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Obesity and Breast Cancer Risk in Men: A National Case-Control Study in England and Wales

Swerdlow, Anthony J; Bruce, Cydney; Cooke, Rosie; Coulson, Penny; Griffin, James; Butlin, Alison; Smith, Beverley; Swerdlow, M Jill; Jones, Michael E

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Anthony J Swerdlow

Rosie Cooke

Penny Coulson

James Griffin

Alison Butlin

Beverley Smith

M Jill Swerdlow

Michael E Jones


Breast cancer is rare in men, and information on its causes is very limited from studies that have generally been small. Adult obesity has been shown as a risk factor, but more detailed anthropometric relations have not been investigated.

We conducted an interview population-based case-control study of breast cancer in men in England and Wales including 1998 cases incident during 2005-2017 at ages younger than 80 years and 1597 male controls, with questions asked about a range of anthropometric variables at several ages. All tests of statistical significance were 2-sided.

Risk of breast cancer statistically significantly increased with increasing body mass index (BMI) at ages 20 (odds ratio [OR] = 1.07, 95% confidence interval [CI] = 1.02 to 1.12 per 2-unit change in BMI), 40 (OR = 1.11, 95% CI = 1.07 to 1.16), and 60 (OR = 1.14, 95% CI = 1.09 to 1.19) years, but there was also an indication of raised risk for the lowest BMIs. Large waist circumference 5 years before interview was more strongly associated than was BMI with risk, and each showed independent associations. Associations were similar for invasive and in situ tumors separately and stronger for HER2-positive than HER2-negative tumors. Of the tumors, 99% were estrogen receptor positive.

Obesity at all adult ages, particularly recent abdominal obesity, is associated with raised risk of breast cancer in men, probably because of the conversion of testosterone to estrogen by aromatase in adipose tissue. The association is particularly strong for HER2-expressing tumors.

Journal Article Type Article
Acceptance Date Aug 26, 2021
Online Publication Date Aug 28, 2021
Publication Date 2021-10
Deposit Date Feb 1, 2023
Publicly Available Date Feb 2, 2023
Journal JNCI Cancer Spectrum
Electronic ISSN 2515-5091
Publisher Oxford University Press (OUP)
Peer Reviewed Peer Reviewed
Volume 5
Issue 5
Article Number pkab078
Keywords Cancer Research; Oncology
Public URL
Publisher URL


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