Obese people and overweight people have a very significant increased
risk of cancer. For postmenopausal women breast cancer +40%, colorectal +61%,
leukaemia +50%, pancreatic +24%
and mortality in relation to body mass index in the Million Women Study: cohort study
BMJ 2007;335:1134 (1 December),
doi:10.1136/bmj.39367.495995.AE (published 6 November 2007). http://www.bmj.com/content/vol335/issue7630/index.dtl
Gillian K Reeves, statistical
epidemiologist, Kirstin Pirie, statistician,
Valerie Beral, director, Jane Green, clinical research scientist, Elizabeth Spencer, nutritionist, Diana Bull, senior statistician, Million Women Study Collaboration
Cancer Epidemiology Unit, University of Oxford, Oxford OX3 7LF
Objective To examine the relation between body mass index (kg/m2) and cancer incidence and mortality.
Design Prospective cohort study.
Participants 1.2 million UK women recruited into the Million Women Study, aged 50-64 during 1996-2001, and followed up, on average,
for 5.4 years for cancer incidence and 7.0 years for cancer mortality.
outcome measures Relative risks of incidence and mortality for all cancers,
and for 17 specific types of cancer, according to body mass index, adjusted for age, geographical region, socioeconomic
status, age at first birth, parity, smoking status, alcohol intake, physical activity, years since menopause,
and use of hormone replacement therapy.
Results 45 037 incident cancers and 17 203 deaths from cancer occurred over the follow-up period.
Increasing body mass index was associated with an increased incidence of endometrial cancer (trend in
relative risk per 10 units=2.89, 95% confidence interval 2.62 to 3.18), adenocarcinoma of the oesophagus (2.38,
1.59 to 3.56), kidney cancer (1.53, 1.27 to 1.84), leukaemia (1.50, 1.23 to 1.83), multiple myeloma
(1.31, 1.04 to 1.65), pancreatic cancer (1.24, 1.03 to 1.48), non-Hodgkin's lymphoma (1.17, 1.03 to
1.34), ovarian cancer (1.14, 1.03 to 1.27), all cancers combined (1.12, 1.09 to 1.14), breast cancer in postmenopausal
women (1.40, 1.31 to 1.49) and colorectal cancer in premenopausal women (1.61, 1.05 to 2.48). In general,
the relation between body mass index and mortality was similar to that for incidence. For colorectal
cancer, malignant melanoma, breast cancer, and endometrial cancer, the effect of body mass index on risk differed
significantly according to menopausal status.Conclusions Increasing body mass index is associated with a significant increase in the risk of cancer for 10 out of
17 specific types examined. For endometrial cancer and adenocarcinoma
of the oesophagus, body mass index represents a major modifiable risk factor; about half of all cases in
postmenopausal women are attributa