This study was conducted to describe the functioning of Activities of Daily Living (ADL) and to examine socio-economic effects on ADL functioning among adults with intellectual disabilities (ID) aged 45 years and older (N = 480) in Taiwan. The Barthel Index (BI) was used to determine a baseline level of ADL functioning in the study participants. There are five categories of functional impairment using the following cut-off values in Taiwan: total dependence (BI score 0–20), severe (BI score 21–60), moderate (BI score 61–90), mild (BI score 91–99), and total independence (BI score 100) (Taiwan Department of Health, 2012). The results revealed that 2.3% of adults with ID were in total dependence, 11.9% were in severe dependence, 27.9% were in moderate dependence, 8.1% had a mild dependence, and 49.8% were totally independent. In the multiple linear regression model of the ADL score, we determined that educational level, comorbid Down's syndrome, and disability level are the variables able to significantly predict ADL score (R2 = 0.190) after controlling for the factors of age, marital status, and other comorbidity conditions. Those ID adults with a lower education level (primary vs. literate, β = 4.780, p = 0.031; intermediate vs. literate, β = 6.642, p = 0.030), with comorbid Down's syndrome (β = −7.135, p = 0.063), and with a more severe disability condition (severe vs. mild, β = −7.650, p = 0.007; profound vs. mild, β = −19.169, p < 0.001) had significantly lower ADL scores. The present study highlights the need to support mobility in older adults with ID as much as possible to optimize independence in this group.
