Biological Age Calculator Methodology

Outliyr · Methodology · v1

How we measure biological age.

Outliyr Biological Age composes eight published scientific frameworks into one outcome metric. Every sub-age is transparent — inputs, weights, reference curves, and citations are listed in the open.

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Cardiovascular

Formula version: 1.0.0

Inputs

  • vo2max — tier l3, weight 0.28
  • resting_hr_avg — tier l3, weight 0.14
  • hrv_avg — tier l3, weight 0.10
  • stair_climb_q — tier l1, weight 0.12
  • exercise_minutes_week — tier l1, weight 0.10
  • smoker — tier l1, weight 0.10
  • apob — tier l2, weight 0.08
  • lpa — tier l2, weight 0.04
  • bp_self_report — tier l1, weight 0.04

Citations

  • Mandsager K et al. JAMA Netw Open 2018 — cardiorespiratory fitness and mortality
  • Ridker PM. Circulation 2008 — apoB and cardiovascular risk
  • ACC/AHA 2013 — pooled cohort risk equations

Metabolic

Formula version: 1.0.0

Inputs

  • fasting_glucose — tier l2, weight 0.22
  • hba1c — tier l2, weight 0.22
  • homa_ir — tier l2, weight 0.16
  • fasting_insulin — tier l2, weight 0.10
  • waist_cm — tier l1, weight 0.14
  • fasting_tolerance_q — tier l1, weight 0.08
  • post_meal_crash_q — tier l1, weight 0.08

Citations

  • Matthews DR et al. Diabetologia 1985 — HOMA-IR
  • IDF 2006 — Metabolic Syndrome consensus

Inflammatory

Formula version: 1.0.0

Inputs

  • hs_crp — tier l2, weight 0.32
  • homocysteine — tier l2, weight 0.18
  • fibrinogen — tier l2, weight 0.12
  • ferritin — tier l2, weight 0.10
  • joint_pain_q — tier l1, weight 0.10
  • fatigue_q — tier l1, weight 0.08
  • allergy_load_q — tier l1, weight 0.05
  • alcohol_recovery_q — tier l1, weight 0.05

Citations

  • Ridker PM. Circulation 2008 — hs-CRP and cardiovascular risk
  • Refsum H et al. Clin Chem 2004 — homocysteine reference ranges

Immune

Formula version: 1.0.0

Inputs

  • illness_frequency_q — tier l1, weight 0.22
  • recovery_time_q — tier l1, weight 0.18
  • viral_reactivation_q — tier l1, weight 0.15
  • autoimmune_q — tier l1, weight 0.12
  • antibiotic_use_q — tier l1, weight 0.08
  • vitamin_d — tier l2, weight 0.15
  • neutrophil_lymphocyte_ratio — tier l2, weight 0.10

Citations

  • Sayed N et al. Nat Aging 2021 — iAge inflammatory clock
  • Shen-Orr SS et al. Cell Syst 2016 — IMM-AGE immune trajectory

Musculoskeletal

Formula version: 1.0.0

Inputs

  • chair_stand_30s — tier l1, weight 0.28
  • pushups_one_set — tier l1, weight 0.18
  • stair_pace_q — tier l1, weight 0.12
  • groceries_in_one_trip_q — tier l1, weight 0.08
  • grip_strength_kg — tier l1, weight 0.12
  • recent_injury_q — tier l1, weight 0.07
  • activity_load_avg — tier l3, weight 0.15

Citations

  • Leong DP et al. Lancet 2015 — grip strength + mortality
  • Bohannon RW. Percept Mot Skills 2006 — 30-sec chair stand reliability

Neuro-cognitive

Formula version: 1.0.0

Inputs

  • cognition_q — tier l1, weight 0.22
  • brain_fog_q — tier l1, weight 0.18
  • sleep_consistency_q — tier l1, weight 0.12
  • word_recall_q — tier l1, weight 0.10
  • homocysteine — tier l2, weight 0.12
  • vitamin_d — tier l2, weight 0.08
  • sleep_rem_avg — tier l3, weight 0.10
  • sleep_deep_avg — tier l3, weight 0.08

Citations

  • Buysse DJ et al. Psychiatry Res 1989 — PSQI
  • Seshadri S et al. NEJM 2002 — homocysteine + cognitive decline
  • Smith AD et al. Proc Natl Acad Sci USA 2010 — B-vitamins + brain atrophy

Hormonal / Stress

Formula version: 1.0.0

Inputs

  • pss10_total — tier l1, weight 0.22
  • hpa_cluster_q — tier l1, weight 0.14
  • energy_curve_q — tier l1, weight 0.08
  • testosterone_total — tier l2, weight 0.12
  • testosterone_free — tier l2, weight 0.08
  • shbg — tier l2, weight 0.06
  • dhea_s — tier l2, weight 0.06
  • cortisol_am — tier l2, weight 0.06
  • tsh — tier l2, weight 0.06
  • hrv_stress_avg — tier l3, weight 0.12

Citations

  • Cohen S et al. J Health Soc Behav 1983 — PSS-10
  • Bhasin S et al. J Clin Endocrinol Metab 2010 — testosterone reference

Sleep / Circadian

Formula version: 1.0.0

Inputs

  • meq_total — tier l1, weight 0.18
  • psqi_global — tier l1, weight 0.22
  • sleep_duration_hours_q — tier l1, weight 0.12
  • sleep_consistency_q — tier l1, weight 0.10
  • nocturnal_waking_q — tier l1, weight 0.08
  • sleep_total_avg — tier l3, weight 0.12
  • sleep_efficiency_avg — tier l3, weight 0.10
  • sleep_timing_std_hours — tier l3, weight 0.08

Citations

  • Horne JA, Östberg O. Int J Chronobiology 1976 — MEQ
  • Buysse DJ et al. Psychiatry Res 1989 — PSQI