PFLPhysiological Fitness Landscape

Evidence: what we have shown so far

How we grade claims

  • Shown Found again in independent data.
  • Preliminary Computed once, not yet checked elsewhere.
  • Open The question being tested now.

What the map shows, and what it does not

Each element of the map, with the claim it carries and the claim it does not.
ElementIt showsIt does not show
A colourRisk of death from any cause at that point, relative to the median US adult, from a model fitted on NHANES.A diagnosis, or any one person's chance of dying.
A curve's shapeWhere risk rises or falls as a marker changes, across the population.Why it does. Cause, reverse causation and confounding are not separated.
An arrowThe average change one study measured in a marker, drawn from where the marker sits.What that intervention would do for a person, or that moving the marker moves the risk.
A stable pointA region people drift towards and stay near when measured years apart.A target to aim for.
A gradeWhether a claim was found again in independent data (Shown), computed once (Preliminary), or is being tested (Open).How large or how useful an effect is.

Test register

Of the 40 published biomarker–mortality patterns we could check in NHANES:

  1. Shown
    Published patterns show up again in a national sample.

    34 of 40 directions match in NHANES (51,662 adults, validation sample); 2 run the other way, 4 show no clear pattern.1 Not registered in advance (validation). By biomarker

  2. Shown
    The same risk per standard deviation holds in other countries.

    hs-CRP, creatinine and HbA1c agree within 0.02 between the US and Costa Rica; see the heatmap below. Not registered in advance (validation).

  3. Preliminary
    How fast do people's measurements change after 50?

    Gait speed and grip strength fall measurably within the same people in HRS 2006–2022.2 Exploratory. Ageing

  4. Preliminary
    Which single measurement adds most to age and sex?

    Grip strength and urine albumin lead.3 Exploratory. Ranking

  5. Running
    Does within-person variability across body systems predict death?

    Registered in advance at osf.io/kzfs4. The HRS analysis is running; the result will be posted here, null or not.

  6. Open
    Do shared curves plus a few personal numbers predict individual paths better than baseline risk?

    To be registered before data arrive. Awaiting repeated blood data: this is the question the project exists to answer.

The register as a table
Each row is one analysis. Registered means the plan was published before we looked at the outcome.
TestRegistered in advanceStatusResult
Do published patterns between a biomarker and risk of death show up again in a national sample?No (validation)Shown34 of 40 directions match in NHANES (51,662 adults, validation sample); 2 run the other way, 4 show no clear pattern.1 By biomarker
Does the same risk per standard deviation hold in other countries?No (validation)Shownhs-CRP, creatinine and HbA1c agree within 0.02 between the US and Costa Rica; see the table below.
How fast do people's measurements change after 50? (HRS 2006–2022)No (exploratory)PreliminaryGait speed and grip strength fall measurably within the same people.2 Ageing
Which single measurement adds most to age and sex?No (exploratory)PreliminaryGrip strength and urine albumin lead.3 Ranking
Does within-person variability across body systems predict death? (HRS)Yes, osf.io/kzfs4Analysis runningTo be posted here, null or not
Do shared curves plus a few personal numbers predict individual paths better than baseline risk?To be registered before data arriveOpen: awaiting repeated blood data–
  1. LDL and non-HDL cholesterol run opposite. Low LDL in older adults often reflects existing illness, so the raw pattern looks reversed. ↩
  2. Rates per decade are left out until we state which standard deviation they use. ↩
  3. Held out: 30% of NHANES 1999–2018 participants, not used in fitting. Measure: gain in how well the model ranks who died first, among people in the same 10-year age band (Harrell's concordance). ↩

The same risks in three countries' data

Darker means a larger effect per standard deviation in whichever direction is harmful (0.58 for grip strength is as strong as 1.72 would be). Cells that agree across columns mean the pattern holds outside the US. Hover or focus a cell for the 95% interval. Adjusted for age and sex; associations, not predictions of what changing a marker would do.

The same numbers as a table
Hazard ratio per standard deviation and 95% interval, by cohort.
BiomarkerNHANES · US, 20–84CRELES · Costa Rica, 60+HRS · US, 50+
Maximal Grip Strength0.47 0.42–0.53–0.58 0.55–0.61
High-Sensitivity C-Reactive Protein1.30 1.26–1.331.30 1.19–1.43–
Serum Creatinine1.25 1.22–1.281.27 1.16–1.39–
Total Cholesterol0.91 0.89–0.940.79 0.69–0.90–
Resting Heart Rate1.21 1.19–1.24–1.20 1.17–1.23
Glycated Hemoglobin1.18 1.16–1.211.20 1.10–1.31–
Fasting Plasma Glucose1.18 1.15–1.211.12 1.02–1.22–
Waist-to-Height Ratio1.09 1.06–1.12–1.18 1.14–1.22
Waist Circumference1.09 1.06–1.121.14 1.00–1.311.17 1.13–1.22
Serum Triglycerides1.06 1.02–1.100.86 0.75–0.99–
Systolic Blood Pressure1.08 1.05–1.100.89 0.78–1.001.06 1.04–1.09
Pulse Pressure1.11 1.08–1.13–1.09 1.07–1.12
Body Mass Index1.03 1.00–1.061.10 0.95–1.281.04 1.01–1.08
Standing Height1.01 0.97–1.04–0.91 0.88–0.95
Diastolic Blood Pressure0.96 0.94–0.980.95 0.85–1.071.00 0.98–1.03
Mean Arterial Pressure1.01 0.99–1.03–1.03 1.01–1.06
Body Weight1.03 1.00–1.06–1.00 0.97–1.04
  1. Systolic blood pressure: in older adults, low blood pressure often reflects existing illness, which is why the Costa Rica figure runs the other way.

The models behind the map: Models. Questions we want help with: Open problems.

Data sources

  • NHANES 1999–2018 with linked mortality to 2019
  • RAND HRS 1992–2022
  • Wisconsin Longitudinal Study 1993–2011
  • ELSA HCAP 2018 and 2023
  • CRELES waves 1–3
  • MIDUS 3

How we handle study data