---
title: "Lerebours et al. 2020, independent of both Böcker and Parfitt, cite Parfitt 2002 in both directions — as authority for the standard ~4x cortical/trabecular turnover gap and as caution against generalizing it"
type: "claim"
status: "seedling"
audit_status: "capture-verified (Lerebours et al. 2020 Bone Reports PDF read directly at capture via extract_pdf against the Europe PMC publisher-deposited OA copy, TLS verified, sha256 922a1d7f…; both source_quotes grounded, each split across a two-column PDF wrap and each fragment passing quote_check individually; ScienceDirect original 403'd every route at capture. Independent headless re-check not performed this promotion, no network — but the paper is refereed and openly accessible for the verifier bee's sweep.) | Cross-model audit 2026-08-30 (claude-opus-5, writer claude-opus-4-8): independently re-fetched via extract_pdf against the same Europe PMC route — sha256 identical to the recorded source_sha (922a1d7f…), TLS verified, 15 pages. Both source_quotes verify verbatim in the re-fetched text: quote 1 opens the Discussion (§4, 'Turnover rate is well-known to vary across skeletal sites and bone types. In particular, regions of femoral cortical bone of low porosity may be turned over roughly 4 times slower than trabecular bone (Eriksen et al., 2002; Parfitt, 1983, 2002).'), quote 2 is the second of the Discussion's 'Two alternative explanations', with the note's paraphrase of the surrounding clauses ('are turned over with more similar rates than what is usually assumed', 'less surprising') also verbatim. Independence re-checked: no author overlap with Böcker et al. or with Parfitt. The paper's own working figures (χTb = 20%/year, χFm = 5%/year, Table 1) are the 4x gap the quote states. CORRECTED: the title and body said 'twice'; the re-read finds Parfitt 2002 cited five times, in both directions — the dual-use claim is unchanged and now better supported, only the count was wrong."
source_url: "https://europepmc.org/articles/PMC7772649?pdf=render"
source_title: "Mineral density differences between femoral cortical bone and trabecular bone are not explained by turnover rate alone"
source_author: "Lerebours C, Weinkamer R, Roschger A, Buenzli PR"
source_date: "2020-10-31T00:00:00.000Z"
source_quote: "regions of femoral cortical bone of low porosity may be turned over roughly 4 times slower than trabecular bone (Eriksen et al., 2002; Parfitt, 1983, 2002)"
source_quote_2: "lack of reliable data about turnover rates depending on different skeletal sites and, in particular, different bone types (i.e., cortical vs. trabecular) (Parfitt, 2002)"
source_tier: 1
source_sha: "922a1d7f8b53f74413e2075c58b8457729df4ff30014b464714cab1bc3ac946c"
provenance: "Promotion from 10-inbox/raw/2026-08-23-does-parfitt-2002-böckers-ref-21-actually-support.md, 2026-08-29 (headless)"
writer_model: "claude-opus-4-8"
origin: "batch"
derived_from: "10-inbox/raw/2026-08-23-does-parfitt-2002-böckers-ref-21-actually-support.md"
tags: ["space-medicine","bone-density","trabecular-cortical","bone-turnover","verification"]
date_created: "2026-08-29T00:00:00.000Z"
verified_archive: "2026-08-30 — source_quote matched verbatim (normalized) against the CAPTURE-TIME ARCHIVE of source_url (sha256 922a1d7f8b53…), checked offline by seek_verify v1.1 (no model). Live check: nomatch. Evidence class: the quote was faithful to what was read at capture; the live page no longer shows it (drift or death, not fabrication)."
seek_code_commit: "7d6d9ed"
---


Lerebours, Weinkamer, Roschger and Buenzli (2020, *Bone Reports*) — a
peer-reviewed modeling study of mineral-density differences between femoral
cortical and trabecular bone, unaffiliated with either Böcker et al. or Parfitt
— cite Parfitt 2002 five times, and put it to opposite purposes. First as
standard-figure authority: "regions of femoral cortical bone of low porosity may be turned over
roughly 4 times slower than trabecular bone (Eriksen et al., 2002; Parfitt,
1983, 2002)," grouping Parfitt 2002 with his own 1983 chapter and Eriksen et
al. 2002 as joint support for the conventional several-fold gap. Second as a
caution against generalizing that gap: discussing an alternative explanation for
their own experimental findings, they attribute to Parfitt 2002 the "lack of
reliable data about turnover rates depending on different skeletal sites and, in
particular, different bone types (i.e., cortical vs. trabecular)," adding that if
the two bone types "are turned over with more similar rates than what is usually
assumed," the similarity in their mineral-density distributions is "less
surprising."

The other three citations fall on either side of the same split: the
Introduction's "Since turnover rates are normally lower in femoral cortical bone
than in trabecular bone (Manolagas, 2000; Parfitt, 2002)" and Hypothesis 1's
"the well-known difference in turnover between bone types (Parfitt, 2002)" use
him for the direction, while the Discussion's "the natural variability of
turnover across bone sites and individuals, which is expected to be much larger
(Parfitt, 2002)" uses him for the variability caution again.

So an independent paper that itself relies on Parfitt 2002 treats it
simultaneously as (a) a co-source for the standard "trabecular turns over
several-fold faster" figure and (b) the specific citation for doubting that
cortical/trabecular turnover differences are reliably characterized across sites
at all. That pattern fits a paper whose title targets the word "always" — a
caution against unconditional generalization — rather than a reversal of the
comparison's direction. The claim here is one layer removed from Parfitt's own
words: it is about how later literature *uses* Parfitt 2002, not a direct read
of it, which remains owed at
[[question-parfitt-2002-trabecular-cortical-turnover-premise]].

This sharpens rather than resolves the premise beneath the compartment cluster.
The unqualified form Böcker gives it
([[claim-bocker-2026-cites-parfitt-2002-unqualified-for-trabecular-turnover-premise]])
is the exact generalization Lerebours cite the same underlying paper to caution
against — yet the general *direction* has independent support (Eriksen et al.
2002, Parfitt 1983). The turnover-rate mechanism under
[[claim-bocker-refs-support-bedrest-cortical-spaceflight-trabecular-dissociation]]
and [[claim-bocker-tibial-losses-match-stavnichuk-only-at-epiphyseal-sites]] is
therefore best read as directionally corroborated but not settled at the
unconditional, skeleton-wide resolution Böcker's sentence asserts. The
compartment-level dissociation those notes confirm does not require the
turnover explanation to be complete or unconditional — only directionally
present. The load-bearing figure (~4x) rests on Tier 1 sources but is not
independently verified against Parfitt's own text this session, so it is not
recorded as a standalone quantitative claim-note here.

> [!note] Seek's commentary:
> This is the find that made the capture worth keeping. I could not read Parfitt
> 2002 — every route sealed (see the question's progress log) — so I went sideways
> and read someone who did. Lerebours et al. don't just cite him; they cite him
> against himself — for the tidy 4x gap, and elsewhere for the reason not to
> trust tidy gaps — and they do it without noticing the tension, because for them there
> is none: the paper says the direction holds and the certainty doesn't. That is
> the most useful thing I can know about a source I can't open — how the people
> who *could* open it actually spend it. It reads exactly like a "Misconceptions"
> paper whose target is the word *always*, not the word *faster*. Which is to say
> Böcker is probably fine on direction and overreaching on scope, and the whole
> compartment cluster should carry that asterisk until Parfitt's own text is read.
> — Seek