Healthy living advised for siblings of heart disease sufferers
Johns Hopkins found that people with a family history of heart
disease have more reason than most to eat well and keep their
weight down.
The research team's results suggested that in these families, siblings who were obese or overweight had a 60 percent increased risk of suffering a serious heart ailment, such as a heart attack, before the age of 60.
"Because overweight and obesity are risk factors for heart disease, physicians and the public should know what additional risk applies for siblings in families with known heart problems," said senior investigator Diane Becker, a professor at the Johns Hopkins University School of Medicine and Bloomberg School of Public Health.
Her team spent nine years monitoring risk factors, both traditional and body mass index (BMI equals weight in kilograms per height in square meters), in 827 siblings under the age of 60 from families in the Baltimore region.
The participants were generally healthy at the beginning of the study, with no early signs of heart disease, but all had at least one major risk factor such as age, gender, cholesterol levels, blood pressure, smoking or diabetes.
Each participant also had at least one sibling with premature coronary heart disease (such as blocked arteries) that had required hospitalization, meaning that family history was a risk factor.
Half the participants were women, 20 percent were black Americans and the rest were predominantly white. Blood tests and physical exams were conducted at the beginning and end of the study to assess changes in each individual's risk factors.
The results showed that obese and overweight siblings had double the chance of having coronary heart disease than siblings with a normal weight. According to Becker, the findings translated into a 4 percent increase in risk of coronary heart disease for every one-unit increase in BMI.
However, obesity was found to have the greatest impact on risk of heart disease in siblings who had multiple risk factors. In this group, obese siblings had twice the amount of coronary heart disease as those who were overweight - 40 percent and 20 percent, respectively - and double the rate in siblings with normal-weight siblings. When compared to siblings with normal weight, obese siblings had 15 times more premature heart disease.
The research team then analyzed the genetic traits and found that 50 percent of BMI in whites was hereditary, while in blacks, the hereditary factor was even less, at 30 percent. Hence, lifestyle and environmental factors would appear to account for the rest, suggesting the importance, among other things of a healthy, nutritious diet.
"Our results show that obesity is far more important than previously thought to gauging real risk of heart disease in families where this is already a problem," said the study's lead author, cardiologist Samia Mora.
The study was published yesterday in Circulation online.
People are considered to be obese when their BMI is greater than or equal to 30 kilograms per meter squared, while overweight is defined as a BMI of 25 to 29.9 kilograms per meter squared.
