| N | Intervention group (n = 94) | Control group (n = 66) | p | ||
---|---|---|---|---|---|---|
n | % | n | % | |||
Child’s sex | ||||||
 Male | 81 | 51 | 62.96 | 30 | 37.04 | 0.273 |
 Female | 79 | 43 | 54.43 | 36 | 45.57 |  |
Family composition | ||||||
 Single-parent family | 9 | 3 | 33.33 | 6 | 66.67 | 0.111 |
 Two-parent family | 151 | 91 | 60.26 | 60 | 39.74 |  |
Presence of siblings | ||||||
 0 | 32 | 18 | 56.3 | 14 | 43.8 | 0.748 |
  ≥ 1 | 128 | 76 | 59.4 | 52 | 40.6 |  |
Annual household income (million JPY) | ||||||
  < 4 | 31 | 17 | 54.84 | 14 | 45.16 | 0.796 |
  ≥ 4–8 | 80 | 49 | 61.25 | 31 | 38.75 |  |
  ≥ 8 | 30 | 17 | 56.67 | 13 | 43.33 |  |
Maternal educational level | ||||||
 Middle school or high school | 60 | 36 | 60.00 | 24 | 40.00 | 0.167 |
 Junior college or vocational school | 55 | 34 | 61.82 | 21 | 38.18 |  |
 University or graduate school | 37 | 16 | 43.24 | 21 | 56.76 |  |
Paternal educational level | ||||||
 Middle school or high school | 53 | 32 | 60.38 | 21 | 39.62 | 0.913 |
 Junior college or vocational school | 31 | 18 | 58.06 | 13 | 41.94 |  |
 University or graduate school | 62 | 35 | 56.45 | 27 | 43.55 |  |