Problems encountered in epidemiologic health research in older adults with intellectual disabilities (ID) are how to recruit a large-scale sample of participants and how to measure a range of health variables in such a group. This cross-sectional study into healthy ageing started with founding a consort of three large care providers with a total client population of 2322 clients of 50 years and over, and two academic institutes. This consort made formal agreements about a research infrastructure and research themes: (1) physical activity and fitness, (2) nutrition and nutritional state, and (3) mood and anxiety. Subsequently, preparation was started by carefully reviewing and selecting instruments to measure a wide set of health variables to answer the research questions. Specific demands of these instruments were that they could be executed efficiently and accurately on-site in a large sample of participants and that the burden of these measurements for participants as well as their caregivers was as minimal as possible. Then, preparation was continued by designing and executing a thorough communication plan for clients, legal representatives and staff of the care providers, preceding the informed consent procedure. In this plan, which had a top-down structure, specific attention was given to personally informing and motivating of key stakeholders: the professional care givers. This preparation led to a recruitment of 1050 participants (45.2%) and to high participation rates in key parts of the assessment. A detailed description is provided about the recruitment and organization and the selected instruments.
Life expectancy of adults with intellectual disabilities (ID) is lengthening towards that of adults without intellectual disabilities, but daily practice indicates that this ageing is relatively often not a healthy ageing. With a higher risk of motor impairments, sensory impairments and epilepsy since earlier in life, these people are prone to develop multiple physical and mental comorbidities at older age (Davidson et al., 2003, Fisher and Kettl, 2005 and Janicki and Jacobson, 1986). ‘Frail patients’ (multiple diagnoses, complex medical routines, frequent hospitalisation, and functional impairment) (Chess, Krentzman, & Charde, 2007), requiring individualised managed care, are expected to be highly prevalent in this population. Furthermore, functional deterioration is frequent (Evenhuis, 1997), leading to diagnostic and therapeutic uncertainty, transfers from community-based to central residential settings, and high costs.
With these risks in mind, three Dutch care organizations (Abrona, Huis ter Heide; Amarant, Tilburg; Ipse de Bruggen, Zwammerdam) and two academic departments (Intellectual Disability Medicine, Department of General Practice, Erasmus MC in Rotterdam; Center for Human Movement Sciences, UMCG, Groningen) intended to start a large-scale project to study health in older adults with intellectual disabilities in 2006. Inspired by questions of the care organizations themselves (formulated by client panels and staff panels), three themes were chosen: (1) physical activity and fitness, (2) nutrition and nutritional state, and (3) mood and anxiety. These themes cover a substantial impact on health and quality of life and are supposed to have strong mutual relationship, but have hardly been studied in ageing people with intellectual disabilities. The scientific aims of this project were: (a) to perform baseline assessments of prevalences and secondary health effects for each theme and to identify risk groups; (b) to assess mutual relationships between the themes and their underlying concepts; (c) to select and evaluate diagnostic tools to assess each theme.
To meet these aims, an observational cross-sectional design was chosen for this multi-center research project. However, before such a study in this particular and complex target population could be executed, two major obstacles needed to be dealt with.
This paper describes how to successfully include a large sample of older adults with ID and to measure their health. A selection of instruments suitable for large-scale health assessment in this group is presented. Involvement of top and middle management in the entire process and a thorough communication plan (with a focus on key groups such as professional caregivers) proved of paramount importance to effectively organize this kind of large-scale research projects.
Not documented in this study, but an important factor in recruitment and measurements, was the actual involvement and cooperation of professional caregivers. Feedback from management of all levels in the care organizations, combined with our personal experiences in this process, suggest that the professional caregivers reacted positively to the personal communication and cooperativeness of the researcher to follow their preferences in the organization of measurements, leading to widespread cooperation during the consent procedure as well as the measurements themselves.
The actual percentage of clients with informed consent was 49.7%. This percentage seems low, but considering the extensive health screening, which could be seen as a burden for the participant, it might be relatively good. In a multi-center study with only an assessment of visual and hearing function, the consent percentage was 61% (Evenhuis et al., 2004).
