TUESDAY, Oct. 12, 2004 (HealthDayNews) -- What parents do -- and don't do -- before the birth of a child and through the early years of life has a significant effect on the child's risk of developing heart disease as an adult, two studies find.
One study of Australian women and their children found that a woman's smoking habits during pregnancy, her decision on breast-feeding, and even her weight affected a child's blood pressure, a major risk factor for heart disease.
And a study that hits closer to home found that a startlingly large percentage of American teens have one or more risk factors for heart disease, such as high blood pressure, obesity, and bad cholesterol readings. It's a finding the lead researcher attributes to a lack of parental guidance.
Both studies appear in the Oct. 12 issue of the American Heart Association journal Circulation.
The U.S. study used data on 1,960 children aged 12 to 19 gathered in the third National Health and Nutritional Examination Survey, conducted between 1988 and 1994.
"The most surprising thing is that so many of them had at least one problem," said Dr. Sarah de Ferranti, an assistant in cardiology at Children's Hospital Boston, and lead author of the report. "Nine percent had three or more. These children are at high risk of future problems such as diabetes, heart disease, or stroke."
The most common risk factor was a low level of HDL cholesterol (the "good" type), seen in more than 40 percent of the teens. About 30 percent had elevated levels of triglycerides -- blood fats that can clog arteries -- and more than 30 percent had waist circumferences that met the definition of obesity.
Overall, 63.4 percent had one or more risk factor. Nearly one in 10 had what cardiologists call "metabolic syndrome" -- three or more major risk factors.
These problems are not predestined, de Ferranti said. "Lifestyle is likely affecting these children," she said. "My goal as a clinician would be to pinpoint these children and work with them in an intensive way to modify their risk factors."
But it's expensive and time-consuming for a doctor to assume that burden, de Ferranti said, so parents must take their share of responsibility.
"The parents should look at the type of foods their children are eating, the things they bring into the house, the activities they are doing," she said. "I try to tell the families that I see in clinical practice to keep television viewing down to no more than two hours a day, to have the children do aerobic activity for at least 30 minutes every day, and preferably 60 minutes."
Diet should be another parental concern, de Ferranti said: "We have a responsibility to our children to help them find healthy eating habits."
Without such basic lifestyle measures, "in 20, 30 or 40 years, we will see a very large problem," she said.
In the other study, researchers matched a number of characteristics of 8,500 Australian women with the blood pressure of their children at age 5.
Some factors were uncontrollable, such as the mother's age. Blood pressure in children was 0.7 millimeters of mercury (mm Hg) higher for every five years of age when a woman gave birth.
But smoking during pregnancy had a greater effect, raising the children's blood pressure by 1 mm Hg. Obesity in either parent was another risk factor.
However, breast-feeding for at least six months was associated with lower blood pressure.
"Since childhood blood pressure tracks into adulthood, interventions aimed at early risk factors, such as quitting smoking during pregnancy, breast-feeding, and prevention of obesity in all family members may be important for reducing the population distribution of blood pressure," said Dr. Debbie A. Lawlor, a consultant senior lecturer in epidemiology at the University of Bristol in England, who led the study.
The American Heart Association offers a guide to a heart-healthy lifestyle.