| Any OC useb |  | |||
---|---|---|---|---|---|
Never | Ever | Â | |||
N = 26,718 | % | N = 2,191 | % | p value± | |
Age at enrollment | |||||
 ≤ 44 | 13,153 | 49.23 | 447 | 20.40 | < .0001 |
 45–54 | 6,677 | 24.99 | 771 | 35.19 |  |
 55–64 | 4,823 | 18.05 | 731 | 33.36 |  |
 ≥ 65 | 2,065 | 7.73 | 242 | 11.05 |  |
Race | |||||
 White | 26,164 | 97.93 | 2,178 | 99.4 | < .0001 |
 Other | 510 | 1.91 | 8 | 0.37 |  |
 Missing | 44 | 0.16 | 5 | 0.23 |  |
State of Residence | |||||
 North Carolina | 8,739 | 32.71 | 632 | 28.85 | 0.0002 |
 Iowa | 17,979 | 67.29 | 1,559 | 71.15 |  |
Educational Attainment | |||||
 High School or less | 13,905 | 52.04 | 1,102 | 50.3 | 0.0015 |
 Some College or College Graduate | 8,662 | 32.42 | 679 | 30.99 |  |
 1 or more years of Graduate School | 3,833 | 14.35 | 378 | 17.25 |  |
 Missing | 318 | 1.19 | 32 | 1.46 |  |
Body Mass Index | |||||
 0–24.99 | 11,756 | 40.67 | 902 | 41.17 | < .0001 |
 25.00–29.99 | 7,448 | 25.76 | 717 | 32.72 |  |
 ≥ 30.00 | 4,298 | 14.87 | 440 | 20.08 |  |
 Missing | 3,216 | 11.12 | 132 | 6.02 |  |
Alcohol | |||||
 Never | 12,042 | 45.07 | 939 | 42.86 | 0.2371 |
 Less than once/month | 7,099 | 26.57 | 603 | 27.52 |  |
 ≥ 1–3 times per month | 7,277 | 27.24 | 621 | 28.34 |  |
 Missing | 300 | 1.12 | 28 | 1.28 |  |
Cigarette Smoking (Pack-years) | |||||
 Never Smoker | 18,820 | 70.44 | 1,493 | 68.14 | 0.0003 |
 ≤ 6.75 | 3,544 | 13.26 | 294 | 13.42 |  |
 6.751–16.75 | 1,752 | 6.56 | 127 | 5.80 |  |
 ≥ 16.751 | 1,700 | 6.36 | 186 | 8.49 |  |
 Missing | 902 | 3.38 | 91 | 4.15 |  |
Family History of Cancer | |||||
 No/Missing | 13,949 | 52.21 | 949 | 43.31 | < .0001 |
 Yes | 12,769 | 47.79 | 1,242 | 56.69 |  |
Grew up on a farm | |||||
 No | 10,913 | 40.85 | 534 | 24.37 | < .0001 |
 Yes | 15,579 | 58.30 | 1,643 | 74.99 |  |
 Missingc | 226 | 0.85 | 14 | 0.64 |  |
Menopause at Enrollment | |||||
 No | 8,922 | 33.39 | 534 | 24.37 | < .0001 |
 Yes | 6,777 | 25.36 | 1,127 | 51.44 |  |
 Unsure | 245 | 0.92 | 22 | 1.00 |  |
 Missingc | 10,774 | 40.32 | 508 | 23.19 |  |
Number of Live Births | |||||
 0 | 235 | 0.88 | 29 | 1.32 | < .0001 |
 1 or 2 | 7,216 | 27.01 | 688 | 31.40 |  |
 > 2 | 7,526 | 28.17 | 887 | 40.48 |  |
 Missingc | 11,741 | 43.94 | 587 | 26.79 |  |
Oral Contraceptive Use | |||||
 Never | 4,236 | 15.85 | 576 | 26.29 | < .0001 |
 Ever | 11,722 | 43.87 | 1,106 | 50.48 |  |
 Missingc | 10,760 | 40.27 | 509 | 23.23 |  |
Age of first menarche | |||||
 12 years or less | 7,099 | 26.57 | 788 | 35.97 | < .0001 |
 13 years | 4,851 | 18.16 | 493 | 22.5 |  |
 14 years or greater | 3,855 | 14.43 | 398 | 18.17 |  |
 Missingc | 10,913 | 40.85 | 512 | 23.37 |  |
OC Insecticides | |||||
 Overall OC (Any OC) | - | - | 2,191 | 7.58 | - |
 Chlordane | - | - | 1,196 | 4.13 | - |
 DDT | - | - | 1,028 | 3.55 | - |
 Lindane | - | - | 430 | 1.47 | - |
 Aldrin | - | - | 235 | 0.81 | - |
 Hepatchlor | - | - | 222 | 0.77 | - |
 Toxaphene | - | - | 203 | 0.70 | - |
 Dieldrin | - | - | 105 | 0.36 | - |