Despite long-standing recommendations that doctors check children's blood pressure at every office visit, a new review of research says there is not enough evidence to support that guideline.

The researchers say more studies looking at the benefits and harms of blood pressure screening in kids are needed before all doctors are told to do it.

"There is a lot of discussion about screening for cardiovascular risk factors early in life and I wanted to explore this topic more," said Dr. Arnaud Chiolero, the study's lead author, from Lausanne University Hospital in Switzerland.

Chiolero and his colleagues, who published their findings in JAMA Pediatrics on Monday, say high blood pressure in adults is linked to serious heart problems, and is responsible for more than 7 million deaths worldwide every year.

Less is known, however, about high blood pressure in children and what impact it might have throughout their lives, they write.

For the new review, the researchers developed five questions they felt needed to be answered to judge the role of high blood pressure tests in children, including whether treatment is effective and safe and whether screening reduces the risk for heart problems and death.

Overall, they found that previous studies have tied high blood pressure to signs of heart problems in children, including damage to their veins. Previous research also showed a link between high blood pressure in childhood and high blood pressure in adulthood.

The study also found several gaps in research the authors said need to be addressed, however, including whether or not checking a child's blood pressure is reliable.

For example, they cited a study of Texas school students that found 10 percent of 10th graders had high blood pressure after one test. After two more tests, though, less than a fifth of that original 10 percent group ended up consistently having high blood pressure.

The team also raised the concern that too little research has been done on the possible harms of testing children for high blood pressure - which can include stress and the possibility of leading to more expensive and invasive tests.

Another question, according to the researchers, is what should be done once a child is diagnosed with high blood pressure?

They write that the first step after diagnosis is typically a lifestyle change that makes the child lose weight and eat healthier. The second step is medication, but they note that the safety of long-term use of blood pressure drugs is still unknown.

"It can be concluded that, for now, there is no compelling evidence in favor of universal blood pressure screening among healthy children," the researchers write.

They add that the new review is based on a method used by the U.S. Preventive Services Task Force (USPSTF), which issues screening recommendations and other guidelines for disease prevention.

In 2003, the USPSTF said there was not enough information to say whether children should or should not get their blood pressure checked, but the organization is now in the process of updating that recommendation.

The U.S. National Heart, Lung and Blood Institute currently recommends that all children over three years old routinely get their blood pressure checked. The European Society of Hypertension and the American Academy of Pediatrics signed on to that recommendation.

In September, a study found about a third of U.S. doctors were not checking children's blood pressure during office visits.

Dr. Stephen Daniels, co-author of an editorial accompanying the new study and member of the group that issued the U.S. National Institutes of Health (NIH) report on childhood blood pressure in 2004, told Reuters Health that it's still important to check a child's blood pressure.

"We know if blood pressure is very high it can cause immediate problems. While high blood pressure is sometimes symptomatic, it's not always. So it's important to always monitor it," said Daniels, chair of the department of pediatrics at the University of Colorado School of Medicine in Aurora.

He added that he also worries about some of the questions the review's authors posed, including those that would require tracking children through adulthood.

"Our concern is that some of their questions are essentially unanswerable, and that the studies needed to answer them will essentially never be done," he said.

Another member of the NIH high blood pressure report panel told Reuters Health that she does not think doctors should change what they do based on the review.

"I don't think this article does much to advance healthcare in any way. In fact, I think it's regressive," said Dr. Bonita Falkner, from Thomas Jefferson University in Philadelphia.

Falkner, who was not involved in the new study but chaired the NIH report panel, added that she thinks it is time to review the new evidence since that last NIH report in 2004.