Measurement of physical activity and its impact on inflammatory markers linked to cardiovascular disease in rheumatoid arthritis

The studies which compose this thesis stem from two literature reviews. The first literature review determined that definitive conclusions regarding physical activity levels in the RA population and how they compare to a control population cannot be determined due mainly to methodological concerns in the studies in the area, in particular the use of subjective and/or unvalidated physical activity measurement tools. The second literature review concluded that a link exists between inflammation and the increased risk of cardiovascular disease in the RA population. Furthermore, a link was also found between physical activity and inflammation and cardiovascular disease in populations other than the RA population. However, limited research has been conducted in the RA population to determine if a link exists between physical activity and inflammation. Thus, initially a study was designed to assess the validity of an objective physical activity measurement tool to estimate physical activity in the RA population. The findings of this research determined that the SWA provides an accurate measure of energy expenditure in this population. This tool was then utilised in studies which assessed physical activity in the population. Studies were designed and undertaken to assess energy expenditure levels in the RA population, assess how these levels compared to a control population and determine some correlates of energy expenditure in the population. A study was also designed and undertaken to assess the relationship between a wide range of inflammatory markers which are known to be linked to cardiovascular disease, and energy expenditure in the RA population. Two further studies were also undertaken in order to complement the previously mentioned studies. Firstly, a study was designed to assess the validity of a frequently used subjective physical activity measurement tool when compared to the SWA in the RA population. Users’ experiences of having their health, in particular their physical activity levels, monitored in the home through technological means were also assessed as part of this thesis.