Table 2. Factors associated with missing birth data from GP records received.
| Number of GPs who responded a | Missing birth data (%) |
Univariable models
|
Multivariable model
|
|||
|---|---|---|---|---|---|---|
| OR (95% CI) | Pb | OR (95% CI) | Pb | |||
| Child’s age (per year) | 1.20 (1.12; 1.30) | <0.0001 | 1.14 (1.04; 1.26) | 0.007 | ||
|
Sex
| ||||||
| Girls | 634 | 61 | Baseline |
Baseline |
||
| Boys | 568 | 58 | 0.89 (0.71; 1.12) | 0.33 | 1.12 (0.82; 1.53) | 0.49 |
|
Ethnicity
| ||||||
| White | 511 | 53 | Baseline |
Baseline |
||
| Black African origin | 284 | 75 | 2.61 (1.90; 3.59) | <0.0001 | 1.55 (0.95; 2.53) | 0.08 |
| South Asian | 268 | 55 | 1.08 (0.80; 1.45) | 0.63 | 0.50 (0.33; 0.77) | 0.002 |
| Other | 139 | 65 | 1.63 (1.10; 2.40) | 0.01 | 1.60 (0.97; 2.64) | 0.07 |
|
Born in UK
| ||||||
| Yes | 1,037 | 56 | Baseline |
Baseline |
||
| No | 143 | 86 | 4.88 (3.00; 7.96) | <0.0001 | 5.00 (2.59; 9.65) | <0.0001 |
|
Dominant language in family
| ||||||
| English | 600 | 50 | Baseline |
Baseline |
||
| Other | 226 | 72 | 2.58 (1.86; 3.59) | <0.0001 | 1.71 (1.12; 2.62) | 0.01 |
|
Family’s IMD domain
c
| ||||||
| 1st quintile (least deprived) | 79 | 39 | Baseline |
Baseline |
||
| 2nd quintile | 176 | 39 | 0.98 (0.57; 1.68) | 0.93 | 1.10 (0.57; 2.10) | 0.78 |
| 3rd quintile | 167 | 41 | 1.09 (0.63; 1.88) | 0.76 | 0.86 (0.44; 1.67) | 0.65 |
| 4th quintile | 342 | 68 | 3.31 (2.00; 5.49) | <0.0001 | 2.51 (1.31; 4.80) | 0.006 |
| 5th quintile (most deprived) | 436 | 73 | 4.17 (2.54; 6.87) | <0.0001 | 2.17 (1.15; 4.12) | 0.02 |
|
FAS
c
d
| ||||||
| High (5–6) | 286 | 42 | Baseline |
Baseline |
||
| Moderate (2–4) | 757 | 64 | 2.43 (1.84; 3.20) | <0.0001 | 1.59 (1.10; 2.30) | 0.01 |
| Low (0–1) | 83 | 78 | 5.00 (2.82; 8.86) | <0.0001 | 2.86 (1.27; 6.43) | 0.01 |
Abbreviations: FAS, family affluent score; GP, general practitioner; IMD, index of multiple deprivation; OR (95% CI), odds ratio (95% confidence interval).
GPs who responded could not provide any data on BW or GA for 720/1,202 (60%) children (see Figure 1).
P values derived through univariable or multivariable logistic regression models to evaluate the factors related with the likelihood of missing birth data. Multivariable model was adjusted for age, sex, ethnicity, country of birth, language, family’s IMD domain and FAS.
Detailed information regarding the IMD distribution of income and GPs domain and the individual components for FAS is presented in Supplementary Table S1.
FAS was grouped in three categories owing to the small sample size in the lower scores.