Table 3. Multilevel Regression Models to Investigate the Likelihood of Antipsychotic Medication Use Given Parental Consanguinity, Adjusting for the Clustering of Individuals Within GP Practices.
| Variable | OR (95% CI) | ||
|---|---|---|---|
| Unadjusted | Model 1 | Model 2 | |
| Consanguineous parents | |||
| Not related | 1 [Reference] | 1 [Reference] | 1 [Reference] |
| First cousins | 2.30 (1.40-3.77) | 2.09 (1.26-3.44) | 2.13 (1.29-3.51) |
| Second cousins | 1.39 (0.80-2.42) | 1.39 (0.79-2.43) | 1.37 (0.79-2.40) |
| Not known | 0.97 (0.89-1.06) | 0.92 (0.84-1.01) | 0.92 (0.84-1.01) |
| Sex | |||
| Male | NA | 1 [Reference] | 1 [Reference] |
| Female | NA | 0.57 (0.55-0.60) | 0.57 (0.55-0.60) |
| Age, y | |||
| 26-29 | NA | 1 [Reference] | 1 [Reference] |
| 30-33 | NA | 1.04 (0.98-1.11) | 1.04 (0.98-1.11) |
| 34-37 | NA | 1.10 (1.03-1.17) | 1.10 (1.03-1.17) |
| 38-41 | NA | 1.15 (1.08-1.23) | 1.15 (1.08-1.22) |
| SGA | |||
| No | NA | 1 [Reference] | 1 [Reference] |
| Yes | NA | 1.16 (1.07-1.26) | 1.18 (1.09-1.28) |
| Delivery method | |||
| Vaginal | NA | 1 [Reference] | 1 [Reference] |
| Vaginal assisted (ie, forceps, vacuum) | NA | 1.04 (0.97-1.11) | 1.03 (0.96-1.10) |
| Cesarean delivery | NA | 1.09 (1.01-1.18) | 1.08 (1.00-1.17) |
| Parity | |||
| Firstborn | NA | 1 [Reference] | 1 [Reference] |
| 1 | NA | 1.04 (0.98-1.11) | 1.05 (0.98-1.11) |
| 2 | NA | 1.08 (1.00-1.15) | 1.08 (1.01-1.16) |
| ≥3 | NA | 1.15 (1.07-1.23) | 1.18 (1.10-1.26) |
| Unknown | NA | 1.03 (0.93-1.13) | 1.03 (0.93-1.14) |
| Mother’s age, y | |||
| <18 | NA | 1.12 (0.93-1.35) | 1.15 (0.96-1.39) |
| 18-35 | NA | 1 [Reference] | 1 [Reference] |
| >35 | NA | 0.98 (0.90-1.06) | 0.97 (0.90-1.05) |
| Not known | NA | 0.90 (0.60-1.35) | 0.88 (0.59-1.33) |
| Father’s age, y | |||
| <18 | NA | 1.43 (0.84-2.42) | 1.45 (0.85-2.47) |
| 18-35 | NA | 1 [Reference] | 1 [Reference] |
| >35 | NA | 1.02 (0.95-1.10) | 1.01 (0.94-1.09) |
| Not known | NA | 1.32 (1.23-1.42) | 1.35 (1.26-1.45) |
| Deprivation at birth | |||
| Not deprived | NA | 1 [Reference] | NA |
| Deprived | NA | 1.34 (1.28-1.41) | NA |
| Not known | NA | 1.13 (0.94-1.35) | NA |
| Urbanicity at birth | |||
| Urban | NA | NA | 1 [Reference] |
| Rural | NA | NA | 0.92 (0.85-0.99) |
| Not known | NA | NA | 0.89 (0.74-1.07) |
| Variance | 0.354988 | 0.318330 | 0.348805 |
| P value | <.001 | <.001 | <.001 |
| Variance partition coefficient | 0.097 | 0.088 | 0.096 |
Abbreviations: GP, general practitioner; NA, not applicable; OR, odds ratio; SGA, small for gestational age.