Childhood dairy intake and adult cancer risk: 65-y follow-up of the Boyd
Orr cohort1,2,3
Jolieke C van der Pols, Chris Bain, David Gunnell, George Davey Smith,
Clare Frobisher and Richard M Martin

http://www.ajcn.org/cgi/content/abstract/86/6/1722

1 From the Longitudinal Studies Unit, Division of Epidemiology and
Social Medicine, School of Population Health, University of Queensland,
Brisbane, Australia (JCvdP and CB); the Department of Social Medicine,
University of Bristol, Bristol, United Kingdom (DG, GDS, and RMM); and
the Department of Public Health and Epidemiology, The University of
Birmingham, Birmingham, United Kingdom (CF)

Background: Dairy consumption affects biological pathways associated
with carcinogenesis. Evidence for a link between cancer risk and dairy
consumption in adulthood is increasing, but associations with childhood
dairy consumption have not been studied adequately.

Objective: We investigated whether dairy consumption in childhood is
associated with cancer incidence and mortality in adulthood.

Design: From 1937 through 1939, some 4999 children living in England and
Scotland participated in a study of family food consumption, assessed
from 7-d household food inventories. The National Health Service central
register was used to ascertain cancer registrations and deaths between
1948 and 2005 in the 4383 traced cohort members. Per capita household
intake estimates for dairy products and calcium were used as proxy for
individual intake.

Results: During the follow-up period, 770 cancer registrations or cancer
deaths occurred. High childhood total dairy intake was associated with a
near-tripling in the odds of colorectal cancer [multivariate odds ratio:
2.90 (95% CI: 1.26, 6.65); 2-sided P for trend = 0.005] compared with
low intake, independent of meat, fruit, and vegetable intakes and
socioeconomic indicators. Milk intake showed a similar association with
colorectal cancer risk. High milk intake was weakly inversely associated
with prostate cancer risk (P for trend = 0.11). Childhood dairy intake
was not associated with breast and stomach cancer risk; a positive
association with lung cancer risk was confounded by smoking behavior
during adulthood.

Conclusions: A family diet rich in dairy products during childhood is
associated with a greater risk of colorectal cancer in adulthood.
Confirmation of possible underlying biological mechanisms is needed.