Table 1 Folate variables and maternal characteristics
|  |  |  |  | Total folate intake (μg/d) | Initiation of preconceptional folic acid supplementation, n (%) | ||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Â | Â | n | (%) | median (IQR) | p1 | >8 w | 0-8 w | no | p2 | ||||
Total |  | 65668 | (100) | 266 | (153–543) |  | 15471 | (24) | 12308 | (19) | 37889 | (58) |  |
|  | <25 | 7583 | (12) | 228 | (143–504) |  | 842 | (11) | 879 | (12) | 5862 | (77) |  |
Maternal age | 25-29 | 22745 | (35) | 275 | (154–547) | <0.0001 | 4990 | (22) | 4605 | (20) | 13150 | (58) | <0.0001 |
in years | 30-34 | 27782 | (42) | 270 | (155–546) |  | 7475 | (27) | 5662 | (20) | 14645 | (53) |  |
|  | >34 | 7558 | (12) | 276 | (160–547) |  | 2164 | (29) | 1162 | (15) | 4232 | (56) |  |
Pre- | <18.5 | 2004 | (3) | 294 | (160–554) |  | 439 | (22) | 344 | (17) | 1221 | (61) |  |
pregnancy | 18.5-24.9 | 43198 | (66) | 278 | (157–549) | <0.0001 | 10611 | (25) | 8388 | (19) | 24199 | (56) | <0.0001 |
BMI in | 25-30 | 13448 | (21) | 248 | (148–533) |  | 2999 | (22) | 2483 | (18) | 7966 | (59) |  |
kg/m2 | ≥30 | 5341 | (8) | 229 | (141–515) |  | 1146 | (21) | 822 | (15) | 3373 | (63) |  |
|  | missing | 1677 | (3) | 226 | (144–491) |  | 276 | (16) | 271 | (16) | 1130 | (67) |  |
|  | 0 | 33501 | (51) | 320 | (165–566) |  | 8753 | (26) | 6031 | (18) | 18717 | (56) |  |
|  | 1 | 20743 | (32) | 233 | (146–526) | <0.0001 | 4581 | (22) | 4466 | (22) | 11696 | (56) | <0.0001 |
Parity | 2 | 9199 | (14) | 211 | (144–480) |  | 1752 | (19) | 1525 | (17) | 5922 | (64) |  |
|  | 3+ | 2140 | (3) | 200 | (140–388) |  | 370 | (17) | 272 | (13) | 1498 | (70) |  |
|  | missing | 85 | (0,1) | 183 | (121–401) |  | 15 | (18) | 14 | (16) | 56 | (66) |  |
Marital | yes | 63134 | (96) | 268 | (154–544) | <0.0001 | 15184 | (24) | 12101 | (19) | 35849 | (57) | <0.0001 |
status | no | 2534 | (4) | 232 | (147–493) |  | 287 | (11) | 207 | (8) | 2040 | (81) |  |
Maternal | <13 | 20618 | (31) | 214 | (138–483) |  | 3237 | (16) | 2774 | (13) | 14607 | (71) |  |
education | 13 - 16 | 27249 | (41) | 291 | (157–553) | <0.0001 | 6841 | (25) | 5601 | (21) | 14807 | (54) | <0.0001 |
in | >16 | 16415 | (25) | 331 | (171–569) |  | 5096 | (31) | 3718 | (23) | 7601 | (46) |  |
years | missing | 1386 | (2) | 243 | (144–528) |  | 297 | (21) | 215 | (16) | 874 | (63) |  |
History of | no | 63433 | (97) | 267 | (154–543) | <0.0001 | 14980 | (24) | 11879 | (19) | 36574 | (58) | 0.18 |
preterm | yes | 2155 | (3) | 237 | (151–521) |  | 472 | (22) | 411 | (19) | 1272 | (59) |  |
delivery | missing | 80 | (0,1) | 252 | (144–554) |  | 19 | (24) | 18 | (23) | 43 | (54) |  |
History of | no | 53123 | (81) | 269 | (154–544) | <0.0001 | 11655 | (22) | 10112 | (19) | 31356 | (59) | <0.0001 |
abortion | yes | 12545 | (19) | 251 | (150–540) |  | 3816 | (30) | 2196 | (18) | 6533 | (52) |  |
|  | never | 59678 | (91) | 277 | (156–548) |  | 14752 | (25) | 11691 | (20) | 33235 | (56) |  |
Smoking | occasionally | 1879 | (3) | 218 | (141–453) | <0.0001 | 255 | (14) | 231 | (12) | 1393 | (74) | <0.0001 |
habits | daily | 3733 | (6) | 190 | (128–390) |  | 399 | (11) | 319 | (9) | 3015 | (81) |  |
|  | missing | 378 | (1) | 221 | (140–451) |  | 65 | (17) | 67 | (18) | 246 | (65) |  |
Alcohol | no alcohol | 55368 | (84) | 289 | (159–551) |  | 13360 | (24) | 10672 | (19) | 31336 | (57) |  |
consumption | <0.5 | 6565 | (10) | 245 | (150–528) | <0.0001 | 1403 | (21) | 1162 | (18) | 4000 | (61) | <0.0001 |
in units/week | ≥0.5 | 3735 | (6) | 149 | (117–209) |  | 708 | (19) | 474 | (13) | 2553 | (68) |  |
Partners with | 0 | 19439 | (30) | 225 | (143–507) | <0.0001 | 3246 | (17) | 2853 | (15) | 13340 | (69) |  |
income of | 1 | 26938 | (41) | 265 | (154–542) | 6287 | (23) | 5253 | (20) | 15398 | (57) | <0.0001 | |
>300,000 | 2 | 17472 | (27) | 337 | (169–572) | 5687 | (33) | 3939 | (23) | 7846 | (45) |  | |
NOK/year | missing | 1819 | (3) | 227 | (147–511) |  | 251 | (14) | 263 | (14) | 1305 | (72) |  |
Baby's | male | 33445 | (51) | 262 | (152–541) | 0.003 | 7875 | (24) | 6198 | (19) | 19372 | (58) | 0.3 |
sex | female | 32223 | (49) | 270 | (155–545) |  | 7596 | (24) | 6110 | (19) | 18517 | (57) |  |
Tertiles of | 1 | 21890 | (33) | 179 | (115–503) |  | 5251 | (24) | 4031 | (18) | 12608 | (58) |  |
energy intake | 2 | 21890 | (33) | 263 | (155–548) | <0.0001 | 5397 | (25) | 4307 | (20) | 12186 | (56) | <0.0001 |
in MJ | 3 | 21888 | (33) | 325 | (203–591) |  | 4823 | (22) | 3970 | (18) | 13095 | (60) |  |