Table 1. Demographic characteristics of participants with and without a suspected ID.
| Suspected ID | No suspected ID | p-value | |
| Mean age in years (sd) (n = 387) | 39.9 (13.0) | 36.6 (13.2) | t (385) = −2.294; p = 0.022 |
| Gender % male (n = 387) | 84.2 | 71.8 | ?2 (1) = 6.693; p = 0.010 |
| Education % (n = 384) | ?2 (3) = 21.414; p <0.001 a | ||
| Lowest | 44.6 | 25.4 | |
| Low | 37.5 | 50.0 | |
| Intermediate | 6.3 | 17.6 | |
| High | 11.6 | 7.0 | |
| Ethnicity % (n = 379) | ?2 (2) = 3.037; p = 0.219 | ||
| Native Dutch | 34.8 | 39.7 | |
| First-generation immigrant | 47.3 | 37.8 | |
| Second-generation immigrant | 17.9 | 22.5 |
p-values in bold indicate a significant difference (p<0.05); ID = intellectual disability; sd = standard deviation
a
Post-hoc χ 2: Lowest; ID > no ID; χ 2 (1) = 13.782, p<0.001, OR = 2.27, CIs [1.495–3.766] Low; ID < no ID; χ 2 (1) = 4.985, p<0.05, OR = 0.60, CI [0.382, 0.941] Intermediate; ID < no ID; χ 2 (1) 8.397, p<0.01, OR = 0.31, CI [0.136–0.711].