Childhood BP Linked to Adult Atherosclerosis, but Reversing BP May Help

Shelley Wood

June 04, 2013

LYON, France — Children with high blood pressure are more likely than their normotensive classmates to have hypertension as adults; they are also, if they remain hypertensive, significantly more likely to have evidence of worrisome atherosclerosis progression on carotid intima-media thickness (CIMT), new data from the International Childhood Cardiovascular Cohort (i3C) consortium suggest.

Dr Markus Juonala (University of Turku, Finland) reported the results from i3C here at the European Atherosclerosis Society 2013 Congress .

The i3C has combined four longitudinal studies, initiated in kids, from around the world: the Bogalusa Heart Study , from Louisiana; the Muscatine Study , from Iowa; the Young Finns Study , from Finland; and the CDAH study, from Australia. The studies began during the 1970s or 1980s, enrolling schoolchildren between five and 18, and together the iC3 has prospective data from 4210 subjects.

The current analysis used baseline blood pressure plus CIMT testing performed at least 20 years later.

Up and Up, or Down

Dr Markus Juonala

In all, 1632 (39%) of children in the combined cohort had elevated blood pressure (by National High Blood Pressure Education Program [NHBPEP] definitions) in childhood, and 2078 participants (49%) had high BP in adulthood (defined as >120/80 mm Hg).

Of kids with normal BP at study outset, 42% had hypertension at follow-up; by contrast, 60% of those with high BP initially had elevated BP as adults.

"Significant tracking was observed between child and adult BP levels," Juonala said (r=0.32 for systolic BP and r=0.22 for diastolic BP).

Investigators then looked at which study participants went on to develop CIMT levels at or above the 90th percentile by age, sex, race, and cohort.

They found that compared with study participants with no hypertension in childhood or adulthood, those who developed hypertension in adulthood or those who had hypertension in both time periods had high levels of atherosclerosis on CIMT.

Somewhat reassuringly, the few participants who had high BP in childhood but managed to get their BP to normal levels in adulthood had a smaller relative risk of atherosclerosis that was not statistically significant.

Relative Risk for High CIMT in Adulthood, by BP Status

BP group n/N RR p
Normal childhood BP/normal adulthood BP 109/1440 1.00 Ref
High childhood BP/normal adulthood BP 60/633 1.24 0.17
Normal childhood BP/high adulthood BP 143/1059 1.57 <0.001
High childhood BP/high adulthood BP 155/969 1.82 <0.001

"Persistently elevated BP levels in childhood and adulthood are associated with increased risk of carotid atherosclerosis on carotid IMT," Juonala concluded. "However, the effect of elevated BP in childhood on carotid atherosclerosis is markedly reduced if these individuals become normotensive adults."

To heartwire , Juonala stopped short of calling the findings proof that reversing hypertension improves atherosclerosis profile, saying "there was some residual risk in that group, but in this case it was nonsignificant. . . . The other issue is that if you have high levels in childhood you are also at high risk of having high BP in adulthood. But still I think it is good news that if you do something after childhood it has a real effect."

The key message for clinicians is that childhood BP matters, because as other studies have shown, it is a strong predictor of adult BP as well, and this has implications for atherosclerosis development as well as other, harder end points, Juonala said. "So those kids who have high BP, they should be [targeted for intervention]: lose weight, have more physical activity, etc."

Full results of the iC3 study will be published in an upcoming issue of Circulation, Juonala added.

Hard Outcomes After Lifelong Exposures

Dr George Davey-Smith

Commenting on the study for heartwire , sessioncochair Dr George Davey-Smith (University of Bristol, UK) said he'd like to see hard end points before being reassured that children who get their BP under control as adults are able to improve their long-term outcomes.

"The issue I have with this study is that CIMT as an outcome isn't telling you everything about CV events. . . . Other studies that have been done with BP measured in adolescents with 40-year follow-up show that BP measured in adolescents does predict heart attacks and strokes."

The question of whether an intervention or behavioral changes can reverse a lifelong exposure--to high blood pressure, high body weight, or high lipid levels, for example--that begins in young childhood remains to be seen, he said.

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