Table 1.

Characteristics of included studies^a

ID	Authors	Year	Design	Location	Menopausal status	Sample size	# TNBC cases	Race specification	Exposures studied
1	Akinyemiju et al. (20)	2021	Case-control	Nigeria	Any	338	52	Black	BMI, MHT use
2	Ambrosone et al. (21)	2015	Case-control	USA	Any	36 304	1356	Black	Age at menarche, age at first live birth
3	Ambrosone et al. (22)	2014	Case-control	USA	Any	1146	131	Black	Breastfeeding, parity
4	Atkinson et al. (23)	2016	Case-control	USA	Any	620	64	Not specified	Breastfeeding, family history, parity
5	Azubuike et al. (24)	2022	Case-control	Nigeria	Any	759	71	Black	OC use, parity
6	Beaber et al. (25)	2014	Case-control	USA	Any	1867	171	Not specified	Duration of OC use, OC use
7	Bethea et al. (26)	2016	Case-control	USA	Any	21 940	696	Black	Family history
8	Bethea et al. (27)	2015	Case-control	USA	Any	12 935	494	Black	Duration of OC use, OC use
9	Bigman et al. (28)	2022	Case-control	Nigeria	Any	1400	123	Black	Alcohol, BMI, breastfeeding, parity, smoking
10	Ellingjord-Dale et al. (29)	2017	Case-control	Norway	Any	26 236	386	Not specified	Age at first live birth, breastfeeding, duration of breastfeeding, MHT use, OC use, parity
11	Figueroa et al. (30)	2020	Case-control	Ghana	Any	2198	102	Black	Parity
12	Gaudet et al. (31)	2011	Case-control	USA	Post-menopausal	3678	246	Not specified	BMI, family history, OC use
13	Gomes et al. (32)	2022	Case-control	Brazil	Any	634	43	Hispanic	Alcohol, BMI, family history, OC use, parity, smoking
14	Islam et al. (33)	2012	Case-control	Japan	Any	1415	68	East Asian	Age at first live birth, alcohol, BMI, breastfeeding, family history, parity
15	John et al. (34)	2018	Case-control	USA	Any	5669	558	Black/East Asian/Hispanic	Age at menarche, breastfeeding, duration of breastfeeding, parity
16	Kleinstern et al. (35)	2021	Case-control	USA	Any	13 640	369	Not specified	BMI, breast density, family history, MHT use
17	Klintman et al. (36)	2022	Cohort	Sweden	Post-menopausal	31 510	60	Not specified	BMI
18	Lee et al. (37)	2020	Case-control	Hong Kong	Any	1150	137	East Asian	BMI, duration of breastfeeding, parity
19	Li et al. (38)	2013	Case-control	USA	Any	1125	184	Not specified	Age at menarche, age at first live birth, breastfeeding, duration of breastfeeding, parity
20	Ma et al. (39)	2009	Case-control	USA	Post-menopausal	482	106	Not specified	Breast density
21	Ma et al. (40)	2017	Case-control	USA	Any	3002	554	Not specified	Age at menarche, age at first live birth, duration of breastfeeding, parity
22	Ma et al. (41)	2018	Case-control	USA	Post-menopausal	3416	1030	Not specified	BMI
23	McCarthy et al. (3)	2021	Cohort	USA	Any	198 278	300	Not specified	Age at menarche, age at first live birth, BMI, breast density, family history, parity
24	Palmer et al. (42)	2014	Case-control	USA	Not mentioned	14 747	567	Black	Breastfeeding, parity
25	Park et al. (43)	2016	Case-control	USA	Any	18 070	694	Black	Smoking
26	Phipps, Buist, et al. (44)	2011	Cohort	USA	Not mentioned	1 055 171	705	Not specified	Family history
27	Phipps et al. (45)	2011	Cohort	USA		155 723	307	Not specified	Age at menarche, age at first live birth, BMI, duration of breastfeeding, duration of OC use, family history, MHT use, OC use, parity, smoking
28	Phipps et al. (46)	2008	Case-control	USA	Post-menopausal	1554	78	Not specified	Age at menarche, age at first live birth, breastfeeding, family history, MHT use, parity
29	Razzaghi et al. (47)	2013	Case-control	USA	Any	1019	48	Not specified	Breast feeding, family history, OC use
30	Shin et al. (48)	2018	Case-control	Korea	Any	1883	31	East Asian	Breast density
31	Wang et al. (49)	2022	Cohort	USA	Post-menopausal	121 744	529	Not specified	Age at menarche, breastfeeding, BMI, family history, parity, smoking
32	Wang et al. (50)	2020	Case-control	China	Any	7974	448	East Asian	Age at menarche, age at first live birth, breastfeeding, duration of breastfeeding, parity
33	Williams et al. (51)	2016	Case-control	USA	Any	1495	229	Black	Alcohol

^aBMI = body mass index; MHT = menopausal hormone therapy; OC = oral contraceptive; TNBC = triple-negative breast cancer.