Table 1

Sociodemographic characteristics of the child and adolescent mental health sample linked and non-linked to the National Pupil Database absence data

Linked pairs (n=29 278) (%)Non-linked residuals (n=6231), n (%)OR (95% CI) for positive linkageaOR (95% CI)†
Male16 430 (56.1)3296 (52.9) Reference Reference
Female12 848 (43.9)2935 (47.1)0.88 (0.83 to 0.93)**1.04 (0.97 to 1.11)
Age at first referral to mental health services
  Infant (<7 years)3657 (12.5)535 (8.7) Reference Reference
  Primary (7–11 years)10 980 (37.5)1284 (20.3)1.25 (1.12 to 1.39)**1.23 (1.10 to 1.38)**
  Secondary (12–15 years)7048 (24.1)1140 (18.4)0.90 (0.81 to 1.01)0.98 (0.88 to 1.10)
  College (16–18)7570 (25.9)3228 (52.2)0.34 (0.31 to 0.38)**0.67 (0.59 to 0.75)**
Ethnicity
  White/white British13 838 (47.3)2786 (44.7) Reference Reference
  Asian/Asian British984 (3.4)312 (5.0)0.63 (0.56 to 0.76)**0.65 (0.56 to 0.75)**
  Black British/African5667 (19.4)1181 (19.0)0.96 (0.89 to 1.04)0.82 (0.76 to 0.89)**
  Black British/Afro-Caribbean1474 (5.0)232 (3.7)1.28 (1.11 to 1.48)**0.98 (0.84 to 1.14)
  Mixed/multiple ethnicity2184 (7.5)315 (5.1)1.40 (1.23 to 1.58)**1.12 (0.99 to 1.28)
  Other ethnic group1109 (3.8)419 (6.7)0.53 (0.47 to 0.60)**0.55 (0.48 to 0.63)**
  Not stated4022 (13.7)986 (15.8)0.82 (0.76 to 0.89)**0.93 (0.85 to 1.02)
Resident within Local catchment area22 481 (76.8)4192 (67.2)1.61 (1.52 to 1.71)**1.04 (0.97 to 1.12)
National quartiles of neighbourhood deprivation
 First (most deprived)14398 (49.2)2822 (45.3) Reference Reference
 Second9796 (33.5)2179 (34.9)0.88 (0.83 to 0.94)**0.90 (0.83 to 0.96)**
 Third2956 (10.1)762 (12.2)0.76 (0.69 to 0.83)**0.81 (0.74 to 0.89)**
 Fourth (least deprived)2126 (7.3)468 (7.5)0.89 (0.79 to 0.99)*1.03 (0.92 to 1.15)
Address data available‡
 Postcode 117 587 (60.1)1987 (31.9) Reference Reference
 Postcode 22956 (10.1)990 (15.9)0.34 (0.31 to 0.37)**0.50 (0.45 to 0.56)**
 Postcode 35776 (19.7)1187 (19.1)0.55 (0.51 to 0.59)**0.63 (0.58 to 0.68)**
 Postcode 41933 (6.6)1010 (16.2)0.22 (0.20 to 0.23)**0.35 (0.31 to 0.39)**
 Postcode 51026 (3.5)1057 (17.0)0.11 (0.09 to 0.12)**0.15 (0.14 to 0.17)**
Any ICD-10 disorder17 749 (60.6)3290 (52.8)1.38 (1.30 to 1.45)**1.11 (1.04 to 1.18)**
  • *P<0.05, **p<0.01.

  • †Adjusted for all other covariates listed in the table.

  • ‡Postcode. For a large proportion of cases, there are several addresses available for each case. Therefore, postcodes were extracted according to a hierarchy (postcode 1 being the highest), which we believed to be most likely to have been the place of residence on the day of the 16 January 20XX (variable date) census (see figure 1 legend).

  • aOR, adjusted OR; ICD-10, International Statistical Classification of Diseases, 10th Revision.