Table I.

Selected characteristics of the 34 832 women in the Nurses’ Health Study II (NHSII) included in the analysis overall and for the lower and upper quartiles of average high school exposure to total suspended particulate matter (TSP).

Characteristic	Overall	TSP < 65.5	TSP > 110.0
N	34 832	8722	8719
Age in 1989 (years), Mean ± SD	34.8 ± 4.6	31.2 ± 3.7	38.2 ± 3.6
Race, N (%)
White	33 982 (97.6)	8540 (97.9)	8471 (97.2)
Other races	850 (2.4)	182 (2.1)	248 (2.8)
Average total suspended particulate (TSP, μg/m3), ages 14–18, Mean ± SD	90.1 ± 32.6	54.3 ± 8.2	135.3 ± 22.4
Average distance to the nearest TSP monitor (km), Mean ± SD	19.3 ± 31.3	16.0 ± 31.7	22.4 ± 30.2
High school Alternative Healthy Eating Index, Mean ± SD	46.2 ± 9.8	46.8 ± 10.1	45.8 ± 9.8
High school physical activity (hours/week), Mean ± SD
Strenuous	3.7 ± 2.8	4.0 ± 2.8	3.5 ± 2.7
Moderate	3.3 ± 2.3	3.5 ± 2.3	3.2 ± 2.3
Walking	2.1 ± 1.9	1.8 ± 1.8	2.4 ± 2.0
Body mass index (BMI, kg/m2) at age 18, Mean ± SD	21.3 ± 3.2	21.3 ± 3.2	21.2 ± 3.2
Age at menarche, N (%)
<12	8340 (23.9)	2003 (23.0)	2143 (24.6)
12	10 715 (30.8)	2629 (30.1)	2668 (30.6)
13	9648 (27.7)	2441 (28.0)	2494 (28.6)
≥14	6025 (17.3)	1616 (18.5)	1393 (16.0)
Missing or not known	104 (0.3)	33 (0.4)	21 (0.2)
Number of Years until Menstrual Regularity, N (%)
<1	15 933 (45.7)	3846 (44.1)	4054 (46.5)
1–2	8597 (24.7)	2202 (25.3)	2154 (24.7)
3–4	2397 (6.9)	643 (7.4)	550 (6.3)
5+	4069 (11.7)	907 (10.4)	1111 (12.7)
Never	3660 (10.5)	1084 (12.4)	805 (9.2)
Missing	176 (0.5)	40 (0.5)	45 (0.5)
Cigarettes per day during high school, N (%)
0	33 136 (95.1)	8232 (94.4)	8336 (95.6)
1–4	1096 (3.2)	317 (3.6)	245 (2.8)
≥5	600 (1.7)	173 (2.0)	138 (1.6)
Region of residence in high school
Northeast	13 243 (38.0)	3883 (44.5)	3407 (39.1)
Midwest	12 845 (36.9)	2572 (29.5)	3144 (36.1)
West	4139 (11.9)	766 (8.8)	1335 (15.3)
South	4343 (12.5)	1489 (17.1)	692 (7.9)
Missing	262 (0.8)	12 (0.1)	141 (1.6)