family history
Meaning of family history: A map of who in a family had what and when, and one of the cheapest risk assessments available in any consultation.
Definition of family history
A family history is a record of the illnesses that have occurred among a person's blood relatives, set out alongside how each relative is related, their age at diagnosis, and their age and cause of death. It captures shared genes and shared surroundings together. Patterns within it can point to an inherited condition, raise or lower estimated risk, and change which screening tests are offered.
What makes a family history informative?
Not the list of diagnoses on its own. Three details do most of the work: how closely the relative is related, how old that relative was when the illness began, and how many relatives on the same side are affected. A parent or sibling counts for far more than a cousin, because they share more genes. Disease appearing unusually early carries more weight than the same disease appearing late, since common conditions become common with age anyway. Several cases clustered on one side of a family is a stronger signal than the same number scattered across both.
Does it measure genes or environment?
Both, and it cannot separate them. Relatives share far more than DNA: diet, cooking, smoking, alcohol, exercise, income, air quality and access to care all run in families as reliably as genes do. A run of heart disease through several generations may reflect an inherited cholesterol disorder, a shared way of eating, or the two reinforcing each other. That mixture is a strength rather than a weakness, because the risk estimate it produces already includes influences no genetic test can see. The same record is often labeled a family medical history, and it has nothing to do with a natural history study, which follows the course of a disease rather than a family.
What patterns raise concern?
| Pattern | What it may suggest |
|---|---|
| The same cancer in several close relatives | An inherited cancer risk gene running in the family |
| Disease at an unusually young age | A stronger inherited component |
| Two separate primary cancers in one person | An underlying inherited syndrome |
| Male breast cancer or a rare tumor type | A recognized syndrome regardless of family size |
| Sudden death in a young relative | An inherited heart rhythm or heart muscle disorder |
A small family, adoption, early death from unrelated causes or simple loss of contact can hide a pattern that genuinely exists. An unremarkable history is therefore weaker evidence of low risk than a striking history is of high risk, and the record is worth revisiting as relatives age and diagnoses accumulate.
Also known as
Used in a sentence
The family history was notable for early onset heart disease on the paternal side.
Good to know
A family history reflects shared habits and surroundings as well as shared genes, and a small family or lost contact with relatives can conceal a real pattern, so an unremarkable history offers weaker reassurance than a striking one offers warning.