Table 1.
Percent loss in bone mineral density at femoral neck in astronauts (N = 69) after 132- to 228-day spaceflights.
Fig 1.
Bone mineral density change (%) at the femoral neck of astronauts versus duration of spaceflight.
Grey dots represent experimental data obtained in previous missions as measured by dual-energy x-ray absorptiometry (DXA). Two different potential human missions to Mars are highlighted: (i) opposition-class, with a duration of 400–600 days (area with red dots) and (ii) conjunction-class, with a duration of 1000–1200 days (area with red lines). The predictive model is represented by the solid, black line, with the 95% confidence interval limits plotted in dashed, black lines, and the plateau by the dot-dashed, black line. A comparison with the (unphysical) linear model can be found in S1–S3 Figs.
Table 2.
Values of the parameters obtained for the mathematical model for the bone mineral density loss for long duration spaceflights.
Table 3.
Estimated T-scores for each sex/ethnicity/age group.
The color code is defined as by the international reference standard, osteoporosis is colored in red (T-score < -2.5), and osteopenia in orange (-2.5 < T-score < -1). Normal T-score is colored in green (T-score > -1). NASA´s non-permissible outcome is T-score < -2, highlighted by bold numbers in the table.