Table 1 Baseline demographics and family characteristics of the participants by grandparent co-residence (n = 3,578).
All (n = 3,578) | Grandparent co-residence | p | |||||
|---|---|---|---|---|---|---|---|
No (n = 3,247) | Yes (n = 331) | ||||||
n | % | n | % | n | % | ||
Sex | 0.48 | ||||||
Male | 1,814 | 50.7 | 1,640 | 50.5 | 174 | 52.6 | |
Female | 1,754 | 49.0 | 1,597 | 49.2 | 157 | 47.4 | |
Unknown | 10 | 0.3 | 10 | 0.3 | 0 | 0.0 | |
Age (month) | 85.2 | 2.4 | 85.2 | 2.6 | 85.2 | 25.7 | 0.71 |
Living arrangement with parents | <0.001 | ||||||
Living with two parents | 3,265 | 91.3 | 3,020 | 93.0 | 245 | 74.0 | |
Lone-parent household | 310 | 8.7 | 224 | 6.9 | 86 | 26.0 | |
Missing | 3 | 0.1 | 3 | 0.1 | 0 | 0.0 | |
Maternal education | <0.001 | ||||||
Highschool graduate or less | 1,235 | 34.5 | 1,093 | 33.7 | 142 | 42.9 | |
Some college | 1,504 | 42.0 | 1,379 | 42.5 | 125 | 37.8 | |
College or University graduate | 753 | 21.0 | 703 | 21.7 | 50 | 15.1 | |
Other | 23 | 0.6 | 17 | 0.5 | 6 | 1.8 | |
Missing | 63 | 1.8 | 55 | 1.7 | 8 | 2.4 | |
Household income (yen) | 0.010 | ||||||
<3 million | 376 | 10.5 | 329 | 10.1 | 47 | 14.2 | |
3 million ~ <6 million | 1,434 | 40.1 | 1,309 | 40.3 | 125 | 37.8 | |
6 million ~ <10 million | 1,118 | 31.2 | 1,028 | 31.7 | 90 | 27.2 | |
10 million and above | 310 | 8.7 | 285 | 8.8 | 25 | 7.6 | |
Missing | 340 | 9.5 | 296 | 9.1 | 44 | 13.3 | |
Birth order | 0.12 | ||||||
Middle or last-born | 1,896 | 53.0 | 1,734 | 53.4 | 162 | 48.9 | |
First-born or only child | 1,682 | 47.0 | 1,513 | 46.6 | 169 | 51.1 | |
