Table 1. Characteristics of the 13163 study participants, according to breastfeeding status.
| Variable | Breastfed >4 months | p value a | |
|---|---|---|---|
| yes (n = 5650) | no (n = 7513) | ||
| Age in years (mean (SD)) | 9.06 (4.10) | 10.35 (4.19) | <0.001 |
| Mother’s age at childbirth(mean (SD)) | 29.43 (4.69) | 27.87 (5.14) | <0.001 |
| Female sex, n (%) | 2840 (48.3) | 3628 (50.3) | 0.025 |
| Socioeconomic status, n (%) | <0.001 | ||
| low | 511 (9.1) | 1345 (18.1) | |
| medium | 3160 (56.3) | 4778 (64.1) | |
| high | 1945 (34.6) | 1326 (17.8) | |
| Migration background, n (%) | 0.464 | ||
| none | 4582 (81.4) | 6067 (80.9) | |
| one-sided | 393 (7.0) | 507 (6.8) | |
| two-sided | 655 (11.6) | 923 (12.3) | |
| Older siblings ≥1, n (%) | 3077 (54.5) | 3867 (51.5) | 0.001 |
| Smoking of mother during pregnancy, n (%) | <0.001 | ||
| regularly | 103 (1.8) | 473 (6.4) | |
| once in a while | 407 (7.3) | 1223 (16.5) | |
| Parental overweight, n (%) | <0.001 | ||
| both parents | 1049 (18.7) | 1754 (23.6) | |
| one parent | 2419 (43.1) | 3347 (45.0) | |
| Overweight, n (%) | 658 (11.6) | 1304 (17.4) | <0.001 |
| Obesity, n (%) | 235 (4.2) | 555 (7.4) | <0.001 |
aTo obtain p values we used t-tests for continuous variables (age in years, mother’s age at childbirth) and chi-square test for categorical variables; p values are two-sided.