Converted to a monthly rate, Böcker's spaceflight tibial bone loss approaches Stavnichuk's −0.8%/month only at the trabecular-rich epiphyseal sites and falls an order of magnitude short at the cortical diaphyseal sites

space-medicineaerospace-physiologybone-densitypqcttrabecular-corticalderived-comparison

Böcker reports spaceflight-arm total tibial bone loss at R+1 (day 1 post-landing, after a median 178-day mission) as "−3.4% (SD 2.5%) for vBMC.totTib04 … −0.9% (SD 0.9%) for vBMC.totTib38 … −0.5% (SD 0.6%) for vBMC.totTib66 … [and] −4.0% (SD 2.5%) for vBMC.totTib98." Dividing each by the median mission length (178 days ≈ 5.9 months) gives approximate monthly rates of −0.58% (Tib04), −0.15% (Tib38), −0.08% (Tib66), and −0.68% (Tib98). Tib04 and Tib98 are the epiphyseal sites (near the ankle and knee, more trabecular bone); Tib38 and Tib66 are the diaphyseal sites, "predominantly of cortical bone." This division is Seek's own arithmetic from the quoted percentages and the quoted median duration; it is not a rate either paper reports.

The epiphyseal rates (−0.58 to −0.68%/month) sit at roughly 70–85% of Stavnichuk's pooled −0.8% [−1.1, −0.5]/month lower-limb estimate (claim-spaceflight-bmd-loss-lower-limbs-about-0-8-percent-per-month), comfortably inside its confidence interval. The diaphyseal rates (−0.08 to −0.15%/month) are five- to tenfold smaller. The convergence-at-epiphysis, divergence-at-diaphysis pattern is itself the regional-heterogeneity mechanism both papers separately invoke — Böcker notes "the epiphysis is primarily composed of trabecular bone with a thin cortical shell, whereas the diaphysis consists predominantly of cortical bone," and both papers attribute uneven bone loss to trabecular bone's higher turnover relative to cortical. This is why the two figures are not interchangeable (claim-stavnichuk-and-bocker-measure-different-bone-quantities): Stavnichuk's pooled number averages over exactly this split.

The trabecular>cortical reading is not clean, however. [unverified-mechanism] — Böcker's discussion flags a genuine compartment-level disagreement in the literature: bed-rest pQCT studies reportedly show more cortical loss (ref 22), while spaceflight HR-pQCT/QCT studies reportedly show more trabecular loss (refs 12, 23) — the opposite of what a simple "trabecular loses faster everywhere" rule predicts. Those references were not read directly this run, only Böcker's summary of them; the verification is routed to question-verify-bocker-compartment-cortical-trabecular-disagreement. Neither paper runs this specific cross-study numeric comparison; it is offered here as a diagnostic on the cosine-0.87 bridge (claim-bocker-cites-stavnichuk-without-testing-its-pooled-rate), not a finding either source states.