Growing evidence supports healthy older people continuing to donate blood into later life

I nternationally, there has long been concern about the suitability of older adults as blood donors. These concerns center on the potential risk of morbidity due to the increasing incidence of cardiovascular disease with age, and an increased risk of adverse reactions, particularly vasovagal reactions, associated with the physiological changes of aging. The World Health Organization’s blood donor selection guidelines indicate a “usual” upper age limit of 65 years but permit physicians to allow first-time donors over 60 and regular donors over 65 to donate (consistent with European recommendations). Further, on the basis that some countries whose populations have high life expectancies have safely removed upper age limits on donors, the World Health Organization’s guidelines suggest that the healthy life expectancy of the population from which donors are drawn can also be considered. Reflecting this potential for discretion, there is wide variation among and within countries in applying age-related eligibility criteria, including the specific upper age limit used and whether additional medical assessment or approval is required. In the context of a growing awareness that the over 60s are the fastest-growing age group and will likely comprise up to one-quarter of the populations in most regions of the world by 2050, the requirement to restrict blood donation among older people has been challenged. Age restrictions on who can donate blood, coupled with a likely increase in demand from a higher incidence of health conditions in this demographic, has led to concerns about potential blood shortages. Several authors have suggested prioritizing strategies to engage young people in blood donation to minimize the risk of shortages resulting from this change in population demographics; however, reconsideration of the policy of restricting blood donation among older donors has also been put forward as a potential solution, at least for the short to medium term. The relative benefits of these two strategies need to be considered, taking into account the cost-effectiveness of recruiting and retaining these donor cohorts, given likely variation in willingness to donate, retention rates, and length of donor career. Consideration of donor age also requires attention to the safety and quality of donated products and any implications for patients in receiving blood from younger versus older donors. However, a particularly critical factor, and the primary focus within the literature to date, is the physical impact of donating blood on donors themselves, in terms of both their immediate safety and their ongoing health. A 1991 TRANSFUSION editorial noted that limited data were available on the safety of blood donation in later life. At that point, much of the evidence was either anecdotal or from studies of autologous older donors, who may not have met standard eligibility criteria, raising concerns about the generalizability of findings to healthy volunteer donors. A study published in that issue indicated that the standard selection process successfully identified contraindicated medical conditions in the older donors recruited (aged 63 years or greater), and those who donated experienced few adverse reactions. This supported an earlier study that found no difference in the rate of immediate reactions between donors aged 55–65 years and those 66 years and over. A second study in the same TRANSFUSION issue reported a concern about reduced iron stores found in a small sample of older donors. However, these researchers did not compare the donors’ iron stores with those of younger donors, and it was notable that the sample had donated at a high frequency— five units over 12 months—which is just below the maximum currently allowed for donors of any age by most blood centers in the United States. In the 27 years since this editorial, evidence on adverse effects of blood donation for older versus younger donors has accumulated, with several large retrospective reviews published. Regression analyses on 2006 data from the American Red Cross examined the impact of sex, age, donor experience, and donor center location on donor complications (defined as vasovagal reactions, and other types of adverse events such as hematomas and painful venipunctures). While donors over 60 years of age had a higher proportion of small hematomas than younger donors, Eder and colleagues showed that younger age, rather than older age, was the strongest predictor of adverse reactions to whole blood donation. The complication rate in whole blood donation was low in older donors, with donors aged 80 years or over being three times less likely to suffer a complication from donating than an 18or 19-year-old and having a risk equivalent to donors in their 40s. Similarly, in apheresis donors, younger age was a risk factor for adverse events, albeit to a smaller degree than with whole blood donation. Multivariate analyses of Japanese Red Cross Tokyo Blood Center data on vasovagal reactions showed a similar pattern, with younger age (<50 years) found to be the most significant risk factor for an adverse event. Donors aged 18 and 19 years were at the highest risk of an adverse event following a 400-mL whole blood donation, while donors doi:10.1111/trf.15237 © 2019 AABB TRANSFUSION 2019;59;1166–1170