title: Prior lactation reduces future diabetic risk through sustained postweaning effects on insulin sensitivity.
abstract: Breastfeeding for ≥12 mo is recommended for optimal infant nutrition but may hold maternal benefits as well. Indeed, lactation has been associated with lower long-term risk of diabetes in the mother, but the mechanism by which it imparts sustained postweaning effects on glucose tolerance remains unclear. In this context, we postulated that lactation could potentially induce postweaning beneficial effects on glucose tolerance by modifying the natural history of insulin sensitivity and/or pancreatic β-cell function over time. Thus, in this study, we evaluated the relationships between duration of lactation [≤3 mo (n= 70), 3-12 mo (n= 140), and ≥12 mo (n= 120)] and trajectories of insulin sensitivity/resistance, β-cell function, and glycemia over the first 3 yr postpartum in a cohort of 330 women comprising the full spectrum of glucose tolerance in pregnancy, who underwent serial metabolic characterization, including oral glucose tolerance tests, at 3 mo, 1 yr, and 3 yr postpartum. The prevalence of dysglycemia (pre-diabetes/diabetes) at 3 yr postpartum was lower in women who breastfed for ≥12 mo (12.5%) than in those who breastfed for ≤3 mo (21.4%) or for 3-12 mo (25.7%)(overallP= 0.028). On logistic regression analysis, lactation for ≥12 mo independently predicted a lower likelihood of prediabetes/diabetes at 3 yr postpartum (OR = 0.37, 95% CI 0.18-0.78,P= 0.009). Notably, lactation for ≥12 mo predicted lesser worsening of insulin sensitivity/resistance (P< 0.0001), fasting glucose (P< 0.0001), and 2-h glucose (P= 0.011) over 3 yr compared with lactation ≤3 mo but no differences in β-cell function (P≥ 0.37). It has thus emerged that adherence to current breastfeeding recommendations reduces future diabetic risk through sustained postweaning effects on insulin sensitivity/resistance but not β-cell function.
authors.affiliation: Leadership Sinai Centre for Diabetes, Mount Sinai Hospital, Toronto, Ontario, Canada.
authors.forename: Harpreet
authors.initials: H
authors.lastname: Bajaj
authors.affiliation: Leadership Sinai Centre for Diabetes, Mount Sinai Hospital, Toronto, Ontario, Canada.
authors.forename: Chang
authors.initials: C
authors.lastname: Ye
authors.affiliation: Leadership Sinai Centre for Diabetes, Mount Sinai Hospital, Toronto, Ontario, Canada.|Department of Nutritional Sciences, University of Toronto, Toronto, Ontario, Canada.
authors.forename: Anthony J
authors.initials: AJ
authors.lastname: Hanley
authors.affiliation: Division of Endocrinology, University of Toronto, Toronto, Ontario, Canada.|Keenan Research Centre for Biomedical Science of St. Michael's Hospital, Toronto, Ontario, Canada.|Department of Laboratory Medicine and Pathobiology, University of Toronto, Toronto, Ontario, Canada.
authors.forename: Philip W
authors.initials: PW
authors.lastname: Connelly
authors.affiliation: Division of Obstetrics and Gynecology, University of Toronto, Toronto, Ontario, Canada; and.
authors.forename: Mathew
authors.initials: M
authors.lastname: Sermer
authors.affiliation: Leadership Sinai Centre for Diabetes, Mount Sinai Hospital, Toronto, Ontario, Canada.|Division of Endocrinology, University of Toronto, Toronto, Ontario, Canada.|Lunenfeld-Tanenbaum Research Institute, Mount Sinai Hospital, Toronto, Ontario, Canada.
authors.forename: Bernard
authors.initials: B
authors.lastname: Zinman
authors.affiliation: Leadership Sinai Centre for Diabetes, Mount Sinai Hospital, Toronto, Ontario, Canada; ravi.retnakaran@sinaihealthsystem.ca.|Division of Endocrinology, University of Toronto, Toronto, Ontario, Canada.|Lunenfeld-Tanenbaum Research Institute, Mount Sinai Hospital, Toronto, Ontario, Canada.
authors.forename: Ravi
authors.initials: R
authors.lastname: Retnakaran
mesh_terms: D000328:Adult; D001786:Blood Glucose / Q000378:metabolism; D001942:Breast Feeding / Q000706:statistics & numerical data*; D015331:Cohort Studies; D003924:Diabetes Mellitus, Type 2 / Q000453:epidemiology* / Q000378:metabolism; D016640:Diabetes, Gestational / Q000453:epidemiology* / Q000378:metabolism; D005215:Fasting; D005260:Female; D018149:Glucose Intolerance / Q000453:epidemiology* / Q000378:metabolism; D005951:Glucose Tolerance Test; D006801:Humans; D007333:Insulin Resistance; D050417:Insulin-Secreting Cells / Q000378:metabolism; D007774:Lactation; D016014:Linear Models; D016015:Logistic Models; D011236:Prediabetic State / Q000453:epidemiology* / Q000378:metabolism; D011247:Pregnancy; D011446:Prospective Studies; D012306:Risk; D013997:Time Factors
chemical_list: D001786:Blood Glucose
keywords: breastfeeding; diabetes; insulin sensitivity; lactation; prediabetes