Prevention of type 2 diabetes in high risk groups: epidemiology, progression rates and patient views and experiences.

Background: People with gestational diabetes mellitus (GDM) and impaired glucose regulation (IGR) are at increased risk of developing type 2 diabetes but lifestyle change can help to delay or prevent type 2 diabetes in these groups. Aims: This thesis comprises five publications which inform the development of lifestyle interventions for people with IGR and GDM by describing the epidemiology, progression to type 2 diabetes, and patient views and perceptions associated with these conditions. Methods: Publications one and two used systematic review and meta-analysis methods to describe the prevalence of IGR and GDM in Europe. A retrospective cohort design utilising routinely collected health care data from one region in Scotland was used in publications three and four to describe the incidence of IGR, and the progression from GDM and IGR to type 2 diabetes. Publication five explored women’s perceptions and experiences of GDM using semi-structured interviews informed by behaviour change theory. Results: Mean prevalence of IGR and GDM in developed Europe was 22.3% and 5.4% respectively. Rates of progression to type 2 diabetes were 9% in a mean time of 34 months for IGR and 25% in a mean time of eight years for GDM. Older people with IGR living in deprived areas and women with GDM who were overweight and with higher fasting plasma glucose levels were at most risk of developing type 2 diabetes. Publication five highlighted how perceptions about the consequences of GDM and timeline and consequences of type 2 diabetes may be linked to the lifestyle change women make after diagnosis of GDM and their lack of success in maintaining these changes postnatally. Conclusions: This thesis provides a clear understanding of the prevalence of IGR and GDM, rates of progression to type 2 diabetes, and patient views and perceptions on which to base intervention planning and health care delivery.