Introduction

For centuries, family history has represented an inevitable part of consultation with patients. It enables family doctors to gain insight into the patients’ social background and helps to provide a context for their symptoms, both in terms of possible environmental and lifestyle causes of disease and their concerns about the nature of their illness [1]. Teaching family history taking is also an important part of family medicine education [2].

Traditionally, family history taking is focused on patients with symptoms or problems which might imply that the patient has an increased risk of certain chronic diseases, such as diabetes, coronary disease, asthma etc. [3,4]. Rarely, healthy patients or patients with acute problems are asked about their family history [5]. As previous studies have shown, inadequate knowledge of family history in the medically underserved population is a major obstacle, limiting quality management of such patients and often leading to delayed treatment [6].

In recent years, family history has not only been used as a method of social assessment, but also as a genetic risk predictor [7,8]. Specifically, a family history of a particular disease usually reflects the combined effects of genetic susceptibility, shared environmental exposure and common behaviours in relatives [4]. Also, it is known that a family history of a common chronic disease is associated with a 2- to 5-fold relative risk of developing the condition, and this increases with the number of affected relatives [9].

Cardiovascular diseases, diabetes and cancer are the leading causes of the burden of disease and also the leading causes of death from non-communicable diseases in the developed world [10]. Since there is a lot of evidence on the preventable nature of these diseases [11], it is of the utmost importance to detect people at risk at the earliest possible time. One of the possibilities for such early detection is family history.

A positive family history is a risk factor for the development of cardiovascular diseases, diabetes and cancer. Furthermore, family history also seems to be an independent risk factor for diabetes and cardiovascular diseases [12]. Studies have shown that the presence of a cardiovascular disease in at least one parent doubled the eight-year risk of cardiovascular disease among men and increased the risk among women by 70% [13]. The risk of cardiovascular disease (OR) associated with sibling cardiovascular disease was 2.0, and with parental cardiovascular disease 1.5 [14,15]. Studies in diabetes showed that people with one or more first degree relatives who are affected by diabetes are 2-6 times more likely to have the disease compared with people who have no affected relatives [16]. The risk of diabetes was also highly associated with maternal diabetes (OR = 3.4), parental diabetes (OR = 3.5) and with both parents with diabetes (OR = 6.1) [17]. Studies which focused on the most common cancer sites reported that 5-10% of women with breast cancer had a mother or sister who also contracted the disease, and up to 20% had a first or second degree relative with breast cancer [18]. Also, 5% of adult respondents reported having one or more first degree relatives with colorectal cancer [19].

The Centre for Disease Control (CDC) developed a structured approach for risk assessment of various diseases based on the morbidity and mortality data from a three generation family history [20], which can be used for determining the risk of diseases solely on the data from the family history.

In Slovenia, but also in Europe, there is a lack of data on the prevalence of healthy individuals in the general population at risk of developing cardiovascular diseases, cancer, and diabetes, based on their family history; this study aims to address this gap.

Materials and Methods

Results

Discussion

This study showed that, based on their family history, 20.9% of participants had moderate or high risk for the development of cardiovascular diseases, 11.5% for the development of diabetes and 12.1% for cancer. As many as 3% of participants had a high risk of the development of cardiovascular diseases and were therefore in need of genetic counselling.

In Slovenia, and also in Europe [23,24], there is a lack of data on the prevalence of a family history of most common chronic diseases, especially in the healthy adult population. In 2011, 4.5% of the general Slovenian population had cancer and 9.1% had diabetes, but no data were collected on cardiovascular diseases [25]. In 2011, cardiovascular diseases were the most common cause of death in Slovenia, and diabetes and cancer were among the commonest ones [26]. These facts point to a large public health problem and many preventive campaigns in Slovenia are directed at early detection of these diseases [27-30]. However, not much attention has been directed to the screening of family history, which has already been shown to be useful in conducting a risk assessment [4,31].

In other countries, especially in the USA, some efforts have already been made to gather data on the healthy population at risk of developing cardiovascular diseases, diabetes and cancer based on their family history. The results showed that approximately 50% of healthy respondents had a first or second degree relative with cardiovascular diseases [32], and that 33% of the participants had a higher than average risk of developing cardiovascular diseases [4,31]. Similarly, 30-50% of healthy screened adults had a family history of diabetes in a first degree relative [33] and 11% of healthy individuals had a higher than average risk of developing diabetes [34]. A large study in USA reported that 34% of healthy individuals were at high or moderate risk of at least one of the cancers [35].

In our study, the prevalence of first and second degree relatives with cardiovascular diseases, diabetes, and cancer was similar or slightly lower than described in previous studies [17,18,33–35]. Currently, screenings for cardiovascular diseases [27], breast cancer [28], colorectal cancer [30] and cervical cancer [29] are employed in Slovenia as a part of national preventive programmes. However, these programmes start at a relatively late stage in life. For example, screening for cardiovascular diseases starts at the age of 35 for men and 40 for women, whereas screening for colorectal and breast cancer start at the age of 50.

Since family history seems to be an independent risk factor for diabetes and cardiovascular diseases [12], and since previous studies have shown that it is possible to identify people at risk only through assessing their family history [12,15,20], it becomes obvious that family history should also become an obligatory part of regular check-ups in younger healthy people. Family doctors should therefore regularly ask their patients, especially rare visitors, about their family history.

It has been shown that to conduct a risk assessment, ideally a full three-generational pedigree should be taken, asking about parents, aunts, uncles, siblings and grandparents on both sides of the family [4,31]. However, this may require up to 30 minutes of family doctors’ time [36] which is often unacceptable or not feasible [37]. Therefore, several questionnaires and computer programmes or tools have been developed to assist family doctors in this task [4,7,36,38]. The best studied is Family Healthware, a family history screening tool aimed at preventing common chronic diseases [15].

In order to employ the full potential that assessing risk by family history can offer, we should develop a public screening programme which would start at a younger age (possibly in childhood) [12]. Electronic tools or paper forms for family history taking should be adopted and designed for the easy collection of the data needed in such screening programmes, and should also contain an evidence-based decision-making system with regard to the findings. Such a tool would reduce the time burden of family doctors and enable regular periodic updates on people’s family history, as it is a dynamic structure that is susceptible to change over time[12]. Also, people should be informed about the criteria for genetic susceptibility and the benefits of reporting their family history to their family doctors.

The known family history of young healthy individuals would enable us to provide individually tailored and personalized advice on healthy life styles and also to plan targeted preventive activities which could save a great deal of money. It has been shown that family history has a better predictive value in very common inherited conditions like coronary artery disease than single nucleotide polymorphism-based methods [39]. On the other hand, there is growing evidence that next generation sequencing may provide clinically relevant information, especially in people with a strong family history of a given disease [40]. People at high risk of the development of different diseases should be referred to clinical geneticists for individual genetic counselling, while people with moderate risk could be managed by their family doctors [20].

The strength of this study is the inclusion of all regions in Slovenia. Slovenia is geographically a very diverse country and we were able to include all the main regions in the sample. However, the sample was not representative of the general population as it only included individuals who were employed (and therefore probably healthier than the overall general population) which could be a source of a selection bias. Another limitation is the problem of self-reporting of data; they were not checked in medical records or through personal interviews with relatives. The results might therefore be subjected to a recall bias.

Conclusion

This study is the first study on this subject in Slovenia and one of very few in Europe. It provides us with the first information on the relevance of family history at a time when genetic medicine is becoming more and more important. It also points to the need for genetic counselling by clinical geneticists for the healthy population at high risk. There is a need for further studies, possibly on larger samples collecting objective information on family history.

Acknowledgments

The authors would like to thank Professor Janko Kersnik for his help in data gathering and his ideas for the article. We also thank Marjanca Kamenik, the chief nurse of Velenje Health Centre, Jože Zupančič, the director of Velenje Health Centre, and Valentina Tasič, Alenka Simonič, and Miran Becner, the heads of occupational practices in Maribor Health Centre for their help in collecting the data.