Age at the time of first blood donation and donation pattern of blood donors in Australia

Regular blood donation is essential to ensure the availability of blood and its products. Blood and its components are vital for the treatment of medical emergencies and chronic diseases, such as massive bleeding, trauma, and cancers. In Australia, and globally, advances in medical treatment have continuously increased the demand for blood and blood products. Currently, Australia is relying on imported plasma to meet its plasma demands. Thus, improving our understanding of the relationship between demographic and other variables with blood donation patterns can help blood collection agencies to refine policies to meet the changing demand of blood and its products. This thesis aims to improve our understanding of blood donation patterns in Australia, particularly the relationship between the age at first blood donation and donation pattern. I started by identifying major demographic factors associated with return to donate in high-income countries (HICs), including Australia, and low- and middle-income countries (LMICs). The systematic review included LMICs to fill the knowledge gap as previous systematic reviews focused only on HICs. Results from studies conducted in HICs and LMICs were compared to identify if the same factor had different effects in each setting. I then explored the donation pattern of blood donors in Australia with a cohort study using data from the Australian Red Cross Blood Service. The study factor of this thesis is the donor's age at first donation. Analyses were adjusted for several factors identified to be associated with prospective donation pattern among first-time donors in the systematic review. The systematic review identified the demographic factors and other factors that are associated with return behaviour in blood donors - first-time and repeat donors - across the globe. Shorter inter-donation interval, positive past donation history, a feeling of satisfaction, initial intention to return, and a convenient location to donate were associated with positive return behaviour in both settings. Adverse events, anxiety, and deferrals from donation reduced the likelihood of return in both settings. Sex and level of education showed varying effects on return behaviour in studies conducted in HICs and LMICs. Comparatively more studies reported older age as a predictor for return in HICs while younger donors were more likely to return in LMICs. Although the systematic review was not limited to studies specifically looking at age at first donation or studies conducted on first-time donors, I found the factors affecting return in both first-time and repeat donors were similar. The cohort study used donation data that was collected from 1 January 2007 to 31 March 2019. This study showed that donors who started donating at less than 30 years of age donated less frequently in the future than donors who started at 30 years or older. Donors who started to donate for the first time at middle age were shown to actively donating for a longer period of time. Additionally, women donated less frequently compared to men, but their return rate for at least one donation was higher compared to men. Overall, the results of this thesis suggest that the recruitment of middle-aged donors is more effective in meeting the short- to mid-term demand for blood products in Australia. The cohort study could not detect whether young donors would continue to donate blood after reaching middle age due to the relatively short period of follow up. Further studies need to be conducted to better understand the factors contributing to the lower donation rate of younger donors in Australia. Future research could explore the motivational factors and barriers to blood donation in the Australian population, as well as measuring the incidence and impacts of adverse events and deferrals on future donations. A cohort study, with a much longer period of follow-up, will enable us to answer whether young donors will donate more often after reaching middle age. Efforts to identify barriers to donation in the Australian population especially in young donors will inform donor recruitment policies to target this population better.