Abstract: Objective To explore the effects of high-frequency plateletpheresis on bone metabolism markers and bone mineral density (BMD) in donors. Methods (1) Twenty-one donors were enrolled and completed 30 plateletpheresis procedures within a 2-year timeframe. Specimens were collected at the 1 st, 10th, 20th, and 30th donations, with sampling time points including pre-donation, during donation, 1 hour post-donation, and 24 hours post-donation. (2) Fifty donors with ≥10 plateletpheresis sessions and over 70 cumulative apheresis procedures, together with 50 whole blood donors in the past two years, were recruited. Specimens were collected prior to donation to detect baseline levels of calcium (Ca), intact parathyroid hormone (iPTH), osteocalcin (OST/OC), C-terminal telopeptide of type I collagen (CTX-Ⅰ, β-crosslaps), and 25-hydroxyvitamin D [25-(OH)D]. The OST/CTX-Ⅰ ratio was calculated to evaluate the dominant direction of bone turnover. (3) Twenty-six donors with ≥10 plateletpheresis sessions and more than 80 cumulative apheresis procedures, as well as 24 healthy physical examination participants, underwent BMD measurement. BMD was assessed by dual-energy X-ray absorptiometry (DXA) at the lumbar spine and hip joints. Results (1) Significant differences in Ca levels in 30 plateletpheresis donors were noted among different donation frequencies and sampling time points. The levels of iPTH, OST, CTX-Ⅰ, OST/CTX-Ⅰ ratio, and 25-(OH)D differed significantly across various sampling time points (P<0.05). A negative correlation was found between Ca and iPTH, while positive correlations existed between iPTH and OST, and between OST and CTX-Ⅰ (all P<0.05). (2) Donors with over 70 cumulative apheresis procedures (≥10 times annually) had lower baseline serum Ca levels and higher OST and CTX-Ⅰ levels compared with blood donors (P<0.05). (3) Donors with over 80 cumulative apheresis procedures (≥10 times annually) showed lower lumbar spine BMD than the healthy non-donors (P<0.05), whereas no statistically significant difference in hip BMD was detected between the two groups (P>0.05). Conclusion High-frequency plateletpheresis can alter bone metabolism and BMD, accelerate bone metabolism, and render bone formation the dominant process during donation. As the total number and frequency of donations rise, it is essential to strengthen targeted guidance and health education for donors, and intensify monitoring (e.g., detection of bone metabolism markers, BMD) to better protect donor safety.

Key words: Plateletpheresis, Serum calcium, Bone metabolism, Bone mineral density, Citrate, Parathyroid hormone