Table 1. Dropout analysis. Results from questionnaires mailed to 1000 women who had received an invitation during pregnancy, but chosen not to participate in the COPSAC2010 pregnancy cohort, compared with mothers of children participating in the study. The questionnaire response rate was 86%.
| Non‐participants, N = 870a | COPSAC2010 N = 690b | P‐value | |
|---|---|---|---|
| Natural birth | 82% | 78% | 0.098 |
| Furred pets in the home | 36% | 38% | 0.458 |
| Smoking during pregnancy, more than one cigarette per week | 9% | 7% | 0.256 |
| Alcohol during pregnancy, more than one unit per week | 2% | 2% | 0.697 |
| Asthma (self‐reported) | 11% | 30% | <0.001 |
| Eczema (self‐reported) | 12% | 21% | <0.001 |
| Allergy (self‐reported) | 27% | 34% | <0.0001 |
| Hayfever (self‐reported) | 20% | 38% | <0.0001 |
| Education level, university education longer than 3 years | 33% | 36% | 0.18 |
| Employment | 0.006 | ||
| Unemployed | 10% | 6% | – |
| Student | 8% | 8% | – |
| Non‐professional | 8% | 9% | – |
| Professional | 73% | 78% | – |
| Household income | <0.001 | ||
| Below 400 000 DKK | 22% | 12% | – |
| 400 000 DKK–600 000 DKK | 27% | 22% | – |
| 600 000–800 000 DKK | 27% | 29% | – |
| Above 800 000 DKK | 24% | 37% | – |
a
The response rate for the different variables varied from 849 to 870 of 870 non‐participants.
b
The response rate for the different variables varied from 620 to 690 of 690 participants.
Significant associations (P < 0.05) were marked in bold.