The Nine Biomarkers That Reveal Your Biological Age
Chronological age tells you how many birthdays a person has had. Biological age tells you something far more useful: how well the body is actually functioning. Two people born in the same year can show very different disease risk and mortality outcomes, which points to real variation in how quickly each person is ageing at a physiological level. Research now shows that biological age and the rate of ageing predict morbidity and mortality more accurately than chronological age alone.
A well-studied nine-biomarker panel, drawn from routine blood work, has been used to calculate biological age with striking accuracy. Using data from thousands of participants in the National Health and Nutrition Examination Survey, this panel predicted 10-year survival with 90 per cent accuracy. It has since been validated against lifespan remaining, chronic disease accumulation, cognitive and physical decline, and mortality risk across multiple conditions including obesity, metabolic syndrome, Parkinson's disease, Alzheimer's disease, breast cancer, and HIV.
Follow-up research confirmed that for every one-year increase in biological age, the risk of all-cause mortality rises by 9 per cent, cardiovascular mortality by 10 per cent, cancer mortality by 7 per cent, and diabetes mortality by 20 per cent. In people with multivessel coronary artery disease, each 10-year increase in biological age was linked to a 51 per cent increase in mortality risk.
Each marker reflects a different physiological system. Together they build a biological age picture that predicted 10-year survival with 90 per cent accuracy across thousands of participants.
Fasting Glucose
Metabolic regulation
C-Reactive Protein (CRP)
Systemic inflammation
Albumin
Liver function, nutrition, inflammation
Alkaline Phosphatase (ALP)
Liver, bone, vascular health
Creatinine
Kidney function
Red Cell Distribution Width (RDW)
Red blood cell production and inflammation
Lymphocyte Percentage
Adaptive immune function
White Blood Cell Count (WBC)
Immune competence and inflammation
Mean Corpuscular Volume (MCV)
Red blood cell size and turnover
Fasting glucose: metabolic health at the cellular level
Chronic exposure to high glucose levels sets off a cascade of physiological changes across nearly every tissue and organ system. Hyperglycaemia drives oxidative stress, promotes the formation of advanced glycation end products, damages pancreatic beta cells, and drives insulin resistance, setting the stage for diabetes and its associated complications including cardiovascular disease, nephropathy, retinopathy, and neuropathy. Elevated glucose also encourages cancer cell proliferation and creates a favourable environment for infection.
In the Atherosclerosis Risk in Communities study, researchers tracked close to 13,000 participants over 20 years. Low levels of 1,5-anhydroglucitol, a marker of glycaemic peaks, were associated with a significantly increased risk of dementia, with each incremental rise linked to a 16 per cent higher risk. This suggests glucose variability (the peaks and troughs) may drive cognitive decline more than sustained high averages alone.
C-reactive protein: the inflammation signal
CRP is one of the most widely studied inflammation markers and an independent risk factor for ischaemic cardiovascular disease. It contributes directly to atherosclerosis by activating vascular cells, promoting monocyte and lipid accumulation, encouraging coronary artery thrombosis, and suppressing nitric oxide release, which impairs healthy endothelial function.
Chronic inflammation driven by elevated CRP can disrupt immune function and contribute to hyperglycaemia, hypertension, depression, sarcopenia, osteoporosis, and cancer. Elevated CRP has been closely linked to cognitive impairment and mortality. CRP has also been detected within beta-amyloid plaques and neurofibrillary tangles in people with dementia.
A study of more than 41,000 adults found that high CRP combined with prediabetes or diabetes produced a substantially greater acceleration in biological age than either factor alone, with biological age increasing by close to nine years in that group compared to under two years in those with high CRP but no diabetes.
Albumin: liver function, inflammation and nutritional status
Albumin is a protein produced in the liver that accounts for roughly 75 per cent of serum antioxidant capacity. Persistent inflammation can cause albumin to degrade and leak into surrounding tissue, leading to low albumin even when the liver is still producing it at a normal rate.
Low albumin reflects physiological stress and predicts mortality, particularly as a sign of inflammaging, the subclinical inflammatory process associated with advancing age. In a study of adults 65 and older, those with the lowest albumin levels were up to six times more likely to be cognitively impaired than those with the highest. Albumin also binds the majority of circulating beta-amyloid, and reduced levels have been associated with greater cerebral beta-amyloid deposition, a hallmark of Alzheimer's disease.
Alkaline phosphatase: a liver marker with whole-body implications
Although alkaline phosphatase is often read as a liver marker, its influence extends well beyond hepatic function. Elevated ALP is associated with all-cause mortality and a cluster of conditions that shorten lifespan including vascular calcification, endothelial dysfunction, cardiovascular disease, and metabolic syndrome. A large NHANES analysis of more than 34,000 adults found that those with an ALP above 82 U/L had more than double the mortality rate of those at 55 U/L or below.
ALP also plays a role in GABA metabolism and influences neuroplasticity and cortical activity. In the Oxford OPTIMA study, ALP was significantly higher in Alzheimer's patients than in controls, with an inverse relationship between ALP and cognitive performance even in healthy individuals.
Creatinine: a direct line to kidney function
The kidneys remove metabolic waste, regulate blood pressure, balance electrolytes and secrete key hormones including erythropoietin and active vitamin D. With age, filtering capacity declines and creatinine rises. An eGFR below 60 mL/min/1.73m2 is associated with chronic kidney disease, and a doubling of serum creatinine likely represents a 50 per cent reduction in filtration capacity.
Declining kidney function is independently associated with declining cognitive function. Biological age increases by three to nine years across the progressive stages of chronic kidney disease, and CKD is closely tied to cardiovascular disease, with GFR inversely related to cardiovascular mortality worldwide.
Red cell distribution width: a marker with reach beyond anaemia
RDW reflects the degree of variation in red blood cell size and is traditionally used to differentiate types of anaemia. However, it is strongly correlated with cardiovascular and all-cause mortality, as well as hypertension, atherosclerosis, heart failure, atrial fibrillation, ischaemic stroke, diabetes, cancer, and sepsis.
Elevated RDW is associated with cognitive impairment including verbal memory deficits and dementia prevalence, even in the absence of anaemia. In a study of over 27,000 participants, those with the highest RDW were significantly more likely to die of cancer and cardiovascular disease. A broad review of the literature links elevated RDW to inflammation, metabolic syndrome, dyslipidaemia, and nutrient insufficiency, marking it as an independent risk factor for mortality in the general population.
Lymphocyte percentage: the immune system's adaptive arm
Lymphocytes drive adaptive immunity through B cells and T cells. Ageing is associated with an overall reduction in both cell types, which impairs the ability to clear infection and reduces antibody response to vaccination. An ageing immune system is also linked to impaired wound healing, cancer susceptibility, and reactivation of dormant viral infections.
Lymphocytes appear to help protect cognitive function, and decreased levels are associated with vascular cognitive impairment. Chronic stress can hasten lymphocyte decline by activating the HPA axis, linking elevated cortisol, reduced lymphocytes, and frailty. Lymphocyte proliferation itself has been proposed as a marker of biological age and remaining lifespan.
Mean corpuscular volume: red blood cell size as an ageing clue
MCV measures the average size of red blood cells. MCV tends to rise with age, thought to reflect a shorter red blood cell lifespan and a compensatory release of younger, larger red cells into circulation. Larger red cells may struggle to move efficiently through capillaries, potentially impairing oxygen and nutrient delivery at the tissue level.
Data from the Baltimore Longitudinal Study of Aging found higher MCV significantly correlated with worse performance across several cognitive domains including attention and verbal memory, with cognitive decline accelerating notably once MCV reached 97 fL or above, independent of anaemia or inflammation status. Elevated MCV has also been tied to arterial stiffening in young, otherwise healthy people.
White blood cell count: a window into immune ageing
White blood cells are central to fighting infection, driving inflammatory responses, and coordinating the body's reaction to injury. As the body ages, immune regulation tends to shift toward a low-grade, chronic inflammatory state often called inflammaging.
Even within a normal reference range, higher white blood cell counts have been linked to lower scores on standardised cognitive testing in older adults. The 44-year Baltimore Longitudinal Study of Aging found the lowest mortality risk between 3.5 and 6 k/cumm, with a two-fold increase in mortality above 10 k/cumm and a three-fold increase below 3.5 k/cumm. Both very high and very low counts carry risk.
Why these nine markers matter together
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| Biomarker | System reflected | Key biological age and mortality link |
|---|---|---|
| Fasting Glucose | Metabolic regulation | Glucose variability linked to 16% higher dementia risk per incremental rise; drives cardiovascular, renal, and cognitive complications over time |
| C-Reactive Protein | Systemic inflammation | Combined with prediabetes, high CRP accelerates biological age by close to nine years and raises cardiovascular mortality risk more than threefold |
| Albumin | Liver, nutrition, inflammation | Albumin below 3.6 g/dL associated with higher mortality in elderly; low levels linked to up to six times higher cognitive impairment risk |
| Alkaline Phosphatase | Liver, bone, vascular | ALP above 82 U/L associated with double the mortality rate; higher ALP linked to Alzheimer's disease and post-stroke cognitive impairment |
| Creatinine | Kidney function | Biological age increases by 3 to 9 years across CKD stages; eGFR decline below 45 strongly associated with cognitive impairment |
| Red Cell Distribution Width | Red blood cell production | Elevated RDW associated with dementia, cognitive impairment, and all-cause mortality; considered one of the most significant biomarkers of ageing |
| Lymphocyte Percentage | Adaptive immune function | Absolute count below 1.54 k/cumm associated with increased all-cause mortality; lymphocyte proliferation proposed as a marker of biological age and remaining lifespan |
| White Blood Cell Count | Immune competence | Lowest mortality between 3.5 and 6 k/cumm; two-fold increase above 10 k/cumm and three-fold increase below 3.5 k/cumm — both extremes carry risk |
| Mean Corpuscular Volume | Red blood cell size and turnover | MCV above 97 fL associated with accelerated cognitive decline; elevated MCV linked to Alzheimer's, Parkinson's, and arterial stiffening in young adults |
Taking a root cause approach to biological age
Understanding these nine biomarkers is only useful if it leads to action. A functional medicine assessment looks beyond whether a value sits inside a standard reference range and instead asks what is driving that value, whether that is insulin resistance, chronic low-grade inflammation, liver congestion, nutrient insufficiency, kidney strain, or gut dysfunction.
At Wave Functional Health, we assess biological age markers as part of a broader picture of physiological function, connecting metabolic, immune, hepatic, renal, and haematological health rather than treating each result in isolation. This root-cause approach aims to identify what is accelerating the ageing process for each individual, so meaningful changes can be made before biological age drifts too far ahead of chronological age.
Frequently asked questions
Fasting glucose, C-reactive protein, albumin, alkaline phosphatase, creatinine, red cell distribution width, lymphocyte percentage, white blood cell count, and mean corpuscular volume. Each reflects a different physiological system and together they build a far more complete picture of biological age than any single marker alone.
Research using this nine-biomarker panel has predicted 10-year survival with 90 per cent accuracy and has been validated against morbidity and mortality across multiple large population studies including the National Health and Nutrition Examination Survey. For every one-year increase in biological age, all-cause mortality risk rises by 9 per cent.
CRP is the primary inflammatory marker in the panel, though RDW, albumin, and white blood cell count also reflect inflammatory processes. The interplay between these markers means inflammation often shows up across several values simultaneously rather than in CRP alone.
A persistently low lymphocyte percentage can reflect immune compromise, malnutrition, or frailty, and several studies have linked it to increased mortality risk. It is worth investigating rather than dismissing, particularly when it is accompanied by other markers that suggest physiological ageing or immune dysregulation.
Biological age is influenced by modifiable factors including diet, inflammation, blood sugar regulation, kidney and liver function, toxin exposure, and physical activity, so it can shift in either direction depending on lifestyle and underlying physiological function. Identifying the specific drivers that are accelerating biological age in a given individual is the starting point for meaningful intervention.
Your chronological age is fixed.
Your biological age is not.
At Wave Functional Health we assess biological age markers as part of a broader picture of physiological function, identifying what is accelerating the ageing process for each individual so meaningful changes can be made before biological age drifts too far ahead of chronological age.
Book a ConsultationDr Matt le Roux is a chiropractor and functional medicine practitioner at Wave Functional Health, Suite 326, 34-36 Glenferrie Drive, Robina QLD 4226. Consultations available in clinic in Robina Gold Coast and worldwide via telehealth.