Table 1.

Sample characteristics by birthplace and race/ethnicity (n = 477)

U.S.-Born by Race/ethnicityForeign-Born Hispanic by Age at Migration*
White (n = 49)African American (n = 62)Hispanic (n = 54)<20 years (n = 93)20–29 years (n = 128)≥30 years (n = 90)
Mean (SD)
Age at mammogram (year)a,b51.1 (5.8)51.8 (5.2)48.3 (5.3)51.6 (6.1)51.2 (5.6)52.4 (6.0)
Age at menarche (year)a,c12.8 (1.3)12.3 (1.9)12.2 (1.5)12.4 (1.9)13.2 (1.9)12.9 (1.8)
Paritya1.3 (1.0)1.8 (2.0)1.8 (1.4)2.5 (1.2)2.4 (1.2)2.4 (1.2)
Age at first live birth (in parous women, year)a,b,c33.8 (6.9)21.9 (5.5)25.0 (7.1)22.6 (5.0)24.5 (5.0)25.6 (6.3)
Age at natural menopause (year)b52.2 (2.1)45.9 (4.6)44.3 (8.1)48.4 (4.2)48.3 (5.0)48.6 (5.1)
Body mass index (kg/m2)b28.4 (5.3)32.5 (7.4)30.2 (6.2)30.0 (5.2)29.9 (5.0)29.9 (4.6)
Percent densitya31.0 (19.1)25.8 (16.4)30.3 (17.7)23.8 (14.4)25.2 (14.4)22.5 (11.6)
 Premenopausal34.4 (18.6)28.3 (14.7)33.9 (17.8)28.6 (14.5)30.2 (15.4)26.8 (12.1)
 Postmenopausal25.6 (18.8)24.0 (17.7)22.1 (13.1)20.7 (13.6)21.1 (12.1)20.2 (10.7)
Dense area (cm2)a48.2 (27.0)54.9 (36.5)54.3 (34.7)45.3 (26.6)45.3 (30.2)42.8 (28.1)
 Premenopausal51.0 (27.9)61.5 (38.1)55.2 (34.2)51.6 (25.7)51.2 (30.7)47.0 (31.0)
 Postmenopausal44.7 (26.0)49.2 (35.0)51.2 (35.8)41.4 (26.7)40.5 (29.1)40.8 (26.6)
Non-dense area (cm2)b126.0 (79.4)193.0 (110.4)141.5 (81.3)157.0 (63.3)143.1 (65.3)151.7 (61.8)
 Premenopausalb109.4 (63.9)183.0 (111.5)121.6 (75.2)141.9 (60.5)124.2 (56.1)131.9 (56.0)
 Postmenopausala151.5 (95.0)198.4 (111.9)185.3 (80.2)166.5 (63.8)158.7 (68.5)163.3 (63.0)
N (%)
Educational Attainmenta,b,c
 High school graduate or less education1 (2.04)26 (41.9)12 (22.2)47 (50.5)83 (64.8)53 (58.9)
 Some college6 (12.2)21 (33.9)16 (29.6)31 (33.3)27(21.1)16 (17.8)
 Bachelor's degree or more42 (85.7)15 (24.2)26 (48.2)15 (16.1)18 (14.1)21 (23.3)
Body size at age 10a,b
 Level 17 (14.3)22 (36.1)14 (25.9)48 (51.6)74 (57.8)54 (60.0)
 Level 212 (24.5)10 (16.4)15 (27.8)15 (16.1)27 (21.1)11 (12.2)
 Level 324 (49.0)18 (29.5)13 (24.1)18 (19.4)22 (17.2)15 (16.7)
 Level 46 (12.2)11 (18.0)12 (22.2)12 (12.9)5 (3.9)10 (11.1)
Current Alcohol Consumptiona,b
 Never or former drinker10 (20.4)38 (61.3)26 (48.2)52 (55.9)76 (60.3)55 (61.8)
 Fewer than 3 servings/week23 (46.9)12 (19.4)13 (24.1)26 (28.0)36 (28.6)26(28.3)
 3–7 servings/week12 (24.5)7 (11.3)12 (22.2)8 (8.6)8 (6.4)5 (5.6)
 7 or more servings/week4 (8.2)5 (8.1)3 (5.6)7 (7.5)6 (4.8)4 (4.5)
Duration of lifetime breastfeeding (in parous women)a,b,c
 Never breastfed5 (14.3)19 (41.3)12 (26.7)16 (18.2)22 (18.0)5 (6.1)
 Less than 6 months7 (20.0)17 (37.0)19 (42.2)33 (37.5)40 (32.8)13 (15.9)
 6–11 months5 (14.3)6 (13.0)8 (17.8)14 (15.9)23 (18.9)27 (32.9)
 12 or more months18 (51.4)4 (8.7)6 (13.3)25 (28.4)37 (30.3)37 (45.1)
Duration of lifetime hormonal contraceptive use
 Less than 1 year5 (14.3)11 (26.8)9 (25.0)15 (24.6)25 (31.3)13 (29.6)
 1–4 years9 (25.7)14 (34.2)14 (38.9)23 (37.7)27 (33.8)16 (36.4)
 5 or more years21 (60.0)16 (39.0)13 (36.1)23 (37.7)28 (35.0)15 (34.1)
Ever hormone replacement therapy5 (10.2)3 (4.8)4 (7.4)6 (6.5)5 (3.9)4 (4.4)
Menopausal statusa,b
 Premenopausal30 (63.8)25 (41.0)31 (62.0)36 (38.7)58 (45.3)32 (36.0)
 Postmenopausal17 (36.2)36 (59.0)19 (38.0)57 (61.3)70 (54.7)57 (64.0)
Personal History of Breast Biopsy11 (22.5)7 (11.30)12 (22.2)23 (24.7)34 (26.6)19 (21.1)
Personal History of Benign Breast Diseasec6 (12.2)3 (4.8)3 (5.6)4 (4.3)14 (10.2)1 (1.1)
Family history of breast cancera11 (22.5)10 (16.1)5 (9.3)11 (11.8)11 (8.6)8 (8.9)
  • SD, standard deviation; * one (1) Hispanic foreign-born participant missing age at migration.

  • aComparison of U.S.-born versus foreign-born women; P-value <0.05.

  • bComparisons among racial/ethnic groups in U.S.-born women; P-value <0.05.

  • cComparisons among women migrated at different ages in foreign-born women; P-value <0.05.