Table 2.
Environmental factors influencing EBF rates until 6 months postpartum in Japan.
| Total number (n) | Percent EBF to 6 months | Odds ratio | 95% confidence interval | Adjusted odds ratio | 95% confidence interval | |
|---|---|---|---|---|---|---|
| Child-related factors | ||||||
| Gender of the childd (n = 80,491) | ||||||
| Female | 39,254 | 38.2 | Reference | Reference | ||
| Male | 41,237 | 36.6 | 0.935 | (0.909–0.962) | 0.964 | (0.932–0.997) |
| Gestational periodd (in weekly intervals) | 80,491 | 1.067 | (1.056–1.077) | 1.044 | (1.029–1.059) | |
| Birth defects in the childd (n = 80,491) | ||||||
| Absent | 78,850 | 37.6 | Reference | Reference | ||
| Present | 1641 | 27.7 | 0.638 | (0.572–0.711) | 0.764 | (0.669–0.873) |
| Social factors | ||||||
| Confidencea (n = 79,490) | ||||||
| Never available | 1692 | 37.1 | Reference | Reference | ||
| Rarely available | 5902 | 32.0 | 0.797 | (0.712–0.892) | 0.864 | (0.755–0.990) |
| Somewhat available | 15,960 | 34.3 | 0.884 | (0.797–0.981) | 0.874 | (0.771–0.989) |
| Nearly always available | 8202 | 37.0 | 0.996 | (0.894–1.110) | 0.912 | (0.802–1.039) |
| Always available | 47,734 | 39.2 | 1.094 | (0.990–1.210) | 0.983 | (0.872–1.109) |
| Regional social capitala (n = 78,820) | ||||||
| Extremely low | 16,462 | 34.5 | Reference | Reference | ||
| Low | 22,392 | 35.5 | 1.043 | (1.000–1.088) | 0.992 | (0.943–1.043) |
| Medium | 31,489 | 39.5 | 1.235 | (1.187–1.284) | 1.084 | (1.033–1.138) |
| High | 8477 | 41.2 | 1.328 | (1.259–1.402) | 1.133 | (1.061–1.210) |
| Second-hand smokeb (n = 79,921) | ||||||
| Absent | 38,928 | 39.5 | Reference | Reference | ||
| Smoked outside of the presence of the baby | 39,192 | 35.6 | 0.845 | (0.821–0.870) | 0.952 | (0.917–0.988) |
| Smoked in the presence of the baby | 1801 | 31.4 | 0.699 | (0.632–0.774) | 0.906 | (0.797–1.029) |
| Child attends childcare at 6 monthsc (n = 80,345) | ||||||
| Absent | 74,919 | 39.5 | Reference | Reference | ||
| Present | 5426 | 8.4 | 0.14 | (0.127–0.155) | 0.126 | (0.113–0.141) |
| Returning to one’s parents’ houseb (n = 79,614) | ||||||
| Did not return to parents’ house | 30,608 | 38.2 | Reference | Reference | ||
| Returned home for no more than 1 month | 18,457 | 39.2 | 1.039 | (1.001–1.079) | 1.032 | (0.985–1.081) |
| Returned home for longer than 1 month | 20,871 | 36.6 | 0.930 | (0.897–0.965) | 0.930 | (0.881–0.981) |
| Live together | 9678 | 33.5 | 0.815 | (0.776–0.855) | 0.795 | (0.746–0.848) |
| Did you send your child to a nursery?b (n = 79,193) | ||||||
| No | 61,110 | 39.0 | Reference | Reference | ||
| Yes | 18,083 | 32.3 | 0.748 | (0.722–0.774) | 0.712 | (0.683–0.743) |
| Paternal participation in parentingb (n = 79,009) | ||||||
| No participation | 2490 | 37.8 | Reference | Reference | ||
| Participates often | 30,455 | 35.8 | 0.914 | (0.840–0.995) | 0.852 | (0.769–0.945) |
| Participates occasionally | 36,983 | 38.1 | 1.012 | (0.931–1.100) | 0.921 | (0.832–1.018) |
| Almost never participates | 9081 | 41.1 | 1.147 | (1.047–1.257) | 1.043 | (0.935–1.163) |
| Person doing most of the houseworkb (n = 79,919) | ||||||
| Mother herself | 35,168 | 38.0 | Reference | Reference | ||
| Father | 4023 | 35.1 | 0.885 | (0.827–0.948) | 0.961 | (0.886–1.043) |
| Siblings | 228 | 27.6 | 0.625 | (0.467–0.835) | 0.794 | (0.547–1.153) |
| Maternal grandmother | 33,749 | 37.5 | 0.983 | (0.953–1.014) | 0.971 | (0.928–1.015) |
| Maternal grandfather | 364 | 31.3 | 0.746 | (0.597–0.932) | 0.739 | (0.565–0.967) |
| Paternal grandmother | 5219 | 36.8 | 0.953 | (0.897–1.012) | 0.928 | (0.859–1.001) |
| Paternal grandfather | 55 | 36.4 | 0.934 | (0.539–1.619) | 0.799 | (0.415–1.536) |
| Other, not listed above | 1113 | 31.6 | 0.756 | (0.665–0.860) | 0.854 | (0.731–0.999) |
Data acquisition.
aDuring mid-pregnancy/ b1 month postpartum/ c6 months postpartum/ dattending physician diagnosed just after delivery.