Childhood cancer patients are more than twice as likely to develop hypertension as older adults, according to a study published this week in Cancer Epidemiology, Biomarkers & Prevention.

The increased risk factor for high blood pressure isn’t a direct result of common treatments like radiotherapy or chemotherapy, but rather stems from exposure to cardiotoxic therapies like anthracyclines or chest radiation, lead author Todd M. Gibson, PhD, said in a release from the American Association for Cancer Research.

Gibson and colleagues at St. Jude Children’s Research Hospital in Memphis, Tennessee, examined 3,016 childhood cancer survivors who are regularly monitored through the St. Jude Lifetime Cohort Study. The researchers took each patient’s blood pressure just once—a limitation of the study that Gibson recognizes—defining hypertension as a systolic blood pressure of 140 or greater or a diastolic blood pressure of 90 or greater. Gibson et al. also took into account whether any of the patients had been previously diagnosed with high blood pressure or had been taking any antihypertensive medications.

The trial yielded surprising results, Gibson said—the prevalence of hypertension in survivors was 2.6 times higher than expected, and it increased with a patient’s age.

At age 30, 13 percent of the survivors had hypertension, Gibson’s team reported, and that number climbed to 37 percent by age 40. By the time a patient turned 50, they said, more than 70 percent of survivors recorded high blood pressure.

The ubiquity of hypertension in this population, Gibson said in the AACR release, matched prevalence of high blood pressure in a group of patients about a decade older.

Survivors were more likely to develop high blood pressure if they were men, older, black, overweight or obese.

“The good news is that, unlike prior cancer therapy high blood pressure is a modifiable risk factor,” Gibson said. “Research is needed to identify effective interventions to prevent hypertension in survivors, but our results emphasize the importance of blood pressure surveillance and management.”