Regular high-frequency whole blood donation and risk of cardiovascular disease in middle-aged and older blood donors in Australia.

Abstract

Previous mixed findings on the associations between whole blood (WB) donation and risk of cardiovascular diseases (CVD) may in part reflect inadequate adjustment for the "healthy donor effect" (HDE). We used the Sax Institute's 45 and Up Study linked with blood donation history and other health-related databases to examine the association between regular, high-frequency WB donation and the risk of CVD. To mitigate the impact of HDE, we used a "5-years qualification period," in which donors must donate at least 1 WB donation in the 1st and 5th year of "qualification period." We then compared the risk of CVD in the years following the "qualification period" between the regular high-frequency WB donors (≥2 WB donation in each qualification year) and others using Cox proportional-hazards models. Analyses were adjusted for potential confounders, such as sociodemographic, lifestyle, and health-related variables, and results are reported separately for male and female donors. A total of 2736 male and 2917 female donors were included in the analyses. The median years of follow-up per donor was 5.84 years (Q1-Q3, 5.47-6.23). The rate of CVD hospitalization was 11.20 and 4.50 per 1000 person-years for males and females, respectively. In fully adjusted models, the risk (hazard ratio) of CVD in regular high-frequency donors compared to other donors was 0.93 (95% Confidence Interval (CI), 0.68-1.29) for males and 0.79 (95% CI, 0.49-1.28) for females. We did not observe a statistically significant reduction of CVD risk in regular, high-frequency WB donors when adjusted for potential confounders.