Table 1 Baseline characteristics by menstrual characteristics status
Characteristics | Irregular cycles (N = 215 378) | Regular cycles (N = 386 825) | Frequent/infrequent cycles (N = 36 947) | Normal cycle frequency (N = 65 593) |
|---|---|---|---|---|
| Â | n (%) | n (%) | n (%) | n (%) |
Age; median (IQR) | 27.5 (22.1–33.2) | 27.2 (22.0–32.7) | 27.5 (21.8–33.8) | 27.4 (21.9–33.4) |
Townsend deprivation quintile | ||||
 1 (least deprived) | 36,877 (17.1) | 71,109 (18.4) | 6913 (18.7) | 12,912 (19.7) |
 2 | 33,111 (15.4) | 61,786 (16.0) | 5916 (16.0) | 10,949 (16.7) |
 3 | 38,970 (18.1) | 70,821 (18.3) | 6765 (18.3) | 12,014 (18.3) |
 4 | 39,909 (18.5) | 68,329 (17.7) | 6630 (17.9) | 11,310 (17.2) |
 5 (most deprived) | 31,911 (14.8) | 50,707 (13.1) | 5054 (13.7) | 8171 (12.5) |
 Missing | 34,600 (16.1) | 64,073 (16.6) | 5669 (15.3) | 10,237 (15.6) |
BMI categories in kg/m2 | ||||
 18.5–25 | 87,884 (40.8) | 157,658 (40.8) | 14,245 (38.6) | 26,492 (40.4) |
 < 18.5 | 10,107 (4.7) | 15,996 (4.1) | 1561 (4.2) | 2589 (4.0) |
 25–30 | 37,110 (17.2) | 61,591 (15.9) | 6233 (16.9) | 10,537 (16.1) |
 > 30 | 33,194 (15.4) | 41,996 (10.9) | 6234 (16.9) | 6925 (10.6) |
 Missing | 47,083 (21.9) | 109,584 (28.3) | 8674 (23.5) | 19,050 (29.0) |
Smoking status | ||||
 Non-smokers | 121,477 (56.4) | 220,926 (57.1) | 20,922 (56.6) | 37,065 (56.5) |
 Current smokers | 53,576 (24.9) | 81,706 (21.1) | 8629 (23.4) | 13,766 (21.0) |
 Ex-smokers | 23,951 (11.1) | 38,887 (10.1) | 4012 (10.9) | 6434 (9.8) |
 Missing | 16,374 (7.6) | 45,306 (11.7) | 3384 (9.2) | 8328 (12.7) |
Alcohol status | ||||
 Non-drinker | 40,821 (19.0) | 65,386 (16.9) | 6469 (17.5) | 10,345 (15.8) |
 Drinker with excess | 4720 (2.2) | 5887 (1.5) | 737 (2.0) | 932 (1.4) |
 Drinker no excess | 111,018 (51.6) | 192,483 (49.8) | 18,887 (51.1) | 32,934 (50.2) |
 Ex-drinker | 2329 (1.1) | 3397 (0.9) | 348 (0.9) | 580 (0.9) |
 Missing | 56,490 (26.2) | 119,672 (30.9) | 10,506 (28.4) | 20,802 (31.7) |
 Current lipid medication | 456 (0.2) | 527 (0.1) | 87 (0.2) | 79 (0.1) |
 Connective tissue disorders | 999 (0.5) | 1498 (0.4) | 168 (0.5) | 289 (0.4) |
 Migraine | 59,873 (27.8) | 82,328 (21.3) | 10,550 (28.6) | 13,877 (21.2) |
 Reproductive factors | ||||
 Current combined oral contraceptive pills | 65,820 (30.6) | 104,274 (27) | 10,266 (27.8) | 17,339 (26.4) |
 Polycystic ovary syndrome | 11,970 (5.6) | 6448 (1.7) | 3755 (10.2) | 1017 (1.6) |
 Pelvic inflammatory disease | 6283 (2.9) | 6941 (1.8) | 1100 (3.0) | 1193 (1.8) |
 Endometriosis | 2353 (1.1) | 3730 (1.0) | 417 (1.1) | 639 (1.0) |
 Fibroids | 698 (0.3) | 1268 (0.3) | 144 (0.4) | 210 (0.3) |
 Miscarriage | 19,745 (9.2) | 23,954 (6.2) | 3083 (8) | 4225 (6) |
 Gestational diabetes | 1280 (0.6) | 1603 (0.4) | 232 (0.6) | 253 (0.4) |
 Pre-eclampsia | 812 (0.4) | 1081 (0.3) | 134 (0.4) | 203 (0.3) |
 Pre-term births | 1452 (0.7) | 2403 (0.6) | 228 (0.6) | 378 (0.6) |
Baseline cardiovascular diseases | ||||
 Hypertension | 2631 (1.2) | 3181 (0.8) | 471 (1.3) | 562 (0.9) |
 Diabetes | 1898 (0.9) | 2359 (0.6) | 334 (0.9) | 392 (0.6) |
 Ischemic heart disease | 119 (0.1) | 123 (0.0) | 14 (0.0) | 22 (0.0) |
 Stroke/TIA | 307 (0.1) | 379 (0.1) | 50 (0.1) | 73 (0.1) |
 Heart failure | 46 (0.0) | 76 (0.0) | 12 (0.0) | 14 (0.0) |