Impact of frequent apheresis blood donation on bone density: A prospective,longitudinal, randomized, controlled trial

Background Blood for transfusion is lifesaving and essential to many elements of modern medical practice. The global blood supply relies on volunteer blood donors. Apheresis is increasingly used to collect blood and requires anticoagulant to prevent extracorporeal coagulation. Citrate, the standard apheresis anticoagulant, chelates ionized calcium with consequent perturbations of serum calcium, parathyroid hormone, vitamin D, and markers of bone remodeling in donors. Cross-sectional studies of bone mineral density (BMD) among apheresis donors exhibit conflicting results. Methods The longitudinal, randomized, controlled ALTRUYST trial (NCT02655055) was undertaken to determine whether BMD declined following high frequency apheresis blood donation over 1 year. The study was powered at 80% to detect the primary outcome of a 3% decline in BMD. Subjects new to apheresis agreed to make ≥20 apheresis donations in a one-year period and were randomized to treatment (high frequency apheresis) or control (no apheresis). Dual-energy x-ray absorptiometry was performed before and after participation. Two-sided t-test and multivariable logistic regression were used to assess outcomes. Findings Mean lumbar spine BMD did not change during the study among control donors (−0.002 g/cm2, 95%CI [−0.020, 0.016], p = 0.78), or among donors in the apheresis arm (mean change = 0.007 g/cm2, 95%CI [−0.005, 0.018], p = 0.24). Mean total hip BMD did not change for control donors (mean change = 0.002 g/cm2, 95%CI [−0.006, 0.009], p = 0.63) or apheresis donors (−0.004 g/cm2, 95%CI [−0.10, 0.002], p = 0.16). Tests for differences in proportions of donors with change in BMD exceeding the least significant change at the lumbar spine in either a positive [8 apheresis (31%), 4 control (27%), p = 0.78] or negative direction [4 apheresis (15%), 5 control (33%)] were statistically non-significant (p = 0.18). Proportional increases [0 apheresis (0%), 1 control (7%), p = 0.18] and decreases [3 apheresis (12%), 1 control (14%)] were also not significantly different at the total hip (p = 0.61). Interpretation ALTRUYST is the first longitudinal trial to demonstrate that apheresis blood collection guidelines in the United States adequately protect the skeletal health of male volunteer blood donors

A proposal for curriculum content in transfusion medicine and blood banking education in pathology residency programs

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/71606/1/j.1537-2995.2007.01417.x.pd

Global maps of soil temperature

Research in global change ecology relies heavily on global climatic grids derived from estimates of air temperature in open areas at around 2 m above the ground. These climatic grids do not reflect conditions below vegetation canopies and near the ground surface, where critical ecosystem functions occur and most terrestrial species reside. Here, we provide global maps of soil temperature and bioclimatic variables at a 1-km² resolution for 0–5 and 5–15 cm soil depth. These maps were created by calculating the difference (i.e., offset) between in-situ soil temperature measurements, based on time series from over 1200 1-km² pixels (summarized from 8500 unique temperature sensors) across all the world’s major terrestrial biomes, and coarse-grained air temperature estimates from ERA5-Land (an atmospheric reanalysis by the European Centre for Medium-Range Weather Forecasts). We show that mean annual soil temperature differs markedly from the corresponding gridded air temperature, by up to 10°C (mean = 3.0 ± 2.1°C), with substantial variation across biomes and seasons. Over the year, soils in cold and/or dry biomes are substantially warmer (+3.6 ± 2.3°C) than gridded air temperature, whereas soils in warm and humid environments are on average slightly cooler (-0.7 ± 2.3°C). The observed substantial and biome-specific offsets emphasize that the projected impacts of climate and climate change on near-surface biodiversity and ecosystem functioning are inaccurately assessed when air rather than soil temperature is used, especially in cold environments. The global soil-related bioclimatic variables provided here are an important step forward for any application in ecology and related disciplines. Nevertheless, we highlight the need to fill remaining geographic gaps by collecting more in-situ measurements of microclimate conditions to further enhance the spatiotemporal resolution of global soil temperature products for ecological applications

Global maps of soil temperature.

Research in global change ecology relies heavily on global climatic grids derived from estimates of air temperature in open areas at around 2 m above the ground. These climatic grids do not reflect conditions below vegetation canopies and near the ground surface, where critical ecosystem functions occur and most terrestrial species reside. Here, we provide global maps of soil temperature and bioclimatic variables at a 1-km2 resolution for 0-5 and 5-15 cm soil depth. These maps were created by calculating the difference (i.e. offset) between in situ soil temperature measurements, based on time series from over 1200 1-km2 pixels (summarized from 8519 unique temperature sensors) across all the world's major terrestrial biomes, and coarse-grained air temperature estimates from ERA5-Land (an atmospheric reanalysis by the European Centre for Medium-Range Weather Forecasts). We show that mean annual soil temperature differs markedly from the corresponding gridded air temperature, by up to 10°C (mean = 3.0 ± 2.1°C), with substantial variation across biomes and seasons. Over the year, soils in cold and/or dry biomes are substantially warmer (+3.6 ± 2.3°C) than gridded air temperature, whereas soils in warm and humid environments are on average slightly cooler (-0.7 ± 2.3°C). The observed substantial and biome-specific offsets emphasize that the projected impacts of climate and climate change on near-surface biodiversity and ecosystem functioning are inaccurately assessed when air rather than soil temperature is used, especially in cold environments. The global soil-related bioclimatic variables provided here are an important step forward for any application in ecology and related disciplines. Nevertheless, we highlight the need to fill remaining geographic gaps by collecting more in situ measurements of microclimate conditions to further enhance the spatiotemporal resolution of global soil temperature products for ecological applications

Hepatitis C virus prevalence and clearance among US blood donors, 2006-2007: associations with birth cohort, multiple pregnancies, and body mass index.

BackgroundDuring the period 1992-1993, the prevalence of hepatitis C virus (HCV) antibodies (anti-HCV) among US blood donors was 0.36%, but contemporary data on the prevalence of antibody to HCV and the prevalence of HCV RNA are lacking.MethodsWe performed a large, cross-sectional study of blood donors at 6 US blood centers during 2006-2007. Anti-HCV was measured with enzyme-linked immunosorbent assay followed by immunoblot, and HCV RNA was measured with nucleic acid testing. Adjusted odds ratios (aORs) were derived using multivariable logistic regression.ResultsOf 959,281 donors, 695 had anti-HCV detected (prevalence, 0.072%). Of those with anti-HCV, 516 (74%) had test results positive for HCV RNA, and 179 (26%) had test results that were negative for HCV RNA. Compared with the prevalence during the period 1992-1993, prevalence during 2006-2007 was lower and peaked in older age groups. Anti-HCV was associated with a body mass index (BMI) >30 (aOR, 0.6; 95% confidence interval [CI], 0.5-0.8), and among women, it was associated with higher gravidity (aOR for 5 vs 0 pregnancies, 3.2; 95% CI, 1.9-5.4). HCV RNA negative status was associated with black race (aOR, 0.4; 95% CI, 0.2-0.7), having more than a high school education (aOR, 1.6; 95% CI, 1.1-2.4), and BMI >30 (aOR, 2.4; 95% CI, 1.4-3.9).ConclusionsDecreasing HCV prevalence is most likely attributable to culling of seropositive donors and a birth cohort effect. We found new associations between anti-HCV prevalence and gravidity and obesity. Recently discovered genetic factors may underlie differences in HCV RNA clearance in black donors

Hepatitis C virus prevalence and clearance among US blood donors, 2006-2007: associations with birth cohort, multiple pregnancies, and body mass index.

BackgroundDuring the period 1992-1993, the prevalence of hepatitis C virus (HCV) antibodies (anti-HCV) among US blood donors was 0.36%, but contemporary data on the prevalence of antibody to HCV and the prevalence of HCV RNA are lacking.MethodsWe performed a large, cross-sectional study of blood donors at 6 US blood centers during 2006-2007. Anti-HCV was measured with enzyme-linked immunosorbent assay followed by immunoblot, and HCV RNA was measured with nucleic acid testing. Adjusted odds ratios (aORs) were derived using multivariable logistic regression.ResultsOf 959,281 donors, 695 had anti-HCV detected (prevalence, 0.072%). Of those with anti-HCV, 516 (74%) had test results positive for HCV RNA, and 179 (26%) had test results that were negative for HCV RNA. Compared with the prevalence during the period 1992-1993, prevalence during 2006-2007 was lower and peaked in older age groups. Anti-HCV was associated with a body mass index (BMI) >30 (aOR, 0.6; 95% confidence interval [CI], 0.5-0.8), and among women, it was associated with higher gravidity (aOR for 5 vs 0 pregnancies, 3.2; 95% CI, 1.9-5.4). HCV RNA negative status was associated with black race (aOR, 0.4; 95% CI, 0.2-0.7), having more than a high school education (aOR, 1.6; 95% CI, 1.1-2.4), and BMI >30 (aOR, 2.4; 95% CI, 1.4-3.9).ConclusionsDecreasing HCV prevalence is most likely attributable to culling of seropositive donors and a birth cohort effect. We found new associations between anti-HCV prevalence and gravidity and obesity. Recently discovered genetic factors may underlie differences in HCV RNA clearance in black donors