Obesity is one of the strongest predictors of hypertension in young adults.
The U.S. Centers for Disease Control and Prevention tracked the health and nutrition of Americans in the National Health and Nutrition Examination Surveys for more than forty years. NHANES I encompassed the years 1971-1974, NHANES II covered 1976-1980, NHANES III covered 1988-1994 and the most recently completed survey, NHANES IV, part I, followed Americans from 1999-2000.
Comparing data from the four surveys, researchers found a trend between overweight and high blood pressure in children 8 to 17 years-old. Rebecca Din-Dzietham, M.D., M.P.H., Ph.D., assistant professor in the social epidemiology research division of the Department of Community Health and Preventive Medicine at Morehouse School of Medicine, and colleagues analyzed data on 3,417 children from NHANES I, 3,039 from NHANES II, 3,432 from NHANES III and 2,211 from NHANES IV. They recorded age, gender, blood pressure and body mass index (BMI, an index of height-adjusted weight) on black and white children.
The researchers categorized the children based on definition from the National Task Force on High Blood Pressure in Children and Adolescents. Children with blood pressure in the 90th percentile or above were classified as having high blood pressure. Children with BMI in the 95th percentile or above were classified as obese according to the CDC growth chart. Overweight was defined as BMI in the 85th to 94.9th percentile range. Normal weight was below the 85th percentile.
High blood pressure among children decreased between NHANES I (1971) and NHANES III (1988). However, between NHANES III and IV, (1988 and 1999), high blood pressure rose sharply.
The increase in high blood pressure prevalence was greater among obese children than in children with lower BMIs. Prevalence of high blood pressure increased 4.2 percent in overweight children, 3.5 percent in obese children and 2.6 percent in normal weight children between NHANES III and NHANES IV. Similar patterns were seen for both systolic and diastolic blood pressure.
The increase in high blood pressure follows 10 years after an increase in body mass index years in the children.
"The HBP trends in youth mirrors adult trends in hypertension," said Din-Dzietham. "After NHANES II, BMIs start climbing like we're going up Mt. Everest."
Children started eating more fat, eating larger servings and exercising less. Television is often a big factor, as are fewer hours of physical education at school. Parents need to be educated about the importance of body mass index as a ratio of weight over height and not just consider weight.
"Intervention on weight control needs to start early. We know that children with high blood pressure develop signs of heart disease early," she said.
"Weight is the main culprit, and obesity is turning into a major public health risk factor."
Co-authors are Yong Liu, M.S., Rakalle Collins, Ph.D., Gary Gibbons, M.D., Sharon Davis, M.Ed., M.P.A, Ph.D. and Tonya Stancil, Ph.D.
Abstract LB 10