The purpose of this thesis was to address two broad research questions. The first was to explore the associations between physical and mental health in adults with ID who live in residential settings.Given the considerable numbers of adults with intellectual disabilities who live within residential settings, it is somewhat surprising how little systematic research attention has been given to this area. The second aim of this thesis, was, in collaboration with a local service provider, to design and implement interventions to improve the health of adults with ID who live in residential settings. To address these two broad research aims, it was first necessary to develop an appropriate method to measure the physical activity levels of adults with ID. Given the wide range of ability levels of adults with ID in these settings, it was decided to design a measure that proxy respondents, for example, support staff, could complete. Chapter 2 describes the process of validating this measure and the results showed that this measure had very good criterion validity for measuring physical activity levels over a seven-day period when compared to data gathered from an accelerometer during the same period.
Chapter 3 begins the work of describing the physical health, mental health and challenging behavioursof adults with ID who live in residential settings, using descriptive data. Chapter 3 also describesthe associations between physical health, mental health and challenging behaviour using correlational and regression methods. The data revealed relatively poor physical health in terms of the number of residents who were overweight, obese or morbidly obese, who did not participate in adequate levels of physical activity, and in terms of the numbers of adults with ID who displayed the signs and symptoms of physical ill-health. Physical health variables accounted for some of the additional variance in mentalhealth problemsand problem behaviours.Chapter 4 describes the results of a systematic review and meta-analysis summarising the evidence for multi-component weight-loss interventions for adults with ID. Despite these types of interventions being carried out for severaldecades (e.g. Fisher, 1986) and these types of interventions being the treatment of choice for adults who are overweight or obese (e.g. NICE, 2006) only eight studies met inclusion criteria forthis review. All of the eight studies reportedthat adults with ID lost weight between pre-and post-intervention. However, when all of the studies were combined, the pre-to post-intervention meta-analytic mean difference effect size for changes in BMI and weight were not statistically significantand were also small in terms of clinical meaning.
Thefinal empirical studyaddressedchanges in the physical healthof participants as a resultof the collaborating service designingand implementinginterventions to improve the health of adults with ID within the service. Chapter 5 also looks investigates if improving physical health improves participants’ mental health and challenging behaviours over the same18-month period. The data described in this chapter were the follow-up data of the first survey inChapter 3. The results showed that between T1 and T2 the majority of participants improved in terms of their physical health. Improvements in some aspects of physical health were also associated with some improvements in mental health and challenging behaviour.However, these associations were once again small in number.Findings from the three empirical studies were discussed in relation to their theoretical value and their implication in intervention research. Recommendations for further study were also made.