Table 1.
Comparison of characteristics of subjects included in this analysis and those lost to follow-up.
| Subjects included in this analysis (N = 370) | Subjects lost to follow up at 11.5 years (N = 246) | Difference between included and lost to follow-up | ||
|---|---|---|---|---|
| Variable | n (%) | n (%) | P-value 1 | |
| Child’s gender | ||||
| Male | 187 (51) | 125 (51) | 0.95 | |
| Female | 183 (49) | 121 (49) | ||
| Maternal smoking in pregnancy | ||||
| No | 292 (79) | 174 (71) | 0.02 | |
| Yes | 78 (21) | 72 (29) | ||
| Age of parents at child’s birth (years, mean ± SD) | ||||
| Mother | 29.0 ± 5.1 | 27.6 ± 5.6 | 0.002 | |
| Father | 31.2 ± 5.9 | 30.2 ± 6.3 | 0.047 | |
| Australian born | ||||
| Mother | 272 (74) | 185 (75) | 0.64 | |
| Father | 255 (69) | 166 (68) | 0.71 | |
| Tertiary educated | ||||
| Mother | 191 (52) | 85 (35) | <0.001 | |
| Father | 175 (47) | 90 (37) | 0.009 | |
| Full-time employment | ||||
| Mother | 183 (49) | 95 (39) | 0.008 | |
| Father | 323 (87) | 195 (79) | 0.008 | |
| Primigravida | 131 (35) | 68 (28) | 0.04 | |
1 The P-value to test the difference between those included and lost to follow-up in this study was calculated by a chi-squared test for all variables except age of the parents where a t-test was used.