Family history is the most cost-effective and well known "genetic test" we have in clinical practice today. Understanding your family history helps identify risk, both environmental and genetic. It can help direct care towards targeted risk reduction and genetic testing when indicated.
There is a free online family history tool from the U.S. Surgeon General called My Family Health Portrait, which allows you to collect and store family history data.
In addition, Duke led development of MeTree, which calculates your risk from the information you enter and tells you what options are available to lower your risk.
View a news interview about Family History and MeTree.
Why is my family health history so important? Because some conditions run in families asking relatives about your family health history can help you find out if you and your children are at increased risk for any medical conditions. Depending upon the disease and your risk level (see below) you may meet criteria for more or different kinds of prevention and/or screening. How much your risk is increased depends upon the type of risk you have.
There are two kinds of RISK:
Familial risk. This means you have a slightly higher chance (about 2-3 times higher) of getting the disease than most people outside your family. An example of a family history for familial risk is a mother with breast cancer after age 50.
- What does it mean to be 2 to 3 times more likely to get cancer? Here are examples:
- Breast cancer occurs in 1 out of 9 women; this means the average person has an 11% chance of getting breast cancer in their lifetime (called population risk). If you have a familial risk for breast cancer then you would have a 22-33% chance of having breast cancer in your lifetime.
- The below image shows the difference between a population risk of 11% and what the familial risk would be at 22-33%
Hereditary risk. This means you have a much higher chance (50-100%) of getting the disease than most people outside your family. These risks are inherited from a parent through DNA segments (genes) and are not common (only about 1 in 500 people have them). An example of a family history that might indicate risk for hereditary risk is a parent with breast cancer at age 40.
- In the example of breast cancer, if you have hereditary breast and ovarian cancer syndrome you have an 80% chance of getting breast cancer in your lifetime.
- The same image shown for familial risk is shown below with the addition of hereditary risk
What exactly is a family health history and what do I ask about?
A family health history is a record of your blood family members (parents, grandparents, aunts/uncles, brothers/sisters, children, and cousins). Your partner and his/her relatives are not your blood relatives and therefore, their family health history is not helpful in determining your risk. You should record relationship to you (mother, grandmother on mom's side, etc.), any disease they had, the age they developed the disease, and if they have died -what age they died and what the cause of death was. A worksheet with a list of all the conditions you should ask family members about is provided separately. As you saw in the description of familial vs. hereditary risk it is very important to know how old someone was when they developed a disease. There are some important distinctions to make when asking about cancers. Most cancers start in one site (site of origin) but often they will spread to other places (metastases). For example lung cancer can frequently spread to the brain. When asking about cancer we only need to know the site of origin. The other sites are not helpful in assessing your risk level.
How do I ask about family health history?
Family members are the best source of information. Start with your parents if they are still alive. Often there is one family member who is considered the family historian and knows everything about everyone. If there is a person like this in your family you should talk with him/her. Family events like birthdays, Christmas, and weddings are an excellent time to ask, because so many relatives are in one place. In fact, Thanksgiving is the U.S. National Family History Day and would be a great time to bring it up! Some relatives are uncomfortable talking about health and/or medical histories. If that happens to you, you can explain how it will help you and your children
Your personal health history is important for risk assessment too
To perform a risk assessment for some conditions like hereditary cancer syndromes or hereditary liver diseases you only need family health history to calculate risk; however other diseases need information about yourself and your lifestyle to fully calculate your risk. Examples of these include cholesterol and blood pressure for heart disease risk, radiation exposure for breast cancer risk, and diet for diabetes risk.
For more information, view the following documents:
Family health history is a critical part of understanding a patient's risk. For example, a family history of uterine cancer and colon cancer, while seemingly unrelated at first glance, may point to risk of Lynch syndrome in the family. Risk assessment does this through three potential mechanisms: tailoring prevention, motivating healthier lifestyles, and directing treatment.
Risk stratification, which identifies patients at higher than population risk, is a crucial element of the right patient/right time/right treatment philosophy. It does this through three potential mechanisms: tailoring prevention, motivating healthier lifestyles, and directing treatment.
Tailoring prevention and risk-management:
- Many guidelines now recommend assessing risk and providing options for more intensive or alternative risk management strategies,as indicated by risk. For example, women with a lifetime risk for breast cancer >20% can alternate MRIs with mammograms every 6 months or those with certain family history characteristics can undergo genetic counseling to assess for hereditary conditions such as long QT or Lynch Syndrome.
- Currently there are recommendations to offer to high risk individuals actionable prevention/risk-management strategies that differ from population-based screening for the following conditions: breast cancer, ovarian cancer, colon cancer, lung cancer, type 2 diabetes, coronary artery disease, aortic and cerebral aneurysm, ischemic CVA, hemochromatosis, alpha-1 anti-trypsinase deficiency, Wilson's disease, and others.
Motivating healthier lifestyles:
- Providing risk information to patients can raise awareness and personalizes health messages
- In cardiovascular disease this has been shown to improve diet and exercise behaviors
Selecting optimal therapy:
- When therapeutic interventions are necessary risk assessment can target interventions, particularly medications, to the patients most likely to benefit
- The most common examples are for chemotherapy, however, a family or personal history of statin intolerance or an elevated GAIL score may indicate consideration of change in medical therapy.
The above pedigree demonstrates the importance of collecting through family history for optimal risk assessment. The proband's family history of breast cancer in her mother and maternal grandmother suggest a possible hereditary syndrome and current guidelines would recommend consideration of genetic counselling. Without thorough collection of family history, including age of onset of disease, this risk would not have been picked up on and the patient might not receive the guideline-concordant care.
Despite being an important component of clinical care, risk-stratification is not commonly performed. Reasons include: the information needed to assess risk is often not readily available, the risk calculations are complex and not easily accessible, and providers are not always aware of the appropriate actions to take based on the risk score. To address these barriers, Duke has led the development of MeTree, a patient-facing web-based family history risk assessment tool designed for use in primary care.
- General stratification guidelines
- Taking a target family history
- Standard pedigree symbols
- Shared genes by generational relatedness
Risk Stratification Information related to breast cancer
- Assessing breast cancer risk
- Environmental factors
- Gail model
- Supplementary materials
- Risk for each cancer with a BRCA mutation
Risk Stratification Information related to colon cancer
Online CME courses are available through North Carolina Area Health Education Centers (AHEC).
Learn more about MeTree software.