A new collaborative study, by the University of Wits and the University of North Carolina, published in the BMC Pediatrics, has revealed that high blood pressure in adults begins in childhood. The research participants consisted of an urban black population, who were tracked from birth.
High blood pressure is a global problem linked to numerous health conditions including heart disease. South Africa has the highest prevalence of hypertension in adults (78%), based on statistics obtained from the World Health Organization.
“Approximately one-third to a half of the children who were hypertensive at some time during childhood and adolescence were hypertensive at age 18 years. The risk of having elevated blood pressure at 18 years of age was lowest at age five years and highest at age 14 years,” said the study authors.
A previous study published in the Journal of the American College of Cardiology has demonstrated that elevated blood pressure at an early stage is a predictor for heart failure, after the age of 50. The researchparticipants consisted of 2,479 men and women between ages 18 and 30. Their blood pressure was assessed seven times over a period of 25 years. The estimated “cumulative blood pressure exposure” was evaluated by multiplying their systolic blood pressure (when the heart is contracting) and diastolic blood pressure (between beats) at each of the seven time points by the year in which they were measured. Three percent of people younger than age 18 years have high blood pressure,
Normal blood pressure should be less than 120 millimeters of Mercury systolic over 80 nn HG diastolic. High blood pressure is diagnosed at 140/90 mmHg or more.
“Our findings provide further support for the importance of good risk factor control early in life,” said senior author Dr. Joao A.C. Lima of the cardiology division at Johns Hopkins University School of Medicine in Baltimore, Maryland.
“Many participants were not hypertensive at the beginning of the study; however, chronic exposure to higher blood pressure, even within what is considered the normal range, is associated with cardiac dysfunction 25 years later,” he said in a news release.
The research findings specified that by age 50, 135 of the participants had left ventricle dysfunction, in which the heart was markedly weaker at pumping blood to the body, during beats or between beats. Those who had higher blood pressure readings in their younger years, between 120/80 to 139/89 before age 30, were more likely to have left ventricular dysfunction between heartbeats than those with lower blood pressure.
“In children (high blood pressure) should elicit a careful hunt for secondary causes – especially kidney disease, endocrine and vascular problems,” Marwick said.
“Weight management, control of salt intake and physical activity are important lifestyle interventions that are important across the population,” to decrease the risk of elevated blood pressure, he said.
Blood pressure tracking in urban black South African children: birth to twenty cohort, Juliana Kagura, Linda S Adair, Mogi G Musa, John M Pettifor and Shane A Norris, BMC Paediatrics, doi:10.1186/s12887-015-0402-z, published 15 July 2015.