1. ¹Western Australian Institute for Medical Research, Nedlands, Perth, Western Australia 6009, Australia
2. ²School of Population Health, University of Western Australia, Nedlands, Perth, Western Australia, Australia
3. ³Hereford County Hospital, Hereford, UK

Correspondence: Dr L Fritschi, Western Australian Institute for Medical Research, Ground Floor, B Block, Hospital Avenue, Nedlands, Western Australia 6009, Australia. E-mail: fritschi@waimr.uwa.edu.au

Received 1 May 2007; Revised 3 July 2007; Accepted 11 July 2007; Published online 7 August 2007.

Abstract

Left-handedness may be an indicator of intrauterine exposure to oestrogens, which may increase the risk of breast cancer. Women (n=1786) from a 1981 health survey in Busselton were followed up using death and cancer registries. Left-handers had higher risk of breast cancer than right-handers and the effect was greater for post-menopausal breast cancer (hazard ratio=2.59, 95% confidence interval 1.11–6.03).