People with intellectual disability (ID) in the general population and people in prison experience unrecognised medical conditions and inadequate disease prevention. Among prisoners, those with an ID may be particularly disadvantaged. The aim of this study was to identify demographic, health and health-related characteristics of adult prisoners who screened positive for ID.

Cross-sectional data were collected via face-to-face administration of a structured questionnaire in seven prisons in Queensland, Australia, between 2008 and 2010. Participants were adult prisoners within 6 weeks of release from custody. We identified ID using a pragmatic screening tool. Prisoners who scored <85 on the Hayes Ability Screening Index and either (a) reported having attended a special school or (b) reported having been diagnosed with an ID were considered to have screened positive for ID. We compared the characteristics of participants who screened positive and negative for ID using univariable and multivariable logistic regression.

Screening positive for ID was associated with younger age, identifying as Indigenous and lower educational achievement. Prisoners who screened positive for ID were more likely to have been diagnosed with medical conditions such as heart disease (odds ratio; 95% confidence interval = 2.1; 1.0-4.2) and hearing problems (2.2; 1.3-3.7), after adjustment for age, sex, education level and Indigenous status. Screen-positive prisoners were less likely to have received preventive care interventions such as testing for hepatitis A infection (0.4; 0.2-0.6), and immunisation for tuberculosis (0.4; 0.2-0.8). Prisoners with possible ID were more likely to be obese (1.7; 1.1-2.7).

Adult prisoners who screen positive for ID have worse health outcomes than their non-disabled peers. An improved understanding of physical health characteristics prior to release can direct treatment and support pathways out of the criminal justice system and inform transitional planning of health services for this profoundly disadvantaged group.