Family history is both a genealogy subject and a health-information practice. CDC survey findings from 2004 and 2020 measure how people value family health history, what they know about relatives’ conditions, whom they ask, and how confidently they record that information. The figures below describe U.S. respondents and families in the specific studies; they are not a current estimate of every population.
Contents
- How people value and collect family health history
- Who reported collecting information in 2004
- What respondents knew about diabetes
- Family history and early disease events
- Knowledge of family cancer history in 2020
- Who people talked with about cancer history
- Confidence, providers, and differences by group
How people value and collect family health history
The CDC’s MMWR: Awareness of Family Health History as a Risk Factor for Disease reported that 96.3% of survey respondents considered knowledge of family history very important or somewhat important to their personal health. That combined measure includes two levels of importance: 72.5% called family history very important, while 23.8% called it somewhat important. These measurements come from the 2004 survey and should be read as historical survey results rather than a present-day national estimate.
Valuing family history did not mean that everyone was actively building a record. In the same CDC report, 29.8% said they were collecting information from relatives to develop a family health history. The difference between the 96.3% who attached at least some importance to the information and the 29.8% who reported active collection describes an important practical gap: awareness was widespread, while the reported record-building activity was lower.
The study’s respondent profile provides context for those results. Women represented 51.7% of respondents, and 70.5% were non-Hispanic White. Adults aged 18–54 represented 69.3% of the sample. In education, 62.9% had at least some college education. A total of 78.1% had ever been married, and 54.2% reported annual income above $40,000. These are characteristics of the 2004 respondents, not demographic benchmarks for all people researching family history.
Who reported collecting information in 2004
The 2004 CDC report also showed differences in reported collection across several groups. Among women, 36.3% had collected family health history information, compared with 22.9% of men. Hispanic respondents reported a collection rate of 24.4%. Among respondents with a high school education or less, 25.5% had collected family health history information.
Personal experience with type 2 diabetes was associated with a higher reported collection rate in this survey. Among respondents with personal type 2 diabetes, 37.2% had collected family health history information. This figure is a subgroup result from the study; it does not establish that personal diabetes caused people to collect records, and it should not be treated as a forecast.
Together, these measurements show why a family history project can begin in different ways. Some people may start with a general interest in health, some may ask relatives after a personal diagnosis, and others may use an existing family or genealogy conversation as an entry point. The CDC figures quantify the reported patterns but do not explain every individual reason for collecting information.
What respondents knew about diabetes
The 2004 CDC survey asked respondents whether they knew the type 2 diabetes status of relatives. Knowledge was highest for siblings: 94.5% reported knowing their siblings’ type 2 diabetes status. The corresponding figure for mothers was 91.2%, and 87.8% reported knowing their fathers’ status.
Knowledge was lower when the question moved beyond the immediate family. A total of 77.0% reported knowing the type 2 diabetes status of maternal relatives, while 70.4% reported knowing the status of paternal relatives. The pattern is useful for organizing a genealogy or health-history interview: people may have more accessible information about parents and siblings than about extended relatives on either side of the family.
| Relationship group | Reported knowledge of type 2 diabetes status |
|---|---|
| Siblings | 94.5% |
| Mother | 91.2% |
| Father | 87.8% |
| Maternal relatives | 77.0% |
| Paternal relatives | 70.4% |
These percentages measure what respondents said they knew in the 2004 CDC survey. They do not measure whether each answer was medically confirmed, and they do not indicate how complete a respondent’s wider family tree was.
Family history and early disease events
The same CDC MMWR article described a school-based project that identified a family history of coronary heart disease in 14% of families. Those families accounted for 72% of all early-onset coronary heart disease events in that project. The study also identified a family history of stroke in 11% of families, and those families accounted for 86% of early stroke events.
The project figures are especially different from ordinary survey percentages because the denominators describe families and early-onset events in a school-based project. The 14% and 11% figures are not national prevalence estimates. Likewise, the 72% and 86% figures describe the share of early events associated with the identified family-history groups in that project. They should not be generalized to every family or used to calculate an individual’s risk.
For genealogy researchers, the practical significance is that a family tree can preserve information that is relevant beyond names and dates. A record of a diagnosis, the relationship to the affected person, and the approximate timing may help a household organize questions for a qualified health professional. The supplied CDC measurements support the importance of documenting family history, while the project design limits how broadly the numbers can be applied.
Knowledge of family cancer history in 2020
The CDC’s PCD: Prevalence and Correlates of Family Cancer History Knowledge and Communication Among US Adults measured family cancer-history knowledge among U.S. adults in 2020. In that study, 31.1% reported knowing their family cancer history very well. When “well” and “very well” were combined, 60.1% said they knew their family cancer history well or very well.
Other respondents described more limited knowledge. A total of 23.9% reported knowing their family cancer history somewhat, while 16.0% knew it a little or not at all. The categories provide a fuller picture than the high-knowledge figure alone: 39.9% of adults in the study did not report knowing their family cancer history well or very well.
| Self-reported level of family cancer-history knowledge | U.S. adults, 2020 |
|---|---|
| Very well | 31.1% |
| Well or very well | 60.1% |
| Somewhat | 23.9% |
| A little or not at all | 16.0% |
The categories above come directly from the CDC’s 2020 measurement. They should not be added together as if they were all mutually exclusive: “well or very well” is a combined measure, and “a little or not at all” is another combined measure. The findings concern reported knowledge, not the completeness or accuracy of an individual family cancer record.
Who people talked with about cancer history
In the 2020 CDC study, 70.0% of U.S. adults had discussed family cancer history with at least one biological relative. The mother was the most frequently listed specific relative: 54.4% had discussed the subject with their mother. A total of 35.2% had talked with their father, 28.1% with sisters, and 21.0% with brothers.
Conversations also extended to other generations and relatives. The study reported that 16.9% had discussed family cancer history with their children, and 24.0% had talked with other biological family members. More than one relationship could be involved: 55.4% had discussed family cancer history with multiple biological family members. In contrast, 24.2% had not discussed family cancer history with any of the listed biological relatives.
These results show why interviewing one relative may not provide the whole record. A parent, sibling, child, or another biological relative may remember different diagnoses or branches of the family. The 2020 results measure whether conversations occurred, not whether the information exchanged was complete or consistent.
Confidence, providers, and differences by group
The CDC’s 2020 study found that 39.0% of adults had discussed family cancer history with a health care provider. Confidence in completing medical forms was mixed. A total of 49.6% were very confident or completely confident completing family cancer history on medical forms. Within that combined result, 27.4% were very confident and 22.2% were completely confident.
The remaining confidence categories were also quantified. A total of 13.5% were not confident at all, while 11.4% were a little confident completing family cancer history on medical forms. These figures highlight a practical record-keeping issue: knowing that family history matters does not guarantee that a person has enough information to complete a form confidently.
The CDC report identified several differences in odds between groups. Women had 2.26 times the odds of high family cancer-history knowledge versus men. Women also had 2.30 times the odds of discussing family cancer history with at least one biological relative, 2.20 times the odds of discussing it with a health care provider, and 2.03 times the odds of high confidence completing family cancer history on medical forms, each compared with men.
Age and income were associated with additional differences. Adults aged 75 and older had 0.30 times the odds of discussing family cancer history with at least one biological relative versus adults aged 18–34. Adults with annual household income of $50,000–$74,999 had 2.54 times the odds of discussing family cancer history with at least one biological relative versus adults with income below $20,000. The same income group had 3.10 times the odds of discussing family cancer history with a health care provider. Adults with annual household income of at least $75,000 had 2.23 times the odds of high confidence completing family cancer history on medical forms versus adults with income below $20,000.
Odds ratios describe relative odds between the groups named by the CDC study; they are not percentage-point differences and do not mean that a person in one group is guaranteed to have a particular level of knowledge or communication. For a genealogy project, the results suggest documenting uncertainty clearly, recording which relative supplied each detail, and bringing unresolved health-history questions to an appropriate health care provider.