Characteristics | Years | ||||||||
2009 N (%) 6433 (100) | 2010 N (%) 10 447 (100) | 2011 N (%) 9626 (100) | 2012 N (%) 9905 (100) | 2013 N (%) 9496 (100) | 2014 N (%) 9454 (100) | 2015 N (%) 10 108 (100) | 2016 N (%) 7281 (100) | Total N (%) 72 750 (100) | |
Mother’s age (years)* | |||||||||
<20 | 131 (2) | 209 (2) | 181 (1.9) | 188 (1.9) | 190 (2) | 193 (2) | 209 (2.1) | 157 (2.2) | 1458 (2) |
20–29 | 6044 (94) | 9867 (94.4) | 9056 (94.1) | 9269 (93.6) | 8834 (93) | 8743 (92.5) | 9266 (91.7) | 6640 (91.2) | 67 719 (93.1) |
>29 | 258 (4) | 371 (3.6) | 389 (4) | 448 (4.5) | 472 (5) | 518 (5.5) | 633 (6.3) | 484 (6.6) | 3573 (4.9) |
Mother’s education (grades)* | |||||||||
Primary or less (≤4) | 1476 (22.9) | 2281 (21.8) | 1846 (19.2) | 1927 (19.5) | 1882 (19.8) | 693 (7.3) | 633 (6.3) | 329 (4.5) | 11 067 (15.2) |
Secondary (5–10) | 3814 (59.3) | 6210 (59.4) | 5818 (60.4) | 5880 (59.4) | 5432 (57.2) | 4962 (52.5) | 5101 (50.5) | 3522 (48.4) | 40 739 (56) |
University (>10) | 1139 (17.7) | 1956 (18.7) | 1958 (20.3) | 2071 (20.9) | 2172 (22.9) | 3768 (39.9) | 4358 (43.1) | 3415 (46.9) | 20 837 (28.6) |
Missing | 4 (0.1) | 0 (0) | 4 (0) | 27 (0.3) | 10 (0.1) | 31 (0.3) | 16 (0.2) | 15 (0.2) | 107 (0.1) |
Parity* | |||||||||
Nulliparous | 2905 (45.2) | 5118 (49) | 4706 (48.9) | 4817 (48.6) | 4384 (46.2) | 4530 (47.9) | 4967 (49.1) | 3598 (49.4) | 35 025 (48.1) |
1–2 | 3300 (51.3) | 5032 (48.2) | 4669 (48.5) | 4827 (48.7) | 4907 (51.7) | 4721 (49.9) | 4888 (48.4) | 3544 (48.7) | 35 888 (49.3) |
>2 | 228 (3.5) | 297 (2.8) | 249 (2.6) | 261 (2.6) | 204 (2.1) | 197 (2.1) | 234 (2.3) | 137 (1.9) | 1807 (2.5) |
Missing | 0 (0) | 0 (0) | 2 (0) | 0 (0) | 1 (0) | 6 (0.1) | 19 (0.2) | 2 (0) | 30 (0) |
Anaemia (g/dL) | |||||||||
Moderate/severe (<10) | 2962 (46) | 5283 (50.6) | 4620 (48) | 4730 (47.8) | 4682 (49.3) | 4418 (46.7) | 5058 (50) | 3457 (47.5) | 35 210 (48.4) |
Mild (10<11) | 2743 (42.6) | 4341 (41.6) | 4033 (41.9) | 4337 (43.8) | 4006 (42.2) | 4152 (43.9) | 4041 (40) | 2948 (40.5) | 30 601 (42.1) |
Normal (≥11) | 728 (11.3) | 823 (7.9) | 973 (10.1) | 838 (8.5) | 808 (8.5) | 884 (9.4) | 1009 (10) | 876 (12) | 6939 (9.5) |
BMI (kg/m2)* | |||||||||
Underweight (<18.5) | 1784 (27.7) | 3537 (33.9) | 3391 (35.2) | 3450 (34.8) | 3411 (35.9) | 3424 (36.2) | 3786 (37.5) | 2788 (38.3) | 25 571 (35.1) |
Normal (18.5–24.9) | 4426 (68.8) | 6558 (62.8) | 5931 (61.6) | 6061 (61.2) | 5699 (60) | 5619 (59.4) | 5789 (57.3) | 4095 (56.2) | 44 178 (60.7) |
Overweight or obese (≥25) | 223 (3.5) | 352 (3.4) | 304 (3.2) | 394 (4) | 386 (4.1) | 411 (4.3) | 533 (5.3) | 398 (5.5) | 3001 (4.1) |
Anaemia (g/dL)–BMI (kg/m2) factors | |||||||||
Anaemic (<11)–normal (≥18.5) | 4070 (63.3) | 6256 (59.9) | 5522 (57.4) | 5823 (58.8) | 5463 (57.5) | 5384 (56.9) | 5569 (55.1) | 3857 (53) | 41 944 (57.7) |
Anaemic (<11)–underweight (<18.5) | 1635 (25.4) | 3368 (32.2) | 3131 (32.5) | 3244 (32.8) | 3225 (34) | 3186 (33.7) | 3530 (34.9) | 2548 (35) | 23 867 (32.8) |
Non-anaemic (≥11)–normal (≥18.5) | 579 (9) | 654 (6.3) | 713 (7.4) | 632 (6.4) | 622 (6.6) | 646 (6.8) | 753 (7.4) | 636 (8.7) | 5235 (7.2) |
Non-anaemic (≥11)–underweight (<18.5) | 149 (2.3) | 169 (1.6) | 260 (2.7) | 206 (2.1) | 186 (2) | 238 (2.5) | 256 (2.5) | 240 (3.3) | 1704 (2.3) |
BMI (kg/m2) (mean/SD/IQR) | 20.1/2.6/3.4 | 19.7/2.6/3.2 | 19.6/2.6/3.4 | 19.7/2.7/3.5 | 19.7/2.8/3.6 | 19.7/2.9/3.6 | 19.7/3/3.7 | 19.7/3/3.7 | 19.7/2.8/3.6 |
Haemoglobin (g/dL) (mean/SD/IQR) | 9.8/0.9/1 | 9.7/0.9/1 | 9.7/0.8/1.1 | 9.8/0.8/1 | 9.9/0.8/0.8 | 9.9/0.8/0.8 | 9.9/0.8/1 | 9.9/0.9/1 | 9.8/0.8/1 |
*Highly significant (p<0.001) non-parametric trend over years of enrolment.
BMI, body mass index.