Can radiation exposure cause Hypertension (HTN)?

From the Guidelines

Radiation exposure can potentially contribute to hypertension (HTN), though the relationship is complex and depends on several factors, as documented in patients who have undergone radiation therapy for cancer, especially those with abdominal or thoracic radiation exposure 1. High doses of radiation, particularly to the kidneys or whole body, may damage blood vessels and lead to endothelial dysfunction, oxidative stress, and inflammation—all of which can elevate blood pressure over time. The mechanism involves radiation-induced damage to vascular structures, impaired nitric oxide production, and activation of the renin-angiotensin-aldosterone system. Some key factors that increase the risk of radiation-associated heart damage include:

• dose >30–35 Gy
• dose per fraction >2 Gy
• large volume of irradiated heart
• younger age at exposure
• longer time since exposure
• use of cytotoxic chemotherapy
• endocrine therapy or trastuzumab
• presence of other risk factors such as diabetes, hypertension, dyslipidaemias, obesity, smoking etc. 1. However, typical environmental or occupational radiation exposures at low doses are not strongly associated with hypertension development. For individuals with significant radiation exposure history, regular blood pressure monitoring is advisable, and standard hypertension treatments (including lifestyle modifications, ACE inhibitors, ARBs, calcium channel blockers, or diuretics) would be used if hypertension develops. The latency period between significant radiation exposure and hypertension development can be years or even decades, making long-term follow-up important for those with substantial radiation history, as noted in studies on childhood cancer survivors who received radiation therapy 1. Some studies suggest that the risk of hypertension is higher in survivors treated with certain chemotherapeutic agents, such as anthracycline chemotherapy at a cumulative dose of ≥100 mg/m², although the evidence is not conclusive 1. In any case, regular monitoring and timely intervention are crucial to mitigate the potential cardiovascular risks associated with radiation exposure.

From the Research

Radiation Exposure and Hypertension

• Radiation exposure has been linked to an increased risk of cardiovascular disease, which includes hypertension (HTN) as a major risk factor 2.
• Studies on atomic bomb survivors have shown that radiation exposure is associated with some cardiovascular diseases that are often linked to hypertension, with a non-linear dose response among those exposed at younger ages 3.
• However, the relationship between radiation exposure and hypertension is not fully understood and may be influenced by various factors, including genetic background 4.

Mechanisms and Effects

• Radiation can cause damage to the cardiovascular system, leading to increased blood pressure and other cardiovascular effects 2, 5.
• The effects of radiation on blood pressure may be influenced by genetic background, as evident from studies on spontaneously hypertensive rats (SHR) and Wister Kyoto rats (WKY) 4.
• Radiation exposure has been shown to increase systolic blood pressure (SBP) in SHR, while having no effect on SBP in WKY, suggesting a possible genetic component to the relationship between radiation and hypertension 4.

Limitations and Uncertainties

• The current evidence is limited by uncertainties regarding exposure durations, control groups, and the mechanisms involved in radiation-induced cardiovascular disease 2, 6.
• Further studies are needed to define the extent to which diagnostic and therapeutic radiation results in increased risk factors for cardiovascular disease, including hypertension 2.