About

Actuarial science relies on vast datasets to predict mortality risks. While genetics play a significant role, lifestyle choices effectively modify gene expression and overall longevity. This tool combines baseline WHO data with hazard ratios from epidemiological studies to estimate two critical metrics: Total Lifespan and Healthspan (years spent free from serious chronic disease).

Understanding the difference is vital; modern medicine extends life, but not always health. The calculator applies multipliers derived from meta-analyses on smoking, BMI, and physical activity to adjust the statistical baseline.

Formulas

The calculation uses a baseline survival function S(t) adjusted by a composite Hazard Ratio (HR):

LE_adj ≈ LE_base × 1ln(HR) + 1

Where HR is the product of individual risk factors:

HR = ∏ r_i

Reference Data

Factor	Impact on Mortality Risk	Est. Years Gained/Lost
Smoking	2.8x risk	−10 years
Obesity (BMI > 30)	1.5x risk	−3 to 5 years
Regular Exercise	0.7x risk	+3 to 4 years
Healthy Diet	0.8x risk	+2 years
Chronic Stress	1.4x risk	−2.5 years
Alcohol (Heavy)	1.6x risk	−4 years
Sleep (< 6h)	1.12x risk	−1 year
Social Integration	0.65x risk	+3.5 years

Frequently Asked Questions

Lifespan is the total years you are alive. Healthspan is the number of years spent in good health, free from chronic disability or significant pain. The gap between them is the "morbidity phase".

These are statistical estimates based on population averages. They cannot predict accidents or specific genetic conditions but serve as a guide for risk management.

Yes. Data shows that quitting before age 40 reduces the risk of dying from smoking-related disease by about 90%.

It accounts for healthcare access, environmental pollution, accident rates, and historical mortality trends specific to that region.