Breast-feeding and maternal risk of type 2 diabetes: a prospective study and meta-analysis.
OBJECTIVE
We aimed to examine the association between breast-feeding and maternal risk of type 2 diabetes and to investigate whether this association is mediated by anthropometric and biochemical factors.


METHODS
A case-cohort study nested within the European Prospective Investigation into Cancer and Nutrition (EPIC)-Potsdam Study between 1994 and 2005 including 1,262 childbearing women (1,059 in a random sub-cohort and 203 incident cases) mainly aged between 35 and 64 years at baseline was applied. Self-reported lifetime duration of breast-feeding was assessed by questionnaire. Blood samples were used for biomarker measurement (HDL-cholesterol, triacylglycerols, C-reactive protein, fetuin-A, γ-glutamyltransferase, adiponectin). A systematic literature search and meta-analysis was conducted of prospective cohort studies investigating breast-feeding and risk of type 2 diabetes.


RESULTS
The HR for each additional 6 months of breast-feeding was 0.73 (95% CI 0.56, 0.94) in EPIC-Potsdam. Meta-analysis of three previous prospective studies and the current study revealed an inverse association between breast-feeding duration and risk of diabetes (pooled HR for lifetime breast-feeding duration of 6-11 months compared with no breast-feeding 0.89; 95% CI 0.82, 0.97). Adjustment for BMI and waist circumference attenuated the association (HR per six additional months in EPIC-Potsdam 0.80; 95% CI 0.61, 1.04). Further controlling for potentially mediating biomarkers largely explained this association (HR 0.89; 95% CI 0.68, 1.16).


CONCLUSIONS
Longer duration of breast-feeding may be related to a lower risk of diabetes. This potentially protective effect seems to be reflected by a more favourable metabolic profile; however, the role of body weight as a mediator or confounder remains uncertain.
Department of Molecular Epidemiology, German Institute of Human Nutrition Potsdam-Rehbruecke, Arthur-Scheunert-Allee 114-116, 14558, Nuthetal, Germany.
Susanne
S
Jäger
Simone
S
Jacobs
Janine
J
Kröger
Andreas
A
Fritsche
Anja
A
Schienkiewitz
Diana
D
Rubin
Heiner
H
Boeing
Matthias B
MB
Schulze
D000328:Adult; D015415:Biomarkers / Q000097:blood; D001942:Breast Feeding; D002097:C-Reactive Protein; D008076:Cholesterol, HDL / Q000097:blood; D003924:Diabetes Mellitus, Type 2 / Q000097:blood / Q000453:epidemiology / Q000209:etiology*; D005260:Female; D006801:Humans; D015994:Incidence; D008875:Middle Aged; D011446:Prospective Studies; D012306:Risk; D013997:Time Factors; D014280:Triglycerides / Q000097:blood; D005723:gamma-Glutamyltransferase
D015415:Biomarkers; D008076:Cholesterol, HDL; D014280:Triglycerides; D002097:C-Reactive Protein; D005723:gamma-Glutamyltransferase