DOI: 10.5281/zenodo.15267622
title: San Carlos GDM prevention study Cohort. 6 yeras age

description: The Hospital Clínico San Carlos is a public hospital located in the central area of Madrid and had a healthcare population of 445,000 inhabitants assigned during the performance of this study, between 2015-2017. The prenatal screening consultation is located in the hospital, where all pregnant women are received between the 9-12 week of gestation to perform the first ultrasound and the screening test to detect the risk of chromosomal alterations.

San Carlos Cohort. The San Carlos Cohort is constituted of women who took part in the studies for the prevention of Gestational Diabetes carried out between 2015-2017 and registered as RCT (ISRCTN84389045; ISRCTN13389832, ISRCTN16896947). The studies were approved by the Clinical Trials Committee of the Hospital Clínico San Carlos (CI 13/296-E 2013,July 22, CI16/442-E 2016, November 8, and CI 16/316, 2016 July 15). All women signed the informed consent

The aims of these three clinical trials were evaluating the effect of a MedDiet-based intervention on normoglycemic pregnant women initiated before the 12th gestational week (GW) for GDM prevention. Briefly, the first study (ISRCTN84389045), starting in 2015, was a randomized controlled trial (RCT) in which women were allocated into an intervention group (IG) and a control group (CG). Both groups were instructed to eat a MedDiet. But women in the IG were told to increase the consumption of extra virgin olive oil (EVOO) to over 40 mL/day and to eat a handful of pistachios daily, with both provided free-of-cost. The CG women, however, were urged to limit fat intake. The second trial was a real-world clinical study (ISRCTN13389832) in which all participants continued with the same dietary recommendations as the IG of the first trial, but without the provision of EVOO and pistachios. The third trial (ISRCTN16896947) was also a RCT in which women with a BMI ≥25 kg/m² were included. In this case, the participants belonging to the IG were urged to increase the consumption of EVOO and nuts, but, in contrast to the prior studies, only pistachios were provided at no cost. 

Inclusion criteria: Normoglycemic (<92 mg/dL) pregnant women at 8-12 gestational weeks (GW) were invited to participate upon their first ultrasound visit, between 8-14 GW. Gestational age at entry for inclusion was based on the one obtained in this first ultrasound. Inclusion criteria: ≥18 years old, single gestation, acceptance of participation in the study, and signature of the consent form. 

Exclusion criteria: gestational age at entry >14 GW, intolerance to nuts or EVOO, medical conditions or pharmacological therapy that could compromise the effect of the intervention and/or the follow-up program.

A total of 2529 women were enrolled in the studies, of which 2228 women finally completed the study during gestation until delivery (antenatal follow-up), Two thousand two hundred twenty-eight women were evaluated at the end of pregnancy (625 women in the CG and 1603 in the IG). Participants were followed up during gestation and postpartum from 2015-2018. 

- Throughout the years 2017-2020, women belonging to all groups were followed up at a 3-year postpartum visit. Hence, a total of 369/625 (59%) CG and 1031/1603(64.3%) IG women completed all the visits and were finally included in the analysis at both 3 months and 3 years postpartum.

 A total of 1403 completed 6 years of follow-up face-to face visit and have been included in the postnatal study.

At the 6-year postpartum follow-up, 1808 participants completed the evaluation face-to-face and digital records, with 516 in the Control Group (28.53%) and 1292 in the Intervention Group (71.46%) The study analyzes the children of women who participated in these prior clinical trials at 6 years of age, coinciding with mandatory Spanish pediatric monitoring. 

Genotyping samples were obtained from 1711 (79.4%) women, of which 1645 (96%) were valid, and in 1588 (93%), 1069 of Caucasian origin and 519 of Latin American origin, the samples were sufficient to determine >95 snips and have been assessed in this study. Although in 1515 women the sample was sufficient to determine the 110 snips