MAY 31, 2016

The Impact of Family History on Cardiovascular Risk

WRITTEN BY: Kara Marker
According to a Dutch study of 1,374 teenagers, children with a certain family history of cardiovascular disease and/or type 2 diabetes have significantly increased levels of cholesterol, compared to children with little to no family history of these diseases. The study was recently published in the journal Diabetologia, and scientists are intrigued by the new ways these findings suggest for treating cardiovascular disease.
 

Is it an epigenetic inheritance that leads to chronically high levels of cholesterol? Or a tendency to eat a certain way? These new discoveries about the intergenerational shared risk of cardiovascular disease has scientists wondering if new preventative measures should be taken to improve outcomes for high-risk groups. From the National Institute for Public Health and the Environment in the Netherlands, scientists are starting to realize that the BMI of an individual child has less to do with their cardiovascular health than they though, at least when the child comes from a family of people with certain high-risk cardiometabolic markers.

Researchers recruited 12-year-old participants and their families from The Prevention and Incidence of Asthma and Mite Allergy Study, beginning with a clinical assessment of the teens, measuring BMI, waist circumference, blood pressure, and glycated hemoglobin, a measure of blood sugar to determine diabetes status. By the time the children reached age 14, parents returned to answer questions about family history of type 2 diabetes and cardiovascular disease, which the researchers defined as heart attack, myocardial infarction, and/or stroke. 

The severity of a family history of disease was allocated into three groups by the researchers:
  1. No family history of cardiovascular disease or type 2 diabetes
  2. Moderate family history - 1-2 grandparents affected with late disease onset
  3. Strong family history - one affected parent or at least one grandparent with early disease onset or 3-4 grandparents with late disease onset
Early disease onset is considered to be a dangerous cardiovascular event before 55 years of age for males and 65 years of age for females, while late disease onset is defined as after 50 years of age for both males and females. These parameters are commonly used in similar studies.

Over a third of the teens involved in the study reported a “strong” family history of cardiovascular disease and/or type 2 diabetes. Additionally, the participants from the strong family history group had overall higher total cholesterol levels and a distorted ratio of total cholesterol to HDL cholesterol than the other two groups with less family connections to cardiovascular disease.

HDL, also known as high density lipoprotein, is a compound that transorts cholesterol through the bloodstream. Cholesterol can also be carried by low density lipoprotein, or LDL. This type of cholesterol transporter is known as “bad” cholesterol due to the contributions it makes to plaque buildup in blood vessels, causing blockages in artery blood flow that can lead to atherosclerosis and coronary artery disease. HDL, also known as “good” cholesterol, reverses the effect of LDL by dissolving LDL accumulation, carrying the lipoproteins back to the liver to be broken down and excreted. Without the right balance of HDL and LDL, a relationship that is affected by genetics and diet, an individual may be more or less at risk for heart disease.

This study was the first to take into account two generations of disease risk, from child to grandparents. In relation to measurable risk factors in children like environmental influences and lifestyle choices, researchers can begin to map the relationship between genetic predispositions to these chronic diseases and the choices an individual makes to improve their health.
 

Sources: National Institute for Public Health and the Environment, American Heart Association