Table 2.

Associations between race/ethnicity, socioeconomic status, anthropometrics, reproductive history and risk of TNBC

	Cases	Multivariable- adjusted modela
Race/ethnicity
Non-Hispanic White	551	1
Black	92	1.93 (1.52–2.45)
Family history of breast cancer
No	489	1
Yes	159	1.56 (1.30–1.86)
Physical activityb
Exercises 3 or less episodes per week	502	1
Exercises 4 or more episodes per week	141	0.79 (0.65–0.96)
Reproductive history
Parity
0	53	1
1	47	1.18 (0.79–1.76)
2	184	1.59 (1.16–2.18)
3	157	1.44 (1.04–1.99)
4	97	1.41 (0.99–2.00)
5 or more	105	1.63 (1.15–2.32)
P for trends among parous women	590	0.38
Breastfeeding per child among parous women
No breastfeeding	252	1
1–3 months	199	1.07 (0.88–1.29)
4–6 months	77	0.99 (0.77–1.28)
6 months or more	62	0.82 (0.62–1.09)
P value for trends	590	0.26
Low socioeconomic status (SES)c
0	393	1
1	193	1.06 (0.89–1.27)
2	57	0.80 (0.60–1.07)
P value for trend		0.35
Cardiometabolic risk factorsd
0	270	1
1	192	0.85 (0.71–1.03)
2	133	1.08 (0.87–1.34)
3	48	1.27 (0.93–1.74)
P value for trend		0.25

^aAll the variables listed in the table were mutually adjusted for each other in addition to adjustment for age and stratification on different WHI study subcohorts (observational study or clinical trials and different treatment assignments for all 4 clinical trials)

^bPhysical active was defined as having exercises 4 or more episodes per week

^cWe assigned 1 point for education being high school degree or lower, 1 point for annual family income < $20,000, and 1 point for NSES lower than 20% of the population, and summed for a total score from 0 to 3; scores of 2 and 3 were collapsed. A higher score indicates low SES

^dMetabolic dysfunction was assessed by four cardiometabolic risk factors, including elevated WC, self-reported history of diabetes, high cholesterol, and hypertension. We summed the four components with a total score from 0 to 4. A higher score indicates higher metabolic dysfunction. We collapsed scores of 3 and 4 due to a small sample size in the score of 4