Meat and dairy food consumption and breast cancer: a pooled analysis of cohort studies.
BACKGROUND
More than 20 studies have investigated the relation between meat and dairy food consumption and breast cancer risk with conflicting results. Our objective was to evaluate the risk of breast cancer associated with meat and dairy food consumption and to assess whether non-dietary risk factors modify the relation.


METHODS
We combined the primary data from eight prospective cohort studies from North America and Western Europe with at least 200 incident breast cancer cases, assessment of usual food and nutrient intakes, and a validation study of the dietary assessment instrument. The pooled database included 351,041 women, 7379 of whom were diagnosed with invasive breast cancer during up to 15 years of follow-up.


RESULTS
We found no significant association between intakes of total meat, red meat, white meat, total dairy fluids, or total dairy solids and breast cancer risk. Categorical analyses suggested a J-shaped association for egg consumption where, compared to women who did not eat eggs, breast cancer risk was slightly decreased among women who consumed < 2 eggs per week but slightly increased among women who consumed > or = 1 egg per day.


CONCLUSIONS
We found no significant associations between intake of meat or dairy products and risk of breast cancer. An inconsistent relation between egg consumption and risk of breast cancer merits further investigation.
Missmer
Stacey A
SA
Department of Epidemiology, Harvard School of Public Health, Boston, MA 02115-6096, USA. stacey.missmer@channing.harvard.edu
Smith-Warner
Stephanie A
SA
Spiegelman
Donna
D
Yaun
Shiaw-Shyuan
SS
Adami
Hans-Olov
HO
Beeson
W Lawrence
WL
van den Brandt
Piet A
PA
Fraser
Gary E
GE
Freudenheim
Jo L
JL
Goldbohm
R Alexandra
RA
Graham
Saxon
S
Kushi
Lawrence H
LH
Miller
Anthony B
AB
Potter
John D
JD
Rohan
Thomas E
TE
Speizer
Frank E
FE
Toniolo
Paolo
P
Willett
Walter C
WC
Wolk
Alicja
A
Zeleniuch-Jacquotte
Anne
A
Hunter
David J
DJ
D000818:Animals; D001943:Breast Neoplasms / Q000453:epidemiology*; D015331:Cohort Studies; D003611:Dairy Products; D004435:Eating; D015987:Effect Modifier, Epidemiologic; D004531:Eggs; D005260:Female; D006801:Humans; D008460:Meat; D008892:Milk; D012307:Risk Factors