By David Williamson
UNC-CH News Services
CHAPEL HILL -- Many North Carolina third- and fourth-graders have both higher blood pressure and total cholesterol levels than doctors consider healthy and face a higher risk of heart disease or strokes later in life, according to a new study.
A small but significant number of N.C. elementary school children also have begun smoking.
The study, conducted at the University of North Carolina at Chapel Hill School of Nursing, is the first to evaluate cholesterol, blood pressure and smoking exclusively among Tar Heel children. Previous research has examined U.S. children as a group, but other work has shown health measurements in children vary in different parts of the country.
"North Carolina ranks 11th among the states in population, but it sits in the nation's heart disease and stroke belt and is third in the death rate due to stroke," said Chyrise Bradley, research assistant professor of nursing at UNC-CH.
"Even with a strict definition of obesity, we found that 26 percent of children in our study population were overweight," Bradley said. "It is no wonder then that such children grow up to have premature health problems such as high blood pressure, which is a well-established risk factor for heart disease and stroke."
A report on the findings appears in the September/October issue of the North Carolina Medical Journal.
Besides Bradley, UNC-CH authors of the report are Dr. Joanne Harrell, professor of nursing; Dr. Robert G. McMurray, professor of physical education, exercise and sport science; Dr. Shrikant I. Bangdiwala, research associate professor of biostatistics; Dr. Annette C. Frauman, associate professor of nursing; and Julie P. Webb, statistician in nursing.
The new research involved 2,207 children in 21 randomly selected schools in 12 counties from the mountains to the coastal plain, said Harrell, principal investigator for the continuing UNC-CH-based Cardiovascular Health in Children (CHIC) study. Half the schools were located in cities, and the other half in rural areas.
She and colleagues received permission to conduct the study from county school superintendents, principals and parents, who filled out family medical histories . Students agreeing to participate completed simple questionnaires and underwent basic physiologic testing in exchange for a jump rope or Frisbee. Most were ages 8 or 9.
Among the findings:
- Overall, 12.6 percent of the children had cholesterol levels above 200 milligrams per deciliter, which is considered high. Among blacks, almost 19 percent showed elevated cholesterol compared to 11 percent of whites.
- Twelve percent of students had high blood pressure, and 3.2 percent had severe hypertension, meaning that their levels exceeded 99 percent of U.S. children their age. Black youngsters showed slightly more hypertension than whites.
- In 27.5 percent of families, at least one parent reported having high cholesterol and in 47 percent, at least one parent smoked. More than 16 percent of young parents had hypertension, and almost 10 percent had some form of heart disease.
- The average height and weight of N.C. children tested was at the 95th percentile of standard growth curves nationally, which suggests the growth curves may be outdated, but also that N.C. children still are too heavy compared to other U.S. children.
"North Carolina children had more hypertension than expected," Harrell said. "When we applied national norms for diagnosing hypertension to our subjects, we found more than twice as many as expected had high blood pressure."
"We believe this work is important because it suggests we should routinely screen North Carolina children for high blood pressure, high cholesterol and obesity and do it earlier -- not wait until high school or college," Bradley said. "We should advise them and their families about increasing activity levels and increasing the amount of whole grain cereals, fruit and vegetables they consume, while reducing the amount of saturated fat. We also need to make sure all school children get regular vigorous exercise in physical education classes."
The UNC-CH research, the first to report smoking at such early ages in the state, underscores how young children are when they begin experimenting with tobacco products, she said. About one in 25 children already had begun occasional or regular smoking before the fifth grade. Previous studies have shown that the younger kids are when they first try cigarettes, the more likely they are to become habitual smokers as teens.
Note: Bradley and Harrell can be reached at (919) 966-3610.
School of Nursing contact: Renee Kinzie, 966-1412.
News Services contact: David Williamson, 962-2091
Journal
North Carolina Medical Journal