Article Figures & Data
Tables
- Table 1.
Characteristics of the nurses from the DNC at baseline in 1993 or 1999, by incident breast cancer status at follow-up
Total Breast cancer No breast cancer n = 22,877 n = 1,145 n = 21,732 Age, mean (SD) 52.9 (7.8) 53.2 (7.3) 52.9 (7.8) Premenopausal, n (%) 11,579 (51.0) 583 (51.5) 10,996 (51.0) Postmenopausal, n (%) 11,120 (49.0) 548 (48.5) 10,572 (49.0) Menarche ≤ 12, n (%) 5,477 (24.1) 290 (25.6) 5,187 (24.0) Menarche > 12, n (%) 17,222 (75.9) 841 (74.4) 16,381 (76.0) BMI, mean (SD) 23.7 (3.5) 23.8 (3.5) 23.7 (3.5) Underweight (<18.5 kg/m2), n (%) 532 (2.3) 22 (1.9) 510 (2.4) Normal (18.5–25 kg/m2), n (%) 15,698 (69.2) 801 (70.8) 14,987 (69.1) Overweight (25–30 kg/m2), n (%) 5,167 (22.8) 239 (21.1) 4,928 (22.8) Obese (≥30 kg/m2), n (%) 1,302 (5.7) 69 (6.1) 1,233 (5.7) Never smoked, n (%) 7,956 (35.1) 359 (31.7) 7,597 (35.2) Previously smoked, n (%) 6,922 (30.5) 330 (29.2) 6,592 (30.6) Current smoker, n (%) 7,821 (34.5) 442 (39.1) 7,379 (34.2) Smoking intensity (g/day), mean (SD) 7.8 (9.2) 8.4 (8.8) 7.8 (9.2) Never consumed alcohol, n (%) 3,894 (17.2) 195 (17.2) 3,699 (17.2) Alcohol use in drinkers (g/week), mean (SD) 112.5 (127.6) 120.7 (119.8) 112.1 (127.9) Low physical activity, n (%) 1,496 (6.6) 71 (6.3) 1,425 (6.6) Medium physical activity, n (%) 6,132 (27.0) 299 (26.4) 5,833 (27.0) High physical activity, n (%) 15,071 (66.4) 761 (67.3) 14,310 (66.3) Nulliparous, n (%) 3,163 (10.3) 180 (15.9) 2,983 (13.8) Gave birth to 1 child, n (%) 2,680 (11.8) 140 (12.4) 2,540 (11.8) Gave birth to 2 children, n (%) 9,648 (42.5) 467 (41.3) 9,181 (42.6) Gave birth to 3 children, n (%) 5,499 (24.2) 271 (24.0) 5,228 (24.2) Gave birth to 4 children or more, n (%) 1,709 (7.5) 73 (6.5) 1,636 (7.6) Age at first birth 15–24 years, n (%) 8,123 (35.8) 383 (33.9) 7,740 (35.9) Age at first birth 25–29 years, n (%) 8,350 (36.8) 384 (34.0) 7,966 (36.9) Age at first birth 30 years, n (%) 3,065 (13.5) 184 (16.3) 2,881 (13.4) Never used HT, n (%) 16,600 (73.1) 743 (65.7) 15,857 (73.5) Previously used HT, n (%) 2,193 (9.7) 99 (8.8) 2,094 (9.7) Current user of HT, n (%) 3,906 (17.2) 289 (25.6) 3,617 (16.8) Never used OC, n (%) 9,202 (40.5) 475 (42.0) 8,727 (40.5) Ever used OC, n (%) 13,497 (59.5) 656 (58.0) 12,841 (59.5) Rural, n (%) 9,784 (43.1) 514 (45.4) 9,270 (43.0) Provincial, n (%) 3,368 (14.8) 163 (14.4) 3,205 (14.9) Urban, n (%) 9,547 (42.1) 454 (40.1) 9,093 (42.2) Baseline annual PM2.5 (μg/m3), mean (SD) 19.7 (3.5) 20.2 (3.5) 19.6 (3.6) Baseline annual PM10 (μg/m3), mean (SD) 23.5 (3.9) 24.1 (3.8) 23.5 (3.9) Baseline annual NO2 (μg/m3), mean (SD) 12.5 (8.1) 12.7 (8.0) 12.5 (8.1) Abbreviation: OC, oral contraceptives.
- Table 2.
Association between air pollution and breast cancer among the 22,877 nurses from DNC
Model 1a Model 2b Model 3c Unit HR (95% CI) HR (95% CI) HR (95% CI) 3-year mean PM2.5 3.3 μg/m3 1.03 (0.94–1.13) 1.02 (0.93–1.12) 1.00 (0.91–1.09) PM10 2.9 μg/m3 1.04 (0.95–1.14) 1.03 (0.95–1.12) 1.02 (0.94–1.11) NO2 7.4 μg/m3 1.03 (0.97–1.10) 1.02 (0.96–1.08) 1.00 (0.94–1.07)