Studies on cardiovascular disease (CVD) can be used to highlight the problems that occur in using genetic information to understand the etiology of some of the most common chronic diseases. These studies on cardiovascular disease (CVD) are also used to help identify those at the highest risk of developing CVD.
Most cardiovascular disease (CVD) cases have a complex multifactorial etiology, making it extremely difficult to predict due to the multitude of potential causes. Even with a complete knowledge of an individual’s genetic makeup, it is difficult to predict with certainty the susceptibility of developing the disease, the progression, or severity of disease. Cardiovascular disease (CVD) develops as a result of interactions between a person’s genotype and exposures to environmental factors. The influence of these factors begin as early as conception and continue throughout adulthood, greatly impacting cardiovascular phenotypes.
High-risk Environmental Agents
Cardiovascular disease (CVD) research has identified many high-risk environmental agents and hundreds of genes, each with multiple variations that are thought to influence disease risk. As the number of interacting agents involved increases, a smaller number of cases of disease will be found to have the same etiology and be associated with a particular genotype. The emergence of a given individual’s clinical phenotype is connected to the many feedback mechanisms and interactions of agents from the genome through intermediate biochemical and physiological subsystems with exposure to environmental agents.
A large multitude of factors, from the influence of genes on cholesterol to psychosocial factors such as anger and stress, must be considered when trying to sort and identify the contributions of genes and environmental factors to cardiovascular disease (CVD). Hundreds of genes have been identified as having an impact on the susceptibility of developing cardiovascular disease (CVD), its progression, and clinical manifestation. However, little is known about how a person’s environment interacts with these genes to tip the balance between the atherogenic and anti-atherogenic processes that result in clinically manifested CVD.
In addition to these factors, it is also well known that many social and behavioral factors including socioeconomic status, job stress, depression, smoking, exercise, and diet affect cardiovascular disease risk.
As more studies on cardiovascular disease (CVD) and gene-environment interactions consider these factors as part of the environment, which are examined along with genetic variations, several intellectual and methodological challenges arise. One of the first challenges arises when we examine how social factors are embodied such that an interaction with a particular genotype can be associated with differential risk.
Another challenge is how we handle complex interactions to address questions, such as how does an individual’s genotype influence his/her behavior. An example of this is how one’s genetic susceptibility to nicotine addiction is actually a risk factor for CVD. Its effect on CVD risk may be dependent on interactions with other genetic factors.