI, and waist circumference were higher in people with PD than in those without PD and even higher in PD that developed T2D (P < 0.001). A sedentary lifestyle was observed in the PD and NGT subgroups which developed T2D and PD, respectively. Daily energy intake decreased among people with PD who became NGT (P < 0.001) and increased in those who developed T2D (P < 0.05). The glycemic index of diet decreased in those PD people who became NGT and in those people who maintained NGT at follow-up. The MEDILITE score, that describes the Mediterranean pattern of diet, increased significantly in PD group that became NGT and in NGT group that maintained NGT at final observation. CONCLUSIONS: This study suggests that improving individual motivation may be an effective strategy to promote healthier lifestyles. A more physically active lifestyle and Mediterranean dietary habits are associated with a reduction of central obesity, and with a favorable evolution of glucose tolerance in PD people. CLINICAL TRIAL REGISTRATION: ISRCTN15840340 Nutrition and Diabetes (2025)15:39 ; https://doi.org/10.1038/s41387-025-00394-7 INTRODUCTION Concomitant with urbanization, a global spread of the prevalence of obesity and diabetes has been observed with significant costs for society and for health systems [1]. Prediabetes (PD) precedes type 2 diabetes (T2D), it can be easily recognized by fasting plasma glucose (FPG) or glycated hemoglobin (HbA1c) concentrations or 2 h post-glucose load (2h-PG) glycemia [2], thereby enabling prevention strategies [3]. However, the diagnosis of PD is not homogeneous depending which diagnostic criteria is utilized, and few studies, with conflicting results, evaluated the factors associated with the evolution of PD in the general population and concluded that diet may be protective [4–6] or not [7–9]. More than 20 years ago, for the first time, the Diabetes Prevention Program (DPP) study [10] demonstrated that persons with 2h-PG glycemia in the range of actual PD definition, reduced the 4-years risk of T2D of 58% when lifestyle was improved by changes in habitual diet and physical activity level. In the Whitehall II study [11] with a median follow-up of 6.7 years, reversion to normoglycemia from FPG defined PD was 45%, but reduced to 37% and 17% when the diagnosis of PD was based on 2 h PG glycemia or HbA1c values respectively. In general, it has been estimated that about five to ten percent of individuals with prediabetes develop type 2 diabetes annually [12]; so, early detection of prediabetes may offer the possibility of intervention to prevent or delay further progression to type 2 diabetes. Furthermore, people with PD have increased risk of cardiovascular disease (CVD) and mortality [13–15]. So, reversion from PD was also associated with significant cardiovascular (CVD) risk reduction varying according to the diagnostic criteria of PD, and in the Whitehall II study [11] the CVD risk reduction was significant when PD was diagnosed by 2h-PG load glycemia. The aim of this study was to evaluate the evolution of PD, diagnosed by FPG or HbA1c, in a representative sample of the 1 Unit of Internal Medicine, “V. Cervello Hospital”, Palermo, Italy. 2Dipartimento di Promozione della Salute, Materno-Infantile, Medicina Interna e Specialistica di Eccellenza (PROMISE), University of Palermo, Palermo, Italy. 3Unit of Clinical Nutrition, Obesity and Metabolic Diseases; AOU Policlinico “P. Giaccone”, Palermo, Italy. 4Unit of Laboratory Medicine, AOU Policlinico “P. Giaccone”, Palermo, Italy. 5Endocrinology Unit, Clinical Nutrition and Cardiovascular Prevention Service, IRCCS Policlinico San Donato, San Donato Milanese, Italy. 6Department of Biomedical, Surgical and Dental Sciences, University of Milan, Milan, Italy. ✉email: ; Received: 10 September 2024 Revised: 22 September 2025 Accepted: 29 September 2025 C. Buscemi et al. 2 adult general population living in Palermo (Italy), a town of the Mediterranean area. In particular, the 4-years progression of PD to T2D was investigated in relation to lifestyle changes. heart rate (Omron M6; Omron Healthcare Co., Matsusaka, Mie, Japan) were measured by physicians or dietitians, according to standardized procedures. Laboratory analysis SUBJECTS AND METHODS Participants The Nutrition, Cardiovascular Wellness, and Diabetes (ABCD, Alimentazione Benessere Cardiovascolare e Diabete) project (ISRCTN15840340) is a longitudinal observational single-center study of a cohort representative of the adult general population living in Palermo, the largest city in Sicily (Italy) in the Mediterranean area. The ABCD study procedures were described in detail elsewhere [16]. Briefly, the ABCD_1 study cohort was recruited in 2011, the inclusion criteria were participants aged >18 years and residing in Palermo. For this current study, individuals subsequently moved to other cities, or with a known diagnosis of diabetes, tumors, or with incomplete data or deceased, were excluded from calculations. The demographic characteristics of the ABCD cohort were similar to, if not overlapping with, those of the general population of the same age range (18–90 years) as presented elsewhere [17]. At the conclusion of the ABCD_1 study, all participants were interviewed briefly by one of the investigators. During this interview, they received a written report detailing the results of the investigations conducted. This report also highlighted any (...truncated)