A study of childhood cancer survivors (CCSs) suggests these individuals have an increased risk of developing hypertension as adults.

The CCSs studied had more than double the rate of hypertension observed in the matched general population.

Sex, age, race, and weight were all significantly associated with hypertension among CCSs, but most treatment types were not.

The exception was nephrectomy, which was associated with an increased risk of hypertension.

Todd M. Gibson, PhD, of St. Jude Children’s Research Hospital in Memphis, Tennessee, and his colleagues conducted this research and reported the results in Cancer Epidemiology, Biomarkers & Prevention.

“High blood pressure is an important modifiable risk factor that increases the risk of heart problems in everyone,” Dr Gibson said. “Research has shown that high blood pressure can have an even greater negative impact on survivors of childhood cancer who were treated with cardiotoxic therapies such as anthracyclines or chest radiation.”

To assess the prevalence of hypertension among CCSs, Dr Gibson and his colleagues examined 3016 adults who were 10-year survivors of childhood cancers. The subjects were enrolled in the St. Jude Lifetime Cohort Study, which provides ongoing medical assessments of CCSs to advance knowledge of their long-term health outcomes.

The subjects’ mean age at the initial study assessment was 32, and 52% were male. Most (83%) were non-Hispanic white, 14% were non-Hispanic black, 2% were Hispanic, and 1% were “other.”

Thirty-seven percent of subjects had leukemia, 12% had Hodgkin lymphoma, and 7% had non-Hodgkin lymphoma.

Eighty-six percent of subjects had received chemotherapy, and 59% received radiation.

Results

Subjects were considered to have hypertension if their systolic blood pressure was 140 or greater, their diastolic blood pressure was 90 or greater, or if they had been previously diagnosed with hypertension and were taking antihypertensive medication.

The prevalence of hypertension was 2.6 times higher among CCSs than expected, based on age-, sex-, race- and body mass index-specific rates in the general population.

In addition, the incidence of hypertension increased for CCSs over time. Thirteen percent of CCSs had hypertension at age 30, 37% had it at age 40, and more than 70% had it at age 50.

Dr Gibson said rates of hypertension in CCSs matched rates in the general population of people about a decade older.

The researchers identified several factors that were significantly associated with hypertension among CCSs, including:

Male sex (odd ratio [OR], 1.38; 95% CI, 1.14–1.67)

Non-Hispanic black race (OR, 1.66; 95% CI, 1.28–2.16)

Older age at assessment (OR per 1 year of age, 1.10; 95% CI, 1.08–1.11)

Being overweight (OR, 1.58; 95% CI, 1.21–2.07)

Obesity (OR, 3.02; 95% CI, 2.34–3.88).

Exposure to any type of radiation or chemotherapy was not significantly associated with hypertension, but nephrectomy was (OR, 1.68; 95% CI, 1.11–2.53).

Dr Gibson said the lack of an association between hypertension and radiation/chemotherapy was surprising. It suggests the connection between childhood cancer survival and adult hypertension is multifactorial and worthy of future research.

In the meantime, he said, clinicians should be mindful that CCSs are more likely than the general public to develop hypertension.

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

Dr Gibson said a limitation of this study is that it was based on blood pressure measurements taken at a single study visit. A clinical diagnosis of hypertension typically requires measurements taken at multiple intervals.

In addition, the St. Jude Lifetime Cohort is a group of CCSs who undergo frequent clinical follow-up, so its participants may have benefited from being monitored and may therefore be in better health than CCSs who have less comprehensive follow-up.

CCSs have increased risk of hypertension