SWIFT: Study of Women, Infant Feeding and Type 2 Diabetes After GDM Pregnancy
The goal of the Study of Women, Infant Feeding and Type 2 Diabetes after GDM pregnancy (SWIFT) is to determine whether exposure to prolonged, intensive lactation, as compared to formula feeding, reduces the 2-year incidence of type 2 diabetes mellitus among 1,035 women with a recent GDM pregnancy. The study will also examine whether lactation intensity and duration have persistent favorable effects on blood glucose, insulin resistance, weight gain, change in waist circumference, and adiposity during the two-year postpartum period. SWIFT is a prospective, longitudinal observational study in women at high risk for conversion to diabetes and prediabetes during midlife.
Type 2 Diabetes
|Study Design:||Observational Model: Cohort
Time Perspective: Prospective
|Official Title:||SWIFT: Study of Women, Infant Feeding and Type 2 Diabetes After GDM Pregnancy|
- Incident Type 2 Diabetes [ Time Frame: 2 years postpartum ] [ Designated as safety issue: No ]Two-hour 75 gram oral glucose tolerance test; fasting plasma and 2-hour post-load plasma samples analyzed for glucose and insulin concentrations.
- Maternal weight [ Time Frame: 2 years postpartum ] [ Designated as safety issue: No ]Body weight
- Body composition [ Time Frame: 2 years postpartum ] [ Designated as safety issue: No ]Tetra polar Bioelectrical impedance to estimate percent body fat
- Maternal waist circumference [ Time Frame: 2 years postpartum ] [ Designated as safety issue: No ]Waist circumference
- Insulin Resistance Index [ Time Frame: 2 years postpartum ] [ Designated as safety issue: No ]Fasting plasma and 2 hour post-load plasma assayed for concentrations of glucose and insulin. These measures will be used to calculate homeostatic model assessment of insulin resistance (HOMA-IR).
- Insulin secretion Index [ Time Frame: 2 years postpartum ] [ Designated as safety issue: No ]Fasting plasma and 2 hour post-load plasma assayed for concentrations of glucose and insulin. These measures will be used to calculate the homeostatic model assessment of insulin secretion (HOMA-ß).
Biospecimen Retention: Samples With DNA
We collected fasting and 2-hour plasma specimens during each Oral Glucose Tolerance Test (OGTT). The EDTA treated plasma specimens and buffy coats are stored in cryovials at -70 degrees Centrigrade in low temperature freezers.
|Study Start Date:||May 2008|
|Estimated Study Completion Date:||July 2014|
|Estimated Primary Completion Date:||May 2014 (Final data collection date for primary outcome measure)|
Women with recent GDM pregnancy
The study cohort includes women who had gestational diabetes mellitus (GDM) in their index pregnancy for study enrollment. There are two pre-defined groups: 1) women who breastfeed intensively during the first 4 months postpartum, and 2) women who mostly fed formula during the first 4 months postpartum. The study enrolled women into these pre-defined groups, but some women transitioned into mixed feeding groups after enrollment.
SWIFT is a prospective, observational, longitudinal cohort study of 1,035 women diagnosed with GDM during pregnancy who delivered a singleton, live born infant of at least 35 weeks gestation at a Kaiser Permanente Northern California hospital from 2008 to 2011, and were enrolled into the study within 6-9 weeks postpartum. The SWIFT cohort is racially and ethnically diverse with 35% Asian, 9% Black, 31% Hispanic, 23% White, and 2% other race groups. Study enrollment began in mid 2008 and was completed in December 2011, although annual follow up exams will continue through December 2013. Women enrolled into the study met eligibility criteria, and provided written, informed consent for all study procedures prior to the assessments at the in-person exam at 6-9 weeks postpartum (study baseline). Participants were screened for type 2 diabetes at enrollment and thereafter at annual exams during the subsequent two years using the 2-hour 75 gram Oral Glucose Tolerance Test (OGTT). The primary outcome is progression to glucose intolerance, defined as incident diabetes by ADA criteria within 2 years post-delivery based on the 2-hour 75 gram OGTT results at one year and two years postpartum. The primary exposure is lactation intensity and duration assessed from in-patient hospital delivery records, at annual postpartum in-person exams, telephone calls at 1 month postpartum, and via self-administered monthly mailed surveys (from 3 to 11 months postpartum). Data collection after GDM diagnosis started in late gestation throughout the two-year postpartum period, and it was accomplished via electronic medical records for perinatal course (e.g., GDM severity and treatment, gestational weight gain) and for maternal and newborn outcomes, telephone contacts, mailed infant feeding diaries and surveys, self- and interviewer-administered questionaires at in-person exams. Maternal characteristics assessed for this study included breastfeeding intensity and duration, infant feeding practices, sociodemographics, medical and reproductive history, medication use, recurrence of GDM, lifestyle behaviors, depression, and sleep habits. SWIFT also collected these data prospectively via monthly mailings and during annual in-person exams. In addition, trained research assistants measured anthropometry and body composition via bioelectrical impedance according to standardized protocols, processed and stored biospecimens, and collected other data via self- and interviewer-administered questionnaires at each in-person exam.
|United States, California|
|Kaiser Permanente Northern California, Division of Research|
|Oakland, California, United States, 94612|
|Principal Investigator:||Erica P Gunderson, PhD||Kaiser Permanente Northern California|