Appendix Table 1.
Distribution of general, combined, and progestin-only oral contraceptive use and missing values according to study population at baseline and follow-up – The NOWAC Study
| Study population at baseline (n = 74,862) | Study population at follow-up (n = 51,850) | |
|---|---|---|
| General OC use, no. (%) | ||
| Never use | 26,251 (35.1) | 18,073 (24.1) |
| Ever use | 48,611 (64.9) | 33,777 (45.1) |
| Current use | 5,361 (7.2) | 1,956 (2.6) |
| Former use | 43,250 (57.8) | 31,821 (42.5) |
| Missing | 0 (0) | 23,012 (30.7) |
| Duration (years) of OC use1 | ||
| 1–4 | 26,656 (35.6) | 18,598 (24.8) |
| 5–9 | 12,246 (16.4) | 8,490 (11.3) |
| ≥ 10 | 8,529 (11.4) | 5,851 (7.8) |
| Missing | 1,180 (1.6) | 23,850 (31.9) |
| Time (years) since last OC use1 | ||
| < 10 | 16,430 (22.0) | 5,569 (7.4) |
| 11–20 | 22,077 (29.5) | 12,949 (17.3) |
| > 20 | 8,811 (11.8) | 14,637 (19.6) |
| Missing | 1,293 (1.7) | 23,634 (31.6) |
| COC use, no. (%) | ||
| Never use | 38,896 (52.0) | 26,738 (35.7) |
| Ever use | 35,966 (48.0) | 25,112 (33.5) |
| Current use | 3,239 (4.3) | 950 (1.3) |
| Former use | 32,727 (43.7) | 24,162 (32.3) |
| Missing | 0 (0) | 23,012 (30.7) |
| Duration (years) of COC use1 | ||
| < 5 | 19,765 (26.4) | 13,992 (18.7) |
| ≥ 5 | 16,201 (21.6) | 11,120 (14.9) |
| Missing | 0 (0) | 23,012 (30.7) |
| POC use, no. (%) | ||
| Never use | 65,771 (87.9) | 44,737 (59.8) |
| Ever use | 9,091 (12.1) | 7,113 (9.5) |
| Current use | 968 (1.3) | 379 (0.5) |
| Former use | 8,123 (10.9) | 6,734 (9.0) |
| Missing | 0 (0) | 23,012 (30.7) |
| Duration (years) of POC use1 | ||
| < 5 | 6,862 (9.2) | 5,423 (7.2) |
| ≥ 5 | 2,229 (3.0) | 1,690 (2.3) |
| Missing | 0 (0) | 23,012 (30.7) |
COC = Combined oral contraceptives; OC = Oral contraceptives; POC = Progestin-only contraceptives.
1
Among ever-users.