Table 1.
Frequency distribution and mean values of covariates by weight change from age 20 years to baseline (n = 150 257)
| Weight change in kilograms (kg) |
||||||
|---|---|---|---|---|---|---|
| Characteristics | <–2.5 (n = 12 313) | ±2.5 (n = 23 312) | 2.5–5 (n = 17 520) | 5.1–10 (n = 33 960) | 10+ (n = 63 152) | Total (n = 150 257) |
| Mean (s.d.) | ||||||
| Age at recruitment (years) | 48.7 (12.4) | 45.9 (12.6) | 48.7 (10.8) | 50.8 (9.7) | 53.3 (8.4) | 50.7 (10.5) |
| Weight aged 20 years (kg) | 64.6 (10.1) | 57.9 (7.2) | 56.6 (6.9) | 56 (6.9) | 56.1 (7.9) | 57.1 (8) |
| Height (cm) | 163.8 (6.4) | 164 (6.4) | 163.8 (6.3) | 163.6 (6.4) | 163.7 (6.5) | 163.7 (6.4) |
| n (%) | ||||||
| Age at menarche (years) | ||||||
| <12 | 1699 (13.8) | 2964 (12.7) | 2133 (12.2) | 4355 (12.8) | 8931 (14.1) | 20 082 |
| 12 | 2287 (18.6) | 4390 (18.8) | 3333 (19) | 6262 (18.4) | 11 919 (18.9) | 28 191 |
| 13 | 3208 (26.1) | 6380 (27.4) | 4711 (26.9) | 8766 (25.8) | 15 371 (24.3) | 38 436 |
| 14 | 2616 (21.2) | 5227 (22.4) | 3897 (22.2) | 7873 (23.2) | 14 069 (22.3) | 33 682 |
| >14 | 2240 (18.2) | 3943 (16.9) | 3082 (17.6) | 5973 (17.6) | 11 470 (18.2) | 26 708 |
| Missing | 263 (2.1) | 408 (1.8) | 364 (2.1) | 731 (2.2) | 1392 (2.2) | 3158 |
| Age at first birth (years) | ||||||
| <20 | 750 (6.1) | 1320 (5.7) | 1211 (6.9) | 2759 (8.1) | 6791 (10.8) | 12 831 |
| 20–30 | 6756 (54.9) | 12 721 (54.6) | 10 864 (62) | 22 750 (67) | 43 901 (69.5) | 96 992 |
| >30 | 1126 (9.1) | 2128 (9.1) | 1702 (9.7) | 2873 (8.5) | 4712 (7.5) | 12 541 |
| Nulliparous | 3474 (28.2) | 6761 (29) | 3474 (19.8) | 5106 (15) | 6950 (11) | 25 765 |
| Missing | 207 (1.7) | 382 (1.6) | 269 (1.5) | 472 (1.4) | 798 (1.3) | 2128 |
| Number of full-term pregnancies | ||||||
| Nulliparous | 3474 (28.2) | 6761 (29) | 3474 (19.8) | 5106 (15) | 6950 (11) | 25 765 |
| 1 | 2014 (16.4) | 3531 (15.2) | 2788 (15.9) | 5378 (15.8) | 9612 (15.2) | 23 323 |
| 2 | 4176 (33.9) | 8202 (35.2) | 7057 (40.3) | 14 515 (42.7) | 27 130 (43) | 61 080 |
| 3 | 1842 (15) | 3329 (14.3) | 3038 (17.3) | 6477 (19.1) | 13 416 (21.2) | 28 102 |
| 4 | 470 (3.8) | 886 (3.8) | 726 (4.1) | 1649 (4.9) | 3999 (6.3) | 7730 |
| 5 | 118 (1) | 204 (0.9) | 144 (0.8) | 326 (1) | 1022 (1.6) | 1814 |
| >5 | 42 (0.3) | 64 (0.3) | 59 (0.3) | 120 (0.4) | 439 (0.7) | 724 |
| Missing | 177 (1.4) | 335 (1.4) | 234 (1.3) | 389 (1.2) | 584 (0.9) | 1719 |
| Education | ||||||
| None | 63 (0.5) | 94 (0.4) | 61 (0.4) | 174 (0.5) | 445 (0.7) | 837 |
| Primary school | 2376 (19.3) | 3217 (13.8) | 2950 (16.8) | 7012 (20.7) | 18 730 (29.7) | 34 285 |
| Technical/professional school | 3629 (29.5) | 6670 (28.6) | 5645 (32.2) | 11 567 (34.1) | 22 113 (35) | 49 624 |
| Secondary school | 1966 (16) | 4440 (19) | 2988 (17.1) | 5621 (16.5) | 8871 (14.1) | 23 886 |
| University degree | 3386 (27.5) | 7359 (31.6) | 4782 (27.3) | 7346 (21.6) | 9245 (14.6) | 32 118 |
| Missing | 893 (7.2) | 1532 (6.6) | 1094 (6.2) | 2240 (6.6) | 3748 (5.9) | 9507 |
| Alcohol consumption (glass/day) | ||||||
| Non-drinkers | 190 (1.5) | 237 (1.0) | 171 (1.0) | 2172 (1.5) | 1168 (1.9) | 2172 |
| 1 glass/day | 9566 (77.7) | 17 927 (76.9) | 13 570 (77.5) | 11 5848 (77.1) | 48 804 (77.3) | 11 5848 |
| >1 glass/day | 2417 (19.6) | 4970 (21.3) | 3580 (20.40) | 30 529 (20.3) | 12 405 (19.6) | 30 529 |
| Missing | 140 (1.1) | 178 (0.8) | 199 (1.1) | 1708 (1.1) | 775 (1.2) | 1708 |
| Smoking statusa | ||||||
| Never | 5521 (44.8) | 12 325 (52.9) | 8750 (49.9) | 16 802 (49.5) | 30 173 (47.8) | 73 571 |
| Former | 2648 (21.5) | 4968 (21.3) | 4308 (24.6) | 8616 (25.4) | 17 328 (27.4) | 37 868 |
| Current | 3703 (30.1) | 5290 (22.7) | 3874 (22.1) | 7365 (21.7) | 13 447 (21.3) | 33 679 |
| Missing | 441 (3.6) | 729 (3.1) | 588 (3.4) | 1177 (3.5) | 2204 (3.5) | 5139 |
| Physical activityb | ||||||
| Inactive | 2109 (17.1) | 3383 (14.5) | 2649 (15.1) | 5598 (16.5) | 13 334 (21.1) | 27 073 |
| Moderately inactive | 3668 (29.8) | 7411 (31.8) | 5551 (31.7) | 10 914 (32.1) | 21 106 (33.4) | 48 650 |
| Moderately active | 3697 (30) | 7414 (31.8) | 5757 (32.9) | 10 877 (32) | 17 844 (28.3) | 45 589 |
| Active | 2620 (21.3) | 4778 (20.5) | 3269 (18.7) | 5924 (17.4) | 9686 (15.3) | 26 277 |
| Missing | 219 (1.8) | 326 (1.4) | 294 (1.7) | 647 (1.9) | 1182 (1.9) | 2668 |
| Oral-contraceptive use | ||||||
| Never | 4484 (36.4) | 7155 (30.7) | 5540 (31.6) | 11 866 (34.9) | 25 906 (41) | 54 951 |
| Ever | 7686 (62.4) | 15 937 (68.4) | 11 824 (67.5) | 21 683 (63.9) | 36 531 (57.9) | 93 661 |
| Missing | 143 (1.2) | 220 (0.9) | 156 (0.9) | 411 (1.2) | 715 (1.1) | 1645 |
| Menopausal status at baseline | ||||||
| Premenopausal | 5221 (42.4) | 11 760 (50.5) | 5540 (31.6) | 11 473 (33.8) | 14 279 (22.6) | 50 122 |
| Perimenopausal | 1802 (14.6) | 3446 (14.8) | 11 824 (67.5) | 6691 (19.7) | 13 367 (21.2) | 28 384 |
| Postmenopausal | 5290 (43) | 8106 (34.8) | 156 (0.9) | 15 796 (46.5) | 35 506 (56.2) | 71 751 |
| Hormone replacement therapy | ||||||
| Never | 8740 (71) | 17 135 (73.5) | 11 832 (67.5) | 21 556 (63.5) | 37 695 (59.7) | 96 958 |
| Ever | 2819 (22.9) | 4783 (20.5) | 4361 (24.9) | 9907 (29.2) | 20 602 (32.6) | 42 472 |
| Missing | 754 (6.1) | 1394 (6.0) | 1327 (7.6) | 2497 (7.4) | 4855 (7.7) | 10 827 |
a
Never/former (quit ≤10, 11–20 and >20 years ago)/current (current and pipe/cigar smoking, current and 1–15, current and 16–25, and >26 cigarettes/day, missing).
b
Combined Physical Activity Index—using cut-points determined in Cambridge in a heart-rate-monitoring validation study and categorizes the population into four activity levels based on a cross-tabulation of occupational activity in four categories by cycling and sports activities (aerobics, swimming and jogging).