Table 2. Comparison of those recruited and those who have declined or not responded.
All results are all from questionnaires, research clinic assessments or record linkage data on a ALSPAC-G1 participant who has become pregnant, or for male ALSPAC-G1 has a partner who has become pregnant or who had become a parent and were eligible to be recruited to ALSPAC-G2 up to 30 th June 2018.
| Recruited
a
(N = 580) |
Declined or did not
respond b (N = 447) |
|||||
|---|---|---|---|---|---|---|
| Continuous outcomes | N (%)
with data |
Mean (SD) | N (%)
with data |
Mean (SD) | Difference in
mean (95%CI) c Observed (complete) data |
Difference in mean
(95%CI) c Multiple imputed data |
| Age (Years) d | 580 (100) | 22.5 (1.9) | 446 (100) | 22.8 (1.9) | 0.37 (0.13, 0.60) | 0.37 (0.13, 0.60) |
| BMI (Kg/m 2) e | 467 (81) | 26.3 (6.1) | 215 (48) | 25.4 (5.7) | -0.87 (-1.8, 0.1) | -0.89 (-1.79, -0.01) |
| Recruited
a
(N = 580) |
Declined or did not
respond b (N = 447) |
|||||
| Binary outcomes | N (%)
with data |
Number with
the outcome (%) |
N (%)
with data |
Number with the
outcome (SD) |
Odds ratio
(95%CI) c Observed (complete) data |
Odds ratio (95%CI)
c
Multiple imputed data |
| Female | 580 (100) | 444 (77) | 447 (100) | 329 (74) | 0.85 (0.64, 1.14) | No missing data |
| Educational attainment
to A-level or higher f |
401 (69) | 218 (54) | 222 (50) | 115 (52) | 0.9 (0.65, 1.25) | 0.86 (0.62, 1.19) |
| Ever smoked g | 509 (88) | 336 (66) | 252 (56) | 170 (67) | 1.07 (0.77, 1.47) | 1.08 (0.78, 1.48) |
| Attended 17/18-year or
24/25-year follow-up |
568 (98) | 472 (83) | 441 (99) | 221 (50) | 0.2 (0.15, 0.27) | 0.2 (0.15, 0.27) |
| Living in Bristol at time
of (potential) enrolment |
579 (100) | 476 (82) | 446 (100) | 368 (83) | 1.02 (0.74, 1.41) | 1.02 (0.74, 1.41) |
a ALSPAC-G1 participants who were invited and have attended at least one assessment; b ALSPAC-G1 participants who were invited and have declined or not responded;
c Differences in means for age and BMI, odds ratios for educational attainment, smoking and attendance at recent clinics, in all analyses those recruited are the reference category; d At time of invitation; e At either of the two most recent assessments 24/25 years for those with data from that follow-up, otherwise 17/18 years; f A-levels: Advanced-levels, secondary school exams required for University entrance and some other further education/apprentice schemes taken at age 18. Data obtained from record linkage; g Data from any previous questionnaire (data on smoking have been collected repeatedly since age 17 years). h based on having a Bristol (BS) postcode at the time when the ALSPAC-G2 enrolment pack was sent.