Family Health Risk Calculator

Estimate relative health-risk signals from family history, lifestyle, and preventive screening factors.

Relative risk signal

Moderate relative signal

Score 6.5

First-degree history

1

Parent, sibling, or child

Second-degree history

2

Grandparent, aunt, uncle, or similar

Screening offset

3.5

Preventive care signal

Family health inputs

Estimate relative risk signals from family history, lifestyle, and screening habits.

What is the genetic and family health risk calculator?

This calculator translates family medical history into disease-specific relative risk. It follows the Korean source page by using the Korean Disease Control and Prevention Agency health data, Korean meta-analysis figures, and the family-history screening approach recommended by the Korean Society of Family Medicine and the World Health Organization.

The assessment covers 10 major conditions: hypertension, type 2 diabetes, cardiovascular disease, stroke, colorectal cancer, breast cancer, gastric cancer, lung cancer, thyroid disease, and Alzheimer dementia. It considers affected family count, age at onset, first-degree or second-degree relationship, and lifestyle factors such as smoking, drinking, exercise, and BMI.

Relative-risk model

Adjusted relative risk = base relative risk x affected-family-count correction x onset-age weight x lifestyle correction x age and sex correction. First-degree relatives share about 50% of DNA, second-degree relatives share about 25%, and onset before 50 uses 1.5x weight.

Disease-specific risk interpretation

Metabolic and vascular diseases

  • Hypertension prevalence is 28.3% in the Korean adult reference data. A first-degree family history is modeled around relative risk 2.0, so annual blood-pressure checks from the 30s are important.
  • Type 2 diabetes prevalence is 16.7%, with genetic contribution estimated around 40% to 60%. If both parents have diabetes, child onset risk can exceed 4x; fasting glucose and HbA1c are the key screening markers.
  • Coronary artery disease and myocardial infarction use roughly 2.0x family-history risk, and parental onset before age 50 points to possible early-onset disease.
  • Stroke has an estimated 30% to 40% genetic contribution. Carotid ultrasound and brain MRI or MRA can help detect early vascular risk when family history clusters.

Cancer, thyroid, and dementia history

  • Colorectal cancer first-degree family history uses relative risk 2.2. Colonoscopy should start 10 years earlier than the affected relative’s onset age; stage 1 survival is over 90%.
  • Breast cancer in a mother or sister raises risk about 2.1x, and BRCA genetic testing can be considered when family history is strong or early.
  • Gastric cancer remains very common in Korea. With family history, gastroscopy every 2 years from the 30s is recommended in the source guidance.
  • Lung cancer risk rises sharply when family history and smoking overlap, so smokers with family history should consider low-dose CT screening.
  • Thyroid disease has 40% to 65% genetic contribution; TSH testing and thyroid ultrasound from age 25 are recommended when family history exists.
  • Alzheimer dementia has 60% to 80% genetic contribution. A first-degree family history raises risk about 2.5x, so cognitive testing and brain MRI from age 55 can be discussed.

Risk grades and prevention scenarios

How to read the result

  • Low risk is relative risk under 1.0, average is 1.0 to 1.5, caution is 1.5 to 2.5, high is 2.5 to 4.0, and very high is 4.0 or higher.
  • Affected-family-count correction increases when 2 relatives are affected, and rises further for 3 or more relatives.
  • If population diabetes prevalence is 16.7%, relative risk 2.0 implies about 33.4% estimated risk before other adjustments.
  • Smoking cessation is one of the strongest modifiable levers; the source scenario shows quitting smoking can reduce risk by 23%.

This is a family-history screening tool, not a diagnosis. Use high-risk results to plan evidence-based checkups with a clinician, especially when several first-degree relatives were diagnosed young.