Mashall, McConkey and Moore (2003) seek to assess obese and overweight individuals and the steps taken after screening the individuals positively. In addition, the authors of this article seek to know how health promotion classes contribute to weight loss among obese and overweight individuals. The authors are compelled to conduct this study after observing that many individuals with intellectual disabilities present with obesity. Nevertheless, little is known on what steps are taken by carers and health providers to address the health problem. In addition, little is known about the impact of doing exercise and proper diet as health promotion efforts for reducing weight among the screened individuals.
To answer the research questions, the authors of this paper conducted two studies with the first study recruiting 464 participants (non-randomly) who were at least 10 years old and exhibited a learning disability as evidenced by attending a special school or being a beneficiary of the Health and Social Service Trust of Northern Ireland. The participants were then screened for obesity and related health problems by registered nurses with the assistance of local doctors. Questionnaires were also used to garner the health history of the individuals, with carers helping the intellectually disabled persons fill the questionnaire. Conditions that required referral were forwarded to general practitioners in the Trust region. After three months, a follow-up on the impact of referral was made where the persons with intellectual disabilities had to fill a questionnaire. Significance t-tests were then conducted to determine the BMI, hypertension, cholesterol levels, smoking and multiple risks. Exploratory data analysis also gave an overall description of the sample.
The first study demonstrated that there was a significant number of underweight younger people and obese older persons (p<.001). Differences in BMI based on gender, individual’s residence and mobility of the individual were not statistically significant (p =.538,.429 and.232 respectively). Individuals whore were at least 40 years had a statistically significant high blood pressure compared to younger participants (p<.001). Obesity was also significantly associated with high BP (p<.001) whereas being obese/overweight and at least 40 years old significantly predicted high BP (Wilk’s lambda 0.914, p<.001). Cholesterol levels were not strongly correlated with age (p =.086) whereas there was a significant number of male versus female smokers (p<.001). Only 5% of the participants had multiple risks whereas only 34% of those referred had action taken to address their health problems with only 2% of the participants registering weight reduction.
In the second study, which sought to identify the impact of health promotion activities in weight reduction, 10 participants volunteered to take the sessions in a local leisure center, 9 participants took the sessions as one of the programs in the day center whereas 6 participants volunteered to be among the third group of residents from a single facility. The health promotion classes were administered by special nurses using learning materials from Health Promotion Agency in Northern Ireland. The two-hour sessions were conducted for 6 to 8 weeks. Descriptive statistics were used to describe the sample characteristics (age and BMI). Significant t-tests showed a significant reduction in weight after the 6-weeks session (p<.001) and a significant decrease in BMI score (p<.001). Decrease in weight was not significantly associated with gender, presence or absence of Down syndrome or age (p=.289,.848 and.612 respectively).
Since the sample was not selected randomly, this study lacks external validity and the findings of the study can hardly be generalized. In addition, the external validity of this study is likely to be compromised by the fact that the participants were aware that they were being observed, thus they would have intentionally influenced their diet and exercise schedules. Despite the fact that the study established various relationships between obesity among persons with disabilities, one cannot infer causes to outcomes candidly, hence internal validity is compromised. However, both study 1 and study 2 had low participant drop out hence internal validity is not completely compromised. Internal validity is not maintained since participants have different characteristics (e.g. age and health history) and independent variables (intellectual disabilities) were not controlled. If the authors just considered only one intellectual disability such as Down syndrome, it would be possible to make the experiences of the participants be almost similar. T-test statistics have also effectively established the existence of various significant relationships in this study, despite failing to infer the direction of causality.
This study would have been improved by providing control groups, thus improving internal validity. Random selection of the samples would also be useful in improving generalization. The experimental design used in this study would have been enhanced by using single subjects with the subjects being their own controls and then repeating the studies with different subjects to enhance external validity.
Marshall, D., McConkey, R. and Moore, G. (2003). Obesity in people with intellectual disabilities: the impact of nurse-led health screenings and health promotion activities. Journal of Advanced Nursing, 41(2):147-153.