Family-centered approaches to understanding and preventing coronary heart disease

Abstract

Family history represents the contributions and interactions of unique genomic and ecologic factors that affect the metabolic profile and life course of a family and its members. It is well known that a family history of coronary heart disease (CHD) is a significant predictor of an individual’s risk for CHD even after adjusting for an individual’s own established risk factors, such as hypertension, smoking, and abnormal lipoprotein levels. The explanation for the observed familial disease aggregation is not well understood except for the general knowledge that genetic and environmental factors predisposing to CHD also aggregate in families. Given the multifactorial nature of an individual’s risk, it can be argued that an individual’s familial risk of disease may, in fact, be a better indicator of the many complex interactions among predisposing genetic and environmental factors than can be captured by an individual’s own risk factors. Issues of how to assess, quantitate, and apply family history information in clinical settings still need to be resolved. Some clinical risk indicators, such as the National Cholesterol Education Program III guidelines, take into account family history, while others, such as the Framingham Risk Score, do not. Moreover, several family-centered intervention studies have demonstrated the particular advantages of focusing on families rather than just individuals. Although there has been tremendous progress in primary prevention of CHD over the last 20 years, substantial advancements may still be achieved by focusing on the family as its own unit of inference and as a specific target for disease prevention.

Introduction

Recognition of the familial nature of coronary heart disease (CHD) is actually over a century old. The first mention in the English literature of its familial nature in connection with xanthomas was made by Fogge in 1873, and in 1897 Sir William Osler pointed out that angina could recur in families.1 Reports of early heart disease in pedigrees increased after the turn of the 20th century. As a consequence of developments in the field of epidemiology and cardiology, by the mid-1900s, investigators2 began to undertake more systematic population and hospital-based studies. Among the early studies were landmark papers by Thomas and Cohen3 in 1955 and Slack and Evans4 in 1966 that demonstrated the first statistically significant evidence of increased frequency of CHD for individuals with a family history of the disease.

There has been considerable progress in this field of research over the last 25 years. Some would even argue that we are quite close to having established sufficient clinical validity and utility to motivate new national standards and practices for applying family histories as a regular part of preventive medicine and public health programs. In this article, we review the importance of family history for identifying individuals and families at increased risk for CHD, discuss findings from family-centered interventions, and provide a rationale for why family history, as mundane as it might sound in this genomic era, should be considered an important measure of a person’s genomic and total environmental risk of future CHD.