Who is this article aimed at?

Medical doctors and keen healthcare end-users (patients or healthy people).

What's the use of measuring PhenoAge?

This test combines the results of 9 blood tests and runs them through the Horvath-Levine Blood Component PhenoAge Equation (PubMed link to the paper here) and helps you see if you are older or younger than your chronological age.

This is one of the most easily measurable, cheap, and actionable biological age measures available.

From the results, you can see which ones of the 9 blood tests are the furthest away from the 'optimal range for health' (the optimal range is based on interpreting the statistics of the up to date body of interventional and epidemiological evidence for relevant demographics).

You can then focus on interventions, through guidance from your medical doctors, that will move each of the markers that aren't in the optimal range, to the optimal range. For example, you may be optimal for everything but your creatinine is very high suggesting kidney damage, so working out a way to reverse your kidney damage would help reduce your overall biological age, as your kidneys may be your most biologically aged organs relative to your other organs.

Is this test more useful than measuring blood pressure, cholesterol, BMI, etc.?

Therapies to provide reductions in PhenoAge have not been tested in randomised controlled trials yet, so using PhenoAge should not be relied on to prove true biological age increase or reduction or to guide health behaviours.

However, it makes a nice tool for simultaneously analysing these 9 common blood markers that are reasonably validated for their relationship to health.

I hypothesise that PhenoAge could have some role in

1) promoting positive health behaviour change for Longevity Level 1, 2, 3 interventions - e.g. you see your age is older than your target biological age, so it adds further motivation to quit smoking, reduce alcohol, exercise more, eat better or tries more experimental things, etc. (and this integrates 9 reasonably validated tests into a single marker, making it easier for people to understand and keep track of, rather than knowing separate biological ages for each organ, etc.), - and

2) as a role as a cheap 'litmus test' of overall health (and all-cause mortality risk, which is typically what whole body 'biological age' actually means) that would correlate strongly with other more expensive or time consuming to measure markers - perhaps prompting their measurement in a clinically useful manner, e.g. ultrasound or cystatin C for high creatinine, c-peptide and HbA1c for high blood sugar. And

3) as an introduction to helping patients understand optimal and normal ranges, and how to prioritise which tests to optimise in what order, using what intervention strategy: optimising hundreds of markers for longevity can be complex, and this could be a reasonably cost-effective way to start that might not overwhelm patients.

What's a good score?

An optimal score would be being biologically age 10 or so AND being in the optimal range for all markers. However, for people with older chronological ages, this would not be possible due to the nature of the calculator's equation. As a rule of thumb, being 50% below your chronological age (e.g. PhenoAge age 13 at chronological age 26, PhenoAge age 35 at chronological age 70) would be a good score to aim for.

How does it work?

1) Prepare your blood test results.

2) Make sure your test results are in the same units required in the table below, if not then please convert them using an online calculator

3) Put your blood test values in the table

4) Next to your values appears a symbol indicating the status of your result. You can check the meaning of each symbol in the legend below the table.

5) Your biological age and risk of dying in the next 10 years will be shown in the section below. Please note the result is only accurate once you fill all the cells. otherwise, the result will be inaccurate.

What should I do with results?

For all markers: Discuss all results with your licensed medical doctor, however, they are unlikely aware of the maths and studies behind the PhenoAge equation. Notifying them that it is a high accuracy evidence-based way of predicting 10 year all-cause mortality developed by Professors Steve Horvath & Morgan Levine will help them understand the context. Request a telephone call rather than a face to face appointment to reduce the amount of time you need to commit if you prefer.

For all markers: Smoking, Alcohol, Diet, Exercise, and BMI (Longevity Level 1) changes may create significant changes, whilst Longevity Level 2 interventions may provide benefits for a few people. Longevity Level 3 interventions - Rejuvenation therapies - will be needed in most people age 80+ to optimise markers, as Longevity Level 1 and 2 only have limited effect.

Basic interpretation of results (this is for informational purposes only)

Albumin

- too high: may be due to excess protein intake (reduce protein intake)

- too low: may be due to liver aging (unclear how to reverse) or liver disease (requires a medical consultation to diagnose)

ALP

- Too high: may be due to liver, bone or biliary disease

Creatinine

- Too high: may be due to acute dehydration on the day, or kidney aging or kidney disease

Overnight fasting glucose

- Too high: may be due to diabetes (pancreas disease or insulin resistance disease)

- Too low: may be due to starvation or diabetes

CRP

- Too high: too much inflammation, which may be caused by autoimmunity, pathogen mediated immunity, senescent cell secretory proteins (part of inflammaging), other inflammatory conditions

Lymphocyte %

- Too low: may be due to aging of the immune system

- Exceptionally high: may signify a lymphoma

WBC (total)

- Too high: Like CRP, a marker of chronic inflammation

- Too low: may be due to aging of the bone marrow and lack of haematopoietic stem cells

MCV

- Too low: marker of whole body ferritin levels

- Too high: marker of whole body B9 and B12 stores

RDW

- Too high: like WBC and CRP, likely primarily a marker of inflammation

Accuracy of the spreadsheet equations in this calculator?

Horvath & Levine were messaged to determine the accuracy of the excel sheet equations, no response yet received.