Arthritis & Rheumatism, Volume 62,
November 2010 Abstract Supplement
Abstracts of the American College of
Rheumatology/Association of Rheumatology Health Professionals
Annual Scientific Meeting
Atlanta, Georgia November 6-11, 2010.
Bone Density Following Long-Duration Spaceflight and Recovery.
Amin1, Shreyasee, Achenbach1, Sara, Atkinson1, Elizabeth, Melton1, L. Joseph, Khosla1, Sundeep, Sibonga2, Jean
Rapid bone loss in the weight-bearing skeleton is well recognized during microgravity exposure in long-duration spaceflight, but the implications on long-term bone health remain unclear. How bone mineral density [BMD] in US crew members serving on long-duration missions in space [US crew] compare with what would be expected had they not been exposed to microgravity, is unknown.
We therefore examined the observed changes in BMD (g/cm2) among 28 US crew (immediately post-flight and following ~12 months recovery) relative to comparable age- and gender-expected changes derived from 348 men (age range at baseline: 2290 yrs) and 351 women (range: 2193 yrs) representing an age-stratified, random sample of the adult community population. BMD measurements (Hologic QDR 2000) were made at the total hip, lumbar spine, ultradistal and midshaft radius, and total body (sites also measured in US crew). Men were measured at baseline, 2, and 4 yrs; women were measured at baseline, 1, 2, and 4 yrs. Linear mixed effects models were used to predict follow-up BMD using baseline BMD, age, gender, and follow-up time, adjusting for the fact that most people were measured more than once. Models including body mass index (BMI) or lean mass were also considered. In US crew (24 men, age range at pre-flight scan: 3653 yrs; 4 women, age: 4153 yrs), BMD was measured pre-flight, immediately post flight and at ~12 months post-flight using Hologic QDR 2000, QDR 4500 and Discovery scanners. The majority had pre- and post-flight BMD on similar machines. Immediate post-flight BMD was performed a median of 6 (range: 333) days after return, with a median flight duration of 167 (range: 95215) days. 22 men and 4 women had a scan within 618 months post-flight; median days from landing to ~12 months scan was 376 (range: 184534) days.
Using their age, gender, pre-flight BMD and follow-up time, post-flight BMD values for US crew were predicted based on the model developed from the community sample. The predicted and observed BMD and rates of change immediately and ~12 month post-flight for US crew are presented (see Table). Findings were similar using prediction models which included BMI or lean mass. Due to microgravity exposure, the observed immediate post-flight BMD at all sites was significantly lower than predicted. However, at ~12 months post-flight, BMD values at most sites in US crew were still lower than would be expected had they not been exposed to microgravity.
|BMD Site||Mean BMD (g/cm2) (% change in BMD per month) [95% Confidence Interval]|
|Immediate Post Flight||~12 Month Post Flight|
|Total Hip||1.082 (-0.00) [-0.05, 0.04]||1.012 (-0.87) [-1.04, -0.71]||<0.001||1.086 (0.01) [-0.01, 0.02]||1.062 (-0.10) [-0.15, -0.06]||<0.001|
|Spine||1.078 (0.12) [0.10, 0.13]||1.028 (-0.48) [-0.61, -0.34]||<0.001||1.086 (0.05) [0.05, 0.06]||1.068 (-0.03) [-0.01, 0.03]||0.004|
|Ultradistal Radius||0.519 (-0.02) [-0.05, -0.00]||0.511 (-0.21) [-0.34, -0.09]||0.01||0.512 (-0.07) [-0.07, -0.06]||0.517 (-0.002) [-0.07, 0.02]||0.03|
|Mid Shaft Radius||0.710 (0.17) [0.11, 0.23]||0.695 (-0.06) [-0.17, 0.04]||0.001||0.705 (0.06) [0.03, 0.09]||0.694 (-0.01) [-0.06, 0.04]||0.02|
|Total Body||1.264 (-0.05) [-0.05, -0.04]||1.240 (-0.26) [-0.37, -.0.16]||0.002||1.264 (-0.02) [-0.03, -0.02]||1.248 (-0.08) [-0.15, -0.01]||0.08|
These findings have implications on potential long-term adverse effects to bone health of US crew serving on long-duration spaceflight missions.
To cite this abstract, please use the following information:
Amin, Shreyasee, Achenbach, Sara, Atkinson, Elizabeth, Melton, L. Joseph, Khosla, Sundeep, Sibonga, Jean; Bone Density Following Long-Duration Spaceflight and Recovery. [abstract]. Arthritis Rheum 2010;62 Suppl 10 :959