| Personalized medicine is increasingly infused into healthcare. However, current literature offers limited evidence on its theoretical and actual impact on disease prevention. This thesis research asked whether receiving the results of predictive genetic testing that indicated the presence or absence of an inherited predisposition to colorectal cancer (CRC) was associated with change in individual health behaviours that can prevent CRC. The behaviours included colonoscopy use, the fecal occult blood test (FOBT) use, smoking cessation, and the intake of aspirin, folate, and multivitamins. To answer the question, three studies were conducted. In the first study, a literature review was performed to identify, summarize, and critique previous research on the behavioural responses to predictive CRC genetic information. The review identified serious methodological shortcomings in previous studies that compromised the validity of the reported findings and demonstrated that no indisputable evidence on the review topic currently exists. In the second study, a theoretical model grounded in health economics and clinical evidence was devised to generate testable hypotheses on the behavioural responses to predictive CRC genetic information. The model predicted an increased likelihood of colon screening in those who discovered that they carried their family's genetic predisposition to CRC and an increased likelihood of smoking in those who discovered that they did not. In the third study, an empirical analysis on the behavioural responses to predictive CRC genetic information was undertaken, using the Australasian CRC Family Registry data. Consistent with the theoretical model, the empirical analysis found a higher likelihood of colonoscopy use in those who discovered that they carried their family's genetic predisposition to CRC and a higher likelihood of smoking in those who discovered that they did not. There was evidence of change in FOBT use, but those findings were not always significant. No significant change was observed in the intake of aspirin, folate, and multivitamins. Therefore, predictive CRC genetic information did change individual health behaviours but not necessarily in ways to improve population health. The impact of personalized medicine on disease prevention is intricate, warranting a thorough assessment from both clinical and societal perspectives to understand its intended and unintended effects. |
