Radiation exposure linked to CVD risk

February 9, 2010 by  

When we talk about the A-Bomb, what comes to mind is exposure to high doses of radiation and cancer. The event occurred almost 65 years ago but new reports about its after effects continue to appear, highlighting the fact that such an event has some long-term consequences, some of which we’ve seen and some which are still to come.

A teams of Japanese researchers looked at data of 86,611 people who survived the A-bombs dropped on Hiroshima and Nagasaki. Previous reports have shown a disproportionately high incidence of cancer in this population, a finding that was not really surprising. What is surprising is that cardiovascular disorders such as stroke and heart disease also accounted for a significant fraction of excess deaths which are radiation-related. Analysis of the data showed that A-bomb survivors exposed to at least 0.r Gy of radiation have a significantly elevated risk for cardiovascular diseases.

According to the study authors:

This study provides the strongest evidence available to date that radiation may increase the rates of stroke and heart disease at moderate dose levels (mainly 0.5-2 Gy. Given the widespread use of multiple computed tomography scans and other relatively high-dose diagnostic medical procedures, as well as radiotherapy that exposes the heart, the implications are substantial, insofar as effects occur at doses under 1 Gy.”

The study began 50 years ago which aimed to closely follow up the health outcomes of those who survived the immediate effects of the bombs. The participants of the study were survivors who lived within a 2.5 km radius of the bomb blasts and still resided there at the start of the study. Their outcomes were compared to a group of people of similar age and gender profile but who not or less exposed to the blast. The survivors were followed up till 2003. The results showed:

19,054 survivors died from cardiovascular diseases which included 9,622 mortality cases due to stroke and 8463 cases from heart disease. Of those deaths, 210 were considered “excess” deaths linked to exposure to radiation. The excess relative risk of a circulatory-disease-related death per Gy of radiation exposure was 11% but only exposure doses higher than 0.5 Gy.

According to an editorial by Dr Mark Little of the Imperial College London, UK)

 [The study]…”adds to a growing body of evidence suggesting an association between cardiovascular disease and exposure to [low to moderate] levels of radiation, as well as the well-known (and mechanistically well-understood) association at high doses.”

The radiation-cardiovascular disease risk link is especially relevant nowadays when the issue of radiation for medical purposes is becoming a hot topic, with questions regarding its safety.

Do you know your risk for heart disease?

September 8, 2008 by  

Do you have an undiagnosed risk for developing cardiovascular disease (CVD)? You think it’s highly unlikely? Well, think again.

According to a British study, one in three people with high cardiovascular risk over the next years are unaware of their risk, and neither are their health care providers. In other words, it is very often that the risk remains undiagnosed until it manifests in overt symptoms. This oversight in risk assessment is especially strongest in middle-aged men.

The study conducted by Oxford University researchers in a mobile clinic looked at 71,037 men and women aged 18 and older all over England, Wales and Scotland. Tests were performed and questionnaires were filled in. The results do not look good.

  • 20% of all male study participants and 6% of female participants have high likelihood of developing CVD in the next 10 years.
  • CVD risk is highest in the 50 plus age group compared to others. 75% of men and 45% of women in this age group have CVD, diabetes, and are taking anti-cholesterol or anti-hypertension drugs.

Based on the results, the participants were classified as having high, medium, or low risk profiles.

People were defined as high risk if they had more than a 20 per cent chance of developing CVD over the next 10 years. This criterion is in line with the Joint British Societies Guidelines on Prevention of Cardiovascular Disease in Clinical Practice, which were issued in 2005 and endorsed by the UK’s National Institute of Health and Clinical Excellence in 2006.  

Based on their risk profiles, the participants were then given appropriate medical advice. High risk individuals were advised to see their doctor, together with their tests. Those with medium risk profiles were given verbal as well as written advice as to how to reduce the risk.

In the UK alone, almost 8 million people have been diagnosed with CVD or have recognized high risk for CVD. However, it is estimated that there are almost 4 million people out there whose risk are undiagnosed and are therefore unaware of this risk. Because of this, they do not concern about preventive measures, lifestyle changes, professional advice or early treatment. Of these, 2.8 million are male and 900,000 are females. If these figures were to be extrapolated on a global scale, the numbers are staggeringly big. There is clearly a need for more awareness of CVD risks and risk factors on the part of patients and health care providers alike.

The most common risk factors for CVD are:

  • Obesity
  • Lack of exercise
  • Bad nutrition
  • Smoking
  • Genetics

So don’t think you are exempt from CVD risk. Check your lifestyle. Check with your doctor. Remember: early detection means early prevention.

Photo credit: fishmonk at stock.xchng

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NOTE: The contents in this blog are for informational purposes only, and should not be construed as medical advice, diagnosis, treatment or a substitute for professional care. Always seek the advice of your physician or other qualified health professional before making changes to any existing treatment or program. Some of the information presented in this blog may already be out of date.