Characteristics of parents and children associated with multivitamin supplement intake (N=98 787)
| Variables | No intake | Multivitamin intake* | P value |
| N=92 205 | N=6582 | ||
| Sex, boy (%)† | 47,258 (51.3) | 3374 (51.3) | 0.466 |
| Gestational week, median (IQR)† | 39 (38 to 40) | 39 (38 to 40) | <0.001 |
| Birth weight, mean (SD)† | 3009 (434) | 3011 (431) | 0.660 |
| Maternal age at pregnancy, mean (SD)† | 30.7 (5.05) | 31.6 (4.79) | <0.001 |
| Maternal BMI at pregnancy, mean (SD) | 21.3 (3.32) | 20.9 (3.07) | <0.001 |
| First pregnancy, yes (%) | 28,106 (30.5) | 2482 (37.7) | 0.505 |
| History of spontaneous abortion, yes (%) | 18,405 (20.0) | 1294 (19.7) | |
| History of abortion, yes (%) | 13,614 (14.8) | 958 (14.6) | |
| Maternal smoking status during pregnancy, yes (%) | |||
| Never smoker† | 53,270 (57.8) | 3835 (58.3) | <0.001 |
| Past smoker | 21,586 (23.4) | 1676 (25.5) | |
| Quit smoking after pregnancy | 12,224 (13.3) | 766 (11.6) | |
| Current smoker | 4441 (4.82) | 261 (3.97) | |
| Maternal alcohol intake during pregnancy, yes (%) | |||
| Never drinker† | 31,919 (34.6) | 2102 (31.9) | <0.001 |
| Past drinker | 50,869 (55.2) | 3723 (56.6) | |
| Current drinker | 9017 (9.78) | 727 (11.1) | |
| Marital status, yes (%) | |||
| Married† | 87,808 (95.2) | 6299 (95.7) | 0.807 |
| Single | 3211 (3.48) | 207 (3.14) | |
| Divorced/Widowed | 784 (0.85) | 50 (0.76) | |
| Maternal job status† | |||
| Full-time job | 29,877 (32.4) | 2285 (34.7) | 0.003 |
| Part-time or temporary job | 2909 (3.15) | 202 (3.07) | |
| Self-employment | 20,478 (22.2) | 1411 (21.4) | |
| Housewife or others | 35,784 (38.8) | 2473 (37.6) | |
| Maternal education† | |||
| High school (up to 12 years) | 33,405 (36.2) | 1914 (29.1) | <0.001 |
| College (up to 14 years) | 38,080 (41.3) | 2804 (42.6) | |
| University or higher (over 16 years) | 19,304 (20.9) | 1760 (26.7) | |
| Household income† | |||
| Up to 2 million yen | 4876 (5.29) | 257 (3.90) | <0.001 |
| 2–8 million yen | 70,862 (76.9) | 5034 (76.5) | |
| Over 8 million yen | 8942 (9.70) | 890 (13.5) | |
*Multivitamin intake means multivitamin intake during any period of ‘before pregnancy confirmation’, ‘Up to 12 weeks’ or ‘After 12 weeks’.
†Data were missing for sex for 8 (0.01%), for birth weight for 68 (0.07%), for mothers' age at pregnancy for 6134 (6.21%), for mothers' BMI at pregnancy for 42 (0.04%), for smoking status of mothers for 728 (0.74%), for alcohol intake of mothers for 430 (0.44%), for marital status for 428 (0.43%), for job status of mothers for 3368 (3.41%), for education of mothers for 1520 (1.54%) and for household income for 7926 (8.02%) subjects.
BMI, body mass index.