Editorials
General medicine Genetics History and humanities
Volume 192 - Issue 12

Family history: the neglected risk factor in disease prevention

Authors:  Jon D Emery, Fiona M Walter and David Ravine

Med J Aust 2010; 192 (12): 677-678. || doi: 10.5694/j.1326-5377.2010.tb03699.x
Published online: 21 June 2010
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It is time to reconsider the clinical benefits arising from family history and start making better use of it

A patient’s family history may aid clinical diagnosis and contribute to disease risk assessment and prediction. It frequently yields valuable social history, including information about family support structures and insights into individual beliefs about illness.1 Although taking family history is traditionally regarded as a routine part of the medical history, it is not used in a systematic way in clinical practice. In this issue of the Journal, Langlands and colleagues report the results of an audit in an Australian teaching hospital, which found that nearly three-quarters of patients admitted to a short-stay medical unit had no documentation of family history having been considered as part of the diagnostic assessment.2 A similar situation exists in primary care. Although there are no published comparable data from Australian general practice, a primary care study in the United States found that only 16% of subjects (n = 362) had any record of their family history in their clinical chart, including 15 individuals at high risk of an inherited cancer syndrome.3

Internationally, there is growing recognition that a family medical history can support tailored disease prevention, which may be more effective than existing approaches.4 This is also reflected in the Australian Medicare-funded adult health assessment for people aged 45–49 years at risk of developing chronic disease, which specifically includes assessment of the family history of chronic diseases such as diabetes and cardiovascular disease. Family history can also inform the formulation and weighting of differential diagnoses in presentations for a range of common conditions.

The risk of many serious diseases is increased in the presence of a family history of the disorder, representing not only shared genetic factors but also environmental and behavioural exposures. For example, the relative risk of breast cancer is 1.4 times higher for women aged 60 years or older if they have a first-degree relative diagnosed with the disease after the age of 60 years; this risk is more than five times higher for women younger than 40 years with a first-degree relative diagnosed before the age of 40.5 Eleven per cent of women with breast cancer have a first-degree relative with the disease. The relative risk of colorectal cancer for a 50-year-old is increased from around twofold with one affected first-degree relative to almost fourfold in people with at least two affected first-degree relatives.6 About 15%–20% of people with colorectal cancer have an affected first-degree relative. In a US population-based study, 14% of the population had a family history of ischaemic heart disease, but these people accounted for 72% of early ischaemic heart disease and 48% of all cases of the disease.7 A parental history of type 2 diabetes is associated with a relative risk of 2.2 and a lifetime risk of 40%.8 These familial disease risks should be compared with other traditional risk factors that are routinely screened for in general practice. For instance, isolated hypertension is associated with a relative risk of 1.8 for ischaemic heart disease and is present in 14% of men and 5% of women with a coronary event.9

There are effective interventions for primary and secondary prevention of all these common diseases, ranging from disease surveillance to drug treatments and lifestyle management. There is some evidence that having knowledge of a family history of a specific condition is associated with improved uptake of a range of disease-preventive activities for breast, colorectal and skin cancer.10-12 Therefore, it is possible that identifying people with a family history of disease could act as an additional motivator for them to change their lifestyle or participate in disease screening.

Why then do clinicians continue to neglect the family history as part of routine diagnostic assessment and disease prevention? The experienced clinician will know that recording a patient’s family history to assess disease risk ideally requires a three-generation pedigree, but this can take up to 30 minutes, which is unrealistic in most clinical settings. However, not all patients require such a detailed assessment. Simple, self-completed family history screening questionnaires could provide an answer. Several of these already exist, but many are disease-specific and few have been formally tested to determine their screening characteristics.13

Clinicians also cite patients’ uncertainty about their family history as a barrier. However, a systematic review of self-reported family history found high positive predictive values for cancer in first-degree relatives (breast, 93%; prostate, 85%; colon, 81%), although information was less accurate about second-degree relatives (breast, 91%; prostate, 80%; colon, 77%).14 Of course, sometimes the patient’s perception of his or her family history can be just as important as the reality in determining the patient’s risk perception, illness beliefs and likely response to medical advice.

Better methods of recording family history are also required, particularly as we move towards an electronic health record in Australia. Tailored clinical software is potentially the most effective tool for recording and updating a patient’s family history, although current clinical software systems do not support the creation of pedigrees. Previous trials have demonstrated the capacity of computerised pedigree tools to improve the assessment of disease risk and identify those individuals who may benefit most from seeing a clinical geneticist.15 However, while clinicians continue to ignore the importance of the family history in diagnosis and risk assessment, software companies have little incentive to integrate family history tools into their systems.

Raising awareness among consumers is an alternative approach that may drive clinicians to consider family history more often. A family health history campaign run in New South Wales in 2007 resulted in increased community awareness and discussions about family history within families and between patients and their general practitioners.16

While DNA-based disease risk prediction remains to be proven as an effective clinical tool, family history is a simple but potent tool that is available now for disease prevention. Langlands and colleagues audit findings show that this important element of the clinical history is seldom included in routine patient assessments.2 The family history should not be seen as a relic of medical school teaching; it is time to reconsider the clinical benefits arising from family history and start making better use of it in clinical practice.

Authors

  • Jon D Emery MB BCH, FRACGP, DPhil1
  • Fiona M Walter MB BCh, FRCGP, MD2,1
  • David Ravine MB BS, MD, FRCPath3
  • 1. School of Primary, Aboriginal and Rural Health Care, University of Western Australia, Perth, WA.
  • 2. General Practice and Primary Care Research Unit, University of Cambridge, Cambridge, UK.
  • 3. School of Pathology and Laboratory Medicine, University of Western Australia, Perth, WA.

Correspondence: jon.emery@uwa.edu.au

Competing interests

David Ravine is an author of the article that is the subject of this editorial.

References

View this article on Wiley Online Library