Duration of lactation, maternal metabolic profile, and body composition in the Norwegian EBBA I-study.
OBJECTIVE
There is conflicting evidence as to whether duration of lactation may decrease the risk of subsequent development of an unfavorable maternal metabolic profile, including overweight and obesity. We hypothesized that duration of lactation is associated with a more favorable metabolic profile and healthier anthropometric measurements.


METHODS
Ninety-eight parous women were studied from the Norwegian EBBAI-study (Energy Balance and Breast cancer Aspects-study), a cross-sectional study of healthy premenopausal women 25-35 years old. Historical lactation data were collected, anthropometric measurements were taken, fasting blood samples (for serum glucose, triglycerides, total cholesterol, and high-density lipoprotein cholesterol) were drawn, and women were asked to fill in a precoded food diary.


RESULTS
Mean time since last birth was 4.7 years, mean number of children was 1.9, mean total duration of lactation was 19 months, and average length of lactation per child was 10.3 months. Women who on average lactated for less than 10 months per child had higher mean levels of fasting serum glucose (5.2 mmol/L vs. 5.0 mmol/L, p=0.04), serum triglyceride (0.91 mmol/L vs. 0.66 mmol/L, p=0.001), and serum cholesterol (4.78 mmol/L vs. 4.32 mmol/L, p=0.004) and a higher waist-to-hip ratio (0.81 vs. 0.77, p=0.001) than women who lactated for 10 months or more per child. The inverse association between average length of lactation per child and waist-to-hip ratio persisted after adjustment for potential confounders.


CONCLUSIONS
These results support the hypothesis that duration of lactation may be associated with a healthier metabolic profile and healthier anthropometric measurements, especially lipid levels and waist-to-hip ratio, even years after weaning.
Department of Nutrition, Institute of Basic Medical Sciences, University of Oslo, Oslo, Norway.
Christine
C
Tørris
Inger
I
Thune
Aina
A
Emaus
Sissi E
SE
Finstad
Asta
A
Bye
Anne-Sofie
AS
Furberg
Emily
E
Barrett
Grazyna
G
Jasienska
Peter
P
Ellison
Anette
A
Hjartåker
D000328:Adult; D001786:Blood Glucose / Q000378:metabolism*; D001823:Body Composition / Q000502:physiology; D003430:Cross-Sectional Studies; D015930:Diet Records; D005215:Fasting / Q000097:blood*; D005260:Female; D006801:Humans; D007774:Lactation / Q000097:blood* / Q000502:physiology; D008055:Lipids / Q000097:blood*; D055442:Metabolome / Q000502:physiology*; D009664:Norway / Q000453:epidemiology; D009765:Obesity / Q000097:blood* / Q000453:epidemiology; D011247:Pregnancy; D013997:Time Factors; D049629:Waist-Hip Ratio
D001786:Blood Glucose; D008055:Lipids