The global obesity crisis is fuelling high blood pressure in children as young as six, research suggests.

In a systematic review and meta-analysis of 47 articles, the prevalence of childhood hypertension increased from 1994 to 2018, scientists say.

The study published in JAMA Paediatrics, suggests the increase was associated with higher body mass index.

Researchers estimate 4% of youngsters aged 19 or under have hypertension – high blood pressure.

In 2015, the prevalence of childhood hypertension ranged from 4.32% among children aged six years old, to 3.28% among those aged 19.

It peaked at 7.89% among 14-year-olds.

The study findings suggest childhood hypertension is becoming more common in the general paediatric population, representing a considerable public health challenge worldwide.

It provides a global estimate of childhood hypertension prevalence based on blood pressure measurements in at least three separate visits.

But the authors, including Dr Yajie Zhu from the University of Oxford, recognise more high-quality epidemiologic investigations on childhood hypertension are still needed.

In a linked editorial, Dr Stephen Daniels from the School of Medicine, University of Colorado, said: “The data used by Song et al are largely current because more than two-thirds of the 47 articles included were published in 2010 or later, which is important because of the association between obesity and blood pressure and the increasing prevalence and severity of obesity in children and adolescents.

“In fact, Song et al found a higher prevalence of hypertension in those with obesity (15.27%) and overweight (4.99%) compared with the 1.9% prevalence seen in children and adolescents with normal weight.”

He added: “Song et al also found interesting results related to age and the prevalence of hypertension – 4.32% at six years of age, 7.89% at 14 years of age, and 3.28% 19 years of age.

“These findings suggest that the prevalence is increased during puberty but that hypertension may not be sustained after puberty.”