(Reuters Health) - More than one in 12 adult survivors of childhood cancers may have undiagnosed high blood pressure, a U.S. study suggests.

High blood pressure, or hypertension, can be a particular problem for childhood cancer survivors because many of them have heart damage as a result of chemotherapy and radiation treatments.

Even when they do get diagnosed with high blood pressure, more than one in five of these patients don’t take medication or make lifestyle changes necessary to treat it, the study also found.

“It is notable that survivors in our study had a higher-than-expected prevalence of hypertension regardless of their specific childhood cancer diagnosis or treatment,” said lead study author Todd Gibson of St. Jude Children’s Research Hospital in Memphis, Tennessee.

“The good news is that, unlike prior cancer therapy, high blood pressure is a modifiable risk factor,” Gibson said by email.

Previous research has linked cancer drugs known as anthracyclines to weakening of the heart muscle. Research has also tied some radiation therapy to cardiac rhythm disorders and structural damage in arteries and valves.

As a growing number of childhood cancer patients survive well into adulthood, more of them are living long enough to develop hypertension and other chronic health problems that often come with age.

Cardiovascular disease is the second most common cause of death and serious illness for these cancer survivors, second only to malignancies, researchers note in Cancer Epidemiology, Biomarkers and Prevention.

Deaths from cardiovascular disease are eight times more likely in childhood cancer survivors than in people without a history of tumors early in life. Serious events like heart attacks are five times more likely among cancer survivors than among their siblings who never had malignancies.

The current analysis involved 3,016 adults who were part of the St. Jude Lifetime Cohort Study. All had been treated for cancer as kids and survived at least 10 years.

By age 30, 13 percent of them had high blood pressure, the study found. By comparison, the general prevalence of hypertension among 18-to-39-year-olds in the U.S. is about 7 percent, according to the Centers for Disease Control and Prevention (CDC).

The proportion of childhood cancer survivors with hypertension climbed to 37 percent by age 40 and exceeded 70 percent by age 50. In the general U.S. population, according to the CDC, only about 30 percent of people ages 40 to 60 have hypertension.

Certain groups were most likely to have hypertension: men; non-Hispanic blacks, older survivors, and those who were overweight or obese, the study found.

Exposure to chemotherapy or radiation didn’t appear to influence whether cancer survivors developed high blood pressure.

One limitation of the study is that researchers only had blood pressure measurements from a single visit at each point in time, making it possible that some patients may have been misclassified. Some patients get anxious and develop temporary high blood pressure during checkups.

It’s also possible that the findings might not apply to other cancer survivors because the participants received frequent follow-up care that not all survivors might get, the researchers point out.

Even so, the findings suggest that cancer survivors need regular blood pressure checkups, said Dr. Daniel Lenihan, a researcher at Washington University in St. Louis who wasn’t involved in the study.

“A young adult in their 30s or 40s does not think about screening for hypertension very often,” Lenihan said by email. “A cancer survivor needs to consider this issue early in adulthood because their rate of hypertension is very high and starts at a very early age.”

SOURCE: bit.ly/2iBHgXp Cancer Epidemiology, Biomarkers and Prevention, online November 22, 2017.