Participants

The Nutrition, Cardiovascular Wellness, and Diabetes (ABCD) Project (ISRCTN15840340) is a longitudinal observational single-center study of a cohort representative of the general population living in Palermo, the largest city in Sicily (Italy), with 674,742 inhabitants in 2011. The ABCD_1 study cohort was recruited in 2011 as previously described [12]. The inclusion criteria were participants aged >18 years and residing in Palermo. 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 [13]. At the conclusion of their participation in 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 identified clinical issues and health risk factors. An analysis of eating habits was conducted, and recommendations were provided to improve one’s dietary choices and potentially increase levels of physical activity. The report, along with its associated recommendations, was forwarded to the participants’ doctors. The original cohort was recontacted (telephone, e-mail, letter) in 2015, and those who agreed to participate in the study were re-examined between March 21 and July 31 at the Metabolism and Clinical Nutrition Laboratory of the Department of Internal Medicine at the University of Palermo. Demographic characteristics of the ABCD_2 cohort were not significantly different from those of the ABCD_1 cohort, as reported previously [14]. For this study, individuals with a known diabetes diagnosis were excluded from calculations.

The institutional Ethics Committee (“Palermo 1,” Policlinico “P. Giaccone” University Hospital, 11/03/2014, ref: 3/2015) approved the study protocol, and each participant signed an approved informed consent form.

The habitual intake of energy and macronutrients during the past 12 months was assessed using a previously validated medium-length Food Frequency Questionnaire for the local population as described elsewhere [15]. Adherence to the Mediterranean Diet was assessed by using the MEDI-LITE questionnaire [16].

Habitual physical activity level was investigated using a specific questionnaire for the local population that describes 4 levels of physical activity progressively increasing from 1 to 4 [14].

Participants underwent blood sampling for the assessment of blood chemistry and hormonal parameters. For each participant, a blood sample was frozen and stored at −80 °C for subsequent measurements. Type 2 diabetes and pre-diabetes were defined according to the most recent consensus statements [17].