Does breastfeeding influence risk of type 2 diabetes in later life? A quantitative analysis of published evidence.
BACKGROUND
Observational evidence suggests that having been breastfed in infancy may reduce the prevalence of type 2 diabetes in later life.


OBJECTIVE
The objective was to examine the influence of initial breastfeeding on type 2 diabetes and blood glucose and insulin concentrations.


METHODS
A systematic review of published studies identified 1010 reports; 23 examined the relation between infant feeding and type 2 diabetes in later life or risk factors for diabetes. Risk factors in infants were examined separately from those in children and adults. All estimates were pooled by using fixed-effect models; differences <0 and ratios <1 imply a beneficial effect of breastfeeding.


RESULTS
Subjects who were breastfed had a lower risk of type 2 diabetes in later life than did those who were formula fed (7 studies; 76 744 subjects; odds ratio: 0.61; 95% CI: 0.44, 0.85; P = 0.003). Children and adults without diabetes who had been breastfed had marginally lower fasting insulin concentrations than did those who were formula fed (6 studies; 4800 subjects; percentage difference: -3%; 95% CI: -8%, 1%; P = 0.13); no significant difference in fasting glucose concentrations was observed. Breastfed infants had lower mean preprandial blood glucose (12 studies; 560 subjects; mean difference: -0.17 mmol/L; 95% CI: -0.28, -0.05 mmol/L; P = 0.005) and insulin (7 studies; 291 subjects; mean difference: -2.86 pmol/L; 95% CI: -5.76, 0.04 pmol/L; P = 0.054) concentrations than did those who were formula fed.


CONCLUSIONS
Breastfeeding in infancy is associated with a reduced risk of type 2 diabetes, with marginally lower insulin concentrations in later life, and with lower blood glucose and serum insulin concentrations in infancy.
Owen
Christopher G
CG
Division of Community Health Sciences, St George's, University of London, London, United Kingdom. cowen@sgul.ac.uk
Martin
Richard M
RM
Whincup
Peter H
PH
Smith
George Davey
GD
Cook
Derek G
DG
D000293:Adolescent; D000328:Adult; D000368:Aged; D000375:Aging / Q000097:blood / Q000378:metabolism*; D001786:Blood Glucose / Q000378:metabolism*; D001942:Breast Feeding; D002648:Child; D016001:Confidence Intervals; D003924:Diabetes Mellitus, Type 2 / Q000097:blood / Q000453:epidemiology*; D019317:Evidence-Based Medicine; D005260:Female; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D007328:Insulin / Q000097:blood* / Q000378:metabolism; D008297:Male; D008875:Middle Aged; D016017:Odds Ratio; D015995:Prevalence; D012307:Risk Factors
D001786:Blood Glucose; D007328:Insulin