Duration of lactation and incidence of the metabolic syndrome in women of reproductive age according to gestational diabetes mellitus status: a 20-Year prospective study in CARDIA (Coronary Artery Risk Development in Young Adults)

Diabetes. 2010 Feb;59(2):495-504. doi: 10.2337/db09-1197. Epub 2009 Dec 3.

Abstract

Objective: The objective of the study was to prospectively assess the association between lactation duration and incidence of the metabolic syndrome among women of reproductive age.

Research design and methods: Participants were 1,399 women (39% black, aged 18-30 years) in the Coronary Artery Risk Development in Young Adults (CARDIA) Study, an ongoing multicenter, population-based, prospective observational cohort study conducted in the U.S. Women were nulliparous and free of the metabolic syndrome at baseline (1985-1986) and before subsequent pregnancies, and reexamined 7, 10, 15, and/or 20 years after baseline. Incident metabolic syndrome case participants were identified according to National Cholesterol Education Program Adult Treatment Panel III (NCEP ATP III) criteria. Complementary log-log models estimated relative hazards of incident metabolic syndrome among time-dependent lactation duration categories by gestational diabetes mellitus (GDM) adjusted for age, race, study center, baseline covariates (BMI, metabolic syndrome components, education, smoking, physical activity), and time-dependent parity.

Results: Among 704 parous women (620 non-GDM, 84 GDM), there were 120 incident metabolic syndrome case participants in 9,993 person-years (overall incidence rate 12.0 per 1,000 person-years; 10.8 for non-GDM, 22.1 for GDM). Increased lactation duration was associated with lower crude metabolic syndrome incidence rates from 0-1 month through >9 months (P < 0.001). Fully adjusted relative hazards showed that risk reductions associated with longer lactation were stronger among GDM (relative hazard range 0.14-0.56; P = 0.03) than non-GDM groups (relative hazard range 0.44-0.61; P = 0.03).

Conclusions: Longer duration of lactation was associated with lower incidence of the metabolic syndrome years after weaning among women with a history of GDM and without GDM, controlling for preconception measurements, BMI, and sociodemographic and lifestyle traits. Lactation may have persistent favorable effects on women's cardiometabolic health.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adolescent
  • Adult
  • Analysis of Variance
  • Blood Glucose / metabolism
  • Body Mass Index
  • Cohort Studies
  • Coronary Disease / epidemiology
  • Diabetes, Gestational / epidemiology
  • Educational Status
  • Female
  • Follow-Up Studies
  • Humans
  • Incidence
  • Insulin / blood
  • Lactation / physiology*
  • Longitudinal Studies
  • Metabolic Syndrome / epidemiology*
  • Multicenter Studies as Topic
  • Parity
  • Pregnancy / physiology
  • Prospective Studies
  • Racial Groups
  • Risk Factors
  • United States / epidemiology
  • Young Adult

Substances

  • Blood Glucose
  • Insulin