Table 1.
Baseline characteristics of included mother-infant pairs and drop-outs.
| Included (N = 4264) | Drop-outs (N = 6241) | ||||||
|---|---|---|---|---|---|---|---|
| Binary Covariates | N | n | % | N | n | % | p-Value |
| Sex, male | 4261 | 2131 | 50.0 | 5339 | 2677 | 50.1 | 0.900 |
| Family history | 3224 | 2264 | 70.2 | 4535 | 3332 | 73.5 | 0.002 |
| Older siblings | 3229 | 1823 | 56.5 | 4525 | 2323 | 51.3 | <0.001 |
| Breastfeeding at 6 mo | 3702 | 3134 | 84.7 | 4442 | 3571 | 80.4 | <0.001 |
| Mother smoking | |||||||
| Pregnancy | 1896 | 130 | 6.9 | 2488 | 213 | 8.6 | 0.037 |
| 6 weeks | 2178 | 165 | 7.6 | 2405 | 240 | 10.0 | 0.004 |
| 1 year | 2319 | 348 | 15.0 | 2678 | 480 | 17.9 | 0.006 |
| Ever in first year | 3334 | 466 | 14.0 | 4793 | 752 | 15.7 | 0.033 |
| Father smoking | |||||||
| Pregnancy | 1852 | 296 | 16.0 | 2395 | 481 | 20.1 | 0.001 |
| 6 weeks | 2072 | 340 | 16.4 | 2299 | 451 | 19.6 | 0.006 |
| 1 year | 2164 | 371 | 17.1 | 2490 | 506 | 20.3 | 0.006 |
| Ever in first year | 3230 | 665 | 20.6 | 4573 | 1059 | 23.2 | 0.007 |
| Parental smoking | |||||||
| Pregnancy | 1830 | 316 | 17.3 | 2371 | 511 | 21.6 | 0.001 |
| 6 weeks | 2040 | 367 | 18.0 | 2225 | 458 | 20.6 | 0.032 |
| 1 year | 2144 | 460 | 21.5 | 2459 | 612 | 24.9 | 0.006 |
| Ever in first year | 3209 | 779 | 24.3 | 4516 | 1204 | 26.7 | 0.018 |
| Cohort, intervention | 4264 | 1204 | 28.2 | 6241 | 1714 | 27.5 | 0.385 |
| Continuous covariates | N | mean | SD | N | mean | SD | |
| Maternal age, yrs | 4244 | 30.3 | 4.4 | 5258 | 29.3 | 4.7 | <0.001 |
| Birthweight, gm | 3944 | 3583 | 565 | 5100 | 3579 | 597 | 0.716 |
| Breastfeeding duration, mo. | 3392 | 10.7 | 5.6 | 3966 | 9.8 | 5.7 | <0.001 |
| Income, NOK | 4158 | 257,043 | 28,563 | 5664 | 250,535 | 31,617 | <0.001 |
| Maternal education, yrs | 2573 | 15.7 | 2.6 | 1331 | 15.5 | 2.6 | 0.051 |
| Paternal education, yrs | 2543 | 15.1 | 3.0 | 1314 | 15.1 | 3.0 | 0.896 |