Nearly Half of Older Adults With Intellectual Disabilities Are Frail, Landmark Portuguese Study Finds

Nearly half of adults with intellectual disabilities are already frail by their early fifties, according to the first Portuguese study to systematically map the health, functionality, and frailty of this rapidly growing and long-overlooked population. The research, published in Frontiers in Human Neuroscience, paints a stark picture of a group whose life expectancy has risen faster than that of the general population, yet whose aging bodies and care systems are struggling to keep pace with the change.

The study, led by Mariana Letra and colleagues at the University of Aveiro in collaboration with the Portuguese National Federation of Social Solidarity Cooperatives (FENACERCI), surveyed 234 individuals with intellectual disabilities aged 45 and older. Using a cross-sectional, descriptive-correlational design, the researchers recruited participants through organizations affiliated with or similar to FENACERCI, ultimately achieving an 18.5 percent response rate from an eligible pool of 1,308 clients. Questionnaires were completed by organizational mediators—staff members who knew each participant well—rather than by the individuals themselves, a pragmatic choice given the cognitive and communication barriers that often make direct self-report difficult in this population.

The demographic profile of the sample underscores how socially isolated many older adults with intellectual disabilities remain. The mean age was 53.32 years, with participants ranging from 45 to 77. Nearly all—97.9 percent—were single, and 98.3 percent had no children. More than half lived with family members, while 39.3 percent resided in social care settings. Educational attainment was strikingly low: 66.2 percent could not read or write, and only 2.1 percent had completed twelve years of schooling. The vast majority, 89.3 percent, were pensioners or retired, with social security benefits serving as the primary income source for 76.9 percent. Many had been supported by the same organizations for decades, with an average tenure of 26.32 years at their current provider.

Clinically, the picture was complex. Just over half the participants, 52.1 percent, had moderate intellectual disability, while 25.6 percent had severe and 7.3 percent had profound disability. Comorbidities were widespread: epilepsy and dementia each affected 22.6 percent of the sample, impulse control disorder 19.7 percent, and anxiety disorder 15.4 percent. Cerebral palsy, trisomy 21, and depressive and bipolar disorders were also present. Beyond neurological and psychiatric conditions, 30.3 percent reported chronic medical conditions lasting more than three months, including high blood pressure, heart problems, type 2 diabetes, and cancer. Polypharmacy—taking five or more medications daily—affected 26.1 percent of participants, a figure that carries significant implications for drug interactions, side effects, and overall health trajectory.

Nutritional status revealed a striking paradox. While 44.9 percent of participants were at risk of malnutrition and 4.7 percent were frankly malnourished according to the Mini Nutritional Assessment-Short Form, the body mass index data told a different story: 39.3 percent were overweight and 32.9 percent were obese, with a mean BMI of 28.59 kg/m². This coexistence of malnutrition risk with excess weight reflects a well-documented phenomenon in which caloric intake may be adequate or excessive while nutritional quality remains poor, often compounded by swallowing difficulties, oral health problems, polypharmacy, and limited access to adequate healthcare. The researchers note that people with intellectual disabilities face elevated risks of both obesity-related chronic diseases and undernutrition, making nutritional assessment and intervention particularly challenging and particularly urgent.

Functional capacity showed a bifurcated pattern. In basic activities of daily living—feeding, transfers, toileting, bathing, mobility, dressing, and continence—41 percent of participants were independent or only mildly dependent, and the majority were independent in most individual tasks. Yet 23.1 percent had total or severe dependence, with bathing and personal hygiene proving the most problematic domains. The picture for instrumental activities of daily living was far grimmer: not a single participant was fully independent, 85.5 percent were severely dependent, and the remaining 14.5 percent were moderately dependent. Most participants could not do their own laundry, prepare meals, manage finances, or take responsibility for their own medications—tasks that anchor independent community living.

Frailty, the geriatric syndrome characterized by declining strength, endurance, and physiological function, emerged as a central finding. Using the Clinical Frailty Scale with a cut-off at category five, 46.3 percent of participants were classified as frail, while 48 percent remained robust and 5.7 percent were pre-frail. This is a remarkably high prevalence for a group with a mean age of only 53, and it aligns with international evidence suggesting that frailty in people with intellectual disabilities can emerge 20 to 30 years earlier than in the general population. The researchers also observed that frailty was significantly more common among women, those who could not read or write, those with less education, those with more severe intellectual disability, and those living in institutional settings rather than the community.

The statistical associations were compelling. Malnutrition risk showed the strongest relationship with frailty, with a Cramér’s V of 0.60—every single malnourished participant was frail. Frail participants also had significantly worse scores on both basic and instrumental activities of daily living, took more medications on average, and were more likely to have chronic medical conditions lasting over three months. The presence of polypharmacy was more common among frail individuals, while those taking no medication were disproportionately represented among the non-frail. These findings collectively suggest that frailty in this population is not an isolated geriatric phenomenon but rather the convergence of lifelong disability, accumulated comorbidity, nutritional vulnerability, and functional decline.

The implications for care systems are sobering. The authors argue that aging with intellectual disability is not simply a gradual extension of a lifelong condition but a unique and compounding process that deepens dependence and intensifies care needs at a pace current systems are ill-equipped to meet. Informal carers are typically aging parents, while the formal social care workforce in Portugal tends to be over 50 years old itself, potentially limiting its capacity to handle the physical and emotional demands of supporting people with multiple health problems, excess weight, and substantial functional dependence. The researchers call for tailored healthy aging interventions that anticipate earlier frailty onset, promote functional independence and mobility, ensure nutritional care with involvement of dietitians, and draw on multidisciplinary teams.

Limitations temper the findings. The convenience sample was not representative, the 18.5 percent response rate raises the possibility of selection bias, and the instruments used—while validated for older Portuguese adults generally—have not been specifically validated for older Portuguese adults with intellectual disabilities. The cross-sectional design precludes causal inference, and the analyses were exploratory, based on univariable comparisons without adjustment for multiple testing. Falls, a known consequence of frailty, were not assessed. Nevertheless, as one of the first systematic characterizations of this population in Portugal, the study provides an empirical foundation that health and social care planners urgently need. As life expectancy for people with intellectual disabilities continues to climb, the question the researchers pose is no longer whether to act, but whether the systems in place will be ready when the wave arrives.

Subject of Research: Health profiles, functionality, and frailty in older adults with intellectual disabilities in Portugal

Article Title: Aging with intellectual disabilities: a study in Portugal about clinical conditions, functionality, and frailty

Article References: Letra, M., Tavares, J., Guerra, S., Peralta, A. R., Duarte, F., Amaral, R., & Sousa, L. (2026). Aging with intellectual disabilities: a study in Portugal about clinical conditions, functionality, and frailty. Frontiers in Human Neuroscience, 20, Article 1952261. https://doi.org/10.3389/fnhum.2026.1952261

Image Credits: AI Generated

DOI: 10.3389/fnhum.2026.1952261

Keywords: intellectual disabilities, frailty, healthy aging, polypharmacy, malnutrition risk, functional dependence, activities of daily living, comorbidities, Portugal, care systems, obesity, dementia