. Author manuscript; available in PMC: 2015 Apr 29.

Published in final edited form as: Lancet Oncol. 2014 Nov 24;15(13):e625–e634. doi: 10.1016/S1470-2045(14)70364-X

Table.

Epidemiological risk factors for triple-negative breast cancer in women of African ancestry

	Number of cases of African ancestry (% of total cases)	Study design	Factors associated with triple-negative breast cancer
Bauer et al (2007)¹⁵	636 (10%)	Cohort	Aged younger than 40 years (OR 1·53, 95% CI 1·37–1·70); low socioeconomic status (1·12, 1·01–1·24)
Millikan et al (2008)³⁶	787 (43%)	Case-control	Parity (p_trend=0·04); short duration of breastfeeding (p_trend=0·03); large waist-to-hip ratio (p_trend=0·002)
Stead et al (2009)³⁷	178 (43%)	Case-control	Overweight or obese (both non-significant)
Trivers et al (2009)³⁸	116 (24%)	Case-control	Obesity (OR 1·89, 95% CI 1·22–2·92)
Ma et al (2010)³⁹	849 (44%)	Case-control	Short duration of breastfeeding (p_trend=0·03); aged 45–65 years with oral contraceptive use before age 18 years (OR 2·87, 95% CI 1·44–5·74)
Shinde et al (2010)⁴⁰	254 (10%)	Case-case	Parity (OR 1·12, 95% CI 1·06–1·20); short duration of breastfeeding (0·93, 0·90–0·97)
Ambrosone et al (2014)⁴¹	786 (100%)	Case-control	Parity (p_trend=0·03); shorter duration of breastfeeding (non-significant)

OR=odds ratio. All studies were done in the USA.