American Medical News
By — Posted July 29, 2013
Excessive sodium consumption by youths, coupled with their expanding waistlines and rising body mass, is contributing to higher blood pressure rates in that population, a study says.
The likelihood of children and teens having elevated blood pressure increased 27% between 1994 and 2008, according to the study published online July 15 in Hypertension, the journal of the American Heart Assn. Blood pressure was described as elevated if it was at levels considered hypertensive or prehypertensive in a normal weight population of youths.
“We know higher blood pressure in childhood is related to higher blood pressure in adulthood,” said study co-author Stephen R. Daniels, MD, PhD. “We also know that high blood pressure can impact the cardiovascular system during childhood.”
That impact includes developing left ventricular hypertrophy and endothelial dysfunction, he said.
“Primary care physicians should be on the lookout for [elevated blood pressure in young patients] … and they should start working early with young patients on their diet and making sure they have a lower sodium intake,” said Dr. Daniels, chief pediatrician at Children's Hospital Colorado and a spokesman for the heart association.
The average American consumes about 3,400 mg of sodium every day, which is equivalent to 1.5 teaspoons of salt, according to the Institute of Medicine. That amount is more than twice the AHA's recommended limit of 1,500 mg/day of sodium for everyone age 2 and older.
Ten types of food account for 44% of the dietary sodium that Americans have each day, according to a study published in the Feb. 10, 2012, issue of the Centers for Disease Control and Prevention's Morbidity and Mortality Weekly Report. Topping the list are bread and rolls, cold cuts/cured meats, pizza and poultry.
Among adults, consuming excessive sodium is a risk factor for hypertension, which in turn increases the likelihood of cardiovascular disease, stroke and even death, research shows.
For the Hypertension study, researchers examined data on a population-based sample of 3,248 children ages 8 to 17 who participated in the third National Health and Nutrition Examination Survey from 1988-1994. They compared the findings with information on 8,388 same-aged youths who were part of the NHANES from 1999-2008.
An average of three blood pressure readings was obtained with a sphygmomanometer for each participant. Researchers accounted for differences between the two study groups in age, sex, race/ethnicity, body mass, waistline and sodium intake.
They found that body mass index, waist circumference and weight significantly increased for boys and girls between the two NHANES studies.
Surprising to lead author Bernard Rosner, PhD, was that participants' average daily consumption of sodium didn't change significantly during the study period.
“Participants modified their diet perhaps a little bit to avoid very major excesses [of sodium], but they didn't modify it by a lot,” said Rosner, a professor of medicine at Harvard Medical School and professor of biostatistics at Harvard School of Public Health in Boston.
In both NHANES studies, children who consumed the most sodium (more than 3,450 mg/day) were 36% more likely to have elevated blood pressure compared with those who had the lowest intake (2,300 mg/day or less). Black children had a 28% higher risk of having elevated blood pressure than whites.
The participants were not considered to have hypertension because three consecutive elevated blood pressure readings are needed to make that diagnosis, the study authors said.
Dr. Daniels recommends that physicians educate young patients and their parents about the most common sources of dietary sodium.
“Despite the fact that there's been some discussion about sodium, I'm not sure the average person knows all the sources,” he said. “I think parents would be surprised that bread and cereal contribute a fair amount to” the problem.